Del Mar Photonics - Newsletter December 2010 - Newsletter April 2011

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Cleaning uncoated (ZnSe) optics

You should prepare working area accordingly. This is very important because particulate contamination from the work surface or the worker is what usually scratches the coating. Clear the table of everything and wear clean clothing. Work as still as possible so as not to shake particles out of your hair while cleaning. Work in a darkened room under a freshly cleaned high intensity desk lamp so that the reflection of a bright source of light on a dark background will allow you to see what you are doing. Be sure that the work surface will not be eaten by methanol. Read all precautions regarding the safe use of methanol and follow all storage and handling instructions. Any area containing optics should prohibit smoking. Smoke vapor deposits are difficult to remove from optical surfaces. Unless otherwise noted, all methods of cleaning (vacuum, dry nitrogen, brush, cotton, and/or lens tissue) are performed from the center of the surface to its edges. The applicator (cotton, lens tissue) should be rotated as the cleaning advances, always presenting a clean surface to the object being cleaned.

Dust is the most common contaminant and can usually be removed using pressurized gas. If more cleaning is necessary, hold the lens in lens tissue and apply a few drops of reagent-grade acetone or lens cleaning solution. Slowly turn the lens while applying pressure in the center and working outward, to pull dirt off the lens instead of redistributing it on the surface. Fingerprints on a coated lens should be cleaned as soon as possible to avoid staining or damaging the optic. Larger dirt particles, however, should be removed with a dust-free blower before attempting to clean the optic with lens tissue. Larger particles trapped under the cloth will scratch the surface you are attempting to clean. If the lens is still dirty after using acetone - for instance, if the oil was just redistributed and not cleaned off the optic - then a mild soap solution can be used to gently wash the lens. Repeat the procedure with acetone and finish it with isopropyl alcohol to eliminate streaks and soap residue.

Model	Product Name+	Buy Now
PH-ZnSe-25.4-12.7	ZnSe hemicylindrical prism, 25.4 mm
R-ZnSe-25.4-25.4	ZnSe rhomb, 25.4x25.4 mm
RAP-ZnSe-12.7-25.4	ZnSe right angle prism, 12.7 x 25.4 mm
S-ZnSe-10-10-0.5	ZnSe slide, 10x10x0.5 mm
WS-ZnSe-100-100-10	ZnSe square window, 100x100x10, coated
VP-ZnSe-45-3-2 3/4	ZnSe viewport, 2-3/4
VP-ZnSe-73-4-4 1/2	ZnSe viewport, 4 1/2
W-ZnSe-1.5"-2.5"-1/4	ZnSe window, 38.1x63x6.35 mm, coated
W-ZnSe-105-6-AR	ZnSe window, ø 105 mm, thickness 6 mm, coated
W-ZnSe-12.7-1	ZnSe window, ø 12.7 mm, thickness 1 mm
W-ZnSe-20-3	ZnSe window, ø 20, thickness 3 mm
W-ZnSe-25-2-AR	ZnSe window, ø 25, thickness 2 mm, coated
W-ZnSe-25.4-2-AR-3-1	ZnSe window, ø 25.4 mm, thickness 2 mm, AR coated 3-12 µm
W-ZnSe-25.4-3	ZnSe window, ø 25.4 mm, thickness 3 mm
W-ZnSe-60-3-K	ZnSe window, ø 60 mm, thickness 3 mm, coated
W-ZnSe-76.2-3-K	ZnSe window, ø 76.2 mm, thickness 3 mm, coated

Application notes on ZnSe slides (under construction)

The fullerenes of C60 and C70 were deposited onto a zinc selenide slide

Microarray printing of bacteria on zinc selenide slides.
The microarray of microcolonies were stamped on a ZnSe slide after a 2–3 h incubation period.

Accelerating Bacterial Identification by Infrared Spectroscopy on ZnSe slide.
Infrared data analysis of the acquired FTIR spectra.

