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 K.sup.i 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 &lgr;.sub.B.sup.i of grating layer i.