Optical switching

A principal concern in these hquid-ciystal-based switching devices is the response time. However, unlike electro-optical effects which involve the molecular reorientations of hqirid crystals in their nerrratic phase and are slow, nonlinear hquid 

The incident angle is set 2° away from the TIR (0— 0TIR- 2°). It is estimated that, owing to the reflection loss at the air-prism and prism-liquid crystal interfaces. 

NONLINEAR OPTICAL PHENOMENA OBSERVED IN LIQUID CRYSTALS 

Study has also shown that prior to transmission-TIR switching, the incident laser will suffer an even more severe intensity-dependent phase shift, the 

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Kulzer F, Kummer S, Matzke R, Brauchle C and Basche T 1997 Single-molecule optical switching of terrylene in p-terphenyl Nature 387 688-91... 

Sharpness. This describes the steepness of the electro-optical switching as a function of voltage. This is defined in tenns of the ratio of voltages required to achieve 90% compared to 10% transmission of light. This ratio should be as close to unity as possible. 

Clark N A and Lagerwall S T 1980 Submicrosecond bistable electro-optic switching in liquid crystals App/. Phys. Lett. 36 899-901... 

Optical storage disks Optical storage media Optical switches Optical trapping Optical tweezers Optical wave guides... 

In photodetectors (qv) for photocouplers, optical switches, fiber optics, communication, and imaging, the materials used are InGaAs, InGaAsP, and... 

Ca.rhora.nes, These are used in neutron capture therapy (254), and as bum rate modifiers in gun and rocket propellants. They are used as high temperature elastomers and other unique materials, high temperature gas—Hquid chromatography stationary phases, optical switching devises (256), and gasoline additives (257). 

The cadmium chalcogenide semiconductors (qv) have found numerous appHcations ranging from rectifiers to photoconductive detectors in smoke alarms. Many Cd compounds, eg, sulfide, tungstate, selenide, teUuride, and oxide, are used as phosphors in luminescent screens and scintiUation counters. Glass colored with cadmium sulfoselenides is used as a color filter in spectroscopy and has recently attracted attention as a third-order, nonlinear optical switching material (see Nonlinear optical materials). DiaLkylcadmium compounds are polymerization catalysts for production of poly(vinyl chloride) (PVC), poly(vinyl acetate) (PVA), and poly(methyl methacrylate) (PMMA). Mixed with TiCl, they catalyze the polymerization of ethylene and propylene. 

Photo transmitters Optical switches, strobes, toys... 

IR-emitting diodes (GaAs) Remote controls, optical switches, optoisolators, choppers, pattern recognition devices... 

IR-emitting diodes (GaAlAs) Optical switches, encoders, photo IC sensors... 

Advances in laser technology now allow for solid-state lasers of high beam quality. These beams may be projected from a much smaller auxiliary telescope, which negates the need for optical switching and completely eliminates any main telescope fluorescence. Solid-state YAG lasers are the most common type of lasers commercially available. These lasers use a crystal as the lasing... 

The random laser is a simple optical system in which the strong optical scattering in the random medium forms an optical recurrent path. Recent reports on random lasers have described the emission of laser light by metal-oxide polycrystalline and micrometer-sized particles [46]. Because of its structural simplicity and small size, the single random laser is a promising miniature light source for optical devices, such as waveguides and optical switches. 

By the sol-gel-process, inorganic glassy and hybrid polymeric materials are accessible at comparatively low temperatures [1], Therefore, organic molecules or dyes can easily be incorporated into the oxide matrix. This combination is especially attractive for the development of the following devices optical filters, solid-state lasers, optical switches, nonlinear optical laser hosts, optical data storage media, and photoconductive devices and films [2]. 

Winter, Underhill, and co-workers have published extensively on the cubic NLO properties of complexes of DT and related ligands,411 22 particularly those containing formally Ni11 centers. For example, time-resolved 1,064 nm DFWM was used to obtain resonantly enhanced values for group 10 complexes such as (157).411 15 The smaller of (157) compared with (156) is largely due to resonance effects since the absorption maximum of (157) is somewhat removed from the laser fundamental. However, figures of merit derived from measurements of 2 and linear and two-photon absorption (TPA) coefficients show that low optical losses render complexes such as (157) superior to (156)413 for potential all-optical switching applications.411 14... 

BRET [31, 32]), lock-in detection techniques exploiting optical switches [33], and schemes for alternating D/A excitation (ALEX [34]). The increased attention to quantitative FRET imaging encompasses the use of polarization [35-39], the perennial issue of calibration and standards [40-44], and practical guides to operational principles and protocols ([45, 46] and other references above). The fundamental distinctions between the requirements for live and fixed cell imaging cannot be overemphasized, as is exemplified in a report of erroneous FRET determinations with visible fluorescent proteins (VFPs) in fixed cells [47],... 

Gonzalez C., Collins S.D., Magnetically actuated fiber-optic switch with micromachined positioning stages, Optics Lett., 1997 22(10) 709-711. 

Fig. 12 In situ optical switching of the current flowing through a DAE monolayer assembled in a PEDOT PSS interlayer-based LAJ. (a) Comparison of the current densities flowing through as assembled open and closed isomer and upon in-situ photoisomerization.

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