SCIENCE & TECHNOLOGY NOTES a. OBSERVATIONS OF SKY-ILLUMINATION PHE- C. THE EFFECT OF NUCLEAR REACTOR RADIATION e. TRIS(TRIALKYLSILYL) ANTIMONITES p 29-30 g. ULTRABASIC ROCKS FROM THE BOTTOM OF THE N66-28924# Library of Congress. Washington, D. C. Aerospace Technology Div. LASER WITH A NONRESONANT FEEDBACK Charles Shishkevish In its Foreign Sci. Bull., Vol. 2, No. 5 May 1966 p 1-6 refs (See N66-28924 16-16) A laser with a nonresonant feedback is described. The active medium consists of two ruby rods, and one or both of the external mirrors of the laser are replaced by a volume or surface scatterer. The only resonant element in the system is the spectral line. The emission of the device is highly monochromatic but is not spatially coherent. It is shown that this system can be used as a frequency standard for the optical part of the spectrum. Author N66-29032# Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires. MULTIPHOTON PROCESSES BROUGHT ABOUT BY A LASER [PROCESSUS MULTIPHOTONIQUES PROVOQUES PAR UN LASER) Pierre Nelson Dec. 1965 24 p refs In FRENCH (CEA-R-2888) The critical intensity characterizing the multiphoton processes is calculated. The multiphoton effects corresponding to the Compton scattering. the bremsstrahlung, and the photoelectric effect are investigated. The cross sections are evaluated. It is shown how the introduction of a refractive index, in clothing the photons, allows the elimination of the infrared divergence. The theory seems consistent with ex~periment. Author (NSA) N66-29169# Boeing Scientific Research Labs., Seattle, Wash. Plasma Physics Lab. THE FORMATION OF A MAGNETIC PINCH IN InSb AND THE POSSIBILITY OF POPULATION INVERSION IN THE PINCH A sufficiently strong current supported by an electronhole plasma in InSb pinches. As the electron-hole gas is compressed by the current's magnetic field, the plasma temperature increases. The strong electron-phonon coupling, however, keeps the plasma temperature below the characteristic temperature of the optical phonons as long as the lattice remains cold. This early period of the pinch, which includes the initial contraction and some 0.0000001 sec thereafter, is discussed. The collapse of the pinch may be halted by an increase of the plasma pressure caused by the exclusion principle or by the occurrence of impact ionization in the pinch's radial Hall field. An estimate of the particle density in the pinch shows that the conditions for population inversion may be satisfied. hence laser action due to stimulated electron-hole recombination might occur. This effect should influence the development of the pinch decisively. Author (TAB) N66-29240# Radio Corp. of America, Princeton, N. J. Astro- CYCLOTRON RESONANCE PUMPING OF GAS LASERS (Rept.-2; AD-632100) CFSTI: HC $2.00/MF $0.50 Experiments employing combined microwave electroncyclotron resonance with dc pumping as well as experiments with dc pumping only were performed on argon lasers. Effort was directed towards clearly defining the effects of these pumping combinations on discharge behavior and laser operation. Results of these experiments show that in low-wall-loss magnetically confined dc discharges, the gas pressure is greatly reduced by ion-drift pumping towards the cathode, and laser action takes place at considerably lower pressure than had hither-to been supposed. Microwave cyclotron-resonance pumping was seen to have a significant effect in increasing laser output. This increase in output occurred at high initial gas pressures, and is dependent on the magnetic field being at the resonance value. The laser tested was 40 centimeters long and 8 millimeters in diameter. It was fitted into a tunable microwave cavity within a magnetic solenoid. Measurements were made with both pulse and continuous operation. A theory is developed for the description and understanding of laser behavior from a fundamental microscopic point of view. The model consists of N two-level systems interacting with a radiation field. The problems of collective motion, coherence, dissipation and inhomogeneous broadening are treated. This report consists mainly of the abstracts of six papers dealing with these subjects that have or will appear in scientific journals. Author (TAB) N66-29249# Boston Coll.. Chestnut Hill, Mass. AN INVESTIGATION OF PROPERTIES OF THE LASER