We summarize a research program on remote optical measurements of humidity and temperature and give new results of such measurements as well as new data on the near IR absorption spectrum of H20. The basic atmospheric technique is differential absorption lidar (DIAL) using narrow band, tunable dye lasers. Approximate wavelengths are 720, 820, and 940 nm (H20) and 690 and 760 nm (02; temperature). The requisite absorption line strengths and widths are measured in a controlled environment by means of grating spectroscopy and tunable lasers. Prospects for routine lidar meteorology, even from airplane and satellite platforms, appear excellent. In several important applications, the conditions and the optical properties of the atmosphere can be obtained remotely by these means.

Your editor was fortunate to have an interview with the man who, along with Emmett Leith and Juris Upatnieks at the University of Michigan, was responsible for the rebirth of holography in the early 1960s. Professor Denisyuk is seldom seen in the West so I would like to share parts of the conversation that I had with him at the Volvilov Optical Institute, Leningrad, this October 1982. He is a vigorous and enthusiastic man with a great deal of personal charm. Our conversa-tions were of special interest to me because they supported my suspicion that truly great scientists are not merely smarter and harder working than the rest of us, but also are skilled at formulating both questions and answers in starkly simple ways.

Broad beam ion sources have been employed to remove material from (or deposit materials onto) optical surfaces in a highly controlled fashion without mechanically contacting the optic surface. Thus, ion processing techniques should be applicable for figuring high energy laser mirrors. The topo-graphical etching and deposition facility at TRW has been used for etching laser gratings, which illustrate processing capabilities demonstrated to date. The facility includes a 10 cm diameter argon ion source, typically operated at 1000 eV and 1 mA/cm2, microprocessor controlled x-y translation tables, and asso-ciated vacuum equipment, fixturing, and electronics. Etch depth control to better than 100 A at 4.2 micrometers groove spacing was achieved on molybdenum mirrors weighing up to 150 pounds.

This paper deals with an interactive flying spot scanner connected to a digital picture processing system. Its structure is discussed. One of the characteristics is analyzed in detail: the possibility of proceeding to interactive geometrical deformations with a programmable scanning system. A type of deformation was selected, and the principle of its implementation is outlined. The procedure which enables the execution of a geometric matching of a topographic map and a Landsat digital image is given as an application example. The main advantages of this method are pointed out.

One major reason for the limited acceptance of holographic nondestructive evaluation (HNDE) by industry is the complexity of interpreting the holographic interferograms. To alleviate this problem, we developed a system comprising a self-scanned photodiode array, microprocessor controlled acquisition subsystem, and a link to a time-sharing computer. The system is described and results demonstrating auto-mated flaw detection are presented.

The optical damage resistance of diffused lithium niobate wave-guides is discussed. Long-term laser power handling performance is assessed by recording the spatial intensity changes occurring as a function of time in a waveguide's far field. Out-diffused waveguides are found to offer significantly greater long-term resistance to optical power losses caused by optical damage than do waveguides formed by either ion exchange or titanium in-diffusion. Any waveguide's resistance to optical damage is lowered by inadvertent exposure to chemical reducing conditions that can prevail during device fabrication processes. Waveguides exposed to the severe chemical reducing conditions are found to exhibit dramatically nonlinear behavior when exposed to high laser powers and short laser wavelengths.

This paper presents some theoretical analysis and applications of adaptive filtering techniques for the detection of dim targets in the presence of highly structured background clutter. The computer algorithms carry out spatial, temporal, and multispectral filtering processes of forward looking infrared (FLIR) images taken at various times and in different spectral bands. These images were obtained from the Air Force TABILS data base. The basic criterion to drive these adaptive processes is based upon the minimum-mean-square error algorithm. The solution to the problem is to find a set of filter coefficients that will achieve the minimum mean square error at the output of the adaptive filter. The resulting Wiener-Hopf equation involves inverting the covariance matrix. Direct inversion of the covariance matrix, however, is a time-consuming process. To relax the computation complexity, a rapidly convergent adaptive algorithm based upon iteratively estimating the inverse of the covariance matrix was developed. The filtering operation consists of updating the inverse matrix in a sample-by-sample manner. This algorithm lends to a simplified hardware structure because it eliminates the matrix inversion process.

