SPIE Optics and Photonics

SPIE Optics + Photonics
21 - 25 August 2011
San Diego Convention Center
San Diego, California United States

Charge generation dynamics at nano-scale interfaces in all-organic and hybrid materials
Paper 8098-11 of Conference 8098
Date: Sunday, 21 August 2011
Author(s): Laura M. Herz, Univ. of Oxford (United Kingdom)

Conjugated polymers and molecules are increasingly used as cheap artificial light-harvesting materials in photovoltaic devices. The large exciton binding energy in these systems necessitates the use of blends comprising at least two materials at whose interface a type-II heterojunction is formed, thus making charge separation energetically favourable. Examples of all-organic materials are blends of conjugated polymers with single-walled carbon nanotubes (SWNTs) with the latter promising large electron mobilities and percolation paths. We have investigated the charge photogeneration dynamics at the interface formed between SWNTs and poly(3-hexylthiophene) (P3HT) using a combination of femtosecond spectroscopic techniques [1]. We demonstrate that photoexcitation of P3HT forming a single molecular layer around a SWNT leads to an ultrafast ( 430 fs) charge transfer between the materials. The addition of excess P3HT leads to long-term charge separation in which free polarons remain separated at room temperature. Our results suggest that SWNT-P3HT blends incorporating only small fractions (1%) of SWNTs allow photon-to-charge conversion with efficiencies comparable to those for conventional (60:40) P3HT−fullerene blends, provided that small-diameter tubes are individually embedded in the P3HT matrix. In addition, hybrid interfaces comprising organic dyes as sensitizer monolayers on metal-oxide mesostructures films have been highly successful when implemented in so-called dye-sensitized solar cells (DSSCs). We have used optical-pump terahertz-probe spectroscopy to explore the photoinduced conductivity dynamics in such mesoporous metal-oxide films [2]. We extract early-time mobility values and compare these to bulk values in order to determine factors limiting electron movement in these systems. In addition, we have utilized terahertz spectroscopy to investigate the influence of surface treatments for the metal oxide on early-time charge dynamics. For example, surface treatment of the mesoporous TiO2 with TiCl4 has been found to be critical to enable efficient operation of DSSCs. However, we find that neither early-time charge mobility nor charge injection rate or decay times are significantly affected by the treatment, which suggests that it may, instead, have an impact on phenomena occurring on longer time scales. [1] S. D. Stranks, C. Weisspfennig, P. Parkinson, M. B. Johnston, L. M. Herz, and R. J. Nicholas, Nano Lett. 11, 66 (2011). [2] P. Tiwana, P. Parkinson, M. B. Johnston, H. J. Snaith, and L. M. Herz , J. Phys. Chem. C 114, 1365-1371 (2010).

Femtosecond Transient Absorption Measurements system Hatteras Hatteras-D femtosecond  transient absorption data acquisition system
Future nanostructures and biological nanosystems will take advantage not only of the small dimensions of the objects but of the specific way of interaction between nano-objects. The interactions of building blocks within these nanosystems will be studied and optimized on the femtosecond time scale - says Sergey Egorov, President and CEO of Del Mar Photonics, Inc. Thus we put a lot of our efforts and resources into the development of new Ultrafast Dynamics Tools such as our Femtosecond Transient Absorption Measurements system Hatteras. Whether you want to create a new photovoltaic system that will efficiently convert photon energy in charge separation, or build a molecular complex that will dump photon energy into local heat to kill cancer cells, or create a new fluorescent probe for FRET microscopy, understanding of internal dynamics on femtosecond time scale is utterly important and requires advanced measurement techniques.

Reserve a spot in our Ultrafast Dynamics Tools training workshop in San Diego, California.
 

Beacon Femtosecond Optically Gated Fluorescence Kinetic Measurement System - request a quote  - pdf
Beacon together with Trestles Ti:sapphire oscillator, second and third harmonic generators. Femtosecond optical gating (FOG) method gives best temporal resolution in light-induced fluorescence lifetime measurements. The resolution is determined by a temporal width of femtosecond optical gate pulse and doesn't depend on the detector response function. Sum frequency generation (also called upconversion) in nonlinear optical crystal is used as a gating method in the Beacon femtosecond fluorescence kinetic measurement system. We offer Beacon-DX for operation together with Ti: sapphire femtosecond oscillators and Beacon-DA for operation together with femtosecond amplified pulses.

Reserve a spot in our Ultrafast Dynamics Tools training workshop in San Diego, California.
 

Del Mar Photonics Products updates

THz products:
THz Spectrometer kit with Antenna
THz transmission setup
THz time domain spectrometer Pacifica fs1060pca
THz time domain spectrometer Pacifica fs780pca
THz detectors: Golay cell and LiTaO3 piroelectric detectors
PCA - Photoconductive Antenna as THz photomixer
Pacifica THz Time Domain Spectrometer - Trestles Pacifica
Holographic Fourier Transform Spectrometer for THz Region
Wedge TiSapphire Multipass Amplifier System - THz pulses generation
Terahertz Spectroscopic Radar Mobile System for Detection of Concealed Explosives
Band pass filters with center wavelengths from 30 THz into GHz range
Long pass filters with standard rejection edge wavelengths from 60 THz into GHz range
Generation of THz radiation using lithium niobate
Terahertz crystals (THz): ZnTe, GaP, LiNbO3 - Wedge ZnTe

Pulsed terahertz reflection-scattering measurements
Paper 8119-4 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Shu-Zee A. Lo, Edwin J. Heilweil, National Institute of Standards and Technology (United States)

We present a method for measuring terahertz reflection and scattering from samples by modification of an existing pulsed terahertz setup. By scanning both a mirror pair periscope and another directional mirror around the sample under test, we are able to obtain angular dependent time delay scans, spectra, and detailed characteristics of the reflected/scattered terahertz pulse. Using this approach, we report reflection-scattering information from a flat gold mirror, a paper index card and other samples demonstrating the applicability of the approach.