MICROPROBE Final Report (Part I), 1 Jul. 1964-13 Aug. 1965 James J. Devlin and Anthony B. La Conti 13 Aug. 1965 89 p refs (Contract AF 19(604)-8819) (AFCRL-65-855(1): AD-632416) CFSTI: HC $3.00/MF $0.75 An investigation of the laser microprobe as a source for emission spectrochemical analysis is reported. The size and character of the crater: burnt into a number of pure element metals was investigated. Working curves for a series of iron and aluminum alloys were produced. This gave a measure of the sensitivity and reproducibility of the laser microprobe. Author (TAB) N66-29428*# National Aeronautics and Space Administration, Washington, D. C. OPTICAL LOCATION OF THE MOON (OB OPTICHESKOY LOKATSII LUNY] A. Z. Grasyuk, V. S. Zuyev, Yu. L. Kokurin, P. G. Kryukov, and V. V. Kurbasov et al May 1964 6 p refs Transl. into ENGLISH from Dokl. Akad. Nauk SSSR (Moscow), v. 154, no. 6. 1964 p 1303-1305 Presented at the Joint Colloq. of the Oscillations Lab. of Quantum Radiophysics, USSR, 28 Sep. 1963 (NASA-TT-F-8866) CFSTI: HC $1.00/MF $0.50 CSCL 20E The preliminary results of locating the moon with the aid of a ruby laser are presented. A schematic representation of the apparatus used is included. A single telescope was used for both transmitting and receiving the light pulses. A preliminary estimate of signal-to-noise ratio was made. The results of measurements made on September 13, 1963 are included. The chosen target was the crater Albategnius on the dark part of the moon. The value of the signal received was four times greater than the root mean square error in measuring the background, and therefore cannot be ascribed to background fluctuations; the measurements permitted reliable registration of signals reflected from the moon. R.T.K. N66-29552# Joint Publications Research Service, Washington, D. C. PROSPECTS FOR LASER AND OPTICAL COMMUNICATIONS R. Svoren 21 Jun. 1966 25 p Transl. into ENGLISH from Nauka i Zhizn' (Moscow), no. 4, Apr. 1966 p 59-65 (JPRS-36111; TT-66-32545) CFSTI: $1.00 Technological developments and future prospects of lasers and their applications, particularly as radio receivers and transmitters, in optical communications are discussed in a very general way. Among the advantageous characteristics cited for lasers are: (1) The spatial coherence of the laser beam facilitates electromagnetic radiation in only one direction and this property permits a large number of lasers to operate on the same frequency. (2) Lasers generate waves in the optical range of frequencies (infrared, light and ultraviolet), and operate on an unlimited frequency band. (3) The sharp laser beam can be achieved with relatively small emitters, and the ability to emit sinusoidal electromagnetic waves makes it possible to load the laser beam with information, as in radio transmission. Thus, although utilized to a limited extent now. a single, multi-channel laser beam could carry all television and radio programs, radar signals, remote control, and telemetering. The greatest danger in optical communications is that transmission can vary greatly since the propagation range of a light beam is sharply reduced under unfavorable meteorological conditions; this is considered to be the chief obstacle to constructing an earthbound communications link. R.LI. N66-29797# Air Force Systems Command, Wright-Patterson AFB. Ohio. Foreign Technology Div. SOVIET LASERS 23 Mar. 1966 10 p Transl. into ENGLISH from Wojskowy Przeglad Lotniczy (Warsaw), no. 4, 1965 p 86-87 (FTD-TT-65-1953/1+4; AD-631583) CFSTI: HC $1.10/MF $0.50 The following Soviet lasers, presumably on exhibit at the Leipzig fair, are mentioned. A laser with 100-mv power attainable with one hundred millioneth part of a second: for detection of cosmic ships in space and for heating plasma. Laser GOR-100, with an unignited light ray that burns holes in steel plates. Razdan laser, operating continuously at 2 light pulses/sec. Laser OK-1, a ruby laser whose thousandth part of a second ray welds the unstuck retina of the eye. SU-1 device that microwelds the parts of precision apparatus that melt with difficulty. The Lucz-3 miniature semiconductive device that transforms solar light into electricity which in turn is transformed into amplifier laser light. The computer device at Manhasset in New York State computes from meteorological data