Q & A - What is a Faraday Optical Isolator and How Does it Work?

Del Mar Photonics - Kirra Faraday Isolator brochure - Faraday Isolator Models - request a quote

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At high powers optical feedback can damage or disrupt the operation of a laser system. To reduce this feedback, an optical isolator can be inserted into the system. Faraday optical isolators (based on the Faraday effect) are passive unidirectional, nonreciprocal devices that utilize the phenomenon of magneto-optic Faraday Isolator from Del Mar Photonicsrotation to isolate the source and protect the laser oscillator from reflections in an optical system. In other words, they basically act as an optical diode allowing the propagation of light in only one direction.

Faraday isolators (see Figure 1) typically consist of a Faraday rotator, two polarizers, and a body to house the parts. The Faraday rotator, in turn, consists of magnetooptically active optical material placed inside a permanent magnet (Nd-Fe-B).

In the Faraday optical isolator shown in Figure 2, the magneto-optical rod (located inside the Faraday rotator) is cut from glass (MOS-10) polished to flatness of /10, and has parallelism better than 10 arc seconds. Faraday Isolator SchematicIt is anti-reflection coated with residual reflection <0.2% (each side) in the 765-835 nm range. The polarizers are air-spaced Glan prisms made of calcite. Entrance and exit faces of polarizers are anti-reflection coated with residual reflection of <0.3% in the range. Polarizer transmittance is >98%. This gives a total transmittance of better than 85% for the isolator.

Laser light (polarized or unpolarized) enters the input polarizer (P1) and is linearly polarized to 0°. Next, the linearly polarized light enters the Faraday rotator rod (magneto-optical rod). The plane of polarization rotates as the light propagates along the axis of the rod. The Faraday rotator is tuned to rotate the plane of polarization by 45°. (Changing the position of the rod allows tuning over a wavelength range from 765-835 nm.) The light then passes through the output polarizer (P2) whose transmission axis is also at 45°.

Any back reflected light re-enters the isolator through the output polarizer and becomes polarized at 45°. The back reflected light then passes through the Faraday rotator, which produces another 45° of rotation, and is now polarized at 90°, or horizontally, before being stopped by the input polarizer, still at 0°. Thus, the laser is isolated from its own reflections that may occur in the application part of the optical set.

This information was contributed by Sergey Egorov for Del Mar Photonics, located in San Diego, CA.

Del Mar Photonics - Kirra Faraday Isolator brochure - Faraday Isolator Models

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

Near Field Scanning Optical Microscope NSOM Godwit - best spatial optical resolution using the near field scanning optical microscope (NSOM) principle
Near field scanning optical microscope (NSOM) and atomic force microscope (AFM) modes of operation
NSOM images with laser and lamp illumination
Commerciaand custom NSOM probes
Near field optica and luminescence images in photon counting mode
NSOM images in collection and illumination modes
Transmission and reflection NSOM configurations
20 nm optical resolution (Raleigh criteria for spatial resolution)
State-of-the-art optical microscope console: simultaneous sample and tip observation with long working distance objectives
Femtosecond and UV excitation
True single molecule detection
High-resolution AFM imaging of DNA
Godwit-uScope data acquisition and Godwit-FemtoScan image processing software
Ambient light protection with light-tight box

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 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

Pismo pulse picker
The Pismo pulse picker systems is as a pulse gating system that lets single pulses or group of subsequent pulses from a femtosecond or picosecond pulse train pass through the system, and stops other radiation. The system is perfectly suitable for most commercial femtosecond oscillators and amplifiers. The system can pick either single pulses, shoot bursts (patterns of single pulses) or pick group of subsequent pulses (wider square-shaped HV pulse modification). HV pulse duration (i.e. gate open time) is 10 ns in the default Pismo 8/1 model, but can be customized from 3 to 1250 ns upon request or made variable. The frequency of the picked pulses starts with single shot to 1 kHz for the basic model, and goes up to 100 kHz for the most advanced one.
The Pockels cell is supplied with a control unit that is capable of synching to the optical pulse train via a built-in photodetector unit, while electric trigger signal is also accepted. Two additional delay channels are available for synching of other equipment to the pulse picker operation. Moreover, USB connectivity and LabView-compatible drivers save a great deal of your time on storing and recalling presets, and setting up some automated experimental setups. One control unit is capable of driving of up to 3 Pockels cells, and this comes handy in complex setups or contrast-improving schemes. The system can also be modified to supply two HV pulses to one Pockels cell unit, making it a 2-channel pulse picker system. This may be essential for injection/ejection purposes when building a regenerative or multipass amplifier system.
Tourmaline Yb-SS-1058/100 Femtosecond solid state laser system
The Yb-doped Tourmaline Yb-SS laser radiates at 1058±2 nm with more than 1 W of average power, and enables the user to enjoy Ti:Sapphire level power at over-micron wavelengths. This new design from Del Mar's engineers features an integrated pump diode module for greater system stability and turn-key operation. The solid bulk body of the laser ensures maximum rigidity, while self-starting design provides for easy "plug-and-play" operation.
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

