188 research outputs found
Generation of chirp-free picosecond pulses
The frequency spectrum of moderately chirped laser pulses depends upon the portion of the beam which is accepted by the spectrometer. Observation of the development of the chirp in a mode-locked pulse train allows to determine the small incipient chirp of early pulses. A product, bandwidth times pulse duration, of 0.47 ± 0.03 is consistently observed for single pulses switched from a passively mode-locked Nd-glass system
Low temperature reaction dynamics in the primary electron transfer of photosynthetic reaction centers
Time resolved observation of resonant and non-resonant contributions to the nonlinear susceptibility χ(3)
The resonant and nonresonant part of χ(3) are distinguished by their different time behavior. The medium is coherently excited by two picosecond light pulses of defined frequency difference and the state of the system is monitored by a third properly delayed probe pulse. Results are presented on neat liquids of carbontetrachloride and cyclohexane and on the mixture of CCl4: C6H12
A picosecond Raman technique with resolution four times better than obtained by spontaneos Raman spectroscopy
Picosencond lifetimes and efficient decay channels of vibrational modes of polyatomic molecules in liquids
Optical pulse compression
Dramatic and controllable reshaping of frequency-modulated dye laser pulses has been observed. The pulses, nearly resonant with the 2P1/2 line (7948 A) of Rb, first passed through a LiNbO3 frequency modulator, and then through a cell containing dilute Rb vapor where the reshaping took place. Large pulse compressions were obtained with only 400 MHz of frequency modulation due to the extremely large frequency dispersion of the group velocity.Peer reviewedElectrical and Computer Engineerin
Direct determination of the intensity of picosecond light pulses by two-photon absorption
The influence of phase-modulation on femtosecond time-resolved coherent Raman spectroscopy
The influence of phase-modulation on femtosecond time-resolved coherent Raman scattering is investigated theoretically and experimentally. The coherent Raman signal taken as a function of the spectral position shows unexpected temporal oscillations close to time zero. A theoretical analysis of the coherent Raman scattering process indicates that the femtosecond light pulses are amplitude and phase modulated. The pulses are asymmetric in time with more slowly decaying trailing wings. The phase of the pulse amplitude contains quadratic and higher-order contributions
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