bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical Parametric Source Technology for New Remote Sensing Systems
Authors: Ketteridge P.A. , Budni P.A. , Knights M.G. , Schunemann P.G. , Pollack T. , Chicklis E.P.
Published: February 2023

Requirements for the monitoring of pollutants and industrial by-products emitted into the atmosphere have become more demanding, revealing limitations of traditional methods. Optical Parametric Oscillators (OPO) incorporated as sources into LIDAR systems will allow broad spectral coverage as well as providing both high spectral and spatial resolutions.
Raman Lidar and Sun Photometer Measurements of Aerosols and Water Vapor During the ARM RCS Experiment
Authors: Ferrare R. A. , Whiteman D.N. , Melfi S. H. , Evans K.D. , Holben B.N.
Published: February 2023

The first Atmospheric Radiation Measurement (ARM) Remote Cloud Study (RCS) Intensive Operations Period (IOP) was held during April 1994 at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site near Lamont, Oklahoma. This experiment was conducted to evaluate and calibrate state-of-the-art, ground based remote sensing instruments and to use the data acquired by these instruments to validate retrieval algorithms developed under the ARM program. These activities are part of an overall plan to assess General Circulation Model (GCM) parameterization research. Since radiation processes are one of the key areas included in this parameterization research, measurements of water vapor and aerosols are required because of the important roles these atmospheric constituents play in radiative transfer.
Scanning Raman Lidar Measurements of Atmospheric Water Vapor during a Cold Frontal Passage
Authors: Whiteman D. N. , Melfi S. H. , Starr D. O'C. , Ferrare R. A. , Evans K. D. , Lare A. R.
Published: February 2023

The NASA/Goddard Space Flight Center Scanning Raman Lidar (SRL) had a highly successful deployment at the Department of Energy Cloud and Radiation Testbed (CART) Site in Billings, OK during April, 1994 for the first Intensive Operation Period (IOP) hosted there. During the IOP, the SRL operated from just after sundown to just before sunrise for all declared evenings of operation. The lidar acquired more than 123 hours of data over 15 nights with less than 1 hour of data lost due to minor system malfunction.
Water vapor DIAL measurements using an injection seeded Alexandrite ring laser
Authors: Wulfmeyer V. , Bösenberg J.
Published: February 2023

To investigate the effect of water vapor and temperature distribution on weather and climate both night- and daytime measurements in the whole troposphere with high spatial and temporal resolution are required. For daytime measurements the DIAL method has clear advantages over the Raman technique.
Retrieval of the Atmospheric State Using Data Assimilation Methods
Authors: Rodgers Clive D.
Published: February 2023

To date, retrieval of remotely sounded data from the middle atmosphere has usually been carried out on a profile by profile basis, using climatology or sometimes a previous nearby retrieval as a priori data. For weather forecasting purposes in the troposphere and lower stratosphere, it is possible to use forecast profiles as a priori, and this is sometimes done. Once retrieved, profiles are normally gridded in a relatively simple-minded way for the middle atmosphere studies, or assimilated as profiles in the case of meteorological analysis although recently assimilation has begun to be be used in the middle atmosphere for UARS profile data e.g. by Swinbank and O’Neill (1994) and by others. The topic to be discussed here is the assimilation of radiances from middle atmosphere remote sounders into atmospheric models, as a means of improving the retrieved product. This has been mentioned as a possibility by many authors describing assimilation, but has not been attempted to any great extent. One example in the meteorological analysis case is the assimilation of TOVS radiance by Andersson et al (1994).
Meteorological Applications of the Atmospheric Emitted Radiance Interferometer (AERI)
Authors: Feltz W. F. , Smith W. L. , Knuteson R.O. , Revercomb H.E.
Published: February 2023

The Atmospheric Emitted Radiance Interferometer (AERI) is a Ground-based High Resolution Interferometer Sounder (GB-HIS) used to produce temperature and water vapor profiles every ten minutes in the Planetary Boundary Layer (PBL), the lowest 2.5 km of the earth's atmosphere. AERI measures infrared (IR) radiation (3 to 18 µm) passively, yielding high spectral resolution IR radiance (Δv= 0.5 cm-1). Meteorological information is contained within the radiance spectra as shown in Figure 1. These radiance spectra are transformed to vertical temperature and water vapor profiles by inverting the IR RadiativeTransfer Equation (RTE) (Smith, 1994). High temperature and water vapor retrieval skill, within the PBL, have been shown in several field experiments using AERI (Feltz, 1994).
A Satellite-based Multichannel Infrared Radiometer to Sound the Atmosphere
Authors: Esplin Roy W. , Batty J. Clair , Jensen Mark , McLain Dave , Jensen Scott , Stauder John , Stump Charles W. , Roettker William A. , Vanek Michael D.
Published: February 2023

This paper describes a 12-channel infrared radiometer with the acronym SABER (Sounding of the Atmosphere using Broadband Emission radiometry) that has been selected by NASA to fly on the TIMED (Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics) mission.
Multi-Aperture Ranging Visibility Lidar for Automated Roadside Storm Warning
Authors: Puschell Jeffery J. , Chavez Joseph
Published: February 2023

