Diffraction efficiency

About: Diffraction efficiency is a research topic. Over the lifetime, 10320 publications have been published within this topic receiving 158298 citations.

Multiplex holography in strontium barium niobate with applied field

Abstract: We characterize the performance of photorefractive Sr0.6Ba0.4Nb2O6 under an externally applied voltage. We compared the field dependences of the gain coefficient, response time, sensitivity, and diffraction efficiency with predictions of Kukhtarev’s solution [ Sov. Tech. Phys. Lett.2, 438 ( 1976)] for two-wave interaction, using material parameters obtained at zero voltage. Plane-wave holograms were superimposed in the crystal with angular multiplexing. The hologram capacity (or minimum diffraction efficiency) increased by an order of magnitude with a 15-kV/cm applied field.

The minimum Euclidean distance principle applied to improve the modulation diffraction efficiency in digitally controlled spatial light modulators

Abstract: Digital addressing of the electrical signal in spatial light modulators, as it is the case in present liquid crystal on silicon (LCoS) displays, may lead to temporal phase fluctuations in the optical beam. In diffractive optics applications a reduction in the modulation diffraction efficiency may be expected. Experimental work is done characterizing the fluctuations amplitude and phase depth for three different digital addressing sequences. We propose a diffractive model to evaluate the modulation diffraction efficiency of phase diffractive optical elements (DOEs) in the presence of phase fluctuations. Best results are obtained for the most stable electrical sequence even though its phase depth is as small as 280°. The results show good agreement with the numerical calculation given by the model.

Diffractive subtractive color filtering technique

Abstract: A subtractive color filtering technique, suitable for the projection of color pictures, employs diffraction, rather than color dyes, for discriminatingly subtracting unwanted spectral wavelength portions of polychromatic illuminating light. The useful output light may consist of solely the zero-order diffraction output light or, alternatively, one or a certain combination of diffraction orders other than the zero diffraction order (such as the aggregate of all diffraction orders other than the zero diffraction order which corresponds to the complement of the zero-order diffraction output light).

Achromatic diffractive lens written onto a liquid crystal display

Abstract: We propose a programmable diffractive lens written onto a liquid crystal display (LCD) that is able to provide equal focal lengths for several wavelengths simultaneously. To achieve this goal it is necessary that the LCD operate in the phase-only regime simultaneously for the different wavelengths. We design the appropriate lens for each wavelength, and then the lenses are spatially multiplexed onto the LCD. Various multiplexing schemes have been analyzed, and the random scheme shows the best performance. We further show the possibility of finely tuning the chromaticity of the focal spot by changing the relative weights of the multiplexing among the various wavelengths.

Multi beam scanning with bright/dark field imaging

Abstract: Bright and dark field imaging operations in an optical inspection system occur along substantially the same optical path using the same light source by producing either a circular or an annular laser beam. Multiple beam splitting is achieved through the use of a diffractive optical element having uniform diffraction efficiency. A confocal arrangement for bright field and dark field imaging can be applied with multiple beam scanning for suppressing the signal from under-layers. A scan direction not perpendicular to the direction of movement of a target provides for improved die-to-die comparisons.