Rotational collisional narrowing in the NO fundamental Q branch, studied with CW stimulated Raman spectroscopy
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Lempert, W.↗
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Characteristics of Monolithically Integrated InGaAs Active Pixel Imager Array
Switching and amplifying characteristics of a newly developed monolithic InGaAs Active Pixel Imager Array are presented. The sensor array is fabricated from InGaAs material epitaxially deposited on an InP substrate. It consists of an InGaAs photodiode connected to InP depletion-mode junction field effect transistors (JFETs) for low leakage, low power, and fast control of circuit signal amplifying, buffering, selection, and reset. This monolithically integrated active pixel sensor configuration eliminates the need for hybridization with silicon multiplexer. In addition, the configuration allows the sensor to be front illuminated, making it sensitive to visible as well as near infrared signal radiation. Adapting the existing 1.55 micrometer fiber optical communication technology, this integration will be an ideal system of optoelectronic integration for dual band (Visible/IR) applications near room temperature, for use in atmospheric gas sensing in space, and for target identification on earth. In this paper, two different types of small 4 x 1 test arrays will be described. The effectiveness of switching and amplifying circuits will be discussed in terms of circuit effectiveness (leakage, operating frequency, and temperature) in preparation for the second phase demonstration of integrated, two-dimensional monolithic InGaAs active pixel sensor arrays for applications in transportable shipboard surveillance, night vision, and emission spectroscopy.
Kim, Q.↗
Characterization of Organic Materials in the Xenolithic Clasts in Sharps (H3.4) Meteorite Using Micro-Raman Spectroscopy
Graphitization of carbon is an irreversible process which alters the structure of graphitic materials in response to the increase in metamorphic grade (temperature and/or pressure). Carbonaceous materials offer a reliable geothermometer as their Raman spectra change systematically with increasing metamorphic grade. In this study, we identified carbonaceous materials in the xenolithic clasts in Sharps and interpreted their metamorphic history by revealing the structural organization (order) of the polyaromatic organic phases using micro-Raman spectroscopy.
Chan, Q. H. S.↗
Characterization of Organic Materials in the Xenolithic Clasts in Sharps (H3.4) Meteorite Using Microraman Spectroscopy
Graphitization of carbon is an irreversible process which alters the structure of graphitic materials in response to the increase in metamorphic grade (temperature and/or pressure). Carbonaceous materials offer a reliable geothermometer as their Raman spectra change systematically with increasing metamorphic grade [1-3]. In this study, we identified carbonaceous materials in the xenolithic clasts in Sharps and interpreted their metamorphic history by revealing the structural organization (order) of the polyaromatic organic phases using μ-Raman spectroscopy.
Chan, Q. H. S.↗
Infrared Emission Spectroscopy as a Reliability Tool
In this paper we report on a technique based on infrared emission spectroscopy which has been found to be useful for non-contact measurement of the temperature of a hot spot in the gate channel of a GaAs metal/semiconductor field effect transistor (MESFET).
infrared↗
A new ion and electron detector for ion cyclotron resonance spectroscopy.
A new detector using an extremelly driven tuned circuit has been developed for use in ion cyclotron resonance spectroscopy experiments. Based on the Q-meter circuit, this detector will operate at frequencies greater than 1 MHz at rf levels less than 1 mV. Operation in the frequency range 1-15 MHz allows the use of higher magnetic fields for more efficient storage of low mass ions in the trapping mode of operation. In the frequency range 2-6 MHz electrons can be detected in the ion cyclotron resonance cell by their resonant motion in the trapping plane.
Huntress, W. T., Jr.↗
Excitation Spectroscopy as a Tool of Microelectronics Reliability
The main objective of this task was to experimentally determine the feasibility of using a non-contact IR emission spectroscopy technique to measure the hot spot channel temperature of sub-micron GaAs metal semiconductor field effect transistor gate during operation.
Excitation Spectroscopy Microspot Temperature Asse↗
Collisional broadening, line shifting, and line mixing in the stimulated Raman 2nu2 Q branch of CH4
Self-, argon-, and helium-broadening coefficients have been measured for 13 lines in the 2nu2 Raman Q branch of CH4 using stimulated inverse Raman spectroscopy. The linewidths clearly show the symmetry-state dependence characteristic of pressure broadening, and inelastic processes in general, involving spherical-top molecules. Pressure-induced line shifts have also been measured for these features in pure methane. The pressure-shift coefficients do not display the symmetry-state dependence found for the linewidths. By applying the Rosenkranz perturbation treatment to a pair of collisionally mixed lines, an estimate of individual state-to-state contributions to the overall linewidth has been obtained.
Millot, G.↗
High resolution absorption coefficients for Freon-12
The ultra high resolution absorption coefficients of the Q-branch of Freon-12 obtained with tunable diode laser spectroscopy are presented. Continuous spectra are presented from 1155/cm to 1163/cm, and absolute wavelength calibration was obtained using SO2 spectra as a standard and a 5 cm Ge etalon for relative calibration between SO2 lines. The Freon-12 data obtained at a pressure of 0.05 torr showed a rich and highly structured spectra, but with the exception of three isolated features, collisional broadening reduces the spectra to a structureless continuum for nitrogen pressures greater than 20 torr. The spectra at 1161/cm continue to exhibit structure at atmospheric pressure.
Hoell, J. M.↗
Pressure broadening of vibrational Raman lines in N2 at temperatures below 300 K
Using quasi-cw stimulated Raman gain spectroscopy, the pressure broadening coefficients for the N2 vibrational Q-branch transitions have been measured over the temperature range 113-297 K for the rotational components J = 4, 6, 8, 10, and 12. The experimental results are fit to a simple power law to give an empirical formula for the temperature dependence of the pressure broadening over the 100-300 K range. These results are also compared to previously published scaling laws that are based on collision induced rotational transition rates.
