One of the major scientific areas of interest for BioCARS staff and users is Time-Resolved Crystallography. The Laser Laboratory houses several lasers, two micro-spectrophotometers and other equipment necessary for time-resolved experiments.ts on macromolecular crystals, in preparation for time-resolved diffraction experiments.
Lasers Presently Used Include:
- ps laser system
(Spectra Physics, Ti:Sapphire Spitfire Pro 5; 780nm; 2ps; 1kHz; 5mJ/pulse; plus TOPAS OPA; tunable range: 350nm-2µm)
- ns laser system
(OPOTEK Opolette 355 II HE; 7ns pulse duration; 20Hz; 410-600nm: ~3-6mJ; 230-400nm:0.5-2mJ)
- Several CW lasers
(Ar-ion; two He-Ne)
The picosecond laser system was recently acquired in collaboration with Philip Anfinrud (NIDDK/NIH). With this addition, the resolution of time-resolved diffraction experiments is no longer limited to the nanosecond time domain (a limitation imposed by the laser pulse duration), so we can achieve ~100-ps time resolution, determined by the pulse length of the X-ray source.
Laser light is passed from the Laser Lab to the 14 ID-B Station, where time-resolved diffraction experiments are conducted, by an optical fiber or a set of mirrors. Having a separate Laser Lab allows us to conduct off-line time-resolved optical measurements on macromolecular crystals, in preparation for time-resolved diffraction experiments.