bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability Requirements of Optical Coatings for Telecommunication Applications
Authors: Hiremath B. V.
Published: February 2023

The current choice for the telecommunication industry is the lightwave technology which consists of many optical components. The reliability requirements of optical coatings used in such optical components of the current and future lightwave telecommunication sytems are illustrated in the poster. There is a stringent requirement on the quality of optical coatings used in the components such as: beam splitters, couplers, glass fibers, graded index lenses, optical attenuators, optical filters: Fabry-Perot, narrow band, short and long wave pass filters, optical isolators, optical modulators, semiconductor lasers, and wavelength division multiplexers.
Planar Waveguides for Photonic Applications
Authors: Rudigier Helmut
Published: February 2023

Summary not available.
Design of a hot mirror - contest results
Authors: Thelen Alfred
Published: February 2023

Produce optimal visible transmittance (Tvis). Also, maximize IR reflectance (Rir) in the spectral region 750 nm to 1998 nm, as given by where T and R are in percent. The defect function (that is to be minimized) is (3) where L is the number of layers.
Antireflection Coatings for Gemanium Substrate at 7.5-12.5 um
Authors: Dehua Xiao , Lai Wang , Hengyi Li , Shengyong Liu
Published: February 2023

Gemanium which is known as “the third atmosphere windows” is the most important optical material used at the wavelength from 8um to 14um. Because of its high refractive index, antireflection coatings are needed for many applications. Though there are many articles about the antireflection to Gemnium substrate, designs in practical use are very scarce.We constructed a three-layer antireflection coating by which good performance was achived.
Stresses in Thin Films and Characteristic Failure Modes
Authors: Clarke David R.
Published: February 2023

Thin films, irrespective of the techniques used to deposit them, are invariably under a state of residual stress which can, under appropriate conditions, lead to failure. These stresses arise from a variety of different factors including differential grain growth, thermal expansion mismatch and non-equilibrium incorporation of defects. Developments in fracture mechanics indicate that only certain failure modes can occur and that they are dependent on particular combinations of film geometry, film stress, film thickness and fracture resistance. In particular, films fracture or decohere when a figure of merit, the cracking number, appropriate to the pertinent geometry, exceeds a critical value. Since, the two parameters usually unknown are the film stress and the decohesion fracture energy, we have been developing techniques for their measurement. To measure film stress, we have been using the optical techniques of piezo-spectroscopy. An advantage of these is that the information is not restricted to measuring the average strain, as are wafer bending measurements, but can also be used to measure strains from local regions identifiable under an optical microscope or sampled with a laser probe. In order to measure the decohesion energy, a new technique has been developed at UCSB based on a thin-film lithography in which a thin "stressor" film, under very high residual tension, is applied to a narrow strip of the film being tested. When a critical stressor film thickness is reached, the driving force for decohering the film/substrate interface exceeds the interface fracture energy. Thus, through a series of measurements with stressor films of different thicknesses the decohesion energy can be obtained.
Characterization of optical interference films: comparison of the results obtained by different techniques and laboratories
Authors: Masetti E. , Ristau D. , Duparré A. , Kaiser N. , Flory F.
Published: February 2023

The reduction of optical losses is of crucial importance for enhancing the quality of thin film optics, especially when applications with high power lasers are considered. In order to improve the deposition process and the characterization methods a network of different laboratories was stated and one of the organized activity was the comparison of the results obtained by different available techniques for the measurement of the optical constants and optical losses. The reported data are related to oxide (SiO2, Al2O3, Y2O3) and fluoride (MgF2, LaF3) films deposited on fused silica substrates by PVD techniques with and without ion assistance (IAD).
Generalized Variable Angle Spectroscopic Ellipsometric (g-VASE™) Characterization of poly(ethyleneterephthalate) Film
Authors: Johs Blaine , Elman Jim
Published: February 2023

Variable Angle Spectroscopic Ellipsometry (VASE™) is a powerful tool for optical characterization, and is applicable to a wide variety of bulk materials and thin film structures. For most VASE™ measurements, the Jones matrix which represents the sample is assumed to be diagonal; this is always the case for specular isotropic samples. However, for anisotropic samples, the Jones matrix is not diagonal in general (except for special orientations of the optical axis with respect to the measurement frame of reference). For such anisotropic samples, with arbitrary orientation of the optical axis, the traditional ellipsometric ratio of tan(Ψ) e
i
Δ = rp/rs does not adequately describe the reflection of polarized light from the sample.
Dominant wavelength sensitivity of thin-film color filters to spectral centering
Authors: Perilloux B E.
Published: February 2023

Transmissive color filters, in the form of gels, plastics and thin-films, are employed in various lighting systems. To reproduce or match a particular color for the end-user, the filter must have nearly identical spectral transmission properties and the same light source. Additional factors affect the appearance of color, but are not covered in this paper. For any light source (e g. equal-energy, 3200K temperature, etc), the properties of color filters can be quantified using a variety of well established methods, such as 1931 Commission Internationale de l’Eclairage (1931 CIE) or L*a*b*. Using the 1931 CIE method, chromaticity coordinate (x,y) can be calculated from tristimulus values. Furthermore, the dominant wavelength and saturation color performance of a filter can be determined graphically from a chromaticity diagram, or by numerical computation.
Two-Color Imaging Using Patterned Optical Filters Bonded to Focal Plane Array Detectors
Authors: Gluck N. , Bailey R.B. , de la Rosa R. , Hall R. L.
Published: February 2023