Many remote stretches of highway are subject to multi-vehicle accidents resulting from sudden reductions in visibility caused by wind-blown snow or dust. Current approaches for alerting motorists use overhead signs that are manually activated by highway department personnel, based on eyewitness reports from drivers delivered in person or transmitted over CB radio. While this method has resulted in some reduction in the accident rate, it is unreliable and subject to reporting delays. A better technique would be to remotely detect changes in visibility onsite just before they become hazardous and activate warning signs automatically. Relatively inexpensive lidar systems can provide the required measurements.
Cloud Microphvsical and Optical Properties from the Atmospheric Emitted Radiance Interferometer at the April 1994 ARM CART Intensive Operations Period
Authors: Collard A.D. , Knuteson R.O. , Ackerman S.A. , Smith W.L. , Revercomb H.E.
Published: February 2023

The University of Wisconsin's Atmospheric Emitted Radiance Interferometer (AERI) is presently being used as part of the Department of Energy's Atmospheric Radiance Measurement (ARM) program at the Cloud and Radiation Testbed (CART) site near Lamont, Oklahoma. This paper describes the AERI measurements taken during the intensive operations period (IOP) at the CART site from 10thApril to 1stMay 1994.
Cirrus Cloud Remote Sensing Program at FARS
Authors: Sassen Kenneth
Published: February 2023

High level cirrus clouds are believed to be important modulators of the radiation balance of the earth/atmosphere system, yet their effects on our potentially warming climate are poorly understood. Although satellites are well positioned to monitor global cloud cover, improvements in current multichannel radiance cloud algorithms to identify and categorize high level clouds are needed. In support of Project FIRE and a broader program of basic cloud research, passive and active remote sensing instrumentation at the University of Utah Facility for Atmospheric Remote Sensing (FARS) has been applied to the study of cirrus clouds since December 1986. At FARS we maintain a data collection schedule in support of NOAA satellite measurements to provide cloud-truth information, routinely using 0.1 Hz polarization (0.694 µm) lidar and coaligned narrow-beam infrared (9.5-11.5 µm) radiometer, various wideband radiometers, and all-sky photography. Derived data products are cloud top and base heights (and local sounding temperatures), cloud phase and composition information, and estimated visible cloud optical thickness and infrared emissivity. As of this time about 1600-hr of this sort of data have been collected at FARS, and more recent observation periods have also involved high-resolution, two-color (1.06 and 0.532 µm) polarization lidar and W-band (3.2 mm) polarimetric Doppler radar.
Simultaneous Retrieval of Atmospheric Temperature and Water Vapor, Cloud Liquid Water and Surface Properties from Microwave Measurements - Application to Real DMSP Data
Authors: Moncet J.L.
Published: February 2023

A physical retrieval algorithm for the simultaneous retrieval of atmospheric temperature, water vapor and cloud liquid water as well as surface skin temperature and emissivity from microwave sounders has been developed by Moncet and Isaacs (1994, 1992). The algorithm uses a nonlinear inversion method similar to the one described by Rodgers (1976) for the inversion of the measured brightness temperatures. The primary background information is from climatology. As shown by Moncet and Isaacs (1992), climatology provides the desired inter-correlation between the various elements of the state vector. This information is used to effectively reduce the number of degree of freedom in the problem, and therefore reduce the dependence of the solution on the first-guess. Information from other sources, such as forecast models, is integrated by optimally combining it with the primary background information. Emissivity is treated by retrieving one emissivity value per channel. The degree of correlation between the emissivities in the different channels is specified through the first-guess error covariance matrix. This method offers more flexibility than the one proposed by Eyre (1990) and makes it possible to apply the algorithm to combinations of sensors with mixed viewing geometries and polarizations such as the DMSP microwave sensor suite. Cloud liquid water is treated in the same way as Eyre (1990).
Observation of Polar Stratospheric Clouds (PSCs) in Canadian Arctic by Lidar and Balloonborne Optical Particle Counter
Authors: Yasui Motoaki , Mizutani Kohei , Itabe Toshikazu , Uchino Osamu , Nagai Tomohiro , Fujimoto Toshifumi , Fujiwara Motowo , Shibata Takashi , Hayashi Masahiko
Published: February 2023

PSCs play important roles not only in global climate change through its own effects on radiation budget of the earth but also in ozone depletion through heterogeneous chemical processes which occur on the surfaces of the PSCs. The mechanisms of the processes, however, have never clarified enough because of scarcity of data especially in arctic stratosphere. Japanese lidar group started operating Japan Arctic Lidar Network in arctic region in 1993, and plenty of lidar data have been obtained so far. The PSC lidar at Eureka station (80° N, 86° W) in Canadian arctic forms a link in the chain of the network. Adding to the lidar observation, we started to perform balloonborne observation of the PSCs in the last winter. In this presentation, the results of the balloonborne and lidar observation of PSCs are shown.
Preliminary Measurements of Vertical and Horizontal Variation in Marine Aerosol Backscatter in Hawaii
Authors: Lienert Barry , Porter John , Sharma Shiv , Cooney Tom , Clarke Antony
Published: February 2023

