Dynamic multiple wavelength filter using a stratified volume holographic optical element

摘要

A dynamic multiple-wavelength filter which selects at least one wavelength from a beam of radiation incident on a Stratified volume Holographic Optical Element (SVHOE) in accordance with the Bragg condition. The SVHOE has a number n of grating layers i and a hologram of a grating vector Ki is recorded in each grating layer i. A number n-1 of buffer layers are interposed between grating layers i such that the layers SVHOE presents an alternating structure of grating and buffer layers. The filter has a diffraction efficiency control, preferably based on the ECD effect, for selectively varying the diffraction efficiency eta in at least one grating layer i to select from the beam of radiation a narrow bandwidth centered about Bragg wavelength lambda Bi of grating layer i.