The performance of advanced optical sensors can be greatly enhanced by the addition of methods for spectral discrimination. Typically, filter wheels, beamsplitters, or multiple apertures are placed in front of the detector array's focal plane. These approaches complicate the optical and mechanical designs and add additional cooling requirements to the system.
Durable Silver - Based Antireflection Coatings and Enhanced Mirrors
Authors: Wolfe Jesse D. , Laird Ronald E. , Carniglia C.K. , Lehan J.P
Published: February 2023

Various types of thin film designs which incorporate silver metal are well known. The chemical and mechanical durability of these films is usually poor. This fact limits the practical application of the films. A new process has been developed which allows the use of silver metal in various types of thin film designs such as wide-band anti-reflecting and wide-band high reflecting films. This paper describes the patented process and designs used to deposit these film stacks.
Plasma Impulse Chemical Vapour Deposition of Optical Coatings on Plastics
Authors: Heming M.
Published: February 2023

PCVD techniques, although well established in the semi-conductor industry to deposit dielectric coatings had so far little impact on the optical coating industry due to the lack of sufficient uniformity in cw-processes.
Rugate Filter Construction Utilizing Plasma Enhanced Chemical Vapor Deposition.
Authors: Miller S. C. , Mackamul K. K.
Published: February 2023

Successful rugate filter fabrication has been best obtained using processes which employ sophisticated process control techniques. Fundamental limitations on aperture area which directly affect manufacturing throughput are imposed by strong geometric dependencies of current processes. A Plasma Enhanced Chemical Vapor Deposition (PECVD) process, without these limitations ,was developed to fabricate rugate filters. Application of this process to solar cells, is discussed.
Thin Filins: The Gremlins of Laser-Induced Damage
Authors: Soileau M.J.
Published: February 2023

The first laser demonstration was heralded by thin film damage. This
talk attempts to review progress since that fateful event and the
challenges that remain for the designers and producers of thin film
optics.
Dual band one-layer coated Brewster window
Authors: Surdutovich G.I. , Vitlina R.Z. , Baranauskas V.
Published: February 2023

It is apparent from the intensity reflection coefficient for p-polarized light of an ambient-film-substrate system
R(θ)=r01(θ)+r12(θ)e−iδ1+r01(θ)r12(θ)e−iδ2, where r01 and r12 are ambient-film and film-substrate Fresnel coefficients,
δ=4πdλn12−sin2θ, d and n1 are the thickness and refractive index of the film, λ is the free-space-wavelength, θ is the angle of incidence, that one can obtain a sample with two Brewster angles (R(θ1) = R(θ2) = 0), if for given n2 satisfy the equations
An Aqueous Sol-Gel Coating for Epoxy Surfaces
Authors: Marshall Kenneth L. , Rigatti Amy L. , Mitchell Gary L. , Pathak Jay A. , Staley Arthur R. , Warner Joy A.
Published: February 2023

The initial set of Distributed Phase Plate (DPP) optics for the Laboratory for Laser Energetics OMEGA Laser system were fabricated using an epoxy replication technique.1 A requirement for the final production of these epoxy DPP’s was the development of a sol-gel anti- reflection coating compatible with the UV epoxy material. Although ethanol based sol-gel coatings have been successfully applied to a variety of OMEGA components ranging from BK-7 and fused silica optics to KDP frequency conversion crystals, attempts to apply these coatings to epoxy DPP’s resulted in swelling and distortion of the replicated epoxy surface.2 To achieve a good anti-reflection coating on an epoxy replicated surface, the development of an aqueous based sol-gel (ASG) material was deemed essential.
Protected Silver Coating for NIF Flashlamp Reflectors*
Authors: Thomas Norman , Wolfe Jesse , Farmer Joseph , Erlandson Al , Marshall Chris , Woodruff Dan , Bouillez Dan , Glenn Darin , Bjornard Erik
Published: February 2023

The National Ignition Facility at Lawrence Livermore National Laboratory will be a national center to study inertial confinement fusion and the physics of high energy and pressure. The $1.2 billion project consists of 192 laser beams which will direct more than 500 trillion watts towards a tiny target in a pulse only a billionth of a second long. The laser contains neodymium glass amplifiers which are pumped by xenon flashlamps. The flashlamps have silver reflectors to direct the light toward the glass laser slabs. Silver is ideal because of its high reflectance from 400 to 1000 nm wavelength which matches the neodymium absorption cross-section. In order to maintain the overall efficiency of the laser beams, there is an effort to prevent the corrosion of the silver reflectors by various means. One solution is the use of durable protected silver coatings which must survive 24,000 exposures to intense flashlamp light over a 30-year period while being exposed to small levels of atmospheric corrodants. One protected silver reflector has survived 20,717 flashlamp discharges so far in 100% Livermore atmosphere with no change in reflectance. This paper describes another protected silver reflector which is very durable.
High Laser Damage Threshold Hfo2/Sio2 Mirrors Made by Sputtering
Authors: Fornier A. , Bernardino D. , Lam O. , Néauport J. , Dufour F. , Schmitt B. , Mackowski JM.
Published: February 2023

