Associated Scientist: Scott A. Crooker <crooker@lanl.gov> or (505) 665-7595

Fast "dc" multichannel spectroscopy: For photoluminescence, absorption, or reflection spectroscopy from the ultraviolet to the near infrared (250nm to 1000nm), we employ a high-speed, high efficiency CCD camera to continuously acquire complete optical spectra at rates up to 1kHz. This system is ideally suited for measurements in the 60T Long-Pulse (2 second pulse duration) or the 50Tesla mid-pulse magnet (0.5 second pulse duration), where an entire field dependence can be performed in a single magnet pulse. This method is also well-suited to any dc superconducting magnet.

Samples are typically mounted on one of our fiber-coupled, low temperature probes. Additional fibers then couple excitation light and collected signal to the optics lab. Temperatures down to 350mK are possible in the 60T Long-pulse magnet, and 1.3K in the 50T magnet. Light is dispersed in 1/3 meter f=4 spectrometers.

Possible light sources include the 442nm and 325nm lines from a HeCd laser, semiconductor diode lasers (~635nm, 532 nm), and the output from a tunable femtosecond Ti:S laser (700-1000nm, or 350-500nm if frequency doubled). For white-light, a 100W quartz lamp is used.

Single-frequency measurements can be performed in either short- or long-pulse magnets with the appropriate fast photodiode or photomultiplier tube.