Terahertz wave generation with multi-physics mechanisms
Paper 8120-55 of Conference 8120
Date: Monday, 22 August 2011
Author(s): Shizhuo Yin, Yaohui Gao, Jimmy Yao, The Pennsylvania State Univ. (United States)

In this paper, we present a new method of terahertz wave generation by employing multiple physics mechanism, which can improve the overall efficiency of terahertz wave generation.

Design and analysis of metamaterials for the continuous wave terahertz laser
Paper 8093-35 of Conference 8093
Date: Tuesday, 23 August 2011
Author(s): Jun Luo, Huazhong Univ. of Science and Technology (China)

We demonstrate some metamaterials in the terahertz frequency regime fabricated on n-GaAs substrate. The influences of substrate and the shapes of split ring resonators(SRRs) on the terahertz resonance are experimentally investigated at several terahertz frequencies of continuous wave terahertz laser in turn, such as 1.4THz, 2.52THz, 4.25THz, etc., some SRR arrays can obtain about 80 percent absorption of THz amplitude transmission. In addition, computer simulations of the spectral response of the chosen planar metamaterials are performed to analyze the resonance frequency, surface current density and local electric field, which agree well with measured results.

Reflection-geometry sub-terahertz-wave imaging for biological materials using an integrated photonic transceiver
Paper 8119-1 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Hiroshi Ito, Hiroshi Yamamoto, Kitasato Univ. (Japan); Yoshifumi Muramoto, Tadao Ishibashi, NTT Photonics Labs. (Japan)

We developed a microstrip-line-based circulator circuit for operations at around 270 GHz, and obtained a peak internal signal-to-background ratio of about 10. The fabricated circulator was integrated with a photomixer (uni-traveling-carrier photodiode) and a Schottky barrier diode to construct a transceiver module for the sub-THz reflection-geometry imaging. The characteristic of the circulator was evaluated by measuring images at frequencies from 240 to 310 GHz, and it was confirmed that a practical image contrast could be obtained for a bandwidth of about 20 GHz. Based on these results, we demonstrated in-vivo imaging of a human finger at 270 GHz.

Experimental verification of the explosives identification model in THz range
Paper 8119-2 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Przemyslaw Zagrajek, Radoslaw Ryniec, Tomasz Trzcinski, Norbert Palka, Military Univ. of Technology (Poland)

The aim of this paper was the verification of our identification model. The main assumption of our model was the possibility of the distinction between indicated compounds based on several narrow band detectors of terahertz radiation. Achieve of this frequency points was done with measurement data from FT-IR obtained in vacuum. The influence of absorption in water vapor was added numerically from Hitran simulation. The verification procedure was carried out with Time Domain Spectroscopy (for distance below 20 cm) and with narrow band sources (for distances above 20 cm). This verification was prepared in laboratory, controlled conditions. Our results confirm the possibility of application of the model in real THz stand-off security system.

Explosives identification model in reflection mode for THz security system
Paper 8119-3 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Radoslaw Ryniec, Tomasz Trzcinski, Przemyslaw Zagrajek, Mieczyslaw Szustakowski, Military Univ. of Technology (Poland)

The aim of this paper was to obtain the identification model in refection mode. Results Time Domain Spectroscopy were used to prepare our algorithm. This study has focused on developing several feature extraction methods with intuitive justifications in the problem space. A related problem to feature extraction is that of feature selection. For this reasons this extraction and selection methods of THz spectra are introduced. Then a complete THz classification framework including feature extraction scheme and Mahalanobis classifier was presented. Our results confirm the possibility of application of the model in real THz stand-off security system.

Recent advances in molecular spectroscopy and its application to frequency stabilization of terahertz quantum-cascade lasers
Paper 8119-6 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Heinz-Wilhelm Hübers, Deutsches Zentrum für Luft- und Raumfahrt e.V. (Germany) and Technische Univ. Berlin (Germany); Rene Eichholz, Sergeij Pavlov, Heiko Richter, Alexei Semenov, Deutsches Zentrum für Luft- und Raumfahrt e.V. (Germany); Martin Wienold, Lutz Schrottke, Manfred Giehler, Rudolf Hey, Holger Grahn, Paul-Drude Institut für Festkörperelektronik (Germany)

High-resolution gas phase spectroscopy at terahertz (THz) frequencies is a powerful tool for the investigation of of molecules and atoms. However, spectroscopy above 2 THz is hampered by the lack of frequency tunable, continuous-wave, powerful, and narrow linewidth radiation sources. THz quantum-cascade lasers (QCL) have attractive features for spectroscopy, namely, their small intrinsic linewidth, frequency agility, and high output power. We will report on recent advances in molecular spectroscopy with QCLs operating between 3 and 3.5 THz with a few mW output power. The QCLs are integrated in a compact Stirling cooler and their emission is guided through an absorption cell to a Ge:Ga detector. The performance of the spectrometerwill be presented. Sub-MHz frequency stabilization is achieved by locking the frequency of the QCL to a molecular absorption line. Finally, we will discuss the prospects of THz QCLs in high-resolution molecular spectroscopy.

Tunable vertical emission in a THz quantum cascade structure
Paper 8119-8 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): François-Régis Jasnot, Louis-Anne De Vaulchier, Yves Guldner, Gérald Bastard, Ecole Normale Supérieure (France); Angela Vasanelli, Christophe Manquest, Carlo Sirtori, Univ. Paris 7-Denis Diderot (France); Mattias Beck, Jérôme Faist, ETH Zürich (Switzerland)

A vertical emitting magnetic field-tunable device covering the 2 - 5 THz range has been designed. The "Landau level engineering" has been used to observe inter-Landau level surface emission. To block intersubband emission a special processing has been realized which allows to collect from the surface of the device the TE polarized light only. Magnetotransport experiments reveal that electron-electron scattering is dominant. This mechanism allows observation of both cyclotron emission and forbidden optical transitions.