This study was carried out in collaboration with the CEA within the framework of the Megajoule laser project.
Needle Method and Initial Coating Design
Authors: Lin Yongchang , Gu Yonglin , Zhang Cheng , Zhou Jian
Published: February 2023

The optical characteristic of multilayer optical coating is pertinent to the layer refractive indices, thickness and the number of the layers. However, in many cases the merit function of optimization techniques such as Damped-Least-Squaves, Gradient or Variable Metric only deal with the two former, not include the last. So the result is that virtually all optimization techniques are subject to convergence at local minimum and therefore search for the global minimum or even “a locally optimization minimum” is a formidable problem. A very powerful new optical film design technique, called the needle optimization whose merit function includes the three said factor, has been developed to solve problem of the design by Tikhouravov. During mathematical optimization process, the new layer is automatically inserted into the existing multilayer until the design goal are met or the insertion of a new layer effects further improvement.
Parallel Processes in Early Vision: from the computational structure to algorithms and parallel hardware
Authors: Poggio Tomaso
Published: February 2023

One of the best definitions of early vision is that it is inverse optics — a set of
computational problems that both machines and biological organisms have to solve. While in classical
optics the problem is to determine the images of physical objects, vision is confronted with the
inverse problem of recovering three-dimensional shape from the light distribution in the image. Most
processes of early vision such as stereomatching, computation of motion and all the
“structure from" processes can be regarded as solutions to inverse problems. This common
characteristic of early vision can be formalized: most early vision problems are
“ill-posed problems" in the sense of Hadamard. In this article we will first review
a new framework suggested by Poggio and Torre (1984). They suggested that the mathematical theory
developed for regularizing ill-posed problems leads in a natural way to the solution of early vision
problems in terms of variational principles of a certain class. They argued that this is a new
theoretical framework for some of the variational solutions already obtained in the analysis of
early vision processes. They also showed how several other problems in early vision can be
approached and solved. Thus the computational, ill-posed nature of early vision problems dictates a
specific class of algorithms for solving them, based on variational principles of a certain class.
It is natural to consider next which classes of parallel hardware may efficiently implement
regularization algorithms. We are especially interested in implementations that are suggestive for
biology. I will thus review a model of computation proposed by Poggio and Koch (1984) that maps
easily into biologically plausible mechanisms. They showed that a natural way of implementing
variational principles of the regularization type is to use electrical, chemical or neuronal
networks. They also showed how to derive specific networks for solving several low-level vision
problems, such as the computation of visual motion and edge detection.
Raising Venture Capital for Optical Computing
Authors: Guilfoyle Peter
Published: February 2023

Summary not available.
An Optical Processor Based on Symbolic Substitution
Authors: Brenner Karl-Heinz , Huang Alan
Published: February 2023

An importened aspect in the design of a new processor type is the data coding or the way, data are represented. Questions to consider are compatability, the data type (such as numeric or non-numeric data), and certainly also the processor type (i.e optical or electronic). The binary data representation is known to be most efficient for electronic computers. Far optical computers this does not have to be true necessarily. One of the strengths of optics is that it is two-dimensional whereas electronics is zero-dimensional. Symbolic substitution 1 is a kind of spatial logic which we think is tailored well to the capabilities of optics in addition to being efficient, flexible, and compatible to binary coding. In this paper we explain the principle of symbolic substitution and then discuss an optical processor based on this technique.
Engineering Limits for Optical Interconnections
Authors: Hartman Davis H.
Published: February 2023

The all-optical computer has been lauded by many as offering the potential for increasing computation power over electronic computers by many orders of magnitude. However, to date, attempts to develop such a machine have been limited by technology and by the electronics these computers must interface with. An alternative approach, that will aid in the development of the needed technology for optical computers is the hybrid electrical/optical computer. In such a machine, electronics is used where it functions best; ie., as a switching mechanism, and photonics is used where it functions best; ie., as an interconnect medium.
Parallel Readout of Optical Disks
Authors: Psaltis Demetri , Yamamura Alan A. , Neifeld Mark A. , Kobayashi Seiji
Published: February 2023

Optical memory disks have been developed in recent years as mass storage media for audio, video, and computer memory applications. Write-once systems are already widely used, and reprogrammable systems are now starting to become commercially available as well. In all the existing systems the information stored in the optical disk is recorded and readout serially by focusing a laser beam on a single pixel. With an optical memory however it is possible to illuminate the disk with an extended beam and readout (as well as record in principle) large amounts of data in parallel [1]. This distinction between serial and Parallel Readout Optical Disks (PROD) is schematically shown in Fig.1. If the potential of PRODs is realized in practice it can eliminate the bottleneck that currently exists between mass memory and the information processing portion of a computer and thus greatly impact the speed with which computers can execute memory intensive problems. There are three main issues that we will address in this paper: The suitability of commercially available disks for this applications including the experimental characterization of a prototype magnetooptic system from SONY, the limitations imposed on parallel access due to the optical system, and the types of problems and computer architectures that can make effective use of the PROD capability.
Optical Space-variant Logic-gate Using a New Hybrid BSO Spatial Light Modulator
Authors: Ji Zhang , Weiwei Liu , Licheng Zhong , Yili Gou
Published: February 2023