The goal of our research effort is to derive the vertical and horizontal structure of aerosol scatter in the lower marine boundary layer. Our approach is to use a multi-wavelength 3-D scanning lidar to measure the aerosol backscatter. Realistic aerosol size distributions are assumed in order to derive the wavelength dependent aerosol scattering and backscattering coefficient. At the same time we use an instrumented aircraft to simultaneously measure in situ aerosol size distributions for validation purposes. Both coarse mode sea salt and accumulation mode sulfate aerosols contribute to the atmospheric scatter in the marine boundary layer. Typically sea salt dominates under clean conditions but sulfate rapidly becomes the major scatterer as polluted conditions are approached. On average, the accumulation mode aerosols are well mixed with altitude and sea salt variations cause the vertical gradients in atmospheric scatter. Models of the average sea salt size distribution have been made (Porter and Clarke, 1996; Garthman, 1983; Woodcock, 1953) but the vertical gradients remain insufficiently well characterized. Vertical profiles of the total salt aerosol mass remains equally uncertain. Although vertical profiles of salt concentration have been measured successfully, natural atmospheric dynamics cause a wide range of vertical and horizontal variability. Measurements of sea salt vertical concentration have been measured using both kites and aircraft (Blanchard et al., 1984; Daniels, 1989; Woodcock, 1953). On average these measurements show a strong gradient in the lowest 30 m and a gradual decrease above that. Individual measurements show strong variability with altitude with pronounced maxima and minima. While these studies provide us with an initial idea of the structure of sea salt in the marine boundary layer, they do not provide a large enough data set from which to make statistical inferences.
Simulation of Space Lidar Returns under Multiple Scattering from Cloud
Authors: Noguchi Kazuo , Saito Yasunori , Nagao Satomi , Nomura Akio
Published: February 2023

To perform a reliable analysis of space lidar returns, knowledge on the ratio of single scattering to multiple scattering is highly required. In this study, we have carried out a Monte-Carlo simulation of the space lidar signals from cloud.
The Next Generation Carbon Monoxide Mapper
Authors: Roell Marilee M.
Published: February 2023

The next generation carbon monoxide mapper will be included in the GeoTropSat mission concept proposed by NASA Langley Research Center. The enabling technologies needed to produce the 2.3 μm carbon monoxide gas filter correlation radiometer ensure that this instrument shall be state of the art and capable of remotely producing high resolution global temporal and spatial variability of the tropospheric carbon monoxide concentrations. The improvements in the carbon monoxide data sets are possible with this proposed instrument as a result of the location in orbit, sensing wavelength, and the use of advanced technologies. The challenge is to produce this data set within a budget one third the size of those allocated to past remote sensing satellite missions.
The HITRAN Atmospheric Workstation (HAWKS)
Authors: Rothman Laurence S. , Schroeder John , McCann Andy
Published: February 2023

A new edition of the HITRAN molecular spectroscopic database and the high-temperature analog (HITEMP) have recently been released.1,2 They are included in a compilation called HAWKS (HITRAN Atmospheric Workstation). HAWKS represents more fully a “matter” database. Besides an updated HITRAN high-resolution molecular database of about one million transitions, there are files of aerosol indices of refraction, UV line-by-line and cross-section parameters, supplemental files of gases such as ionic species and ozone parameters suitable for atmospheric non-local thermodynamic equilibrium conditions, extensive IR cross-sections now at different pressures and temperatures, and molecular parameters suitable for modeling high-temperature radiance. In addition there is a moderate-resolution band-model code, MODTRAN3. There is also vastly improved software handling of the data in both WINDOWS and UNIX platforms, such as more sophisticated selection filters, plotting capabilities, pointers to significant references, and documentation.
Remote Sensing Measurements of Tropospheric Air Pollutants by Ground-Based Thermal Emission FTIR
Authors: Evans W.F.J. , Puckrin E.
Published: February 2023

The detection of tropospheric ozone and other pollutants are of considerable interest because of their extensive environmental impact on society. Previous in situ measurement techniques have shown enhancements in ground-level ozone by as much as 100 ppbv in the Windsor-to-Quebec corridor (Heidorn and Yap, 1986; Lin et al., 1992). Recently, we have used a novel technique based on FTIR spectroscopy to measure the radiation from ozone against the cold blackbody emission of clouds. From these thermal emission measurements we have been able to estimate the tropospheric ozone amount. Additional measurements also have been made under cloudless conditions during a strong pollution episode in the SONTOS'96 campaign.
The Unreasonable Effectiveness of Mimicking Measured Infrared Extinction by Hexagonal Ice Crystals With Mie Ice Spheres
Authors: Arnott W. Patrick , Liu Y. , Schmitt Carl , Hallett John
Published: February 2023

