Two-color pump-probe laser spectroscopy instrument with picosecond time-resolved electronic delay and extended scan range

An electronically delayed two-color pump-probe instrument was developed using two synchronized laser systems. The instrument has picosecond time resolution and can perform scans over hundreds of nanoseconds without the beam divergence and walk-off effects that occur using standard spatial delay systems. A unique picosecond Ti: sapphire regenerative amplifier was also constructed without the need for pulse stretching and compressing optics. The picosecond regenerative amplifier has a broad wavelength tuning range, which suggests that it will make a significant contribution to two-color pump-probe experiments. To test this instrument we studied the rotational correlation relaxation of myoglobin (tau(r)= 8.2 +/- 0.5 ns) in water as well as the geminate rebinding kinetics of oxygen to myoglobin (k(g1) = 1.7 x 10(11) s(-1), k(g2) = 3.4 x 10(7) s(-1)). The results are consistent with, and improve upon, previous studies. (c) 2005 American Institute of Physics.