Ultrafast Gain switching of THz quantum cascade lasers: THz pulse amplification and injection seeding
Paper 8119-10 of Conference 8119
Date: Sunday, 21 August 2011

Author(s): Sukhdeep S. Dhillon, Nathan Jukam, Dimitri Oustinov, Julien Madeo, Ecole Normale Supérieure (France); Stefano Barbieri, Christophe Manquest, Carlo Sirtori, Univ. Paris 7-Denis Diderot (France); Suraj Khanna, Edmund Linfield, Giles Davies, Univ. of Leeds (United Kingdom); Jerome Tignon, Ecole Normale Supérieure (France)

Terahertz (THz) time domain spectroscopy is now widely used technique where it is essential to know both the amplitude and phase of a THz wave. Nonetheless, THz amplifiers, capable of increasing the THz wave field, are presently lacking. In this context THz quantum cascade lasers (QCL) are very promising devices for amplification. Gain clamping in these devices, however, limits the attainable amplification. Here we circumvent gain clamping by coupling a THz QCL and an integrated Auston-switch to perform ultrafast gain switching. The resulting non-equilibrium gain is not clamped above laser threshold and large amplification of input terahertz pulses is demonstrated.

Electric control of THz reflectivity assisted by interface phonon-polaritons
Paper 8119-15 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Simon Vassant, François Marquier, Alexandre Archambault, Jean-Jacques Greffet, Lab. Charles Fabry (France); Fabrice Pardo, Jean-Luc Pelouard, Ctr. National de la Recherche Scientifique (France)

We present an original approach for a THz modulator with an electric control, by using interface-phonon-polaritons and epsilon-near-zero material (ENZ). We designed and fabricated a structure to efficiently couple an incident THz wave to an interface mode of a single quantum well. Due to the ENZ properties of the well at the mode frequency, the electromagnetic energy is highly confined in the well, thus enhancing interaction with electrically controlable intersubband transitions. THz reflectivity measurements demonstrate an amplitude change of 15% in reflectivity, at room temperature, with a single quantum well at a frequency of 8.5 THz.

Tunable terahertz radiation from an ultrashort-laser-pulse-induced discharge in biased air
Paper 8119-20 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Fuminori Suzuki, Takeshi Higashiguchi, Hiroaki Anno-Kashiwazaki, Noboru Yugami, Utsunomiya Univ. (Japan); Yasuhiko Sentoku, Univ. of Nevada, Reno (United States); Ryosuke Kodama, Osaka Univ. (Japan); Patric Muggli, The Univ. of Southern California (United States)

We have demonstrated a proof-of-principle peak-frequency-tunable THz radiation source based on laser-triggered plasma ultrafast-spark. An unified physical picture for the peak frequency-versus laser pulse duration dependency in the spark, based on the plasma sheath current model together with a plasma expansion driven by the OFI (optical-field-induced ionization), is also presented. The new coherent tunable THz source will allow further developments in nonlinear THz photonics and optics, such as nonlinear phonon excitation and THz phase transition on dielectric surfaces.

Grating gated HEMT for tunable THz and mm-wave detection
Paper 8164-7 of Conference 8164
Date: Monday, 22 August 2011
Author(s): Robert E. Peale, Nima Nader, Christopher J. Fredricksen, Himanshu Saxena, Gautam Medhi, Univ. of Central Florida (United States); Josh Hendrickson, Walter R. Buchwald, Air Force Research Lab. (United States); Justin W. Cleary, Solid State Scientific Corp. (United States)

Millimeter wave and terahertz induced plasma resonances in InP-based high-mobility electron transistors lead to tunable array detectors for spectral sensing and space situational awareness applications. Tunable resonant changes in channel conductance are found using frequency modulated backward wave oscillators.

Terahertz wave propagation in surface plasmon photonic crystal
Paper 8120-27 of Conference 8120
Date: Monday, 22 August 2011
Author(s): Shruti Singh, Venus Dillu, Ravindra K. Sinha, Ragunath Bhattacharyya, Delhi Technological Univ. (India)

A surface plasmonic photonic crystal with one-dimensional periodic array of air holes in silicon (Si) with Polyvinylidene fluoride (PVDF) as a substrate is proposed to obtain subwavelength confinement of surface Plasmon modes at THz frequencies. One dimensional periodic hole in a dielectric is bonded with PVDF layer which is utilized to support a Plasmon like excitation in terahertz regime and thus, single mode cavity localization for a chosen wavelength is observed. The results showing the transmission spectrum of the cavity mode and Quality factor is calculated and its possible application in the area of plasmonic sensing is elaborated.

Growth, characterization, and applications of ZnO/MgZnO multilayer structures
Paper 8120-53 of Conference 8120
Date: Monday, 22 August 2011
Author(s): Shizhuo Yin, Qi Li, Tianjing Li, Yaohui Gao, Jimmy Yao, The Pennsylvania State Univ. (United States)

In this paper, the growth of ZnO/MgZnO multiple layer structure is presented. The properties of the growth structure are quantitatively characterized by XRD, photoilluminance, and electronic microscopy. The applications of this unique ZnO/MgZnO structure is also discussed.

Carbon nanotube terahertz spectroscopy: study of absorption and dispersion properties of SWNT and MWNT
Paper 8101-16 of Conference 8101
Date: Tuesday, 23 August 2011
Author(s): Horacio Lamela, Ehsan Dadrasnia, Univ. Carlos III de Madrid (Spain); Jean-Francois Lampin, Institut d'Electronique, de Microélectronique et de Nanotechnologies (France); Mohan Babu Kuppam, Frédéric Garet, Jean-Louis Coutaz, Univ. de Savoie (France)

Over the past decade, finding the optical and electrical properties of carbon nanotubes by terahertz time-domain spectroscopy have been an interesting topic in terahertz and nano-sensing fields. The absorption and dispersion of single and multi walled carbon nanotubes films are investigated by terahertz time-domain spectroscopy (THz-TDS). The results show that the frequency-dependent power absorption coefficient and index of refraction for both carbon nanotubes films agree with experimental setups. In this work, we also present the effect of various ranges of filling factor and geometrical factor in the single and multi walled carbon nanotubes films. A comparative analysis obtained from experimental results based on this numerical model will be presented.