An armada of infrared1-2 and other remote sensing equipment have been developed and deployed to characterize clouds from the ground, from airplanes, and from satellites. Perhaps someday we will be able to trust this equipment to provide all the information we need about clouds - we no longer will have to fly through them and directly record particle statistics - but first, we must properly invert cloud radiative signatures to obtain particle information. To invert, obvious common thought has been that we must have proper numerical models for the single scattering properties of generally nonspherical cloud particles. We have been using a cloud box in the laboratory to measure radiative properties of spherical water3 and hexagonal ice particles4 in a controlled environment where clouds can be well characterized. Our first spectral extinction measurements (2-18 µm) were performed on ice clouds grown near water saturation at a variety of temperatures so that a wide range of particle morphologies from nearly equi-axed columns to sector plates were observed.4 Then we measured spectral extinction by water clouds so we could learn how to invert, using Lorenz-Mie theory, the extinction spectra to obtain particle size spectra, with the larger goal in mind of eventually retrieving ice particle size spectra using the discrete dipole approximation.3 We decided to first apply the inversion based on the Lorenz-Mie theory for ice spheres to the measured ice spectra (mostly so we could grin and giggle at the anticipated poor results), and found much to our surprise that the retrieved IR spectra matched the measurements even better than the water cloud results! Though the retrieved ice sphere size spectra are qualitatively in accord with the measured results, we have not yet found a proper principle to guide us in converting from the geometry of a hexagonal ice crystal to the geometry of a sphere. Ok, so the Mie model seems to work for mimicking the infrared spectral extinction by ice crystals, but are the inverted size spectra reasonable and useful? Come to the talk and find out.
Field Performance of the NOAA High Resolution Doppler Lidar
Authors: Grund Christian J. , Cohn Stephen A. , Mayor Shane D.
Published: February 2023

The NOAA High Resolution Doppler Lidar (HRDL) is a coherent detection system that combines an eye-safe1 near-infrared wavelength, diode-pumped solid-state Tm:Lu,YAG laser2 transmitter, and improved signal processing techniques, with an accurate, high speed scanning system. The HRDL program goal is to develop an easily transported system capable of observing the turbulent fluctuations of the wind with better than 50 m spatial resolution and a few cm/s velocity resolution, over volumes of a several km3/sec. The enhanced measurement capabilities are primarily needed to provide improved data sets for boundary layer LES model initialization, and validation, to study the fine scale structure, evolution, and transport of energy in turbulent and stable boundary layers, and for the measurement of fluxes by eddy correlation. The long term stability and high resolution capabilities of this technology also facilitate better estimation of poorly correlated turbulent quantities (e.g. , ).
Remote Sensing of Trace Gas Fluxes Using DIAL and RADAR/RASS
Authors: Bösenberg Jens
Published: February 2023

Trace gases play an important role in the climate system. The most important trace gas certainly is water vapor, because it strongly affects both the radiation budget and the water cycle. It has been stated many times that detailed knowledge about the highly variable distribution of water vapor is mandatory for an understanding of weather and climate systems. In particularly the change of water vapor concentration, and hence the exchange of water vapor between atmosphere and surface, is most interesting in studies of many lower tropospheric processes. Reliable methods for estimating this vertical exchange or flux are therefore highly welcome.
An Algorithm for Hyperspectral Remote Sensing: Solar and Thermal Regimes
Authors: Anderson G.P. , Chetwynd J.H. , Berk A. , Bernstein L.S. , Acharya P.K.
Published: February 2023

“Hyperspectral” is a relatively new descriptor for measurement techniques historically used by the atmospheric remote sensing communities. As opposed to “multi-spectral” sensing, which includes any instrument with a finite number of specific channels, filters, or bands, hyperspectral implies employing enough (usually contiguous) channels to provide redundant information on both the characteristics of the surface and the atmosphere when the instrument is configured for nadir viewing. This definition (Alex Goetz, Univ. of Colorado, private communication) can be contrasted with others, such as ‘any instrument with better than 4 cm-1 resolution.” This latter definition can be inadequate in the infrared spectral range because many overlapping molecular systems will not be sufficiently discriminated at such ‘narrow’ resolution. However, the 4 cm-1 resolution is often much more than adequate in the visible, when typical resolutions of 10 nm (e.g. AVIRIS, Green et al., 1996) at 600 nm corresponds to a frequency resolution of over 200 cm-1.
High Spectral Resolution Remote Sensing of Cirrus Cloud Visible to Infrared Spectral Optical Depth Ratio
Authors: DeSlove D. H. , Piironen P. K. , Eloranta E. W. , Smith W. L.
Published: February 2023

Infrared and visible cirrus cloud optical properties were measured using ground-based high spectral resolution remote sensing data. The optical properties include: downwelling atmospheric radiance at infrared wavelengths in addition to atmospheric aerosol backscatter cross-section and depolarization at a visible wavelength. Data was acquired at the University of Wisconsin-Madison, during a 3 month case study from October through early December, 1995. The instrument suite included: a High Spectral Resolution Lidar (HSRL) (Piironen and Eloranta, 1994), an Atmospheric Emitted Radiance Interferometer (AERI) (Revercomb et al., 1993), and a Cross-chain Loran Atmospheric Sounding System (CLASS).
Development of an All-Solid-State Raman Laser for Ozone DIAL Measurements
Authors: McCray Christophe L. , Chyba Thomas H.
Published: February 2023

