Broadband Subpicosecond Infrared Vibrational Spectroscopy
15 October 1989
Broadband (500 cm sup (-1)) infrared pulses of 350 fs duration tunable from 2.5-5.5microns have been produced by difference frequency mixing in LiIO sub 3 and used to do subpicosecond time-resolved vibrational spectroscopy. Using a synchronized visible pump beam, time-resolved infrared absorption of transient species can be recorded. When the transmitted infrared probe pulses are monitored through a monochromator, vibrational absorption dynamics can be monitored with transform-limited resolution. Evolution of the vibrational spectra of heme proteins after photoexcitation has been studied. In the present paper, we report the results of up-converting the transmitted infrared pulses to the visible. We then use an optical multi-channel analyzer to record the entire absorption spectrum at once.