A Wide-Band Femtosecond Pump–Probe Spectrometer Based on a Laser with an Active Medium Based on Chromium-Doped Forsterite Crystal

An instrument for recording photoinduced-absorption spectra using the pump–probe method with femtosecond time resolution is described, in which a regenerative amplifier based on a chromium-doped forsterite crystal with a fundamental harmonic of 1240 nm is used as the laser system. Two optical schemes with pumping at a wavelength of 620 nm and a wavelength of 413 nm that are described in detail allow measurements in the spectral range of 280–1000 nm. The time resolution of the system is 250 fs.