Cryocondensation step on a ZnSe-slide.
The ZnSe slide itself is cooled via connection to a liquid nitrogen container.

Enzyme-catalyzed modifications of macromolecules.
These macromolecules are reactive either as cryogenically milled powder suspended in the organic solvent or as a thin film deposited onto ZnSe slides.

GC/FT-IR spectra of 8.6 ppm of t-butyl benzene deposited on a ZnSe slide.
The lower spectrum was measured on the bare ZnSe slide.

Synchrotron FT-IR microspectroscopic analysis of necrotic bone.
Sections were fixed on ZnSe slides, suitable for infrared transmission analysis.
Sections were cut from each case; one was placed on ZnSe slide.

Zinc Selenide (ZnSe) Components

Zinc Selenide (ZnSe) is the most popular material for infrared application. Due to very wide transmission range covering 0.6 to 20 m m CVD grown ZnSe high optical quality material is used to manufacture optical components (windows, mirrors, lenses etc.) for high power IR lasers.

Physical Properties

General Specifications of Zinc Selenide Optical Components

Standard ZnSe windows (uncoated) 

Zinc Selenide custom made windows, lenses, Brewster windows, mirrors, beamsplitters and other components are available on request.

Zinc selenide most obvious and important advantage over other materials is its low absorption in the red end of the visible spectrum. This allows the ubiquitous helium neon laser to be used as a convenient and inexpensive alignment or sighting tool for infrared laser beams. Prealignment of optics may be necessary merely because the infrared beam is invisible to the eye, or in addition because the infrared laser beam is of such a high energy misdirected laser beam can be extremely dangerous to equipment or personnel.

Although zinc selenide has this clear advantage over silicon and germanium, unfortunately it is not an easy material from which to produce optics. Firstly, it is not a naturally occurring material and has to be synthesized using a difficult process (CVD). Secondly, the dust, which is generated when zinc selenide is ground and polished constitutes a significant health hazard as a cumulative toxin. Also, it is not a particularly hard substance and scratches easily.

Refractive Index

Transmission

Although the internal transmittance of zinc selenide is very high (absorption <= 0.0005cm^-1 at 10.6mm), the relatively high refractive index (2.4 at 10.6m m) cause reflection losses of nearly 30%. Unless such losses can be tolerated, zinc selenide optics should always be antireflection coated. Because of the high refractive index, single and double layer antireflection coatings can be very effective.

Zinc selenide is not hygroscopic unlike certain salts which are used for windows in the infrared.

Del Mar Photonics featured optical components

Del Mar Photonics continuously expands its optical components portfolio. Browse our online store, read monthly notes about our featured optical products or just send us your requirements or product ideas. 

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. buy online - download brochure

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 - buy online - download brochure

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

Manufacturing challenging optical components Our group works to characterize the interaction of biomolecules with solid surfaces, writes Dennis Hore of University of Victoria, Canada.  Nature designs proteins with well-defined structures in solution.  The conformation of these molecules may serve a structural purpose, or a chemical one in the case of enzymes.  In order to further the progress of technologies that immobilize such molecules on synthetic surfaces (like biosensors employing enzymes), it is important to have a detailed understanding and control of the interactions of these molecules with the surface more For that project Del Mar has been able to manufacture all shapes of prisms from CaF2, fused silica, and ZnSe according to our custom specifications. Del Mar Photonics online store features windows, prisms, lenses, attenuators, etalons, crystals and wafers, and other items. Axicons, barium fluoride windows, germanium etalons, rutile (TiO2) prisms, microchannel plates and detectors, saturable absorber mirrors, photoconductive THz antennas, lithium niobate wafers and crystals and many other high quality affordable components for scientific research and OEM production are delivered globally from stock. Micro Prism from Del Mar Photonics

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

Trestles LH femtosecond lasers with integrated DPSS DMPLH laser pump - DPSS DMPLH lasers