the best routes for travel between Europe and America. TAB N66-29847# Naval Air Engineering Center. Philadelphia, Pa. Aeronautical Materials Lab. UTILIZATION OF MASER AS A MEANS OF EXCITATION FOR THE SPECTROGRAPHIC EXAMINATION OF MICROSTRUCTURES OF METALS Final Report M. D. Smith and J. F. Danovich 31 Dec. 1965 17 prefs (AD-632240) CFSTI: HC $1.00/MF $0.50 Investigation of laser as a source of excitation for emission spectroscopy and techniques developed for its use in this capacity are reported. Results of qualitative detection of segregates and inclusions in metallic alloys and the limits of detection of various elements in aluminum standards by the techniques developed are presented in addition to investigations of this means of excitation for the analysis of ceramics and refractories. It is concluded that the results of investigation show the feasibility of the use of the laser microprobe as a means of excitation for emission spectrography. The techniques developed in the analysis of coatings and modifications of the objective lens have increased the versatility and scope of application. Although the laser microprobe offers many advantages the arc-spark spectrographic source. it nevertheless possesses certain limitations which require that it be considered as a complementary accessory to extend the applications of emission spectroscopy. Author (TAB) over N66-29864# Illinois Univ., Urbana. Electro-Physics Lab. GAS LASER STUDIES IN THE 100 to 1000 MICRON RANGE Final Report Paul D. Coleman 31 Dec. 1965 11 p refs (Grant AF-AFOSR-804-65) (AFOSR-66-0719; AD-632306) CFSTI: HC $1.00/MF $0.50 The report summarizes the first year's activities of research on gas lasers in the 100 to 1000 micron range. A general description and experimental results of a water vapor laser covering the 48 to 118 micron range is described. Research problems to be explored during the second year of the grant are discussed along with a brief comparison with classical electronic methods of generation. Author (TAB) N66-29965# Naval Ordnance Lab., White Oak, Md. Thomas W. Hill and Leonard Rudlin 1 Mar. 1966 31 p refs A Q-switched ruby laser, which cannot explode air directly, has been used to explode various pseudo-air targets. These targets have been. generally, air with increased electron densities, such as a drop of liquid nitrogen or an air-plasma caused by a spark gap. Water drops, to which were added various salts, were also targets in evaluating the feasibility of salting targets. The results consisting of open-shutter photographs, time-integrated spectra, and some photodiode records with micro-second resolution suggest that: (1) twelve spectral lines are found common to nearly all the targets; identification suggests that these lines originate in the air surrounding the targets; (2) the structure of the spectrum resulting from laser interaction with a drop of liquid nitrogen has marked similarity to the structure of lightning spectra; further, most of the twelve lines common to nearly all spectra appear in lightning spectra; (3) the luminous phenomena occur over times like micro seconds from the laser pulses of duration like tens of nanoseconds; and (4) further experiments with nanosecondto-shake time resolution are needed to clarify the 'explosion' details. Author (TAB) N66-29972 # ITT Federal Labs., San Fernando, Calif. (NASA-CR-76078) CFSTI: HC $3.00/MF $0.50 CSCL 20F The degree of coherence for optical beams traversing a fluctuating medium is derived in terms of the correlation coefficient of the atmosphere. Under certain specific conditions, it is shown that the degree of coherence is determined solely by one atmospheric parameter, the mean square angular fluctuation of a ray. The degree of coherence of laser beams traversing artificially created fog atmospheres within the ITTFL optical tunnel has been measured by the two-pinhole interferometric technique. The results obtained are in good agreement with the theoretical predictions. Based on this work, the aperture limitation, imposed by the atmosphere, on an optical heterodyne receiver is predicted. Author N66-29977*# Stanford Research Inst., Menlo Park, Calif. FOR PERFORMANCE SPECIFICATIONS A METEOROLOGICAL SATELLITE LIDAR Final Report W. E. Evans. E. J. Wiegman, W. Viezee, and M. G. H. Ligda Jun. 1966 190 prefs (Contract