Study of optical property change in organic materials induced by ti:sapphire femtosecond laser

Abstract

Femtosecond laser has a very high peak power because of its ultrashort pulse duration. After amplified by a regenerative amplifier, which is based on Chirped Pulse Amplification (CPA) technique, the peak power intensity can reach 10 TW/cm2. Many nonlinear effects will occur under this extremely high Electro-Magnetic field. We exposed an organic transparent material of Polymethyl methacrylate (PMMA) to the amplified Ti:Sapphire laser pulses with 100-fs pulse duration, 800-nm wavelength and 1000 Hz repetition rate under different output power and observed the consequent refractive index change. Meanwhile, an interferometry method was used to measure the refractive index change. A uniquely modified Machelson interferometer was setup and could sensitively monitor the slight change of refractive index change.Femtosecond laser has a very high peak power because of its ultrashort pulse duration. After amplified by a regenerative amplifier, which is based on Chirped Pulse Amplification (CPA) technique, the peak power intensity can reach 10 TW/cm2. Many nonlinear effects will occur under this extremely high Electro-Magnetic field. We exposed an organic transparent material of Polymethyl methacrylate (PMMA) to the amplified Ti:Sapphire laser pulses with 100-fs pulse duration, 800-nm wavelength and 1000 Hz repetition rate under different output power and observed the consequent refractive index change. Meanwhile, an interferometry method was used to measure the refractive index change. A uniquely modified Machelson interferometer was setup and could sensitively monitor the slight change of refractive index change.