Veiling glare caused by reflection of an automobile instrument panel in the windshield may be reduced by coating the windshield with an antireflective multilayer dielectric coating. In this paper, procedures for computing the reflectance of such a coating on a glass substrate are described and used to evaluate the effects of single- and double-layer coatings on the reflectance of obliquely incident, unpolarized light from an automobile windshield. The prac-tical effects of these antireflective coatings on veiling glare are discussed.

A thermal analysis has been completed on an injection laser stack based on the electrical power dissipation within the laser stack material during operation. The thermal gradient existing in the laser stack during operation can cause large wavelength variations among individual lasers of the stack if certain fabrication procedures are not followed. For a given electrical power dissipation, a "monochromatic" injection laser stack can be designed (i.e., the spectral peaks of all lasers within the stack being at the same wavelength). A prescription for laser diode preselection prior to fabrication is given. The dominant source of temperature variations within the stack is electrical resistance nonuniformities of solder connections, causing nonuniform heating of the laser stack during a current pulse. Results of an experiment for measuring the temperature distribution of the injection laser stack after a single pulse which demonstrate electrical resistance nonuniformities within the stack are de-scribed. Finally, the minimum receiver filter spectral bandwidth corresponding to this thermally compensated injection laser stack is calculated.

The use of focusing x-ray systems depends upon the specular reflection at grazing incidence. These systems require mirrors with both excellent surface figure and superior surface finish. In order to obtain an efficient predictable method of fabricating such optics, Perkin-Elmer's computer-controlled polishing techniques have been adapted for grinding and polishing cylindrical mirrors. This process accurately controls the time that the tool polishes at each surface location to achieve the prescribed surface material removal.

When ethylene glycol laser coolant is irradiated by ultraviolet (UV) light from a krypton gas filled titanium- or cerium-doped, fused silica envelope laser flashlamp, thermally assisted photo-oxidation of the ethylene glycol produces glycolic acid and other oxidation products. The data collected show that the laser coolant acidity depends on the type of dopant in the flashlamp envelope. The measurements show that the flashlamp envelope highly doped with cerium not only provides UV protection to the laser coolant but also provides an increase in the laser output due to the cerium fluorescence effect.

An optical setup based on the operation of suitably detuned interference filters to produce oblique illumination for dark ground microscopy is presented. The obtainable performance is illustrated with a series of experimental evidence on calibration targets and on biological samples.

A simple method for testing the 90° angle of a reflecting prism by placing two prisms in contact with one another on a standard test plate and counting the number of fringes is outlined. An angle accuracy of less than a second for the angle of a 90° reflecting prism has been obtained.

The major types of AIGaAs high-power cw single-mode diode lasers are reviewed and compared. The basic approaches for achieving high-power (20 to 50 mW/facet) single-mode operation are presented first. Emphasis is placed on the CDH-LOC (constricted double-heterojunction large optical cavity) laser type, which has demonstrated cw single-mode operation to 40 mW/facet and 50% duty cycle fundamen-tal mode operation to 100 mW/facet. By using CDH-LOC devices, signal-to-noise ratios close to 70 dB were achieved, and peak powers of 40 mW (50% duty cycle) were coupled into 0.2 N.A. fibers. Life tests of CDH-LOC lasers at 40 mW/facet initial output power and 50% duty cycle have shown small drops in output even after 10,000 hours of operation. Monolithic ten-unit arrays of CDH-LOC lasers delivering up to 300 mW in cw operation have been demonstrated as well.