NASr-49(22)) (NASA-CR-76087) CFSTI: HC $5.00/MF $1.25 CSCL 04 B Numerous suggestions have been made regarding measurements of meteorological significance which might be made with a laser radar (lidar) carried in a satellite. In this study a wide variety of possibilities is examined, and it is concluded that the most important thing that can be done with reasonable amounts of power is to provide routine height and density data on cirrus cloud. Cloud-top elevations of lower cloud would also be determined. Calculations, supported by experimental backscatter measurements made with a ground-based pulsed ruby lidar, show that it should be barely possible to measure low-density cirrus cloud at night from a 1000 to 1500 km satellite using a radiated energy of one joule per sounding and a receiving aperture of one square meter. Author 1. MAGNETO-OPTICAL OBSERVATIONS WITH A TENMILLIWATT HELIUM-NEON LASER J. L. Tomlinson p 1-3 refs (See N66-30158 17-16) 2. IMPROVED SYSTEM FOR OBSERVATION OF HIGHSPEED MAGNETIZATION REVERSAL G. H. Moore p 4-10 refs (See N66-30159 17-23) 3. INFRARED ABSORPTION OF Ce 3+ IN LaF 3 AND OF CEF 3 R. A. Buchanan, H. E. Rast, and H. H. Caspers p 1120 refs (See N66-30160 17-26) 4. SYNTHESIS STUDY OF A CONTINUOUS-SOURCE WAVEGUIDE ANTENNA A. P. Boblett p 21-38 (See N6630161 17-07) Hypervelocity impact tests were conducted to evaluate experimental micrometeoroid impact sensors. Photographs illustrate oscilloscope traces of quartz crystal transducer outputs obtained on impacting aluminum target plates with 3.11 mg cylindrical lexan slugs at velocities of 18,000 to 30,000 fps. Stress wave arrival times to the various target points were compared. The lexan projectiles impacted the targets at three different angles: normally to the surface. and at 30° and 60° to the surface normal. Preliminary data analysis indicate: (1) The maximum peak to peak output amplitude is a function of the mass and velocity of the impacted particle, as well as of the distance traveled by the stress wave. (2) Impact location can be calculated from the difference in arrival times of the stress wave. (3) The interfering attenuation factor can be eliminated by comparing amplitudes and arrival times of outputs. (4) Impacting the target surface at oblique angles results in overall decreased output amplitudes. (5) The sensitivity of the sensor-preamplifier combination seemed high enough to detect impacts of projectiles with mass of 10-8 g. A brief review is also given of the laser simulation work performed. L.E.W. Experimental results of a direct measurement of the frequency shift of the output of a single-mode traveling wave ruby laser are reported. A description is included of the preliminary experimental results obtained in a successful attempt at eliminating this frequency shift by introducing a compensating phase shift in the optical cavity with the help of a nitrobenzene Kerr cell. Results of a detailed theoretical study and some preliminary experimental results on the phase locking of modes in solid state lasers are given. These results show the existence of and the reasons for such phase-lockingeffect. Results are reported on an attempt at obtaining singlemode operation of the YAG: ND 3+ laser using the scheme suggested by Prokhorov, Burch, and Siegman. The results suggest that it is possible to achieve a single-mode operation with this scheme. Detailed results are given of a theoretical study on the shape of the resonant modes of the Fabry-Perot cavity of an oscillating solid state laser when the nonlinear spatial saturation effect is taken into account. Finally, a report is given of the results of a detailed study on the propagation of an intense light pulse through an optical medium. TAB M. K. Towne and B. H. Heise [1966] 20 p refs (Contract DA-36-039-AMC-06168(E)) (QPR-2; AD-629170) CFSTI: HC $1.60/MF $0.50 The document reports progress toward improving the ruby crystal growth process for the manufacture of Rangefinder laser rods. Engineering studies during the quarter were concentrated on the effects on individual variables. Definite relations between boule quality and standoff, boule diameters and gas ratios have emerged. Necessity for extended growth runs and repetition of many tests has caused the growth study to slip one and one-half months behind schedule but current use