Optical and electrical characterization of carbon nanotubes by terahertz spectroscopy: comparison between modeling and experimental results
Paper 8096-143 of Conference 8096
Date: Wednesday, 24 August 2011
Author(s): Ehsan Dadrasnia, Horacio Lamela, Univ. Carlos III de Madrid (Spain)

Over the past decade, finding the optical and electrical properties of carbon nanotubes by terahertz time-domain spectroscopy have been an interesting topic in terahertz and nano-sensing fields. The results of this research show that the frequency-dependent power absorption coefficient and index of refraction for both carbon nanotubes films, pure single-walled carbon nanotubes (SWNT) and F-doped SWNT, agree with experimental setups. In this work, we also present the effect of various ranges of filling factor and geometrical factor in these two SWNT samples and multi-walled carbon nanotubes (MWNT). A comparative analysis obtained from experimental results based on this numerical model will be presented.

Photocarrier dynamics in nanostructured phthalocyanine: fullerene films
Paper 8116-34 of Conference 8116
Date: Thursday, 25 August 2011
Author(s): Paul A. Lane, U.S. Naval Research Lab. (United States); Edwin J. Heilweil, National Institute of Standards and Technology (United States); Joseph S. Melinger, U.S. Naval Research Lab. (United States)

We studied photocarrier generation and decay dynamics on a wide range of time scales in thin films of zinc phthalocyanine and C60. Photocarrier generation was studied by terahertz time domain spectroscopy, an optical technique sensitive to photocarrier dynamics on a picosecond to nanosecond time scale. Decay dynamics were studied on microsecond timescale by photoinduced absorption spectroscopy. Photocarrier yield and decay dynamics are sensitive to the composition of C60:ZnPc blends and layer thickness of C60/ZnPc superlattices. Ultrathin layers (10 - 20 Å) have a greatest carrier yield than composites while maintaining the slow decay dynamics of layered structures.

Near-field imaging of terahertz plasmon waves with a subwavelength aperture probe
Paper 8096-4 of Conference 8096
Date: Sunday, 21 August 2011
Author(s): Oleg Mitrofanov, Raimund Mueckstein, Univ. College London (United Kingdom)

Visualization of Terahertz plasmons with local probes allows studying ultra-fast plasmonic phenomena in the time domain. We demonstrate that the integrated sub-wavelength aperture near-field probe can be used to map THz surface plasmon waves in space and time with high resolution. Using experimental near-field observations of plasmon waves formed on a metallic surface by tightly focused THz pulses and of standing plasmon waves in THz antennas, we show that this probe detects the spatial derivative of the electric field rather than the plasmon field itself. The understanding of the coupling mechanism provides a framework for interpretation of near-field images.

Modeling temperature effects in terahertz step-well quantum cascade structures with diagonal optical transitions
Paper 8119-9 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Will Freeman, Naval Air Warfare Ctr. Weapons Div. (United States); Gamani Karunasiri, Naval Postgraduate School (United States)

Temperature effects in terahertz (THz) step well quantum cascade (QC) structures are investigated. Step well QC structures with diagonal optical transitions that use fast intrawell electron-longitudinal optical (LO)-phonon scattering for depopulation are considered. A density matrix method is used to model the electron transport coherence and is incorporated into the Monte Carlo simulations of these structures. A phenomenological dephasing time is also included in these simulations. The influence of the lattice temperature on the population inversion is modeled and the effects due to the gain spectrum broadening as well as potential device performance are also considered.

Recent advances of terahertz quantum cascade lasers
Paper 8119-11 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Manijeh Razeghi, Northwestern Univ. (United States)

InGaAs/GaAsSb: a new material system for terahertz quantum cascade lasers
Paper 8119-12 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Gottfried Strasser, Christoph Deutsch, Hermann Detz, Alexander Benz, Michele Nobile, Maxwell A. Andrews, Pavel Klang, Werner Schrenk, Karl Unterrainer, Technische Univ. Wien (Austria)

We present a novel material system for THz QCLs: InGaAs/GaAsSb, lattice matched to InP. This aluminium-free material system allows to combine a moderate conduction band offset (360 meV) with the lower effective InGaAs electron mass (0.043 m0), offering a higher gain compared to GaAs based THz QCLs. The lower barrier mass (0.045 m0 for GaAsSb) and nonparabolicity allow for thicker barrier layers in the devices, relaxing the demands on the epitaxy. In this contribution we present the second generation of InGaAs/GaAsSb THz QCLs, where the threshold current density could be reduced from 2 kA/cm2 to 0.75 kA/cm2 operating up to 135 K.

Highly absorbing nano-scale metal films for terahertz bi-material sensors
Paper 8119-18 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Fabio Alves, Karamitros Apostolos, Dragoslav Grbovic, Gamani Karunasiri, Naval Postgraduate School (United States)

Interest in terahetz imaging has significantly increased recently. Our work aims to identify nano-scale metal films with enhanced absorption between 1 to 10 THz, to be integrated in imaging sensors. Finite element simulation and absorption measurements of samples with different thicknesses (5 - 30 nm) of chromium and nickel films on silicon substrates reveled absorption close to 50% (Cr) and 35% (Ni), between 1 and 10 THz. Further analysis showed that by decreasing the surface fill-factor of Ni it is possible to increase absorption up to the values obtained for the Cr films, benefiting from lower levels of residual stress after fabrication.

