Protein-Based Integrated Optical Switching and Modulation

András Dér, László Fábián, László Oroszi, Elmar K. Wolff, Jeremy J. Ramsden, and Pál Ormos

Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62., P.O. Box 521, H-6701 Szeged, Hungary



Coupling of optical data-processing devices with microelectronics, as well as with sensory functions, is one of the biggest challenges in molecular electronics. Intensive research is going on to seek suitable nonlinear optical materials, that could meet the demanding requirements of optoelectronic applications, especially regarding high sensitivity and stability. In addition to inorganic or organic crystals, biological molecules have also been considered for use in computer hardware among which the bacterial chromoprotein, bacteriorhodopsin (bR) generated the most interest. bR undergoes enormous absorption and concomitant refractive index shift upon initiation of a cyclic series of photoreactions by a burst of actinic light. This effect can be exploited to create highly versatile all-optical logical elements. We demonstrate the potential of this approach by investigating the static and dynamic response of optical waveguides coated with a thin layer of bacteriorhodopsin, working as an active nonlinear optical material to produce a variety of integrated optical switching and modulation effects.