New spatially resolved ellipso-interferometry has been developed on the basis of the principle that spatially and temporally coherent light reflected from the two surfaces of a thin solid film will interfere to form a two-dimensional fringe pattern which is directly related to the spatial distribution of the film thickness if the optical constants are uniformly distributed. This technique differs from the conventional ellipsometry and interferometry in that the new ellipso-interferometer can be used to map the thickness distribution of a whole thin film without involving the use of any scanning technique, and in that its spatial resolution is high and can reach the diffraction-limited resolution under certain conditions. In this paper the principle and the applications of this technique are described, and some experimental results are presented to demonstrate the use of this technique for checking the thickness uniformity of oxide layers in semiconductor devices. This new technique is nondestructive, and the time required for this kind of measurement is much less than that by any other conventional technique.

Abstract. A passive visible to infrared image transducer is described which, for the first time, allows practical simulation of high resolution dynamic infrared imagery. A theoretical performance analysis is presented which indicates that an MTF (modulation transfer function) of 50% at 5 cycles/mm is achievable with a time response of less than 20 msec and a required input power of less than 2 mW/cm2 per simulated degree AT. Experimental results on working devices are reported which match theoretical predictions. Successful simulation of high speed real-world infrared imagery is described. Suggestions for future work which should further enhance resolution and dynamic range are presented.

The carbon atom is the basis of life. A book on the carbon atom in biology and medicine would be encyclopedic in scope and incomprehensible to most of its readers. So too is the text Lasers in Biology and Medicine. This volume is a compendium of the lectures and seminars presented at the NATO Advanced Study Institute on Lasers in Biology and Medicine at Villa Le Pianore, Camaiore, Italy, during August 19-31, 1979. The volume has four sections: tutorial, laser spectroscopic methods, and biological and clinical laser applications. Each chapter (paper or seminar) is written by an expert and covers a particular laser application in great depth. Few of the chapters are of interest to the optical engineer.

A conference on Conical Optical Element Metrology, Thomas R. Ferguson, Chairman; Marek J. Konopnicki, Co-chairman, was held in Albuquerque, New Mexico, on June 24-25, 1981. The purpose of the conference was to provide a forum for presentation and discussion of work on measurement of surface properties of conical optical elements. An underlying motivation for the conference was the need for developing new techniques for metrology used in the fabrication, polishing, coating, and final testing of the conical elements designed for current and future high energy laser cylindrical resonators. The conference was organized in May and June by personnel from the Advanced Resonator/Optics Branch of the Advanced Radiation Technology Office at the Air Force Weapons Laboratory (AFWL) and was announced mainly by a hastily assembled telephone and mailing list. As a consequence, most of the papers presenting results of testing of conical optical elements arose from current Air Force programs. However, the scope of the conference included current and potentially applicable measurement methods, and many authors discussed the problems associated with adapting conventional methods to highly curved surfaces.

This overview paper was presented at the 1981 Conference on Conical Optical Element Metrology. It briefly discusses the definition and history of conical elements, the Air Force's interest in them, and the nomenclature for elements used in cylindrical resonators. The histories of fabrication, polishing, and coating programs for these elements are mentioned to provide perspective for the varied metrology papers presented at the conference. Metrology uses and goals in Air Force programs are listed, and metrology capabilities at the Air Force Weapons Laboratory are summarized.

Three negative branch waxicons, all with magnifications of 1.875, were fabricated by diamond turning at the Oak Ridge Y-12 Plant, operated for the Department of Energy by Union Carbide Corporation, Nuclear Division. One of the waxicons was a simple beam compactor, and the other two had varying degrees of ray redistribution designed into the surface profiles. I nterferometric data taken during the fabrication process were used to make tool offset position corrections between successive cuts. The final surface was tested by single-and double-pass interferometry. The intensity redistribution effect was mea-sured by using a collimated beam incident on the annular leg and scanning the intensity of the compacted beam. All three waxicons were intended for use in a HSURIA (half-symmetric unstable resonator with internal axicon) confiauration.

