Tunable Infrared Laser Spectrophotometer
Activities:
- High-Resolution Gas-Phase Molecular Spectroscopy
Doppler-limited spectroscopy; accurate transition frequencies and
intensities. Collisional lineshapes of atmospheric molecules; pressure
broadenings and shifts, line mixing, Dicke narrowing and correlations.
Molecular-beam spectroscopy; sub-Doppler resolution, supercooled beams,
structure and dynamics of large molecules and van der Waals species.
Optical Properties of Materials
Transmission, absorption, reflection, emissivity, polarization of crystals,
windows, filters, etc. Detector comparison and characterization.
Instrumentation:
- Difference-frequency spectrometer: mixing of cw single-mode
stabilized argon ion and ring dye lasers in LiNbO3
nonlinear optical crystal using noncritical temperature-tuned phasematching;
tuning range from 2400 to 4400 cm-1 (2.2 to 4.2 m) with
complete continuous coverage, digitally-controlled scanning, linewidth
~1 MHz, low power ~1 µW.
- Color-center laser: cw single-mode stabilized, tuning range
from 3000 to 4000 cm-1 (2.5 to 3.3 m) with complete
continuous coverage, digitally-controlled scanning, linewidth 1 to 3 MHz,
medium power 1 to 20 mW.
- CO2-sideband laser: cw single-mode stabilized,
line-tunable from 900 to 1100 cm-1 (9 to 11 m) with microwave
sidebands imposed from 6 to 18 GHz using broadband GaAs stripline
electo-optic modulator, quasicontinuous coverage about 50% with single isotope,
linewidth ~100 kHz, high power CO2 laser 5 to 10 W, medium
power sidebands 1 to 5 mW.
- Terahertz photomixer: radiation generated at the beat
frequency between two single-mode visible dye or near-infrared diode lasers in
ultrafast low-temperture-grown GaAs photoconductors coupled to submillimeter
antennas,
range from 0.1 to 1 THz (300 to 3000 m) with complete
continuous coverage, linewidth ~2 MHz, low power 1 to 0.01 µW.
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Online: September 1997 - Last updated: April 2002
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