Temperature-Jump Apparatus with Raman Detection Based on a Solid-State Tunable (1.80-2.05 (mu)m) kHz Optical Parametric Oscillator Laser

摘要

The operating characteristics of a pulsed (10 ns) tunable near-infrared (NIR) laser source are described for temperature-jump (T-jump) applications. A Q-switched Nd:YLF laser (approx10 ns pulses) with a 1 kHz repetition rate is used to pump a potassium titanyl arsenate (KTA) crystal-based optical parametric oscillator (OPO), producing approx1 mJ NIR pulses that are tunable (1.80-2.05 (mu)m) across the 1.9 (mu)m vibrational overtone band of water. This T-jump source has been coupled to a deep ultraviolet (UV) probe laser for Raman studies of protein dynamics. T-jumps of up to 30 deg C, as measured via the O-H stretching Raman band of water, are readily achieved. Application to cytochrome c unfolding is demonstrated.