Optical scanning instrument for ultrafast pump-probe spectroscopy of biomolecules at cryogenic temperatures

We demonstrate novel optical scanning and detection instrumentation that is particularly useful for the interrogation of stationary cryogenic samples in pump-probe spectroscopy. The technique uses a spinning lens to scan multiple laser beams over a stationary sample while maintaining the focal prope...

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Veröffentlicht in:Review of scientific instruments 2006-06, Vol.77 (6), p.064303-064303-7
Hauptverfasser: Ionascu, Dan, Rosca, Florin, Gruia, Florin, Yu, Anchi, Champion, Paul M.
Format: Artikel
Sprache:eng
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Zusammenfassung:We demonstrate novel optical scanning and detection instrumentation that is particularly useful for the interrogation of stationary cryogenic samples in pump-probe spectroscopy. The technique uses a spinning lens to scan multiple laser beams over a stationary sample while maintaining the focal properties of the beams. This significantly lengthens the time window for the sample reset to equilibrium and improves the photostability of stationary samples. In addition, we describe a signal processing methodology that discriminates against the strong background signal that can arise from leakage of the pump laser pulse train into the detector. These techniques are particularly useful in pump-probe studies of ultrafast processes in biological systems where sample deterioration, pump induced thermal lensing, and light scattering into the detection channel (e.g., induced by light scattering from a cryogenic matrix) are problematic. Generally, the optical scanning and detection instrumentation described here enable the study of a variety of biological systems, without the need for intricate spinning or flowing sample containers, making it possible to perform ultrafast pump-probe experiments on stationary samples such as a cryogenic matrix.
ISSN:0034-6748
1089-7623
DOI:10.1063/1.2214954