Interfacial state density and terahertz radiation on oxide-GaAs interface
Paper 8120-45 of Conference 8120
Date: Monday, 22 August 2011
Author(s): Chung-Chih Chang, Ming-Seng Hsu, Chinese Military Academy (Taiwan); Wei-Juann Chen, National Cheng Kung Univ. (Taiwan); Jen-Wei Huang, Chinese Military Academy (Taiwan); Yau-Chyr Wang, Nan Jeon Institute of Technology (Taiwan)

The amplitude of terahertz radiation (THz) from a series of oxide films on GaAs was measured by time resolved THz emission system. The barrier heights and the densities of the interfacial states are determined from the PR intensity as a function of the pump power density. The oxide-GaAs structures fabricated by in situ molecular beam epitaxy exhibit low interfacial state densities in the range of 10^11 cm^-2. It is found that the amplitude of THz radiation from Al2O3-, Ga2O3-, and Ga2O3(Gd2O3)-GaAs structures are increases with interfacial electric field. The reason is that the electric field is lower than the "critical electric field", the amplitude is proportional to the product of the electric field and the number of photo-excited carriers. However, as the field higher than the critical electric field, sample of air-GaAs structure, the lower THz amplitude was obtained due to the maximum drift velocity declines slightly as the field increases.

Charge separation dynamics at inorganic/organic nanostructured hybrid photovoltaic interfaces
Paper 8116-43 of Conference 8116
Date: Thursday, 25 August 2011
Author(s): Rainer Eichberger, Christian Strothkaemper, Inara Thomas, Thomas Hannappel, Klaus Schwarzburg, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (Germany); Carlo Fasting, Freie Univ. Berlin (Germany); Andreas Bartelt, Robert Schuetz, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (Germany)

The initial charge separation at inorganic/organic nanostructured hybrid photovoltaic interfaces is studied applying femtosecond broadband transient absorption spectroscopy in ultrahigh vacuum and sub-ps terahertz (THz) photoconductivity. The dynamics of different absorber concepts ranging from simple organic model chromophores to antenna FRET systems adsorbed on TiO2 nanoparticle and ZnO nanorod films were measured in this complementary experimental setup.

Terahertz quantum cascade lasers coupled with high efficiency to the low loss optical modes of cylindrical hollow-core waveguides
Paper 8119-13 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Miriam S. Vitiello, Consiglio Nazionale delle Ricerche (Italy)

 

Product news and updates - Training Workshops - Featured Customer - Other News

Del Mar Photonics is your one stop source for ultrafast (femtosecond) as well as continuum wave (CW) narrow linewidth Ti:Sapphire lasers Trestles LH Ti:Sapphire laser
Trestles LH is a new series of high quality femtosecond Ti:Sapphire lasers for applications in scientific research, biological imaging, life sciences and precision material processing. Trestles LH includes integrated sealed, turn-key, cost-effective, diode-pumped solid-state (DPSS). Trestles LH lasers offer the most attractive pricing on the market combined with excellent performance and reliability. DPSS LH is a state-of-the-art laser designed for today’s applications. It combines superb performance and tremendous value for today’s market and has numerous advantages over all other DPSS lasers suitable for Ti:Sapphire pumping. Trestles LH can be customized to fit customer requirements and budget.

Reserve a spot in our Femtosecond lasers training workshop in San Diego, California. Come to learn how to build a femtosecond laser from a kit
 

DPSS DMPLH lasers
DPSS DMP LH series lasers will pump your Ti:Sapphire laser. There are LH series lasers installed all over the world pumping all makes & models of oscillator. Anywhere from CEP-stabilized femtosecond Ti:Sapphire oscillators to ultra-narrow-linewidth CW Ti:Sapphire oscillators. With up to 10 Watts CW average power at 532nm in a TEMoo spatial mode, LH series lasers has quickly proven itself as the perfect DPSS pump laser for all types of Ti:Sapphire or dye laser.
Ideal for pumping of:

Trestles LH Ti:Sapphire laser
T&D-scan laser spectrometer based on narrow line CW Ti:Sapphire laser
 

New laser spectrometer OB' for research studies demanding fine resolution and high spectral density of radiation within UV-VIS-NIR spectral domains New laser spectrometer T&D-scan for research  that demands high resolution and high spectral density in UV-VIS-NIR spectral domains - now available with new pump option!
The T&D-scan includes a CW ultra-wide-tunable narrow-line laser, high-precision wavelength meter, an electronic control unit driven through USB interface as well as a software package. Novel advanced design of the fundamental laser component implements efficient intra-cavity frequency doubling as well as provides a state-of-the-art combined ultra-wide-tunable Ti:Sapphire & Dye laser capable of covering together a super-broad spectral range between 275 and 1100 nm. Wavelength selection components as well as the position of the non-linear crystal are precisely tuned by a closed-loop control system, which incorporates highly accurate wavelength meter.

Reserve a spot in our CW lasers training workshop in San Diego, California. Come to learn how to build a CW Ti:Sapphire laser from a kit
 

AOTF Infrared Spectrometer
Del Mar Photonics offer a handheld infrared spectrometer based on the acousto-optic tunable filter (AOTF). This instrument is about the size and weight of a video camera, and can be battery operated. This unique, patented device is all solid-state with no moving parts. It has been sold for a wide variety of applications such as liquid fuel analysis, pharmaceutical analysis, gas monitoring and plastic analysis. Miniature AOTF infrared spectrometer uses a crystal of tellurium dioxide to scan the wavelength. Light from a light source enters the crystal, and is diffracted into specific wavelengths. These wavelengths are determined by the frequency of the electrical input to the crystal. Since there are no moving parts, the wavelength scanning can be extremely fast. In addition, specific wavelengths can be chosen by software according to the required algorithm, and therefore can be modified without changing the hardware. After the infrared radiation reflects off of the sample, it is converted into an electrical signal by the detector and analyzed by the computer. Del Mar Photonics is looking for international distributors for RAVEN - AOTF IR spectrometer for plastic identification and for variety of scientific and industrial collaborations to explore futher commercial potential of AOTF technology.
New: AOTF spectrometer to measure lactose, fat and proteins in milk
 

