Abstract

One of the more prominent bio molecular materials emerging in the field of nonlinear optoelectronics is the photochromie protein, baeteritnhodopsin (bR). Compared with photorefractive crystals, this material is relatively inexpensive, very light sensitive and has the advantages of easier fabrication and larger specimens. The molecular engineering approach of modifying the bR protein gives rise to enormous latitude of improved photophysical performance by tuning the protein’s affects on the chromophore. The protein backbone allows for molecular modifications of the functionally important amino acid moieties of bR (such as aspartate 96 replacement) by conventional biotechnological techniques. Investigations have demonstrated that genetic modifications of the bR protein enhance the properties for optical applications.¹ Phase conjugation reflectivity in excess of 26% had been previously reported on thin films of bR in a polyvinyl alcohol matrix.² Improved nonlinear polarization is primarily attributed to electron delocalization of the conjugated π-bond polyene structure during photoisomerization of the protein-bound retinal chromophore and supports the noted, strong third-order susceptibility (X³).^3,4

© 1994 Optical Society of America