In order to measure atmospheric ozone with the DIAL technique, the laser transmitter must generate suitable on-line and off-line wavelength pulse pairs. Preliminary experiments1 at NASA LaRC suggested that the solid state Raman shifting material, Ba(NO3)2, could be utilized to produce these pulse pairs. A Raman oscillator pumped at 532 nm by a frequency-doubled Nd:YAG laser can create first Stokes laser output at 563 nm and second Stokes output at 599 nm. With a frequency doubler, UV output at 281 nm and 299 nm can be subsequently obtained. This all-solid state system can be very compact and has the potential to be very efficient and reliable. Such attributes are essential for the next generation of airborne or space-borne lidar systems.
Atmospheric Raytracing and Air Mass Calculations for Spaceborne Remote Sensing Measurements with the Earth as an Ellipsoid
Authors: Kemnitzer H. , Clarmann T. v. , Stiller G.
Published: February 2023

Raytracing and air mass calculation are the fundamentals for the direct and inverse solution of the atmospheric radiative transfer. For limb viewing instruments refraction is a major concern at least in the case of low tangent altitudes. This paper presents a method for raytracing and airmass calculations which is applicable to an ellipsoidal earth shape. This is in particular important for the MIPAS-ENVISAT instrument [1], because ENVISAT will be a polar orbiter, and MIPAS is planned to be a rear-scanning instrument, such that a single line of sight will cover a wide latitude variation.
Airborne Lidar Results During RACE
Authors: Strawbridge Kevin B.
Published: February 2023

There is an increasing effort towards understanding the role of anthropogenic aerosols regarding their radiative influence on global climate in terms of both the direct and indirect effect (Charlson et al. (1992), Penner et al. (1994). The Radiation, Aerosols and Cloud Experiment consisted of a four week intensive study based in Nova Scotia, Canada during August and September of 1995. The majority of flights took place over the Bay of Fundy and Gulf of Maine. The four main objectives were 1/ to determine the effect of cloud microphysics on the albedo of low stratus cloud 2/ to determine the impact of aerosol particles on cloud microphysics 3/ to examine satellite retrieval methods for determining cloud properties, and 4/ to determine the interaction of chemical constituents with clouds.
Range-resolved lidar measurements of the atmosphere using an eye-safe infrared KTP optical parametric oscillator
Authors: Klein Sarah Harrell , Wilcox William E. , Killinger Dennis K.
Published: February 2023

Developments in the performance of optical parametric oscillators (OPOs) have significantly improved the lidar measurement capabilities in the 0.5 µm to 5 µm spectral region. We have recently developed a new eye-safe, infrared optical parametric oscillator (OPO) and have used it as the source in a direct-detection lidar system to make range-resolved backscatter measurements of the atmosphere. The OPO, which was fabricated by Schwartz Electo-Optics, consisted of a Nd:YAG pumped KTP OPO and produced an output pulse with energy of about 160 mJ, pulse repetition frequency of 10 Hz, wavelength of 1.57 µm, and transverse mode quality described by M2 ≈ 50.
Coincident Comparisons of Ozone Profiles Measured with the NASA Goddard Space Flight Center Stratospheric Ozone Lidar Trailer Experiment (STROZ-LITE) and the Stratospheric Aerosol and Gas Experiment (SAGE) II
Authors: Gross Michael R. , McGee Thomas J.
Published: February 2023

The mobile stratospheric ozone lidar system operating at NASA’s Goddard Space Flight Center has been actively acquiring data at sites around the globe since 1987. It is a primary calibration instrument for the Network for the Detection of Stratospheric Change (NDSC), traveling to various permanent network sites and carrying out ozone, temperature and aerosol comparisons with ground based remote sensing instruments. Since 1991, the system has also been an Upper Atmosphere Research Satellite (UARS) validation instrument. In addition the instrument has been used as ground calibration for several aircraft missions. In 1995, the lidar group joined the science team for the Stratospheric Aerosol and Gas Experiment (SAGE)-II, and has since concentrated on acquiring lidar data coincident with SAGE-II overpasses. This paper will present comparison results from this past year, as well as from previous missions since 1989.
Dual wavelength Raman lidar observations of tropical cirrus clouds during the ALBATROSS campaign 1996
Authors: Beyerle G. , Schäfer H.-J. , Neuber R. , Rairoux P. , Schrems O. , McDermid I. S.
Published: February 2023

Recent model calculations have shown that the extreme dryness of the tropical lower stratosphere can be explained by slow uplift of air masses by large-scale motions leading to the formation of an ubiquitous cirrus cloud layer [1]. We present first results from lidar observations of tropical cirrus clouds above the Atlantic ocean during the ALBATROSS campaign (Atmospheric chemistry and lidar studies above the Atlantic ocean related to ozone and other trace gases in the tropo- and stratosphere) in October-November 1996.
An Improved Charge Controller Model for Solar Powered Standalone Lighting Systems
Authors: Negi Ajit Pratap Singh , Bagai Deepak , Mahajan Rita
Published: February 2023

