Nanosecond time-resolved circular dichroism measurements using an upconverted Ti:sapphire laser

Abstract

Several years ago a time-resolved circular dichroism technique for the far ultraviolet spectral region with submicrosecond (10−7 s) time resolution was developed using a xenon flash lamp probe source for measurements of circular dichroism (CD) signals. Recent improvements in Ti:sapphire lasers, providing the ability to frequency-convert the fundamental outputs to produce second, third, and fourth harmonic pulses, allow single wavelength measurements of CD with nanosecond (10−9 s) time resolution over a broad spectral region (205–910 nm). This provides a powerful technique to study fast biophysical phenomena such as protein folding processes. In this article, the methodology and preliminary application of this new technique are presented.