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.
Lasers presently used include:
- two ns lasers:
- Nd:YAG/dye laser (Continuum, Powerlite 8010/ND6000; 7ns pulse duration; 10Hz; 380-730nm; > 200mJ/pulse)
- Nd:YAG/OPO laser (OPOTEK Brilliant/Vibrant; 4ns pulse duration; 10Hz; 410-600nm: ~20-30mJ; 240-380nm:2-5mJ)
- several CW lasers (Ar-ion; two He-Ne)
- ps laser system (Spectra Physics, Ti:Sapphire Spitfire Pro 5; 780nm; 2ps; 1kHz; 5mJ/pulse; plus TOPAS OPA)
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 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.