The paper proposes an improved charge controller scheme for solar power based standalone lighting systems, by efficient charging and discharging of battery through a common controller circuit with a well known technique, Pulse Width Modulation. The concept is being given keeping in mind the necessity, cost and importance of lighting in remote areas, although the technique can be used in other places too. Assuming the White LED (WLED) lamps to be used as light source, the whole circuit just operates on d.c. Since the battery is efficiently utilized in both charging and discharging process through a common controller circuit, the battery works for a longer life and the overall cost of the system may come out to be very low with a very bright clear WLED lighting, an ideal combination for a energy efficient solar power based standalone systems for lighting in remote areas.
Polyimide Optical Waveguides
Authors: Beuhler Allyson J. , Wargowski David A. , Singer Kenneth D. , Kowalczyk Tony , Cahill Paul A. , Seager Carl
Published: February 2023

Aromatic polyimides are of interest for integrated optics due to a combination of high thermal stability and easy processibility into planar structures. Polyimides can withstand chip attach and package assembly temperatures and are resistant to corrosive etchants and cleaning solvents making them compatible with a variety of substrates and metallization schemes. Waveguides from polyimide can be patterned by photobleaching1 or etching2 using standard semiconductor or printed circuit board technology and equipment. Polyimide properties are easily engineered by co-polymerization with co-diamines or dianhydrides to tailor the refractive indices or incorporate photosensitivity. Electro-optic polyimides have been demonstrated that incorporate non-linear optical chromophores by guest-host doping.3
Interpenetrating Polymer Networks with Stable Second-Order Optical Nonlinearity via an In Situ Sol-Gel Reaction
Authors: Chen J. I. , Marturunkakul S. , Li L. , Jeng R. J. , Kumar J. , Tripathy S. K.
Published: February 2023

Several organic nonlinear optical (NLO) materials possess larger second-order optical nonlinearities than their inorganic counterparts. However, the temporal stability of the NLO properties in the polymeric materials needs to be improved at elevated temperatures. The longterm NLO stability is a critical factor for possible future applications. To enhance the temporal stability, NLO moieties are usually incorporated in a high glass transition temperature (Tg) polymer which is capable of preventing the randomization of the poled (aligned) NLO molecules. Moreover, the temporal stability can be greatly enhanced when a certain degree of crosslinking is introduced.1
Buried channel waveguide electro-optic device fabrication in multi-layer polymer thin films
Authors: Shi Yongqiang , Steier William H. , Ranon Peter M. , Wang Wenshen , Chen Datong , Fetterman Harold R.
Published: February 2023

After nearly a decade of research and development, second order nonlinear optical polymers are now available with sizable NLO coefficients and improved temperature stability. The techniques for fabricating optical devices from these materials are in hand. These materials are particularly attractive for infrared electro-optic modulators and switches operating in the multi-GHz range which are integrated onto a common substrate with high speed electronics. In most of these EO devices, buried channel optical waveguides are necessary to guide the light and to prevent excessive optical loss due to metal electrodes. The ability to fabricate low loss buried channel waveguides is therefore critical to the device technology and we report here our approach using dry reactive ion etching (RIE). Using this approach we have built waveguides, Mach-Zehnder interferometers, and high frequency modulators in several thermosetting polymers and polyimide NLO materials.
Fabrication of molecular oriented films of α-sexithienyl by OMBD and their third order nonlinear optical properties
Authors: Kurata Tetsuyuki , Hamano Kouji , Kubota Shigeru , Koezuka Hiroshi
Published: February 2023

Among third order nonlinear optical materials, π-conjugated polymers such as polydiacetylene, PTS 1) have advantages in terms of the large third order optical susceptibility χ(3) and the fast responce to optical signals.
Azo-dye-doped photorefractive polymers
Authors: Kippelen Bernard , Sandalphon  , Peyghambarian Nasser , Lyon Scott R. , Padias Anne B. , Hall Henry K.
Published: February 2023

Since its recent discovery1, photorefractivity in polymers2-7 has attracted particular attention because photorefractive materials are versatile media for reversible optical storage applications and because organic materials like polymers have potential advantages over inorganic photorefractive crystals: low dielectric constant, ease of processing, and low cost. The capabilities of this new class of composites materials6 have rapidly reached a level comparable to those of some inorganic crystals and further improvement is expected since the magnitude of some intrinsic parameters such as the electro-optic coefficient for instance are not optimized yet. Here, we describe photorefractivity in azo-dye doped polymers. Azo dyes are molecules with strong second order nonlinear optical properties and are also known to undergo trans-cis photoisomerization8-9. The azo-dye-doped polymers presented here, can store two different types of erasable holograms originating from two different physical processes: photorefractivity and trans-cis photoisomerization. We show that the strong polarization nature of the isomerization process allows isolating exclusively the photorefractive effect by selecting the polarization of the reading beam. Moreover, we discuss the possible enhancement of the read-out photorefractive efficiency by photoisomerization-assisted poling of the sample.
Multifunctional Carbazole Polymers for Nonlinear Optics
Authors: Wada Tatsuo , Sasabe Hiroyuki
Published: February 2023

