Diffraction efficiency

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

Gratings in the resonance domain as polarizing beam splitters.

Abstract: Polarization-selective gratings in the resonance domain of diffractive optics are calculated by use of rigorous electromagnetic diffraction theory. The polarizing effects are attained by special surface-relief structures, and the profile of binary surface-relief gratings is optimized with a nonlinear Newton algorithm to design diffractive polarizing beam splitters.

Optimisation of a low cost SLM for diffraction efficiency and ghost order suppression

Abstract: Spatial Light Modulators (SLMs) are a powerful tool in many optics laboratories, but due to the technology required for their fabrication, they are usually very expensive Recently some inexpensive devices have been produced, however their phase shift range is less than 2π, leading to a loss of diffraction efficiency for the SLM We show how to improve the first order diffraction efficiency of such an SLM by adjusting the blazing function, and obtain a 15 times increase in first order diffracted power Even a perfect SLM with 2π phase throw can produce undesired effects in some situations; for example in holographic optical tweezers it is common to find unwanted “ghost spots” near to the array of first-order spots Modulating the amplitude, by spatially modulating the blazing function, allows us to suppress the ghost spots This increases the contrast between desired and unwanted spots by more than an order of magnitude

Diffraction efficiency of volume holograms written by coupled beams.

Abstract: We describe volume holograms written in photorefractive crystals in which the writing beams experience two-beam coupling We obtain analytic expressions for the diffraction efficiency of a weak reading beam that has a different polarization from the writing beams Good agreement is obtained between experimental and theoretical results

System for controlling spot power in a raster output scanner

Abstract: The present invention is a scanning system and a novel method for compensating for the variations in the output power of the beam from an A-O cell. The novel method involves varying the amount of drive current through the laser diode in such a fashion as to compensate for the loss of power due to diffraction inefficiencies. The amount of driving current is dependent upon the amount of power desired in the output beam from the A-O cell. The system and method of the present invention sets the output power from the A-O cell to a desired value. As the diffraction efficiency increases at other portions of the scan, the drive current is cut appropriately to compensate for the increased efficiency; thus keeping the output spot power at the desired value. Likewise, as the diffraction efficiency decreases at other portions of the scan, the drive current should be increased to compensate for the decrease in efficiency; thereby maintaining the desired value.

Holographic elements with high efficiency and low aberrations for helmet displays

Abstract: A recursive design technique for forming holographic elements which can be incorporated into helmet displays has been developed To ensure that the holographic elements have low aberrations and high diffraction efficiency they must be recorded with complex wavefronts These wavefronts are derived from relatively simple intermediate holograms whose readout geometry and wavelength differ from those during recording The overall recursive design technique is illustrated for a single holographic helmet display element having resolution of less than 08 mrad and diffraction efficiency of more than 80 percent over a field of view of 16 degrees x 16 degrees