NANOSECOND TIME-RESOLVED CIRCULAR-DICHROISM MEASUREMENTS USING AN UP-CONVERTED TI-SAPPHIRE LASER

Several years ago a time-resolved circular dichroism technique for the far ultraviolet spectral region with submicrosecond (10(-7) s) time r esolution was developed using a xenon flash lamp probe source for meas urements of circular dichroism (CD) signals. Recent improvements in Ti :sapphire lasers, providing the ability to frequency-convert the funda mental outputs to produce second, third, and fourth harmonic pulses, a llow single wavelength measurements of CD with nanosecond (10(-9) s) t ime resolution over a broad spectral region (205-910 nm). This provide s a powerful technique to study fast biophysical phenomena such as pro tein folding processes. In this article, the methodology and prelimina ry application of this new technique are presented. (C) 1996 American Institute of Physics.