Introduction to the NHMFL Pulsed Field Facility at LANL

Information on the physical set-up of pulsed field measurements

Read about lock-in amplifiers and their role in your measurements

Information about noise and ways to eliminate it from your measurements

How to collect and evaluate your measurement data

Information on optical spectroscopy

Information about time-resolved optics

Information on de Haas van Alphen Effect measurements

Information on Shubinkov de Haas Effect measurements

Information on Absolute Resistivity measurements

Information on Heat Capacity measurements

Information on RF Penetration Depth measurements

Fast dc Multichannel Optical Spectroscopy

Associated Scientist: Scott A. Crooker <> 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.