Optical power limiter in the femtosecond filamentation regime

Abstract We present the use of a power limiting apparatus to evaluate ultrafast optical nonlinearities transparent liquids (water and ethanol) in femtosecond filamentation regime. The setup has been previously employed for same purpose, however, longer pulsewidth (> 20 ps) regime, which leads an ambiguous evaluation critical self-focusing. uncertainty originates from existence threshold breakdown well below self-focusing within this timeframe. Contrarily, using proposed we observe first time unique response, features underlying physics laser filamentation. Importantly, demonstrate dependence transmission limiter on its geometrical, imaging characteristics conditions under distinct demarcation can be determined. result is supported by numerical simulations, indicate that observed power-dependent response are physically related spontaneous transformation pulses into nonlinear conical waves.