Adam D. Devir

Line Width Determination in the 9.4-μ and 10.4-μ, Bands of CO 2 Using a CO 2 Laser

A CO(2) laser was used to measure the ratio of line strength to line width for a great number of rotational lines in the 9.4-micro and 10.4-,micro bands of CO(2) The laser used for this purpose incorporated a grating, which allowed the tuning of the laser to about 100 different rotation lines. By assuming a given value of the line strength of the line P(20) in each of the two bands studied, the line width was calculated up to a rotational quantum number J = 40. These results are compared with other values recently reported in the literature.

Infrared emission from selected areas in ion-beam-irradiated diamond.

The infrared emission properties of an electrically heated single resistive element produced by ion implantation of diamond is reported. It is found that good contrast can be obtained between the implanted and unimplanted regions of the diamond mainly because of the increased emissivity following implantation. The infrared output is stronger if the diamond is viewed with the implanted surface facing away from the detector. The possible utilization of diamond-based pixels in infrared scene generation is discussed.

Contribution Of Oxygen To Attenuation In The Solar Blind UV Spectral Region

The Solar Blind Ultraviolet (SBUV) spectral region covers the interval between 230 nm and 290 nm. The lower limit of this interval is given by the edge of the Schumann-Runge band and the upper limit is determined by solar radiation penetrating the stratospheric ozone shield. The SBUV region is interesting from the experimental point of view, since the lack of solar background is favorable in such applications as lidar, atmospheric communication and remote sensing. The present models (LOWTRAN-6) include as atmospheric attenuators in this region ozone absorption, aerosol and molecular scattering. New theoretical calculations of the Herzberg I oxygen band predict significant absorption by 02. This prediction is confirmed experimentally in the present study. Field measurements at 252, 255 and 264 nm are reported over optical paths of up to 2750 m. Results show that LOWTRAN-6 is inadequate in the SBUV region, as indicated by the present extinction measurements.

Atmospheric aerosols investigated by inversion of experimental transmittance data.

The Twomey-Chahine inversion algorithm is applied to experimental atmospheric transmittance data in the 0.4-2.4-microm wavelength range and atmospheric aerosol size distributions deduced. The conditions for successful inversion of transmittance data are investigated in numerical experiments, and it is shown that too small a wavelength range results in a Junge-type distribution in all cases and that noise in the measurements in excess of 4-5% results in inversion artifacts.

Absolute reflectometer for the mid infrared region

An absolute reflectometer for the 0.8-5.5-mum wavelength region is described. It is based on integrating spheres and uses the third Taylor method in the 7 degrees /d configuration. An improved theory for the reduction of the data is presented, and results for several diffuse gold samples are given.

Water vapor continuum in the 15- to 25-micron spectral region: evidence for (H20)2 in the atmosphere

Recent investigations of the atmospheric transmittance in the 15- to 25-μm spectral region have produced experimental results of the absorption of the water vapor continuum. From these results it is evident that the excessive absorption of the water vapor (the water continuum) cannot be explained simply by the theoretical continuum model based on the modified impact theory and the Van Vleck-Huber model of line broadening. The measured continuum absorption has spectral features similar to those roughly predicted by the water dimer theory. A quantitative agreement between the experimental results and the prediction according to the dimer theory was found.

Contribution of oxygen to attenuation in the solar blind UV spectral region

The solar blind ultraviolet (SBUV) spectral region covers the interval between 230 and 290 nm. The lower limit of this interval is given by the edge of the Schumann-Runge band and the upper limit is determined by solar radiation penetrating the stratospheric ozone shield. The SBUV region is interesting from the experimental point of view, since the lack of solar background is favorable in such applications as lidar, atmospheric communications, and remote sensing. The present models (LOWTRAN-6) include as atmospheric attenuators in this region ozone absorption and aerosol and molecular scattering. New theoretical calculations of the Herzberg I oxygen band predict significant absorption by O(2). This prediction is confirmed experimentally in this study. Field measurements at 252, 255, and 264 nm are reported over optical paths of up to 2750 m. Results show that LOWTRAN-6 is inadequate in the SBUV region, as indicated by the present extinction measurements.

Spectral characteristics of infrared transmittance of the atmosphere in the region 2.8–14 μm—preliminary measurements

Abstract We have made preliminary measurements of the atmospheric transmittance spectrum along horizontal paths up to 44 km in length. The equipment, a collimated radiation source and a moderate-resolution measurement system, is described in some detail, and also the method of processing the results. Some examples of measured spectra are shown and compared with the prediction of the lowtran 4 program. In particular, quantitative discrepancies are indicated in the 2.8–5.5 μm region. Smaller differences were detected in the 8–14 μm region at long distances for which the lowtran program appears to predict consistently small values for the transmittance.

Infrared Spectral Radiance Of The Sky

A method of calculating the self-radiance of the sky based on the LOWTRAN-4 computer code is described. The method is a significant improvement on that included as an option in LOWTRAN-4 itself as a result of two modifications: a) Our method, unlike the one included in LOWTRAN-4, takes into account the radiance scattered into the line of sight. b) The model of the atmosphere in the computer code must be divided into a certain number of layers, each one having approximately uniform conditions. Our method uses a correct optimal division. Consequently, our method gives a better agreement with the experimental data, especially for long optical paths in the lower layers of the atmosphere.

Absolute measurements of diffuse reflectance in the α°/d configuration

An improved theory for data reduction of absolute reflectance measurements using the third Taylor method in the alpha degrees / d configuration is presented. A brief description is given of an absolute reflectometer operating in the 0.8-2.5-microm region. The reflectometer is operated according to the improved theory. Experimental data for some widely used samples are given, as well as data showing agreement between the current measurements and those made by the U.S. National Institute of Standards and Technology.