Open Microchannel Plate Detector MCP-MA25/2

Open Microchannel Plate Detector MCP-MA25/2 - now in stock!
Microchannel Plate Detectors MCP-MA series are an open MCP detectors with one or more microchannel plates and a single metal anode. They are intended for time-resolved detection and make use of high-speed response properties of the MCPs. MCP-MA detectors are designed for photons and particles detection in vacuum chambers or in the space. MCP-MA detectors are used in a variety of applications including UV, VUV and EUV spectroscopy, atomic and molecular physics, TOF mass–spectrometry of clusters and biomolecules, surface studies and space research.
MCP-MA detectors supplied as a totally assembled unit that can be easily mounted on any support substrate or directly on a vacuum flange. They also can be supplied premounted on a standard ConFlat flanges. buy online - ask for research discount!

 

Hummingbird EMCCD camera Hummingbird EMCCD camera
The digital Hummingbird EMCCD camera combines high sensitivity, speed and high resolution.
It uses Texas Instruments' 1MegaPixel Frame Transfer Impactron device which provides QE up to 65%.
Hummingbird comes with a standard CameraLink output.
It is the smallest and most rugged 1MP EMCCD camera in the world.
It is ideally suited for any low imaging application such as hyperspectral imaging, X-ray imaging, Astronomy and low light surveillance.
It is small, lightweight, low power and is therefore the ideal camera for OEM and integrators.
buy online
Terahertz systems, set ups and components
New band pass and long pass THz optical filters based on porous silicon and metal mesh technologies.
Band pass filters with center wavelengths from 30 THz into GHz range and transmissions up to 80% or better. Standard designs
with clear aperture diameters from 12.5 to 37.5 mm.
Long pass filters with standard rejection edge wavelengths from 60 THz into GHz range. Maximum transmission up to 80% or
better, standard designs at 19.0 and 25.4 mm diameters.
Excellent thermal (from cryogenic to 600 K) and mechanical properties
THz products:
THz Spectrometer kit with Antenna
THz transmission setup
THz time domain spectrometer Pacifica fs1060pca
THz time domain spectrometer Pacifica fs780pca
THz detectors: Golay cell and LiTaO3 piroelectric detectors
PCA - Photoconductive Antenna as THz photomixer
Pacifica THz Time Domain Spectrometer - Trestles Pacifica
Holographic Fourier Transform Spectrometer for THz Region
Wedge TiSapphire Multipass Amplifier System - THz pulses generation
Terahertz Spectroscopic Radar Mobile System for Detection of Concealed Explosives
Band pass filters with center wavelengths from 30 THz into GHz range
Long pass filters with standard rejection edge wavelengths from 60 THz into GHz range
Generation of THz radiation using lithium niobate
Terahertz crystals (THz): ZnTe, GaP, LiNbO3 - Wedge ZnTe

iPCA - interdigital Photoconductive Antenna for terahertz waves
Large area broadband antenna with lens array and high emitter conversion efficiency
iPCA with LT-GaAs absorber, microlens array for laser excitation wavelengths
l £  850 nm, adjusted hyperhemispherical silicon lens with a high power conversion efficiency of 0.2 mW THz power / W optical power. The iPCA can be used also as large area THz detector. The two types iPCAp and iPCAs have the same active interdigital antenna area but different contact pad directions with respect to the electrical THz field.
Interdigital Photoconductive Antenna for terahertz waves generation using femtosecond Ti:Sapphire laser

THz books
IntraStage lowers the cost of test data management!

Struggling with gigabytes or terabytes of test data?
IntraStage easily transforms test data from disparate sources into web-based quality metrics and engineering intelligence you can use.

Contact us today to discuss your test management requirements and specifications of your application.
 


Training Workshops

Come to San Diego next summer! Attend one of our training workshops in San Diego, California during summer 2011
Del Mar Photonics has presented training workshops for customers and potential customers in the past 3 years.
Our workshops cover scientific basics, technical details and provide generous time for hands-on training.
Each workshop is a three-day seminar conducted by professional lecturer from 10am to 4pm. It includes lunch, as well as a training materials. We have also reserved two days for Q&A sessions, one-on-one system integration discussions, social networking, and San Diego sightseeing.

The following training workshops will be offered during this summer:
1. Femtosecond lasers and their applications
2. CW narrow line-width widely tunable lasers and their applications
3. Adaptive optics and wavefront sensors

4. Ultrafast (femtosecond) dynamics tools

Featured Customer

Trestles LH10-fs/CW laser system at UC Santa Cruz Center of Nanoscale Optofluidics

Del Mar Photonics offers new Trestles fs/CW laser system which can be easily switched from femtosecond mode to CW and back. Having both modes of operation in one system dramatically increase a number of applications that the laser can be used for, and makes it an ideal tool for scientific lab involved in multiple research projects.
Kaelyn Leake is a PhD student in Electrical Engineering. She graduated from Sweet Briar College with a B.S. in Engineering Sciences and Physics. Her research interests include development of nanoscale optofluidic devices and their applications. Kaelyn is the recipient of a first-year QB3 Fellowship. In this video Kaelyn talks about her experimental research in nanoscale optofluidics to be done with Trestles LH laser.