Femtosecond fiber laser Model Pearl-70P300 - request a quote
Femtosecond pulsed lasers are used in many fields of physics, biology, medicine and many other natural sciences and applications: material processing, multiphoton microscopy, «pump-probe» spectroscopy, parametric generation and optical frequency metrology. Femtosecond fiber lasers offer stable and steady operation without constant realignment.
The Pearl-70P300 laser comprises: a passively mode-locked fiber laser, providing pulses with repetition rate 60 MHz and having duration of 250-5000 fs, an amplifier based on Er3+ doped fiber waveguide with pumping by two laser diodes, a prism compressor for amplified pulse compression.
Pearl Ultra-Compact Ultrafast Picosecond Fiber Oscillator
Autocorrelator Reef RT, Del Mar Photonics, San Diego, CA
Reef femtosecond autocorrelators
The autocorrelation technique is the most common method used to determine laser pulse width characteristics on a femtosecond time scale.
The basic optical configuration of the autocorrelator is similar to that of an interferometer (Figure.1). An incoming pulse train is split into two beams of equal intensity. An adjustable optical delay is inserted into one of the arms. The two beams are then recombined within a nonlinear material (semiconductor) for two photon absorption (TPA). The incident pulses directly generate a nonlinear TPA photocurrent in the semiconductor, and the detection of this photocurrent as a function of interferometer optical delay between the interacting pulses yields the pulse autocorrelation function. The TPA process is polarization-independent and non-phasematched, simplifying alignment.

Reef-RT autocorrelator measures laser pulse durations ranging from 20 femtoseconds to picosecond regime. It measures pulse widths from both low energy, high repetition rate oscillators and high energy, low repetition rate amplifiers. Compact control unit operates autocorrelator head and optional spectrometer through on-screen menus. Autocorrelation trace and spectrum can be displayed and analyzed on screen or downloaded to remote computer.

New: Reef-20DDR autocorrelator - Multishot-FROG for femtosecond fiber laser oscillator and amplifier
Collinear (interferometric) autocorrelation for 1300-2000 nm wavelength range

Near IR viewers
High performance infrared monocular viewers are designed to observe radiation emitted by infrared sources. They can be used to observe indirect radiation of IR LED's and diode lasers, Nd:YAG, Ti:Sapphire, Cr:Forsterite, dye lasers and other laser sources. IR viewers are ideal for applications involving the alignment of infrared laser beams and of optical components in near-infrared systems. Near IR viewers sensitive to laser radiation up to 2000 nm.
The light weight, compact monocular may be used as a hand-held or facemask mounted for hands free operation.

Ultraviolet viewers are designed to observe radiation emitted by UV sources.

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!

Featured application: Analysis of biological molecules on surfaces using stimulated desorption photoionization mass spectrometry

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
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 adaptive optics and wavefront sensors: ShaH-0620 wavefront sensor with telescope Wavefront Sensors: ShaH Family
A family of ShaH wavefront sensors represents recent progress of Del Mar Photonics in Shack-Hartmann-based technology. The performance of Shack-Hartmann sensors greatly depends on the quality of the lenslet arrays used. Del Mar Photonics. developed a proprietary process of lenslet manufacturing, ensuring excellent quality of refractive lenslet arrays. The arrays can be AR coated on both sides without interfering with the micro-lens surface accuracy. Another advantage of the ShaH wavefront sensors is a highly optimized processing code. This makes possible real-time processing of the sensor data at the rate exceeding 1000 frames per second with a common PC. Due to utilizing low-level programming of the video GPU, it is possible to output the wavefront data with a resolution up to 512x512 pixels at a 500+ Hz frame rate. This mode is favorable for controlling modern LCOS wavefront correctors.
The family of ShaH wavefront sensors includes several prototype models, starting from low-cost ShaH-0620 suitable for teaching laboratory to a high-end high-speed model, ShaH-03500. The latter utilizes a back-illuminated EM-gain CCD sensor with cooling down to -100°C. This makes it possible to apply such a wavefront sensor in astronomy, remote sensing, etc.
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:
Portable Terahertz Source
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, GaAs, GaP, LiNbO3 - Wedge ZnTe
Silicon Viewports for THz radiation
Aspheric collimating silicon lens - Aspheric focusing silicon lens

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

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-077 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



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