US 9,696,476 B1Granted

Volume Moiré Bragg gratings in a photosensitive material

AssigneesOptigrate Corporation, University of Central Florida Research Foundation, Inc.

InventorsLeonid B. Glebov, Julien Lumeau, Sergiy Mokhov, Vadim Smirnov, Boris Zeldovich

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Abstract

Complex spectral and angular diffractive optical elements in photosensitive materials based on Moiré pattern are proposed and demonstrated. The process is based on the recording of multiple volume Bragg gratings with controlled difference of the periods in the same volume of photosensitive material. Filters with ultra-narrow bandpass in the range of a few picometers to a few tens of picometers or apodized diffractive optical elements across large aperture are demonstrated. Several methods to fabricating such Moiré Bragg gratings are proposed. Experimental demonstration of a Moiré ultra-narrowband diffractive optical element in PTR glass is performed.

Claims29

Dependent claims

A method of fabricating a complex diffractive optical element, comprising:

providing only one single volume of a permanently-recordable photosensitive material;
and
permanently recording at least two different volume Bragg gratings having different periods, each of which is produced by the interference of two beams in the only one single volume of the permanently-recordable photosensitive material, wherein the two volume Bragg gratings occupy the same cross sectional volume of the permanently-recordable photosensitive material perpendicular to the surface normal of the only one single volume of the permanently-recordable photosensitive material resulting in additional spatial modulation of a permanent refractive index modulation profile characterized by a larger period determined by a difference between the periods of the at least two volume Bragg gratings to obtain a permanent volume Moiré Bragg grating occupying the whole cross sectional volume of the permanently-recordable photosensitive material and having a Moiré period determined by a difference between the two different volume Bragg grating periods.

A method of fabricating a complex diffractive optical element consisting essentially of the step of:

providing only one single plate of a permanently-recordable photosensitive material;
recording a first volume Bragg grating having a first period and a first direction of grating vector in a cross sectional volume of the permanently-recordable photosensitive material by exposure to a first interference pattern produced by a first pair of beams;
and
recording a second volume Bragg grating having a second, different period and second different grating vector in the same cross sectional volume of the photosensitive material by exposure to a second interference pattern produced by a second pair of beams, wherein the first and second periods are determined by an angle between the first and second pair of beams, respectively, resulting in additional spatial modulation of a refractive index modulation profile with a period determined by the difference between the first and second periods of the at least two volume Bragg gratings as a permanent Moiré period.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 12/780,202Filed 14 May 2010 · us provisional application
Priority: 15 May 2009
Granted: 4 Jul 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

G02B 5/32
Optical elements other than lenses: holograms used as optical elements
G03H 1/28
Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique:…
G02B 5/00
Optical elements other than lenses
G02B 5/1857
Manufacturing methods: using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams