Temporal and spectral characteristics of ultrashort pulsed beam interact with matter.

摘要

Research was conducted to investigate the transmission of laser pulses through aerosol sprays to simulate propagation through clouds. Measurements of the transmission through a confined aerosol cloud were performed using various femtosecond laser pulse lengths. These studies were performed to investigate temporal characteristics of ultrashort pulse, including the effect of pulse duration on the transmission and reflection on materials that were constant in time and would not have the variability that aerosols have.;Spectral characteristics of ultrashort pulse are presented on experimental and theoretical work performed to compare diffraction phenomena for ultrashort 10 fs pulses and continuous wave propagation modes illuminating different objects. Results showed that 10 fs pulses do not produce high frequency diffraction like that produced with continuous wave (CW) illumination. Calculations indicate that the lack of high frequency diffraction for pulsed case is due to the broadband nature of the ultrashort laser pulses, i.e., the distribution of frequency contained in the pulse ends up washing out when objects are illuminated with pulses of broad frequency content.