All of the sources and spectrometers at the NHMFL now are coupled to the
experiment in the magnet via optical fibers. This allows the lasers and some
of the spectrometers to remain in one place even though experiments are done in
pulsed magnets, resistive magnets or superconducting magnets located at some
distance. Experiments can be done at wide ranges of temperature and pressure.
Similar capabilities exist in Los Alamos and Tallahassee.
Complete laser systems provide wavelengths from the near ultraviolet to the
near infrared at both locations. Each includes a Coherent MIRA 900 dual mode
locked Ti:Sapphire laser capable of operating in the pulsed (femtosecond or
picosecond) or continuous wave modes, a 10 W argon laser to pump the
Ti:Sapphire, and a 7 W, UV capable argon laser. The lasers have the following
wavelengths: 351.1 nm (300 mW), 363.8 nm (300 mW), 488.0 nm (2.4 W), 514.5 nm
(3.3 W), and a tunable band for the Ti:Sapphire (>=100 mW continuous wave
output) of 700 - 1050 nm . The time scales of the Ti:S laser in modelocked
operation are 130 fs and 2 ps, and the wavelength range is 720 nm to 1000 nm.
The following equipment is available for pulsed fields and in the 20 T
superconducting magnet in Los Alamos:
- 0.25m, f/4 Jarrel-Ash monochromator with a thermoelectrically cooled GaAs
photomultiplier and a liquid nitrogen cooled Ge photo-detector for operation in
the visible and near IR (300-1600 nm)1
- 0.6m, f/10 Spex `Triple-Mate' spectrometer[1 ]with a Photometrics Model 9000
CCD array detector[2] for the
300-1050 nm region
- 0.28m, f/4 Acton Instruments monochromator with a Princeton Instruments
CCD array detector[3] for
operation in the 300-1050 nm region.
- Sample holders for both pulsed and superconducting magnets at temperatures
from 1.6 to 300 K. Samples may be oriented either parallel or perpendicular to
the applied field.
- Diamond anvil cells for optical studies at pressures up to 25 GPa.
- Techniques used have included photoluminescence, transmission and
reflection spectroscopy.
Users of the resistive and superconducting magnets
in Tallahassee have available a MacPherson 0.75 m single grating
monochrometer/spectrometer. The accessories on hand provide 0.01 nm resolution
and cover wavelengths from 300 to 900 nm (7 gratings). It is highly automated
and features a UV coated 1024 X 256 CCD array detector for rapid spectroscopy
in high fields (over 125 spectra in a single 3.5 hour shift).
The following other equipment is available for use in the resistive and
superconducting magnets in Tallahassee:
- Holographic notch filters at 488.0 and 514.5 nm.
- Sample holders are available for all of the superconducting and resistive
magnets.
- Sample temperature control from 1.6 K to 300 K while situated in a vacuum
can in the helium dewar.
- The sample holder for the 50 mm bore resistive magnets has sample
changing capability for up to seven 5 mm diameter samples.
- Techniques used have included photoluminescence and reflection
spectroscopy.
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Curator: Scott Hannahs <sth@magnet.fsu.edu>
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