A novel method on the basis of spatial encoding technique has been advanced by T.Yatagai. In this method, the multiple instruction multiple date-fluent (MIMD) is simply realizable in parallel by varing the decoding mask, but the method for encoding input pattern poses a problem in practical application. One of solution is to use the hybrid system, and encoding can be done with electronic computer. The other is using a new hybrid BSO SLM which can be used to encode input binary pattern with optical method. The hybrid BSO SLM can be used not only in encoding but also in neural logical process. In the further research, we will use it to enhance edge of pattern and to quantize pattern.
Substrate Mode Holograms for Optical Interconnects
Authors: Kostuk Raymond K. , Kato Masayuki , Huang Yang-Tung
Published: February 2023

The advantages and design considerations for free-space holographic interconnects are discussed. Substrate-mode holograms for this application are introduced and experimentally demonstrated.
OEIC Technology for Photonic Switching
Authors: Yamakoshi S.
Published: February 2023

OEIC technology is promising to construct the new optical systems such as photonic switching, routing and other opitcal processing operations. The state-of-the-arts and future prospects of OEICs for photonic switching are discussed.
Massively Parallel Computers Using Holographic Matrix as a Photonic Backplane
Authors: Charrier M. , Houssay B. , Lemoine T. , Paineau S.
Published: February 2023

0 - Massively parallel computers in airborne radars: A communication problem
Optical Processing in Photorefractive Crystals
Authors: Hong John H.
Published: February 2023

We describe the use of photorefractive crystals in several rf signal processing applications where the unique capability of dynamic holography operating in conjunction with acousto-optic devices provides effective processing systems.
Dynamically Interconnected S-SEEDs
Authors: Prince Simon M. , Tooley Frank A.P. , Taghizadeh Mohammad R.
Published: February 2023

A potential advantage of communicating information optically rather than electrically is the ease with which non-local interconnection paths may be set-up. The radix 2 is a general purpose interconnection pattern of potential use in optical computing architectures. A 2-dimensional array of nodes is interconnected to nearest neighbours, neighbours 2 pixels distant, 4 pixels away, etc in both the vertical and horizontal directions. Each node may be a processing cell implemented using smart pixel technology. This interconnection scheme minimises the number of cycles required to solve algorithms involving recursive doubling such as the bitonic sort and fast Fourier transforms.
16 Channel FET-SEED Based Optical Backplane Interconnection
Authors: Plant D.V. , Robertson B. , Hinton H.S. , Robertson W. M. , Boisset G.C. , Kim N. H. , Liu Y. S. , Otazo M.R. , Rolston D.R. , Shang A. Z.
Published: February 2023

Free-space optical interconnects represent a solution to the needs of future connection-intensive digital systems such as ATM switching systems, and massively parallel processing computer systems. These systems will require the large board-to-board connectivity provided by an optical backplane which uses two-dimensional arrays of passive, free-space, Parallel Optical Channels (POCs) to optically interconnect electronic Printed Circuit Boards (PCBs) and/or Multi-Chip Modules(MCMs). Such a backplane could be capable of supporting terabit/second aggregate capacities with connectivity levels on the order of 10,000 input/output channels per PCB.
Mid-Infrared Doppler-Free Saturation Absorption Spectroscopy of the Q Branch of CH4 ν3=1 Band using a Rapid-Scanning Continuous-Wave Optical Parametric Oscillator
Authors: Liu Jinjun , Riyadh S. M. Shah , Telfah Hamzeh , Jones Ian , Bersson Jonathan , Cheng Cunfeng , HU Shui-Ming , Foote David
Published: February 2023

We have developed a mid-infrared Doppler-free saturation absorption spectroscopy apparatus using a continuous-wave optical parametric oscillator (CW-OPO). Here we report a comprehensive spectral scan of the Q branch transitions of the ν3=1 band of methane (CH4) with an average line width (FWHM) of 4.5 MHz. The absolute frequency calibration was achieved using previously reported transition frequencies determined using optical frequency combs, while a Fabry-Pérot etalon was used for relative frequency calibration. We report 12 transitions with improved accuracies of ~3 MHz.
Global Environemntal Studies Using Earth-Orbiting Optical Remote Sensors
Authors: Tilford Shelby G.
Published: February 2023

Summary not available.
Remote Sensing of Air-Surface Interaction Processes
Authors: Chahine Moustafa T.
Published: February 2023

Simultaneous determination of several key atmospheric, ocean and land parameters from the HIRS/MSU infrared/microwave sounders permits monitoring changes in soil moisture, ocean latent heat fluxes, global temperature, cloudiness and ice covers.
Coherent Lidar Measurements of Backscatter and Transmission Loss Profiles
Authors: Rothermel Jeffry
Published: February 2023

A coherent 10.6 micron pulsed Doppler lidar has been operated at the Marshall Space Flight Center, Huntsville, Alabama in a ground-based mode. During the period April 1983 - February 1984 measurements of tropospheric backscatter and transmission loss were made on approximately 30 days of operation.
Signal Fluctuations and Atmospheric Effects in Coherent Laser Radar
Authors: Davis P. H. , Pomeroy W. R. M. , Vaughan J. M.
Published: February 2023

