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.
Highlights
Optical filters based on diffraction gratings have a large range of applications that include optical storage [1, 2], optical communication [3,4,5], strain and chemical sensing [6,7,8,9], and spectroscopy [10,11,12]
Switchable diffraction gratings would be useful for all-optical switching and multiplexing [5] and could be used, for example, in add/ drop [4] modules in optical communication systems that are needed for dense wavelength division multiplexing
We have recently shown that an optically switchable diffraction grating can be made using a photochromic dye/amorphous polycarbonate (APC) composite film
Summary
Optical filters based on diffraction gratings have a large range of applications that include optical storage [1, 2], optical communication [3,4,5], strain and chemical sensing [6,7,8,9], and spectroscopy [10,11,12]. They have been made and researched using different methods and materials.
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