A novel all-optical parallel switching device was proposed based on photoinduced changes of a complex refractive index in a guided mode thin film composed of silver and polymer containing organic dyes. An incident angle of a probe beam was set at a value corresponding to the minimum reflection due to a guided wave mode. Pulsed laser excitation caused changes of absorption of the polymer films due to excited state formation or photochromism, which resulted in the increase of reflection because the guided mode condition was changed. According to the Kramers-Kronig relationship the real part also changes, which results in the shift of the minimum. We can select the wavelength for all-optical switching in this geometry. We used phthalocyanines and photochromic spiropyran dispersed in poly(vinyl alcohol) or polystyrene. For the former system, transient absorption due to the excited triplet gave a highly reversible very fast modulation of green light upon repeated excitation by ns laser. For the latter, self-held switching was achieved upon UV or visible laser excitation with response times less than 20 ns. The details of these systems will be presented.

Date Published: 9 October 1998
PDF: 10 pages
Proc. SPIE 3466, Algorithms, Devices, and Systems for Optical Information Processing II, (9 October 1998); doi: 10.1117/12.326783

Published in SPIE Proceedings Vol. 3466:
Algorithms, Devices, and Systems for Optical Information Processing II
Bahram Javidi; Demetri Psaltis, Editor(s)