ABSTRACT
We have made a diffraction grating in an indoline azobenzene/amorphous polycarbonate film by two-beam interference at 532 nm that periodically photodegrades the indoline azobenzene dye. Subsequent illumination of the film with 532-nm light into the trans-isomer band leads to trans-cis isomerization in the indoline azobenzene dye and results in a decrease in the trans-isomer band absorption coefficient. This causes the diffraction efficiency to decrease when probed at 655 nm. The diffraction efficiency returns to its original value when the 532-nm light is blocked by thermal relaxation from the indoline azobenzene cis-isomer to the trans-isomer. Thus, we have been able to optically modulate the diffraction efficiency in a thin film diffraction grating.
ABSTRACT
An optically switchable diffraction grating has been made in a thin film containing a photochromic dye and amorphous polycarbonate. We show that a film containing the dye 5-chloro-1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-(3H)naphth[2,1-b](1,4)oxazine] can be optically processed so that a diffraction grating can be completely switched on by ultraviolet light and turned off by thermal relaxation. The ability to switch or modulate the diffraction efficiency has a number of practical applications that include optical switches and add/drop multiplexers.
ABSTRACT
An electrically modulated diffraction grating has been demonstrated in poled polymer thin films containing the organic nonlinear optical chromophore, PYR-3 (2-{3-Cyano-4-[3-(1-decyl-1 H-pyridin-4-ylidene)-propenyl]-5,5-dimethy l-5 H-furan-2-ylidene}-malononitrile), and amorphous polycarbonate. A dc electric field induced change in the diffraction efficiency of up to 9% was observed. The diffraction efficiency modulation was likely due to an electric field induced change in the film thickness via a piezoelectric effect rather than via an electronic linear electro-optic effect.