Electric and optical properties of organic charge-transfer (CT) compounds have been attracted a lot of attention from both fundamental science and practical applications. Remarkable progress have been made in development of electroactive CT materials such as organic metals, conducting polymers, and organic photoconductor. Recently organic intracharge transfer compounds have been experimentally and theoretically elucidated to exhibit anomalously large nonlinear optical responses.1 Nonlinear optical properties of several CT complex systems have been studied and recently photorefractive effects have been observed in CT complex crystal and poled photo- conductive polymers. These poled polymers consist of three components: the nonlinear optically active chromophore (NLO-phore) to provide the electro-optic response, a hole transporting molecule and a photosensitizer which exhibit photoconductive properties.2
Second-order nonlinear optical properties and thermal stability of the amino-sulfone chromophore containing polymers
Authors: Ranon Peter M. , Shi Yongqiang , Steier William H. , Xu Chenzeng , Wu Bo , Dalton Larry R.
Published: February 2023

The second-order nonlinear optical (NLO) properties of azo compounds containing amino-donor and sulfone-acceptor groups have been reported by several research groups.1 Their studies demonstrated that these amino-sulfone chromophores have a sizable nonlinearity and can be functionalized at both ends of the molecule for either polymerization or crosslinking. In this paper, we report our study of several side chain and main chain polymers which focused on anchoring both ends of the chromophores within a polymer matrix to improve the thermal stability of the molecular alignment. In particular, we report our study of two new classes of amino-sulfone chromophore containing polymers.
Ultrafast Energy Relaxation in π-Conjugated Polymers
Authors: Kersting R. , Lemmer U. , Mahrt R. F. , Leo K. , Kurz H. , Bässler H. , Göbel E. O.
Published: February 2023

In recent years, the promising prospects for applications of polymers in optoelectronic and nonlinear optical devices have stimulated much interest in their fundamental optical properties. Among the attractive polymers for electroluminescent devices are poly(phenylenevinylene)(PPV) and poly(phenyl-p-phenylenevinylene) (PPPV). Although high quantum yields are demonstrated [1], several fundamental properties like the large Stokes shift between absorption and luminescence are not well understood. For an optimization of material parameters, a detailed understanding of the optical response is needed.
Optimal Design of Polymer-Based Triple-Stack Photonic Devices with Three-Dimensional Dipole Patterns
Authors: Bauer-Gogonea S. , Bauer S. , Gerhard-Multhaupt R.
Published: February 2023

A polarization-independent modulator based on the electro-optical (EO) effect is a key element for optical communication networks, whereas second-harmonic generation (SHG) is essential for high-density optical storage1. Triple-stack layers are required to form a waveguide which usually consists of an EO or nonlinear optically active (NLO) guiding layer and two claddings2. With polymer materials, triple stacks may have three active layers (two active claddings and the guiding layer). For example, the same guest/host or side-chain polymer may be employed, but with a different amount of nonlinear optical dipoles in each layer. Triple-stack preparation by spin coating is still possible if different solvents are used for the individual layers. The device design consists of a two-step procedure. First the waveguide geometry is optimized, then the overall design is developed. It will be shown that poling is as an additional degree of freedom in the system design.
Effective Reduction of Photobleaching Time of Nonlinear Optical Polymer for Fabrication of Waveguide in Thin Film
Authors: Zyung Taehyoung , Hwang Wol-Yon , Kim Jang-Joo , Jung Sang-Don
Published: February 2023

Various techniques have been used for the fabrication of polymeric channel waveguide for active and passive devices: poling, photobleaching, photolocking, reactive ion etching, etc. Among them, photobleaching offers simple processibility and controllability. Some authors[1,2] have reported on the fabrication of channel waveguides by this tehnique. However, it takes long time, typically on the order of tens to hundreds hours, to bleach out a nonlinear optical polymer (NLO) thin film with the thickness of a few µm using mask aligner.
Measurement of Nonlinear Index n2(λ) By Using White Laser Pulses
Authors: Zhao Jianming , Qian Qiuming , Wang Zhijiang
Published: February 2023

Z-scan method proposed in report [1] is proved that it is an effective and simple method to measure the third order nonlinearity. In our early works[2, 3, 4], we modified Z-scan method by using two wavelength picosecond laser pulses to measure the third order nonlinearity and nonlinear response of chloroplastin and chlorophll-a. In our setup, one is a fixed wavelength laser and another is a tunable laser pulses pumped by a same YAG laser. Recently M.Sheik-Bahae and co-worker[5, 6] also improved their Z-scan method to measure the nonlinear response and nondegenerate nonlinearities. Here we introduce another modified Z-scan system, as shown in figure 1, which was set up in our laboratory to measure the nonlinearity and response time by using white laser pulses. We will campare this setup with our early setup. We found this set up is more simple than the old one.
A Mach-Zehnder modulator fabricated with a polymer having improved high temperature characteristics
Authors: Girton D. G. , Eimer S. , Valley J. F. , Van Eck T. E.
Published: February 2023

