Lars LINDVOLD, Husain IMAM and P.S. RAMANUJAM

Optics and Fluid Dynamics Department, RISØ National Laboratory, DK-4000 Roskilde, Denmark

(Accepted November 14, 1994)

In this paper, we present new results describing the spatial frequency response in bacteriorhodopsin (bR), immobilised in gelatin films. It is shown that the spatial frequency response is flat, as compared to bR contained in solution form. An experimental investigation into the photoinduced anisotropy of bR films is also presented. It is shown that the anisotropy can be induced using two wavelengths (632.8 nm and 454 nm) and is dependent on the pH of the gelatin matrix, the 454 nm laser polarisation and the 454 nm pump power. The mechanisms producing the anisotropy are briefly discussed.

Key words : bacteriorhodopsin thin films, spatial frequency response, photoinduced anisotropy, transient effects, pH value of gelatin matrix