Construction of a Versatile Microsecond Time-Resolved Infrared Spectrometer

Abstract

A time-resolved scanning infrared spectrometer has been constructed which consists of a globar light source, a monochromator, an MCT detector, a boxcar integrator, a cw Q-switched Nd:YAG laser, and a personal computer. Both the time-resolved spectra (in the frequency-scanning mode) and the temporal change of the transient signals (in the time-scanning mode) can be observed with this spectrometer. It covers the spectral range of 700 to 4200 cm−1 with the time resolution of 1 μs. Intensity changes as small as one part in 104 can be detected with a slit width of 5 mm (6 cm−1 at 700 cm−1 and 60 cm−1 at 4000 cm−1) and with a typical scanning rate of 20 cm−1/min. High performance of this spectrometer has been achieved by the use of a high-repetition-rate (750 Hz) laser for the actinic light source combined with an ac-coupled detection scheme.