Abstract

With the use of Fourier-transform (FT) limited laser pulses structural and dynamical information can be retained from gas, liquid and solid-phase samples, in principle both from time domain and frequency domain measurements. In many cases it is, however, practical to reduce the bandwidth such that the relevant spectral structures are resolved, and then use the resulting temporal response of the optical pulses to derive dynamical information on the spectrally resolved structures. Using a wavelength-tunable pulsed-dye amplifier, delivering FT-pulses of 5 ns, and pulse compression in a simple two-cell setup (filled with methanol) the resulting pulse duration could be varied in the range 400 - 2000 ps (see Fig. 1). Pulse compression is established by the process of Stimulated Brillouin Scattering (SBS). The resulting pulse duration is governed by the power density of the incident beam, which can be varied by the changing beam diameter. From spectral and time domain measurements it is demonstrated that in all cases ΔvΔr ≤ 1. For all measurements the SBS-conversion efficiency was >80%.

© 1998 IEEE