Signal characteristics in a coherent heterodyne laser radar system have been investigated with techniques that include autocorrelation of the rectified and smoothed detector output. Various experiments have been conducted with the scattering from a moving-belt sander. As the speed of the belt and the angle of incidence of the beam were varied the characteristic coherence time of the fluctuations changed in the manner expected from simple semi-intuitive calculations. However, in other investigations including change of focal position and aperture size at the transmitter the results are much less obvious. Their interpretation are discussed and related to other recently reported investigations.
Results of a Tropospheric CO Measurement Experiment Flown on the Space Shuttle
Authors: Reichle Henry G.
Published: February 2023

The MAPS (Measurement of Air Pollution from Satellites) experiment flew as part of the OSTA-1 payload on the second flight of the Space Shuttle (STS-2) during early November of 1981 and again as part of the OSTA-3 payload on STS-41G during early October 1984. The experiment is designed to remotely measure the mixing ratio of carbon monoxide (CO) in the middle and upper troposphere using a gas filter radiometer as the sensing instrument.
Quantitative Vertical Extinction Profiles with the Visioceilometer Lidar
Authors: Lentz W. J.
Published: February 2023

Significant advances have been made in recent years in lidar theory and hardware. The first of these advances is of special interest to the US Army because it allows extinction calculation from a single laser pulse in low visibility with more certainty than previous methods have allowed. Advances in electronics now allow bulky transient digitizers and computers to be reduced to a hand-held, battery-operated lidar that automatically measures slant visual range at the push of a button with no other inputs. The hand-held lidar, called a visioceilometer, allows the measurement of cloud ceiling height and visibility (Lentz, 1982; Bonner and Lentz, 1979). This lidar is intended for tactical support where visibility and cloud ceiling height are required.
Remote Sensing of Atmospheric Structure and Composition by Pressure Modulator Radiometry from Space: The ISAMS Experiment on UARS
Authors: Taylor FW
Published: February 2023

This paper describes the Improved Stratospheric and Mesospheric Sounder experiment on the Upper Atmosphere Research Satellite. ISAMS uses a technique called pressure modulator radiometry, which permits the measurement of selected atmospheric parameters with high precision and selectivity. Marriage of this technique with the objectives of the UARS programme is aimed at producing a radical improvement in current knowledge of the middle atmosphere. In particular, it is hoped to make significant progress in understanding the coupled behaviour of radiation, dynamics and photochemistry in the stratosphere and mesosphere.
System Aspects of Sensor Suite Design
Authors: Westerman Steve , Paul Dave
Published: February 2023

Lockheed (LMSC) is developing a total space system that will make advances on the current Defense Meteorological Satellite Program (DMSP) capability. This proposed end-to-end system considers the interfaces and interaction between the system requirements and the technology selection process. This paper will briefly discuss some of the system considerations that helped to form the design of the LMSC sensor suite.
Atmospheric Remote Sensing with the Eos Multi-angle Imaging SpectroRadiometer
Authors: Diner David J.
Published: February 2023

The Multi-angle Imaging SpectroRadiometer (MISR) experiment is an Instrument Investigation selected for flight aboard the first NASA Earth Observing System polar platform, Eos-A. The purpose of the MISR investigation is to study the effects of geophysical processes and human activities on the Earth’s ecology and climate. Scientific objectives include study of the climatic and environmental impacts of atmospheric aerosols, characterization of heterogeneous cloud fields and their impact on the shortwave radiation budget, and investigation of biosphere-atmosphere interactions and ecosystem change. A detailed understanding of the causes and effects of regional and global change will require long-term monitoring of the Earth system. MISR is a unique component of the Eos instrument suite in that it will systematically acquire multispectral images of the angular reflectance signatures of terrestrial scenes. Theoretical simulations, ground-based measurements, and remotely-sensed observations of aerosol-laden atmospheres, cloud fields, and vegetated landscapes demonstrate the necessity of multi-angle data for climatological and biogeophysical studies. While the spectral coverage and resolution of nadir-viewing imaging spectrometers provide invaluable information on chemical composition, the angular variation of reflectance furnishes the means of inferring physical quantities related to geometric and optical structure, radiative energy transfer, and biosphere-atmosphere mass exchange.
Remote Sensing Of Toxic Air Pollutants Using Optically Active Long-Path Fourier Transform Infrared Spectroscopy
Authors: Hudson J. , Arello J. , Kimball H. , Holloway T. , Fairless B. , Spartz M. , Fateley W. , Hamaker R. , Carter R. , Thomas M. , Lane D. , Marotz G. , Gurka D.
Published: February 2023

The use of a mobile optically active long-path Fourier Transform Infrared Spectrometer (FT-IR) system to measure toxic pollutants in air is discussed. The hardware is described and data from field tests and site measurements are presented.
Using Satellite Aerosol Optical Depths to Estimate Surface Meteorological Ranges and Aerosol Vertical Profiles
Authors: Longtin D.R. , Shettle E.P. , Hummel J.R.
Published: February 2023