A simple polarizer-surface- analyzer (PSA) ellipsometer was assembled to measure reflection coefficients for coated and bare metal conical optical elements. Configuration and alignment problems unique to testing conical elements are described. The method fails to measure the retardance accurately when its value is near zero or r. Measurements are reported for several coated cones tested during a developmental coating program.

The University of Dayton Research Institute (UDRI) has de-signed and built three infrared ellipsometers in support of the Air Force high energy laser program. One of these instruments is a conventional null-type ellipsometer for operation in the 3.39 to 4.00 um wavelength range. Ellipsometric parameters are determined with a precision of 0.01 ° at any angle of incidence from 20 ° to 85 °. Repeatability and absolute accuracy also approach 0.01 °, which yields optical constants accurate to 0.1 percent in some cases. All components are mounted on removable carriers for easy interchange, although operation is normally in the PCSA (polarizer, compensator, sample, analyzer) configuration. The system software has special provisions for the second instrument, which is also a null-type ellipsometer dedicated to monitoring vacuum deposited coatings in real time at 3.39 Am. The software can model nonideal components in the optical path using Jones or Mueller matrices and provide completely corrected data with a single zone measurement after the instrument is characterized. The third instrument is a rotating polarizer, automated ellipsometer tunable from 1 to 12µm. A dedicated computer operates the instrument and reduces data.

An instrument has been developed for measuring absolute reflectance at near normal incidence in the infrared region of the spectrum. The basic design of the instrument is similar to the Bennett absolute reflectometer except for some differences in implementation. The major sources of systematic errors have been reduced or eliminated. The alignment procedure is described.

The cavity phase shift method can measure high reflectances on spherical surfaces with good spatial resolution. Successful demonstration at 2.9 micrometers wavelength is described. A reflectance of 0.9920±0.0050 has been measured.

Although high energy laser systems require low scattering optical surfaces, conical optical elements have intrinsically high scattering surfaces due to nonconventional fabrication techniques. The scatter-ing behavior of diamond-turned optical surfaces with steep curvatures can be characterized by an equivalent bidirectional reflectance distribu-tion function (BRDF). Existing computer programs can be used to perform a detailed stray radiation analysis of the optical system and to establish optical component scattering tolerances. These scattering tolerances are then translated into surface finish specification through a simplified theory of surface scatter phenomena.

The use of light scatter to determine flat surface statistical information, such as a bandwidth limited section of the surface power spectral density (PSD) function and the associated rms roughness and slope numbers, is well documented in the literature. Systems which mea-sure scatter as a function of angular position often make use of the fact that the surface power spectral density function is essentially produced in the scatter pattern. Low spatial frequencies scatter close to the direc-tion of specular reflection and higher frequencies scatter further out. The technique relies on the one-to-one relationship between spatial frequen-cy and scatter position in the far field. This relationship is exact to within dimensions corresponding to the diffraction limit (i.e., dimensions much smaller than the usual detector aperture). For a curved surface, this one-to-one relationship is destroyed as scatter from a single spatial frequency can spread out to dimensions far exceeding those of a diffraction limited spot. As the spread approaches detector aperture dimensions, the ability to extract useful surface information is impaired. The amount of spread is determined by the illuminated spot radius r, the radius of curvature of the surface R, and the angle of incidence 01(r) and is plotted, for constant 01, as a function of r/R. Analytical data show that by reducing r to 0.5 mm, reasonable results are obtainable with workable scatter system geometries for curved surfaces with R _> 5 cm.

This paper compares some of the advantages and limitations of two methods used for surface topography evaluation, the dual-beam interference microscope and the stylus-type profiling instrument. Consideration is primarily limited to diamond-machined or other high quality surfaces, such as those commonly encountered on optical elements. Parameters discussed include horizontal and vertical resolution, horizontal and vertical range, and surface damage.

This paper presents experimental and analytical results from a study investigating the effect of centrifugal force and gravity on two candidate mirror fixture designs to be used on a diamond-turning ma-chine. The authors illustrate and discuss the use of the finite element method as an aid in the design and fabrication of high precision metallic optical components.