David C Hovde

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An external-cavity diode laser operating at 1500 nm was used to record the combination band of acetylene (C(2)H(2)). By combination of wavelength-modulation spectroscopy with a noise-canceler detection circuit, a minimum detectable absorbance of 4.8 × 10(-4) with a 300-ms time constant was achieved, although this result was limited by étalon fringes. When(More)
A vertical cavity surface-emitting laser was studied for gas-sensing applications. Properties of the 962-nm laser that were measured include side-mode suppression, wavelength tuning with temperature and current, power versus injection current, and the amplitude noise spectrum. With wavelength modulation spectroscopy, a rms noise level of 2 x 10(-4)(More)
Water vapor is measured by use of a near-infrared diode laser and wavelength-modulation absorption spectroscopy. Humidity levels as low as 5 nmol/mol [1 nmol/mol = 1 ppb (1 ppb equals 1 part in 10(9))] of water vapor in air are measured with a sensitivity of better than 0.2 nmol/mol (3varsigma). The sensitivity, linearity, and stability of the technique are(More)
We demonstrate an all-optical magnetometer capable of measuring the magnitude and direction of a magnetic field using nonlinear magneto-optical rotation in cesium vapor. Vector capability is added by effective modulation of the field along orthogonal axes and subsequent demodulation of the magnetic-resonance frequency. This modulation is provided by the ac(More)
An improved Raman gain spectrometer for flame measurements of gas temperature and species concentrations is described. This instrument uses a multiple-pass optical cell to enhance the incident light intensity in the measurement volume. The Raman signal is 83 times larger than from a single pass, and the Raman signal-to-noise ratio (SNR) in room-temperature(More)
We describe research leading to a trace gas detection system based on optical absorption using near-IR diode lasers that is intended to provide early warning of incipient fires. Applications include “high loss” structures such as office buildings, hospitals, hotels and shopping malls as well as airplanes and manned spacecraft where convention smoke(More)
B. Patton, O. O. Versolato, D. C. Hovde, E. Corsini, J. M. Higbie, and D. Budker Department of Physics, University of California, Berkeley, California 94720-7300, USA Kernfysisch Versneller Instituut, University of Groningen, NL-9747 AA Groningen, The Netherlands Southwest Sciences, Inc., Cincinnati, Ohio 45244, USA Department of Physics and Astronomy,(More)
Pure rotational spectra of the X211 vibronic ground states of H3’Cl’ and H3’Cl+ molecular ions have been measured by far-infrared laser magnetic resonance (LMR). The spectrometer, which contains an intracavity transverse dc discharge, is described in some detail. The theoretical formalism used to analyze the LMR spectra of HF+, HCl+, and HBr+ is presented.(More)
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