Ten Point Six Micron Optical Heterodyne Communication System. Phase 3 Progress Report, 1 Aug. - 31 Oct. 1967
Improved carbon dioxide lasers and electronic components for 10.6 micron optical heterodyne communication system
Mocker, H. W.↗
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A 10.6-mu optical heterodyne communication system.
Optical heterodyne communication system with single mode and frequency carbon dioxide laser, noting coherent photon noise limit
Mocker, H. W.↗
Traveling-wave photodetector has sub-nanosecond response
Mercury-doped germanium photodetector uses waveguide which increases the absorption of microwave energy within the photodetectors. Waveguide and photodetector are placed in liquid helium Dewar and cooled. A carbon dioxide laser is light source and klystron provides microwave energy. Measured response times are approximately 1 nanosecond.
Sun, C.↗
Vibrational relaxation studies of the 10/0/0 and 02/0/0 states of shock-heated CO2
Vibrational relaxation measurements of specific carbon dioxide vibrational-rotational states from tunable carbon dioxide laser beam absorption
Bershader, D.↗
Microwave biasing improves detector response in the infrared region
Detection system, which incorporates advantages of microwave biasing, measures output of a carbon dioxide laser at 10.6 microns with a factor of 1,000 improvement in sensitivity. Material lifetime, rather than external circuitry, limits detector response time.
Sun, C.↗
Experimental analysis of mercury cadmium telluride photovoltaic IR mixers for spacecraft receivers
Performance of mercury cadmium telluride photovoltaic infrared mixer for ATS 6 carbon dioxide laser communication system
Mc Elroy, J. H.↗
Experimental investigations of optical propagation in atmospheric turbulence
Analysis of helium-neon and carbon dioxide laser beam propagation in atmospheric turbulence
Fitzmaurice, M. W.↗
N-type mercury-cadmium-telluride photoconductors in optical heterodyne communication systems.
Discussion of the performance of a photoconductive (Hg,Cd)Te detector/mixer in a carbon dioxide laser heterodyne communication system. The utility of computer simulation of the performance of an optical heterodyne detector/mixer is demonstrated. Certain unusual properties of this device are pointed out that, while having a substantial impact on device performance, have received little previous attention.
Cohen, S. C.↗
Manufacturing unique glasses in space
An air suspension melting technique is described for making glasses from substances which to date have been observed only in the crystalline condition. A laminar flow vertical wind tunnel was constructed for suspending oxide melts that were melted using the energy from a carbon dioxide laser beam. By this method it is possible to melt many high-melting-point materials without interaction between the melt and crucible material. In addition, space melting permits cooling to suppress crystal growth. If a sufficient amount of under cooling is accompanied by a sufficient increase in viscosity, crystallization will be avoided entirely and glass will result.
Happe, R. P.↗
Experiment definition phase shuttle laboratory, LDRL-10.6 experiment. Shuttle sortie to ground receiver terminal
System development and technology are described for a carbon dioxide laser data transmitter capable of transmitting 400 Mbps over a shuttle to ground station link.
Goodwin, F. E.↗
Experiment definition phase shuttle laboratory (LDRL-10.6 experiment): Shuttle sortie to elliptical orbit satellite
The following topics were reviewed: (1) design options for shuttle terminal, (2) elliptical orbit satellite design options, (3) shuttle terminal details, (4) technology status and development requirements, (5) transmitter technology, and (6) carbon dioxide laser life studies.
Goodwin, F. E.↗
Ozone monitoring with an infrared heterodyne radiometer
Measurements of the total burden and of the concentration-versus-altitude profiles of ozone have been made with a ground-based heterodyne radiometer at Pasadena, California. The measurements were made in the 9.5-micron wavelength region, where a strong ozone infrared absorption band exists. The radiometer measured solar absorption at selected wavelengths with a spectral resolution of 0.001 reciprocal centimeter, equivalent to the half-width of an ozone absorption line at the 10-millibar altitude level. A carbon dioxide laser served as the local oscillator. This technique can be used to gather important data on both tropospheric and stratospheric ozone, which are not readily accessible with other remote-sensing techniques.