of shorter growth runs and introduction of an improved feeder six months ahead of schedule will compensate for this slippage. Improved control of the distance between burner and boule cap by an automatic photosensitive device has been extneded to both growth stations allocated for contract work. A continuous powder feed has been installed on one station and has operated satisfactorily. Evaluation of boules has been based primarily upon fringe pattern and passive beam divergence. Equipment for active laser testing is not yet available and is cause for a delay in shipment of Engineering Test Samples. Author (TAB) N66-30302# Texas Univ., Austin. RESEARCH ON PLASMA DIAGNOSTIC METHODS FOR HIGH TEMPERATURE PLASMA RESEARCH Ninth Quarterly Report, Apr.-30 Jun. 1965 Arwin A. Dougal, Robert F. Gribble, Marion O. Hagler. David J. Mayhall. Howard N. Roberts et al Wright-Patterson AFB. Ohio, ARL, Dec. 1965 78 p refs (Contract AF 33(615)-3224) (ARL-65-270; AD-631993) CFSTI: HC $3.00/MF $0.75 Investigations on the utilization of a He Ne 3.39 micron infrared maser for experimental time-space resolved diagnostics of highly transient, extreme temperature, deuterium plasmas are reported. The infrared maser coupled resonator technique for measurement of electron density was extended such that usful data were obtained for a theta-pinch plasma source operating at 50 Kg compression with 4 and 6 Kg reverse bias magnetic fields at 0.1 Torr initial pressure. Measurement of the magnetoplasma Faraday rotation of the plane of polarization of the He-Ne maser infrared radiation by the use of an infrared polarization analyzer was extended and uncertainties in the measurements were reduced. The determination of electron density provided further information for obtaining time-space resolved plasma magnetic fields from the Faraday rotation data. Resonant operation permits investigation of the low density plasma sheaths surrounding the dense core of the theta-pinch. An equation for the efficiency of a plane echelette diffraction grating is developed from the vector Kirchoff integral equation for the electric field by making an approximation for the electric and magnetic fields at the surface of the grating. TAB N66-30362*# National Aeronautics and Space Administration. Goddard Space Flight Center, Greenbelt, Md. MODULATOR A FOCUS SPOILING RETRODIRECTIVE Michael W. Fitzmaurice May 1966 92 p refs (NASA-TM-X-55539; X-524-66-246) CFSTI: HC $3.00/MF $0.75 CSCL 09F This paper analyzes a semi-passive optical modulator which can be incorporated into a satellite to ground laser communication link or a ground to ground laser link. The system has limited bandwidth capabilities but is useful as a first step in evaluating the utility of lasers in communication through the earth's atmosphere. Modulation is imposed on a reflected beam by varying the optical properties of the retrodirector by a piezoelectric induced displacement. An analysis of the piezoelectric transducer is carried out and equations developed which are used in a typical design procedure. Experimentally, the validity of a geometrical optics approach to the modulation capabilities of the retrodirector is verified. In addition, the need for high speed displacement measurement techniques is noted and two solutions are presented. The first, employing an accelerometer, offers extreme accuracy but relatively narrow frequency response. The second approach utilizes the fringe pattern in a Michelson interferometer and has reduced accuracy but virtually unlimited frequency response. Author A brief review is presented on the emission process, electromagnetic waves, and emission radiation of a gallium arsenide semiconductor laser. Sketches are included on the band model of a semiconductor, emission process, distribution of the electron concentration on the p-n junction, and recombination radiation along the p-n junction; a semiconductor laser model shows a laser crystal and contact. It is pointed out that laser operation is based on recombination radiation of p-n junctions and that he coherent oscillations are produced over an induced emission radiation. with the aid of a resonator. R.LI. N66-30525# American Optical Co., Southbridge, Mass. Research Div. PREPARATION OF PLATINUM-FREE LASER GLASS Semiannual Technical Report, 1 Jul.