Investigation of atmospheric $$ {\text{O}}_{2}{\text{X}}{^{ 3}}{ \sum_{\text{g}}^{ - }} \,{\text{to}}\, {\text{b}}{^{ 1}}{ \sum_{\text{g}}^{ + }} $$ using open-path tunable diode laser absorption spectroscopy

Rice, Christopher A.; Gross, Kevin C.; Perram, Glen P.

doi:10.1007/s00340-012-5243-y

Cited by 3 publications

(11 citation statements)

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“…Details on the raw data collected, data from shorter open-paths, and how data is post processed have been published where each diode laser has approximately 0.2 nm of mode-hop-free scan range that must be collected individually and then stitched together in post processing to make a complete spectra. 4–6 The laser scan rate is 0.0017 nm/s and signal is sampled at 512 Hz making collection times for the full range of a given diode laser approximately 2 h. The received signal, I t , has a response so that the observed spectral absorbance,includes a frequency dependent cubic baseline, b , in addition to the absorption cross-section, normalσi(trueν∼) for each atmospheric constituent, i , with concentration, N i . During bi-static collections low pressure (no buffer gas) alkali vapor cells inside a heater block set at 30 °C, 60 °C, and 75 °C for Cs, Rb, and K, respectively, were placed between the receive telescope and the detector to provide a co-witnessed reference of the alkali DPAL pump and emission wavelengths.…”

Section: Resultsmentioning

confidence: 99%

“…A detailed description of the device configuration, photos, and method for collecting spectra has been previously discussed. [4][5][6] The tunable diode source laser can now be changed depending on the desired wavelength range with minimal system configuration changes. The laser sources used were New Focus Velocity laser models 6312, 6314, and 6318 with output powers near 10 mW, 300 kHz line widths, and tunable ranges of 759-771 nm, 790-803 nm, and 889-910 nm ranges for K, Rb, and Cs, respectively.…”

Section: Tunable Diode Laser Absorption Spectroscopy Devicementioning

confidence: 99%

“…Calibration of the frequency axis, baseline removal, and further spectral processing has also been reported. 4,5 The broad absorption spectra are highly sampled. A typical spectrum will cover a 10 nm span comprised of 100 free spectral ranges and include over 40 million samples acquired over 2 h. The 512 Hz sample rate gives up to one thousand samples per pressure broadened full width at half-maximum (FWHM) line shape.…”

Section: Introductionmentioning

confidence: 99%

“…Shorter collections of 100 m, 150 m, and 1 km open paths during fair weather conditions with varying site geometries have previously been collected. 4,6 The send and receive telescopes were separated by 1 m in bi-static configurations mounted on QuickSet tip/tilt controllers, each viewing a Newport 6 in. (15.24 cm) flat mirror with 1/20th of a wavelength of flatness placed 1 m above the ground and carefully aligned to reflect laser light to the receive telescope while the mono-static configuration directed the laser to the PLX retro-reflector array placed 1 m above the ground.…”

Section: Introductionmentioning

confidence: 99%

“…Tools for modeling these effects are available 3 but require validated atmospheric absorption data including line shapes and detailed knowledge of the state of the atmosphere. We have developed a deployable, tunable diode laser absorption spectrometer (TDLAS) for this application, [4][5][6] and now extend the performance to include diode pumped alkali lasers (DPAL), solid state lasers (SSL), and chemical oxygen iodine laser (COIL) systems. By comparing the performance of the emerging DPAL system with established performance of COIL and solid-state lasers, laser system trade studies are enabled.…”

Section: Introductionmentioning

confidence: 99%

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Open-Path Atmospheric Transmission of Diode-Pumped Alkali Lasers in Maritime and Desert Environments

et al. 2023

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A tunable diode laser absorption spectroscopy (TDLAS) device has been developed to study long path atmospheric transmission for laser weapons applications. By employing a single aperture and retro reflector in a mono-static configuration, the noise associated with atmospheric and platform jitter were reduced by a factor of ∼ 30 and the open-air path length was extended to 4.4 km. Water vapor absorption lines near the rubidium (Rb) and cesium (Cs) variants of the Diode Pumped Alkali Laser (DPAL) near 795 and 894 nm, oxygen lines near the potassium (K) DPAL near 770 nm, and water vapor absorption in the vicinity of the Nd:YAG 1.064 um and Chemical Oxygen Iodine Laser (COIL) 1.3 um lines were studied. The detection limit for path absorbance increases from ΔA = 0.0017 at 100 m path to 0.085 for the 4.4 km path. Comparison with meteorological instruments for maritime and desert environments yields agreement for the 2.032 km path to within 1.5% for temperature, 4.5% for pressure and 5.1% for concentration while agreements for the 4.4 km path are within 1.4% for temperature, 7.7% for pressure and 23.5% for concentration. An ICOS device was also used as a spectral reference to verify location of atmospheric lines. Implications of TDLAS collection system design on signal-to-noise are discussed as well as the effect of path turbulence on baseline noise.

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