Menzies, R. T.↗
Doppler lidar atmospheric wind measurements
A brief overview is provided of the coherent Doppler lidar work at the Marshall Space Flight Center, taking into account the status and planned development of the system to be used for severe storms research. The considered system is a CW Doppler lidar operating at a wavelength of 10.6 micrometers. This lidar uses a 20 watt carbon dioxide laser. It has a range which is continuously variable from 60 m to approximately 600 m. Range variation is achieved through changing the focus of a 30 cm f/2 Cassegrainian telescope. Successful measurements with the CW lidar have included two and three dimensional wind profiles, wing tip vortex tracks and profiles, dust devil tracks and profiles, and transverse as well as line-of-sight wind velocities. The pulsed lidar in recent ground tests has succeeded in measuring clear air returns to a range of 13 km and has provided substantial information on velocities associated with the gust fronts of thunderstorms.
Bilbro, J. W.↗
Direct thermal water splitting by concentrated solar radiation for hydrogen production. Phase O: Proof of concept experiment
The direct production of hydrogen from water and solar energy concentrated into a high temperature aperture is described. A solar powered reactor able to dissociate water vapor and to separate the reaction product at high temperature was developed, and direct water splitting has been achieved in a laboratory reactor. Water vapor and radiative heating from a carbon dioxide laser are fed into the reactor, and water vapor enriched in hydrogen and water vapor enriched in oxygen are produced. The enriched water vapors are separated through a separation membrane, a small disc of zirconium dioxide heated to a range of 1800 k to 2800 k. To avoid water vapor condensation within the reactor, the total pressure within the reactor was limited to 0.15 torr. A few modifications would enable the reactor to be operated at an increased pressure of a few torrs. More substantial modifications would allow for a reaction pressure of 0.1 atmosphere.
Genequand, P.↗
Airborne remote sensing measurements with a pulsed CO2 DIAL system
The present investigation is concerned with an optical radar instrument which has been developed for airborne remote sensing of atmospheric trace species at infrared wavelengths. The instrument makes use of compact, pulsed carbon dioxide lasers. It was designed for conducting differential absorption lidar (DIAL) measurements. The backscatter of laser pulse energy from the ocean and terrain surface is utilized to determine trace species column content. The instrument, which is carried by the NASA P3 aircraft, is used in a flight test program started in July 1981. The results obtained with the instrument in this program are discussed, taking into account ocean surface backscatter statistics, the ratio of ocean to terrain backscatter, the dual-wavelength correlation coefficient, the dual-wavelength cross-covariance, and the dependence of un-correlated noise variance on the mean backscatter signal.
Bufton, J. L.↗
The laboratory simulation of unmagnetized supernova remnants Absence of a blast wave
Supernova remnants are experimentally simulated by irradiating spherical targets with eight-beam carbon dioxide laser in a chamber containing finite amounts of neutral gas, the gas being ionized by radiation from the hot target. The expansion velocities of the target plasmas are approximately the same as the expansion velocities of supernova ejecta and the experiment is successfully scaled to the case of a supernova remnant in an unmagnetized, low-density, interstellar medium. No sweep-up of the ambient plasma is detected, indicating that no hydrodynamic shock wave is formed to couple the target ejecta to the ambient gas. The experiment implies that if supernova ejecta couple to the interstellar medium, magnetic-field effects may be crucial to the physical description.
Borovsky, J. E.↗
Growth and evaluation of AgGaS2 and AgGaSe2 for infrared nonlinear applications
Significant advances were made in the growth technology of silver thiogallate (AgGaS2) and silver selenogallate (AgGaSe2). High efficiency harmonic generation of carbon dioxide laser radiation and tunable infrared parametric oscillation were demonstrated using these materials. Nonliner frequency conversion in the infrared was limited by the optical properties and the size of the available nonlinear materials. The development of these materials has reduced some of the limitations and generated wide interest. The continued development and application of AgGaS2 and AgGaSe2 now appears assured.
Byer, R. L.↗
Infrared diagnosis using liquid crystal detectors
The possible uses of pulsed carbon dioxide lasers for analysis of plasmas and flows need appropriate infrared image converters. Emphasis was placed on liquid crystal detectors and their operational modes. Performance characterstics and selection criteria, such as high sensitivity, short reaction time, and high spatial resolution are discussed.
Hugenschmidt, M.↗