Almost-common path interferometer using the separation of polarization states for digital phase-shifting shearography

in Optical Engineering : The Journal of the Society of Photo-Optical Instrumentation Engineers (2007), 46(10),

An original experimental setup for shearography with metrological applications is presented. The simplicity and the efficiency of the setup are provided by a shearing device, a prism that separates the TE ... [more ▼]

An original experimental setup for shearography with metrological applications is presented. The simplicity and the efficiency of the setup are provided by a shearing device, a prism that separates the TE and TM polarization modes with a coating and a thin glass plate placed on its face. The use of this shearing device enables an in-line and almost-common path configuration for the shearing interferometer, a path that leads to high stability and a low sensitivity to external disturbances. Moreover, the sensitivity of the interferometer can be easily adjusted for different applications by varying the shearing amount with glass plates of different thicknesses or by moving the shearing device between two lenses along the optical axis. The temporal phase-shifting method is applied through the use of a liquid crystal variable retarder. (c) 2007 Society of Photo-Optical Instrumentation Engineers. [less ▲]

Narrow band-width wavelength filter by guided mode resonance

in Optical Engineering : The Journal of the Society of Photo-Optical Instrumentation Engineers (2004), 43(11), 2631-2639

Simple resonant structures that permit holographic reflection filtering are studied. The filters under study work under a 45-deg incidence for a wavelength of λ=632.8 nm, a condition useful for future ... [more ▼]

Simple resonant structures that permit holographic reflection filtering are studied. The filters under study work under a 45-deg incidence for a wavelength of λ=632.8 nm, a condition useful for future inclusion in substrate mode systems. First, the influence of the structural parameters of the grating and the waveguide on the position and the shape of the resonance peaks are studied by numerical computation. The numerical results, obtained within the rigorous coupled wave theory, are compared with the measured response of some filters. These filters contain a grating recorded by holography deposited on the substrate. In the case of the bilayer filter, a waveguide is introduced between the grating and the substrate. Second, the numerical results are used for the conception of an active substrate mode spectral filter built from electro-optic zinc oxide. [less ▲]

Model-Based System for Automatic Target Recog- nition from Forward-Looking Laser-Radar Imagery

in Optical Engineering : The Journal of the Society of Photo-Optical Instrumentation Engineers (1992), 31(12), 2540-2552