Ultrafast All-Optical Switching Using Doped Chromoprotein Films

Next-generation communication networks require > Tbit/s single-channel data transfer and processing with sub-picosecond switches and routers at network nodes. Materials enabling ultrafast all-optical switching have high potential to solve the speed limitations of current optoelectronic circuits. Chromo-proteins exhibit a large light-controlled refractive index change alleviating the driving energy requirements for optical switching. Here, we report femtosecond transient grating experiments demonstrating the feasibility of < 200 fs all-optical switching by hydrated thin films of photoactive yellow protein and compare the results with those obtained using bacteriorhodopsin. Possibilities for the practical utilization of the scheme in extremely high-speed optical modulation and switching/routing with nominally infinite extinction contrast are discussed.