-31 Dec. 1965 Richard F. Woodcock, George A. Granitsas, and Carl G. Silverberg [1966] 18 p refs (Contract Nonr-4656(00); ARPA Order 306-62; Proj. Defender) (SATR-3: AD-632545) CFSTI: HC $1.00/MF $0.50 The goal of the investigation is the elimination of platinum particles in laser glass. For glasses melted in platinum crucibles, earlier work indicates that platinum-free glasses may be obtained if the glass is melted in an inert atmosphere. Various methods of homogenizing the glass in an atmosphere furnace. other than stirring, were investigated; including bubbling inert gas through the melt, convection currents and diffusion. A parallel approach to this problem, also being investigated, is the melting of high purity laser glass in an all-ceramic system. Such a system was constructed and tested. Problem areas were identified and design modifications were made where necessary. Optimization of the operational procedure of the furnace is now in progress. Author (TAB) N66-30672# Sylvania Electric Products, Inc., Mountain View, Calif. Electronic Defense Labs. Robert L. Iliff Jun. 1965 23 p refs Its Instrumentation Papers No. 70 (AFCRL-65-442; AD-619342) CFSTI: HC $2.00/MF $0.50 A 250-joule, liquid-nitrogen cooled, ruby laser has been used to illuminate a specially equipped satellite. Explorer 22. with sufficient intensity to photograph the cube corner reflectors located on the satellite. The laser system including the photoreceiver is described. A simple method of aligning the optic axis with a known azimuth is presented. Some laser experiments designed to lengthen the lifetime of the laser and to optimize the output energy are also given. Author (TAB) N66-31154# National Aeronautics and Space Administration. Jan. 1966 107 prefs (NASA-TM-X-55504; X-520-66-3) CFSTI: HC $4.00/MF $0.75 CSCL 09F CONTENTS: 1. DIGITAL FILTER DESIGN W. D. Stanley (Clemson Coll.) p 1-26 refs (See N66-31155 17-07) 2. DESIGN PROBLEMS IN A CONTROL SYSTEM USED FOR PRECISE OPTICAL TRACKING OF SATELLITES AND STARS R. V. Monopoli (Mass. Univ.) p 27-42 refs (See N6631156 17-07) 3. TRACKING ACCURACY ANALYSIS OF THE 85-FOOT PARABOLIC ANTENNA AT ROSMAN, NORTH CAROLINA C. Ghaznavi (Pratt Inst.) and T. Mercado-Jimenez (Puerto Rico Univ.) p 43-62 refs (See N66-31157 17-07) 4. NOTES ON THE SPIN-HAMILTONIAN H. A. Sabbagh (Rose Polytech. Inst.) p 63-76 refs (See N66-31158 17-26) 5. A PRELIMINARY STUDY OF HOLOGRAPHY L. G. McCracken, Jr. (Lehigh Univ.) p 77-88 refs (See N66-31159 17-23) 6. CORRELATION BETWEEN JITTER AND INFORMATION RECOVERY IN PCM TELEMETERED DATA P. Goodman (Newark Coll. of Eng.) p 89-93 (See N66-31160 1707) 7. DEVELOPMENT OF THE 10.6-MICRON LASER Z. D. Jastrzebski (Lafayette Coll.) p 95-96 (See N66-31161 17-16) חו conventional approaches involving the suppression of modes. The work of this program is divided broadly between two main activities. The first is to obtain a more complete understanding of the physics governing the operation of the FM and super-mode lasers. The second is concerned with improving the techniques for coupling the modes of the FM laser and finding more efficient means for full power supermode conversion of the FM signal to a monochromatic output. Author (TAR) N66-31142# Air Force Cambridge Research Labs., Bedford, Mass. A LASER FOR AN EARTH-BASED SATELLITE ILLUMINATOR N66-31161 # Lafayette Coll., Easton, Pa. Work was initiated on the development of a 10.6 micron nitrogen-carbon dioxide laser to be used in an optical tracking system for communication between the ground stations and the Echo I satellite. Two experimental setups, which, with respect to the Vycor discharge tube, differed in the mirror arrangement, were designed. In one setup the gold plated mirrors form an integral part of the laser assembly, being vacuum-tight connected to the ends of the discharge tube through metallic bellows. In the second the gold plated mirrors are located externally to the discharge tube, which is terminated by vacuum tight Brewster angle windows. These windows and one of the two gold plated mirrors are made of barium fluoride. This mirror has a one millimeter diameter hole in the gold coating for coupling out the radiation; the other mirror is one hundred percent opaque. The discharge tube is connected through an outlet with the manifold of the vacuum system so that it is possible to control precisely low |