Reserve a spot in our femtosecond Ti:Sapphire training workshop in San Diego, California during summer 2011


Frequency-stabilized CW single-frequency ring Dye laser DYE-SF-007 pumped by DPSS DMPLH laser installed in the brand new group of Dr. Dajun Wang at the The Chinese University of Hong Kong.
DYE-SF-077 features exceptionally narrow generation line width, which amounts to less than 100 kHz. DYE-SF-077 sets new standard for generation line width of commercial lasers. Prior to this model, the narrowest line-width of commercial dye lasers was as broad as 500 kHz - 1 MHz. It is necessary to note that the 100-kHz line-width is achieved in DYE-SF-077 without the use of an acousto-optical modulator, which, as a rule, complicates the design and introduces additional losses. A specially designed ultra-fast PZT is used for efficient suppression of radiation frequency fluctuations in a broad frequency range. DYE-SF-077 will be used in resaerch of Ultracold polar molecules, Bose-Einstein condensate and quantum degenerate Fermi gas and High resolution spectroscopy

Other News

Optical Society of Southern California meeting at UCSD OSSC 2011-04-27
Nd:YAG laser ordered by the University of Leon, UANL, Mexico
Wedge 50 Multipass Amplifier pumped with a Darwin-527-30-M DPSS Laser ordered by Hong Kong customer
New Trestles LH10-fs/CW femtosecond+CW laser ready for delivery to the University of California Santa Cruz
Trestles femtosecond Ti:Sapphire laser delivered to North Carolina State University
Del Mar Photonics sponsor IONS (International OSA Network of Students) conference IONS-NA-2 in Tucson, Arizona IONS-NA-2 website
Best talk and best poster awards at IONS-Moscow 2010 conference sponsored by Del Mar Photonics
Watch Del Mar Photonics videos!
Del Mar Photonics is now on Twitter!

Del Mar Photonics featured components

Del Mar Photonics continuously expands its components portfolio.


 
Solar Prisms for Concentrating Photovoltaic Systems (CPV)
Solar cells made of compound semiconductors such as gallium arsenide are very expensive. Usually very small cells are installed and various means such as mirrors, lenses, prisms, etc..are used  to concentrate sunlight on the cells. Concentration photovoltaic technology (CPV) uses the solar radiation with an efficiency of 40%, double that of conventional solar cells
Del Mar Photonics design custom Concentrating Photovoltaic Systems (CPV) and supply variety of the optical components for CPV such as solar prisms shown in the picture.
 

hexagonal light pipes, optical rods


 
Axicon Lens
Axicon lens also known as conical lens or rotationally symmetric prism is widely used in different scientific research and application. Axicon can be used to convert a parallel laser beam into a ring, to create a non diffractive Bessel beam or to focus a parallel beam into long focus depth.
Del Mar Photonics supplies axicons with cone angles range from 130° to 179.5° for use with virtually any laser radiation. We manufacture and supply axicons made from BK7 glass, fused silica and other materials.

download brochure -
request a quote
Del Mar Photonics offers optical elements made of high quality synthetically grown Rutile Titanium Dioxide crystals. Rutile (TiO2) coupling prisms
Del Mar Photonics offers optical elements made of high quality synthetically grown Rutile Titanium Dioxide crystals. Rutile’s strong birefringency, wide transmission range and good mechanical properties make it suitable for fabrication of polarizing cubes, prisms and optical isolators. Boules having high optical transmission and homogeneity are grown by proprietary method. Typical boules have 10 - 15 mm in dia. and up to 25 mm length. Optical elements sizes - from 2 x 2 x 1 mm to 12.7 x 12.7 x 12.7 mm. Laser grade polish quality is available for finished elements. So far we the largest elements that we manufactured are 12 x15 x 5 mm, in which optical axis is parallel to 15 mm edge, 5 mm is along beam path, 12 x 15 mm faces polished 20/10 S/D, one wave flatness, parallelism < 3 arc.min. (better specs. available on request).

more details - download brochure -
request a quote

Vacuum viewport

Del Mar Photonics offer a range of competitively priced UHV viewports , Conflat, ISO or KF including a variety of coatings to enhance performance. Del Mar Photonics viewports are manufactured using advanced techniques for control of special and critical processes, including 100 percent helium leak testing and x-ray measurements for metallization control. Windows Materials include: Fused silica, Quartz , Sapphire , MgF2, BaF2, CaF2, ZnSe, ZnS, Ge, Si, Pyrex. Standard Viewing diameters from .55" to 1.94 ".
Coating - a range of custom coatings can applied - which include
- Single QWOT
- Broad Band AR
- V coatings
- ITO
- DLC (Diamond like coating)

more details - request a quote

 

 

Hydrogen Thyratrons are used in such devices as radars with different power levels, high-power pulsed technical, electrophysical, medical devices and lasers. Sophisticated design and high quality ceramic-metal envelope determines long lifetime and very accurate and reliable operation of hydrogen thyratrons under wide range of environmental conditions.
Applications:
- radars
- pulsed  lasers power supplies
- medical apparatus
- electrophysical instrumentation

Triggered Three-Electrode Spark Gap Switches are ceramic-metal sealed off gas discharge trigatron-type devices with a co-axial trigger electrode. These Gas Discharge Tubes contain no mercury and, due to an advanced design, feature high reliability and a long lifetime being operating under wide range of environmental conditions.

Applications:
- pulsed installation for processing materials
- installations with plasma focus
- pulse power supplies for lasers and other pulse equipment
- medical apparatus such as lithotriptors and defibrillators
- processing systems for petroleum wells
We are looking forward to hear from you and help you with your optical and crystal components requirements. Need time to think about it? Drop us a line and we'll send you beautiful Del Mar Photonics mug (or two) so you can have a tea party with your colleagues and discuss your potential needs.

 

Sign Up Today to receive Del Mar Photonics newsletter!