Herring, G. C.↗
Line mixing effects in solar occultation spectra of the lower stratosphere - Measurements and comparisons with calculations for the 1932/cm CO2 Q branch
Line mixing effects have been observed in a CO2 Q branch recorded in 0.01/cm-resolution IR solar occultation spectra of the lower stratosphere. The spectral data were obtained by the Atmospheric Trace Molecule Spectroscopy Fourier transform spectrometer during the Spacelab 3 mission in the spring of 1985. Analysis of the 1932.47/cm Q branch of (C-12)(O-16)2 shows absorption coefficients below the band origin about 0.62 times those calculated using a standard Voigt line-shape function. Calculations of line mixing using the Lorentz halfwidths of the lines and a simple energy-gap scaling law to parameterize rotational energy transfer reproduce the observed absorption coefficients to about 10 percent. The present results provide the first quantitative information on air-broadened line mixing effects in a Q branch at low temperatures (about 210 K) and show that these effects are significant even at the low pressures of the lower stratosphere (about 100 mbar).
Rinsland, Curtis P.↗
High-resolution continuous-wave coherent anti-Stokes Raman spectroscopy in a supersonic jet
High-resolution CW coherent anti-Stokes Raman spectra of the nu1 Q branch of methane in an underexpanded supersonic jet were obtained at temperatures as low as 31.5 K and pressures as low as 2 torr. The experimental spectra were well fitted by the calculated theoretical spectra, including transit-time broadening. A temperature of 31.5 K produced the best fit to the data, and the transit-time broadening was comparable to the residual Doppler broadening of about 100 MHz. The supersonic jet provides a convenient method of obtaining molecular cooling at relatively high density, and the ease of construction and the wide range of temperatures and densities available make it a useful tool for high resolution molecular spectroscopy.
Gustafson, E. K.↗
Evidence for the presence of the 802.7/cm band Q branch of HO2NO2 in high resolution solar absorption spectra of the stratosphere
Stratospheric solar absorption spectra recorded at about 0.01/cm resolution by the ATMOS (Atmospheric Trace Molecule Spectroscopy) Fourier transform spectrometer during the Spacelab 3 Shuttle mission (4/30-5/6/85) show a weak absorption feature covering about 802.5-803.3/cm. This feature is identified as the unresolved Q branch of the 802.7/cm band of HO2NO2 and profiles for 31 deg N and 47 deg S are reported.
Rinsland, C. P.↗
Identification of the HNO3 3 nu(sub 9) - nu(sub 9) band Q branch in stratospheric solar occultation spectra
The spectroscopic identification for the HNO3 3 nu(sub 9) - nu(sub 9) band Q branch at 830.4/cm is reported based on 0.01/cm resolution solar occultation spectra of the lower stratosphere recorded by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer and a recent analysis of this band. Least-squares fits to 0.0025/cm resolution laboratory spectra in the Q branch region indicate an integrated intensity of 0.529 x 10(exp -18)/cm/mol/sq cm at 296 K for this weak band. Stratospheric HNO3 retrievals derived from the ATMOS data are consistent with this value within its estimated uncertainty of about +/- 30%. A set of spectroscopic line parameters suitable for atmospheric studies has been generated.
Perrin, A.↗
A simplified CARS measurement system for rapid determination of temperature and oxygen concentration
A new spectroscopic concept for the rapid determination of temperature and oxygen concentration by CARS (Coherent Anti-Stokes Raman Spectroscopy) was described. The ratio of two spectral regions in the broadband Q-branch spectrum was detected by photomultipliers in a monochromator, which ratio depends on temperature and species concentration. The comparison of the measured data with theory was made using a flat flame burner and an electric furnace, with reasonable results. Various optical techniques for alignment were introduced including a highly efficient, stable dye oscillator. The combination of the spectroscopic concept and the optical techniques will make the CARS measurement system rapid in data processing and simple in optical parts.
Fujii, Shoichi↗
Simultaneous measurements of temperature and density in air flows using UV laser spectroscopy
The simultaneous measurement of temperature and density using laser-induced fluorescence of oxygen in combination with Q-branch Raman scattering of nitrogen and oxygen is demonstrated in a low-speed air flow. The lowest density and temperature measured in the experiment correspond to the freestream values at Mach 5 in the Ames 3.5-Foot Hypersonic Wind Tunnel for stagnation conditions of 100 atm and 1000 K. The experimental results demonstrate the viability of the optical technique for measurements that support the study of compressible turbulence and the validation of numerical codes in supersonic and hypersonic wind tunnel flows.
Fletcher, D. G.↗
Observation of several chlorine nitrate (ClONO2) bands in stratospheric infrared spectra
Four of the most prominent and sharpest infrared absorption features of chlorine nitrate at 780.2, 807.7, 809.4, and 1292.6/cm have been observed in a series of infrared solar spectra obtained at an unapodized spectral resolution of 0.01/cm, using the Atmospheric Trace Molecule Spectroscopy instrument from on-board Sapcelab 3. A quantitative analysis of the nu4 Q branch at 780.2/cm has provided insight into the concentration of ClONO2 between 19 and 40 km altitude. While the mean profile deduced from three sunset occultations near 30 deg N latitude exhibits a shape close to that predicted by model calculations, its concentrations in the 20 to 32 km altitude range are, however, about 30 percent larger, reaching a peak concentration of 9 x 10 to the 8th molecules/cu cm at 25 km. The concentrations above 32 km, deduced from one sunrise occultation at 47 deg JS, are even larger than the corresponding sunset values at 30 deg N latitude. Some of these discrepancies may be caused by the rather large uncertainty in the assumed Q branch strength.
Zander, R.↗