Visible intracavity laser spectroscopy with a step-scan Fourier-transform interferometer

A Fourier-transform spectrometer has been used in a step-scan mode to make time-resolved measurements of the evolving laser pulse in intracavity laser spectroscopy (ILS) experiments. Spectra of broadband dye laser pulses at approximately 615 nm were recorded at relatively high spectral (0.5-cm(-1)) and temporal (as high as 5-mus) resolution. In the absence of an absorber, the height of the pulse is shown to be proportional to t(g)(0.57) (where t(g) is the generation time) for generation times as high as 500 mus. The system was constructed for feasibility studies of future use at infrared and near-infrared wavelengths where conventional ILS that uses diode arrays would be either expensive or simply not possible. The CH(4) overtone transition at 619.68 nm was used to test the linearity and sensitivity of the system. Comparable performance to conventional ILS systems was demonstrated, as were the advantages of the present system for studies of laser and absorption dynamics.