NOAA/NESDIS is producing on an experimental basis global data sets of total aerosol optical depth over oceans. These data are derived from the Advanced Very High Resolution Radiometer (AVHRR) measurements aboard NOAA polar orbiting satellites. Effectively, the retrieval algorithm correlates aerosol optical thickness with the radiance from the upwelling Channel 1 (0.58-0.68 μm) as described by Rao et al.1 and Griggs and Stowe2. Regions containing clouds have been filtered out in the aerosol retrieval algorithm.
Some Recent Measurements of CO Overburden and Forest Fire Emissions with Gas Filter Correlation Spectrometers, Gascofil and Gascoscan
Authors: Morrow W. H. , Nicholls R. W.
Published: February 2023

Correlation spectroscopy, which is a powerful diagnostic tool for the determination and monitoring of trace atmospheric contaminants, involves a correlative comparison between the features of a "field spectrum" of a specific region of the atmosphere, and the features of a "mask function" which is representative of the spectral absorption features of the molecular species of interest. The degree of correlation between these can be interpreted quantitatively as a direct measure of the column density of the species of interest in the instrumental field of view.
A Reference Atmosphere for LAWS Trade Studies
Authors: Wood S. A. , Emmitt G. D.
Published: February 2023

A space-based Doppler Lidar Atmospheric Wind Sounder (LAWS) has been proposed by NASA as a facility instrument for the NASA Earth Observing System. A LAWS Simulation Model (LSM) has been developed to assess the impact of a spaced-based Doppler lidar wind profiler on global and regional features. Hardware feasibility and data studies are ongoing.1,2,3 The uniqueness of global Lidar wind measurements from space raises many fundamental questions that may impact the design of such a system. The distribution of aerosols that provide backscatter, the molecular attenuation that reduces signal strength, the effects of wind shear and turbulence that effect measurement accuracy, and the presence of thin cirrus clouds that can enhance the performance are all issues that must be considered.
Airborne IR Spectroscopy of the Atmosphere
Authors: Russell Ray W. , Erwin Peter
Published: February 2023

Increased interest in the performance of IR sensors based on airborne platforms was a main driver for the measurements of atmospheric radiance conducted under the auspices of the Kuiper Infrared Technology Experiment in 1985-1986. In an ideal IR airborne sensor, the noise contributions from the detector(s), the signal processing electronics, the analog to digital converters), and the data storage mechanism would all be smaller than the statistical fluctuations in the incoming photon stream. The intrinsic limit set by the counting statistics of the photons from the atmosphere through which the sensor looks is referred to as BLIP, or background limited performance. (In rare cases the target may be bright enough to be the major source of photons, but we will not consider that case here.) In practice, the background from the light collecting mechanism (usually a telescope and some number of flat mirrors, beamsplitters, and at least one window) contributes as much or more "background" than the atmosphere, and thus represents the source of a sensitive sensor’s performance limit. In order to assess the relative contributions from the platform, the sensor, and the sky, the KITE project undertook a few flights over the continental US and more than 30 over Kwajalein in 1986. This report discusses some of the results of the analysis of the data from that project.
A Reference UV-B Spectroradiometer For Comparison And Auditing of Field Monitoring Instruments
Authors: Bruening Robert J. , Saunders Robert D. , Barnard William F. , McElroy Frank F.
Published: February 2023

As part of the Environmental Protection Agency's stratospheric ozone program, the Atmospheric Research and Exposure Assessment Laboratory of the EPA (AREAL) has been given the responsibility of standardizing absolute measurements of incident ultra-violet radiation being obtained by various environmental research activities, both within and outside of EPA. Of primary interest are quantitative UV radiation flux measurements in the environmentally active wavelength range of 280 to 400 nm, including the UV-B range. Measurements of UV-B radiation are associated with a wide variety of research activities endeavoring to quantitatively relate exposure to incident UV radiant energy intensity - particularly changes or effects on human health and on the various environmental ecosystems. A significant amount of UV-B measurement activity in the scientific community is currently underway or is being planned. Currently, many of the UV-B measurements suffer from substantial lack of comparability and credibility due to wide variations in the quality and calibration accuracy of the UV-B measurement instruments used. To ensure that measurements throughout these activities are of known quality, a quality assurance program should be developed. One of the first steps to ensure known data accuracy is to establish a measurement standard for the monitoring instrumentation.
Overview of Improved Limb Atmospheric Spectrometer (ILAS) and Retroreflector In-Space (RIS) Projects for ADEOS
Authors: Sasano Yasuhiro , Ichihara Nobuo
Published: February 2023

Environment Agency of Japan is developing a solar-occultation type atmospheric sensor (Improved Limb Atmospheric Spectrometer; ILAS) and a retroreflector (Retroreflector In-Space; RIS) for laser absorption measurements for the Advanced Earth Observing Satellite (ADEOS).
Recent Advances in the Analysis of Twilight Spectra to Retrieve Atmospheric Constituents
Authors: Johnston P.V. , McKenzie R.L , Solomon S.
Published: February 2023

