Ultrafast broadband circular dichroism in the deep ultraviolet

The measurement of chirality and its temporal evolution are crucial for the understanding of a large range of biological functions and chemical reactions. Steady-state circular dichroism (CD) is a standard analytical tool for measuring chirality in chemistry and biology. Nevertheless, its push into the ultrafast time domain and in the deep-ultraviolet has remained a challenge, with only some isolated reports of subnanosecond CD. Here, we present a broadband time-resolved CD spectrometer in the deep ultraviolet (UV) spectral range with femtosecond time resolution. The setup employs a photo-elastic modulator to achieve shot-to-shot polarization switching of a 20 kHz pulse train of broadband femtosecond deep-UV pulses (250-370 nm). The resulting sequence of alternating left- and right-circularly polarized probe pulses is employed in a pump-probe scheme with shot-to-shot dispersive detection and thus allows for the acquisition of broadband CD spectra of ground- and excited-state species. Through polarization scrambling of the probe pulses prior to detection, artifact-free static and transient CD spectra of enantiopure [Ru(bpy)(3)](2+) are successfully recorded with a sensitivity of <2 x 10(-5) OD (approximate to 0.7 mdeg). Due to its broadband deep-UV detection with unprecedented sensitivity, the measurement of ultrafast chirality changes in biological systems with amino-acid residues and peptides and of DNA oligomers is now feasible. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement


Published in:
Optica, 6, 1, 56-60
Year:
Jan 20 2019
Publisher:
Washington, OPTICAL SOC AMER
ISSN:
2334-2536
Keywords:
Laboratories:




 Record created 2019-02-01, last modified 2019-06-19

Fulltext:
Download fulltext
PDF

Rate this document:

Rate this document:
1
2
3
 
(Not yet reviewed)