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Nonlinear Optical Transmission Of Silk/Green Fluorescent Protein (Gfp) Films, Donald Ott, R Eby, S Putthanarat, Rajesh Naik

Donald W. Ott

In this initial work, we demonstrate a technique for preparing thin (10–20 μm) films of silk doped with green fluorescent protein (GFP) by casting/annealing at 20 °C and describe the resulting film characteristics. Notably, the GFP molecules maintain their nonlinear optical properties as evidenced by two-photon fluorescence microscopy and two-photon absorption measurements using near-infrared femtosecond pulses. The fractional transmission of focused near-infrared pulses of 775 nm wavelength, 140 fs pulsewidth was observed to decrease as the incident pulse energy is increased and/or the incident spot size is decreased, indicating that nonlinear absorption is taking place. Visible damage from the pulses …