Theoretical diffraction efficiency for slanted uncoupled absorption multiplex holograms

1985 ◽  
Vol 63 (10) ◽  
pp. 1372-1374
Author(s):  
Jean J. A. Couture ◽  
R. A. Lessard
Keyword(s):  
Diffraction Efficiency ◽  
Analytical Solutions ◽  
Angular Separation ◽  
Simple Generalization ◽  
Angular Selectivity

Analytical solutions describing the reconstruction obtained from a multiplex hologram that has been made with two incoherent holographic exposures are presented. Angular separation between the two object waves is greater than the angular selectivity bandwidth of each of the two elementary uncoupled gratings. The analysis gives results characterizing the diffraction efficiency of these gratings. Incoherent superposition of N uncoupled and slanted gratings is easily described by a simple generalization.

Design of high-performance holographic gratings using siloxane-containing mesogenic compounds

2006 ◽  
Vol 78 (10) ◽  
pp. 1835-1842 ◽  
Author(s):  
Yusuke Kawakami ◽  
Man He ◽  
Yeong Hee Cho
Keyword(s):  
Diffraction Efficiency ◽  
Ring Opening ◽  
High Performance ◽  
Liquid Crystalline ◽  
Diglycidyl Ether ◽  
Matrix Component ◽  
Holographic Gratings ◽  
Glycol Diacrylate ◽  
Trimethylolpropane Triacrylate ◽  
Angular Selectivity

Fine holographic gratings were fabricated using siloxane- and mesogen-containing compounds. A grating with 40 % diffraction efficiency was formed with 10 wt % non-liquid-crystalline 4-methoxyphenyl 4-[4-(pentamethyldisiloxanyl)butoxy]benzoate and trimethylolpropane triacrylate. 4-Methoxyphenyl 4-[4-(1,1,3,3,5,5,5-heptamethyltrisiloxan-1-yl)butoxy]-benzoate gave 50 % diffraction efficiency and angular selectivity of 5°. Siloxane-containing liquid-crystalline compounds were also effective in fabricating fine gratings. These compounds induced distinct phase separation over a concentration range from 6 to 20 wt % in the formation of holographic gratings. The use of ring-opening polymerizable bifunctional epoxides as one of the reactive cross-linking matrix components, together with penta- or tetra-acrylate initiated by 3,3'-carbonylbis(7-diethylaminocoumarin)diphenyliodonium hexafluorophosphate, greatly improved the diffraction efficiency. Fine gratings with 70 and 78 % diffraction efficiency and angular selectivity of 5° were formed with 10 wt % 4-cyano-4'-[(5-heptamethyltrisiloxan-1-yl)pentyloxy]-biphenyl and 4-cyanophenyl 4-[(5-heptamethyltrisiloxan-1-yl)pentyloxy]benzoate using pentaerythritol pentaacrylate-neopentylglycol diglycidyl ether-tripropylene glycol diacrylate (4:5:1) as the polymer matrix component.

Interference fringes arising from strong coupling in multiple exposure thick absorption holographic gratings

1984 ◽  
Vol 62 (1) ◽  
pp. 92-96
Author(s):  
Jean J. A. Couture ◽  
R. A. Lessard
Keyword(s):  
Strong Coupling ◽  
Diffraction Efficiency ◽  
Angular Separation ◽  
Multiple Exposure ◽  
Recording Medium ◽  
Holographic Gratings ◽  
Interference Fringes ◽  
Spatial Frequencies

Multiplex holograms can generate modulated interference fringes imaged onto the surface of the recording medium whenever the N reconstructed object waves have a small angular separation. At this reconstruction stage, a strong coupling arises due to the vicinity of the recorded gratings and the small differences of their spatial frequencies. Diffraction efficiency expressions describing the effects of such a coupling are deduced.

scholarly journals Study of the Effect of Methyldiethanolamine Initiator on the Recording Properties of Acrylamide Based Photopolymer

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 734
Author(s):  
Brian Rogers ◽  
Suzanne Martin ◽  
Izabela Naydenova
Keyword(s):  
Refractive Index ◽  
Diffraction Efficiency ◽  
Prolonged Exposure ◽  
Uv Light ◽  
Holographic Recording ◽  
Refractive Index Modulation ◽  
Optical Elements ◽  
The Stability ◽  
Angular Selectivity ◽  
Index Modulation

The use of Holographic Optical Elements (HOEs) in applications, such as in light shaping and redirection, requires certain characteristics such as a high Diffraction Efficiency, low angular selectivity and stability against UV damage. In order to maximize the performance of the HOEs, photosensitive materials are needed that have been optimised for the characteristics that are of particular importance in that application. At the core of the performance of these devices is the refractive index modulation created during holographic recording. Typically, a higher refractive index modulation will enable greater light Diffraction Efficiency and also operation with thinner devices, which in turn decreases the angular selectivity and the stability of the refractive index modulation introduced during recording, which is key to the longevity of the device. Solar concentrators based on volume HOEs can particularly benefit from thinner devices, because, for a solar concentrator to have a high angular working range, thinner photopolymer layers with a smaller angular selectivity are required. This paper presents an optimisation of an acrylamide-based photopolymer formulation for an improved refractive index modulation and recording speed. This was achieved by studying the effect of the concentration of acrylamide and the influence of different initiators in the photopolymer composition on the diffraction efficiency of holographic gratings. Two initiators of different molecular weights were compared: triethanolamine (TEA) and methyldiethanolamine (MDEA). A fivefold increase in the rate of grating formation was achieved through the modification of the acrylamide concentration alone, and it was also found that holograms recorded with MDEA as the initiator performed the best and recorded up to 25% faster than a TEA-based photopolymer. Finally, tests were carried out on the stability of the protected and unprotected photopolymer layers when subjected to UV light. The properties exhibited by this photopolymer composition make it a promising material for the production of optical elements and suitable for use in applications requiring prolonged exposure to UV light when protected by a thin melinex cover.

Optical Diffractive Memories: Angular Selectivity and Diffraction Efficiency in Dichromated Gelatin

1995 ◽  
Vol 2 (6) ◽  
pp. 434-437 ◽  
Author(s):  
Harry Ramenah ◽  
Poul Bertrand ◽  
Patrick Meyrueis
Keyword(s):  
Diffraction Efficiency ◽  
Dichromated Gelatin ◽  
Angular Selectivity
Sign in / Sign up

Export Citation Format

Share Document