For several years, spectral measurements of zenith sky intensities made have been used to measure a range of gases of aeronomie interest. At twilight the geometric path through the atmosphere is long compared with that at midday, so the ratio of a twilight spectrum divided by a midday spectrum can be used to remove solar absorption features and reveal the features due to terrestrial absorption. A least-squares analysis method is then used to convert the excess twilight absorptions to column amounts. The method has been successfully applied to measuring a range of gases, including NO2, NO3, O3, and OCIO.
Rayleigh Lidar Measurements and Noctilucent Clouds
Authors: Burka Michael , Moskowitz Warren , Davidson Gilbert , Meriwether John W. , McNutt Capt. Ross , Farley Robert , Dao Phan
Published: February 2023

Noctilucent clouds (NLC) are ice clouds located in the high latitude summer mesosphere at heights between 81 and 85 km. The formation process is not well understood but it is thought that a growth cycle is activated by the extremely low temperatures of the mesopause region, typically 120 to 130 °K. This process involving condensation nuclei transported into the mesosphere from meteoritic debris and the upwelling of water vapor into the mesosphere from below produces condensation of ice upon particles within the supersaturated region lying several kilometers below the mesopause temperature minimum.
The Along Track Scanning Radiometer: Precise Sea Surface Temperature from the ERS-1 Satellite
Authors: Llewellyn-Jones D.
Published: February 2023

The ATSR is an advance infrared imaging radiometer. It embodies a precise self-calibration scheme and views the earth at 2 angles. These features enable sea surface temperature measurements to be made with the precision now required for climate research.
Spectral Absorption Coefficient Measurements in CFC Bands Relevant to Atmospheric Remote Sensing†
Authors: Prasad Varanasi
Published: February 2023

The so-called line-by-line procedure is an impractical procedure in the case of several chlorofluorocarbons (CFCs). Positions, strengths and widths of individual lines are practically impossible to catalogue since there are literally (densely packed) thousands of them. Lines belonging to hot bands, which are transitions from excited vibrational levels, and isotopic bands further complicate the problem. A proper approach to take in such instances would be to measure the absorption coefficient itself over the range of wavenumbers, temperatures and pressures that are relevant to atmospheric remote sensing experiments. The ultimate goal in the line-by-line scheme is, after all, that of computing the absorption coefficient, a computation that is so desperately dependent on our knowledge, which we can never hope to possess totally adequately in the near future, of all of the parameters mentioned above and of their temperature and pressure dependence. Why not measure the absorption coefficient itself in the laboratory ? To illustrate the atttractiveness of this idea we present below two examples involving CFC-12 (CF2Cl2) and CFC-22 (CHClF2). The spectra were measured with the Doppler-limited spectral resolution of a tunable diode laser spectrometer and using a cryogenically cooled absorption cell, both of which are adequately described in some of our publications.1
NASA Lidar Atmospheric Sensing Experiment's Titanium-doped Sapphire Tunable Laser System
Authors: Barnes James , Edwards William , Petway Larry , Wang Liang-Guo
Published: February 2023

NASA has undertaken an aggressive effort to develop the first fully autonomous airborne DIAL, DIfferential Absorption Lidar, instrument. The LASE, Lidar Atmospheric Sensing Experiment, will be deployed on NASA's ER-2 aircraft at altitudes of 52,000 to 70,000 feet. The science objective is to measure tropospheric H2O and aerosols in phase I and adds O2 for pressure and temperature determination in phase II. The major subsystems of the instrument including the telescope receiver, control and data system, and the laser transmitter are being constructed and tested at Langley Research Center. This paper describes the LASE laser transmitter's requirements, designs, development, and testing.
Diode Laser Injection Seeded, Raman Shifted Alexandrite Laser Tunable Narrowband Lidar Source
Authors: Schmitz S. , Von Zahn U. , Wilkerson T. , Heller D. F. , Walling J. C. , Walling J.C.
Published: February 2023

The immediate purpose of this work is to develop robust, reliable, spectrally narrow light sources for optical remote sensing and specifically for certain atmospheric Lidar studies. One application is the study of the mesospheric sodium layer (80-100 km altitude) to determine altitude profiles of atomic density and temperature. For this purpose we have undertaken comparison of the Na (D2) radiation at 589.159 nm produced by either anti-Stokes or frequency doubled first Stokes conversion of alexandrite laser wavelengths. A second application is the profiling of atmospheric water vapor by means of differential absorption Lidar (DIAL) utilizing alexandrite fundamental and Stokes shifted outputs in the 730 nm, 940 nm and 1140 nm bands of water vapor. The 1.4 μm water vapor band also is accessible using output from the Second Stokes shift of alexandrite (at 760 nm) radiation in D2 gas.
Giant Lidars for Middle and Upper Atmosphere Studies: Observational Capabilities of the New Advanced Electro-Optic System (AEOS) at Haleakala, Hawaii
Authors: Gardner Chester S.
Published: February 2023

The development and refinement of sophisticated remote sensing techniques during the past three decades have contributed enormously to our knowledge of the atmosphere. Lidar technologies have progressed especially rapidly since the invention of the laser in 1961. Today, sophisticated systems are used to probe composition and structure throughout the atmosphere from the troposphere into the lower thermosphere and are making important contributions to several global change studies. While the recent advances in lidar technology have been impressive, the accuracy, resolution and sensitivity of many systems are still limited by signal levels.
Flight Results for the Balloon Borne Ozone Profiler with Variable Footprint
Authors: Heaps William S.
Published: February 2023