* required

*


 

 

Del Mar Photonics, Inc.
4119 Twilight Ridge
San Diego, CA 92130
tel: (858) 876-3133
fax: (858) 630-2376
Skype: delmarphotonics
sales@dmphotonics.com


THz wave up-frequency turning by rapidly plasma creation
Paper 8119-19 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Masahiro Nakata, Takeshi Higashiguchi, Noboru Yugami, Utsunomiya Univ. (Japan); Yasuhiko Sentoku, Univ. of Nevada, Reno (United States); Ryosuke Kodama, Osaka Univ. (Japan)

When plasmas are instantaneously created around an electromagnetic wave, frequency of the wave up-converted to the frequency, which depends on the plasma frequency. We have demonstrated the proof of principle experiment using the interaction between a terahertz wave and plasmas created by an ultra short laser pulse, which ensures the plasma creation time-scale much shorter than a period of electromagnetic source wave and plasma length longer than a wavelength of the wave. We observed frequency up-conversion from 0.35 THz to 3.3 THz by the irradiance of the Ti:sapphire laser in ZnSe crystal.

Active infrared metamaterials
Paper 8095-4 of Conference 8095
Date: Monday, 22 August 2011
Author(s): Igal Brener, Sandia National Labs. (United States)

In this talk I will review the current status of electrically tunable metamaterials, both at Terahertz and shorter infrared frequencies. Scaling these active devices to mid and near infrared optical frequencies poses considerable challenges and requires new tuning mechanisms. Some examples include controlling coupling to other dipolar resonances such as phonons and engineered transitions in semiconductor heterostructures.

Nanoparticle dispersed metamaterial sensors for intelligence, surveillance and reconnaissance (ISR) applications
Paper 8165B-53 of Conference 8165B
Date: Thursday, 25 August 2011
Author(s): Partha Banerjee, Georges T. Nehmetallah, Rola Aylo, Univ. of Dayton (United States); Stanley Rogers, Air Force Research Lab. (United States)

We propose tunable single-layer and multi-layer (periodic and with defect) structures comprising nanoparticle dispersed metamaterials in suitable hosts, including adaptive coded aperture constructs, for possible Adaptive Coded Aperture Imaging (ACAI) applications in microbolometry, pressure/temperature sensors, and directed energy transfer, over a wide frequency range, from visible to terahertz. These structures are easy to fabricate, are low-cost and tunable, and offer enhanced functionality, such as perfect absorption (in the case of bolometry) and low cross-talk (for sensors). Properties of the nanoparticle dispersed metamaterial are determined using effective medium theory.

Nonlinear meta-atoms for multi-functional metamaterials
Paper 8093-3 of Conference 8093
Date: Sunday, 21 August 2011
Author(s): John F. O'Hara, Los Alamos National Lab. (United States) and Oklahoma State Univ. (United States); Matthew Reiten, Lawrence M. Earley, Dibakar Roy Chowdhury, Jiangfeng Zhou, Antoinette J. Taylor, Los Alamos National Lab. (United States)

Nonlinearity adds an unprecedented amount of design flexibility and functionality to technology and is becoming increasingly studied in the context of metamaterials. Nonlinearity is the key to gain, bistability, photon mixing, rectification, and myriad other phenomena. Nonlinear behavior in natural materials begins at the atomic structure. We present a brief survey of some of the fundamentals of nonlinearity in natural materials. Then we present some recent progress in studying analogous behavior in metamaterials and meta-atoms, the fundamental building block of metamaterials. Specifically, we show microwave and terahertz frequency meta-atoms that support self-sustained oscillations, harmonic generation, chaotic broadband generation, and injection locking/pulling.

Limitations of THz QCLs, an experimental approach and an alternative
Paper 8119-7 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Nicolas Péré-Laperne, Ctr. National de la Recherche Scientifique (France); Louis-Anne de Vaulchier, Yves Guldner, Ecole Normale Supérieure (France)

Terahertz quantum cascade lasers (QCLs), based on AlGaAs/GaAs heterostructures, are limited in terms of working temperature and supply. We present experimental data on one particular QCL structure under a strong magnetic field applied parallel to the growth axis. The emitted power shows strong oscillations as a function of B. The analysis of these oscillations exhibits two mechanisms of non-radiative relaxation, an elastic scattering mechanism (interface roughness) and an inelastic one (LO-phonon). This latter scattering process is put in evidence thanks to magnetic field but is limiting operation at high temperature without B. One possible alternative is the use of another material, AlGaN/GaN heterostructures. Thanks to its high value of LO phonon energy, this material theoretically demonstrates the ability to emit in the THz range at room temperature. We are presenting two structures, one optically pumped and another one electrically pumped.

mm wave and THz imaging using very inexpensive neon-indicator lamp detector focal-plane arrays
Paper 8119-16 of Conference 8119
Date: Sunday, 21 August 2011
Author(s): Natan S. Kopeika, Ben-Gurion Univ. of the Negev (Israel); Amir Abramovich, Ariel Univ. Ctr. of Samaria (Israel); Assaf Levanon, Daniel Rozban, Avihai Akram, Ben-Gurion Univ. of the Negev (Israel) and Ariel Univ. Ctr. of Samaria (Israel); Hezi Joseph, Ben-Gurion Univ. of the Negev (Israel); Orly Yadid-Pecht, Ben-Gurion Univ. of the Negev (Israel) and Univ. of Calgary (Canada); Alex Belenky, Simon Lineykin, Ben-Gurion Univ. of the Negev (Israel)
Hide Abstract

The chief bottleneck holding back development of inexpensive real time mm wave and terahertz imaging is the cost of detectors. One solution is the use of neon indicator lamps costing typically about 30 - 50 cents each as detectors. NEP is typically on the order of 10-9 W/Hz1/2 in direct detection. In heterodyne detection, minimum detectable signal is about 2 orders of magnitude less than in direct detection, and decreases with increasing reference power. Focal plane arrays of 8X8 such detectors have been constructed, and good quality 32X32 pixel images obtained at 100 GHz. Presently, a new board to record 32X32 pixel images with a single snapshot each is under construction and should be available shortly. We plan to use it to obtain not only 32X32 pixel images, but also 64X64 and, hopefully, 128X128 pixel images as well.