A prototype of the balloon borne ozone profiler with variable footprint has been developed and was flown from Fort Sumner, New Mexico and September 30, 1992. The instrument was composed of a 100 mm grating spectrograph with an intensified diode array detector covering a spectral range from 250 nm to 350 nm. Scanning of the horizon was accomplished with a right angle dichroic mirror driven by a stepper motor. The viewing direction was determined by a shaft encoder on the scanning mirror and a magnetic compass fixed to the balloon gondola. Altitude was determined using a global positioning system (GPS) receiver.
Solid-State Laser Technology as a Quantitative Solution in Ambient Air Pollution Monitoring
Authors: Smith Craig A.
Published: February 2023

The on-going development of a pulsed Ti:Sapphire DIAL system capable of transmitting wavelengths from 210 nm all the way out to 2.6 μm will be discussed.
Remote Sensing Techniques for Stratospheric and Tropospheric Gas Monitoring
Authors: Woods P T , Jolliffe B W , Milton M J T , Swann N R , Bell W , Martin N A , Gardiner T D , Fogal P F , Murcray D G
Published: February 2023

The National Physical Laboratory is involved with the development and utilisation of different laser-based and other spectroscopic remote sensing techniques for a range of different atmospheric monitoring applications. These include:
Errors introduced in Differential Absorption Lidar Measurements of Stratospheric Ozone by Pinatubo Aerosols
Authors: Steinbrecht W. , Carswell A.I.
Published: February 2023

Differential Absorption Lidars (DIAL) are being used since the early 1980’s to measure stratospheric ozone. They allow a routine, drift free, remote optical measurement of the ozone profile. Therefore they have been chosen as one component of the Network for the Detection of Stratospheric change (NDSC, [1]). Unfortunately, like many optical measurements, their precision is affected by the large amount of aerosols in the stratosphere after a major volcanic eruption. Because of this one has to be very careful when using lidar measurements of ozone together with measurements of stratospheric aerosols, although lidars have been used very successfully in the past to characterize the stratospheric aerosol layers following volcanic eruptions (e.g. [2, 3]).
Comparison of Some CLAES Mixing Ratio Profiles with Correlative Balloon Borne Measurements
Authors: Blatherwick Ronald D. , Murcray Frank J. , Kosters John J. , Goldman Aaron
Published: February 2023

On 24 July, 1992 and 7 April, 1993, the University of Denver conducted two balloon flights designed to obtain correlative measurements for comparison with the CLAES (Cryogenic Limb Array Etalon Spectrometer) instrument aboard the UARS satellite. These flights were performed using our very high resolution (~0.002 cm-1) Fourier transform interferometer-spectrometer operated in solar occultation mode. We present here the results of this intercomparison for several of the trace species which can be measured with both instruments.
Comparison of LBLRTM Calculations with Microwave Radiometric Measurements
Authors: Clough Shepard A , Brown Patrick D. , Miller Nancy E. , Liljegren James C. , Westwater Edward R. , Han Yong
Published: February 2023

Radiative transfer model results from LBLRTM are compared with ground based microwave radiance data from the SPECTRE and ARM experiments.
Calculation of infrared radiance fluctuations using the Strategic High Altitude Radiance Code, SHARC, for space-based remote sensing applications
Authors: Sundberg Robert , Gruninger John , Brown James , Sears Robert D.
Published: February 2023

Simulation of infrared radiance fluctuations in the upper atmosphere depends on fluctuations in atmospheric species number densities, vibrational state populations, and the kinetic temperatures along the sensor line-of-sight (LOS). The model developed in this paper predicts the two-dimensional radiance covariance using linearized equations to connect atmospheric temperature fluctuations and LOS radiance fluctuations. The SHARC1 model is used to calculate mean LOS radiance values and radiance derivatives which are necessary to determine the radiance statistics. The radiance statistics are non-stationary and are explicitly bandpass and sensor FOV dependent.
High Resolution Infrared Solar Spectra from Mauna Loa Observatory
Authors: David Shelle J. , Murcray Frank J.
Published: February 2023

Mauna Loa Observatory (MLO) (19.35°N, 155.58°W, altitude 3.4km), on the big island of Hawaii, is a primary site of the Network for Detection of Stratospheric Change (NDSC). Since November, 1991, a high resolution Fourier transform spectrometer system has been operating on a limited basis collecting spectra in the mid infrared from 750 to 1250 cm-1 (8 to 13 µm) and 2400 to 3050 cm-1 (3.3 to 4.2µm) one sunrise per week. Total column amounts of HC1, HNO3, O3 and N2O are currently processed routinely.
Raman-lidar technique for tropospheric and stratospheric sensing of aerosol optical and microphysical properties
Authors: Wandinger Ulla
Published: February 2023

Tropospheric and stratospheric aerosols and clouds are known to influence the earth’s radiation budget as well as chemical processes of the atmosphere. Thus, remote sensing of optical and microphysical properties of atmospheric particles has important applications in weather and climate research, pollution monitoring, and atmospheric chemistry.