Electro-optic (EO) polymers with high temperature characteristics are required for use in typical systems. During assembly and packaging operations, devices must be able to survive assembly temperatures around 250 C for short excursions, and in system applications they can be subjected to temperatures of 100 °C (125 °C for military) for long periods of time1. The current generation of EO polymers with glass transition temperatures below 200 °C can be used in special applications, but they are inadequate for ordinary system use. An EO polymer with improved temperature characteristics was developed and Mach-Zehnder modulators were fabricated on Si wafers using this material.
Two-photon absorption induced luminescence and second harmonic generation in organic waveguides
Authors: Roux J.F. , Coutaz J.L. , Le Barny P. , Chastaing E. , Robin P.
Published: February 2023

It is of interest to use nonlinear optical materials in a wavelength domain close to the absorption band, in order to increase the nonlinear coefficient value of the material [1]. However, this absorption should appear at a multiphoton level, because single photon absorption gives rise to high optical attenuation of the pump beam. This concept is mainly applied in third order nonlinear experiments [2], for which working near half the band gap leads to high χ(3) coefficient without strong absorption of the pump beam.
Stability-Efficiency Trade-Off in Non-Linear Optical Polymers
Authors: Levenson R. , Liang J. , Rossier C. , Van Beylen M. , Samyn C. , Foll F. , Rousseau  , Zyss J.
Published: February 2023

Organic nonlinear optical materials have been the subject of increasing interest over the past decade[1]. Polymeric materials with highly polarizable molecules exhibit nonresonant NLO responses surpassing those obtained from traditional inorganic NLO materials, e.g. LiNbO3, KDP etc. Polymers offer the possibilities to optimize, by chemical synthesis, properties required for materials such as high mechanical and thermal stability. The dielectric constants of polymers ensure a very fast response-time for polymer devices [2], Compared to guest-host polymers, side chain polymers whereby NLO molecules are covalently attached lead to an increased density of nonlinear chromophores and may therefore exhibit higher nonlinear susceptibilities.
Aromatic polyureas for second-order nonlinear optics
Authors: Nalwa Hari Singh , Watanabe Toshiyuki , Kakuta Atsushi , Mukoh Akio , Miyata Seizo
Published: February 2023

Nonlinear optical materials possessing large second-order optical nonlinearities at short wavelengths are highly desirable for laser frequency conversion to fabricate high-power laser sources.1-4 Organic polymers are important materials because they offer the advantages of thin film processability, ease of structural modification and fabrication. Therefore organic polymers having nonlinear optical (NLO) chromophores either in the main chain or as pendant groups have attracted a great deal of attention. An efficiency/transparency trade-off is the most important factor for practical applications in the field of nonlinear optics. Organic NLO polymers having persistent large second-order optical nonlinearity coupled with desired optical transparency at the fundamental as well as at the second-harmonic wavelengths can be utilized in many applications. Bearing in mind the efficiency/transparency trade-off, we have designed and synthesized a wide variety of polyureas exhibiting large second-order optical nonlinearity and good optical transparency.5,6 This paper describes the second-order optical nonlinearities of novel aromatic polyureas having pendant NLO chromophores. The relationships between molecular structures and optical as well as nonlinear optical properties of polyureas are discussed.
Toward the Practical Application of Polymeric Optical Interconnection Technology
Authors: Yardley James T. , Eldada L. , Stengel K. M. T. , Shacklette L. W. , Wu Chengjiu , Xu C.
Published: February 2023

Intrinsic resistance and capacitance limit the rate at which information can be moved through conventional electronic circuitry. In principle, optics provides means for much higher data transfer rates. In addition, optical information pathways are insensitive to electromagnetic interference. Today glass optical fibers are routinely used for high speed data transfer in many applications. Although these fibers provide a very convenient means for carrying optical information over long distances, they are very inconvenient for complex high density optical circuitry. Furthermore, interconnection devices fabricated from glass optical fibers are difficult to fabricate and are very fragile. Polymeric materials, on the other hand, offer the potential to create highly complex optical interconnection circuitry on a planar substrate. In addition, they provide the possibility for a much higher degree of ruggedness. What has been needed is development and characterization of suitable polymeric materials, development of fabrication techniques for polymeric optical devices, development of technology for interconnection of polymer waveguides with glass optical fibers and full characterization of the resulting optical circuitry. We have developed a technology for polymeric optical interconnection which addresses these needs. The key features of this technology and some example applications will be described here.
Nonlinear Spectroscopy of DANS Side Chain Polymers
Authors: Cha Myoungsik , Otomo Akira , Torruellas William E. , Stegeman George I. , Beljonne David , Brédas Jean Luc , Horsthuis Winfried H.G. , Möhlmann Guus R.
Published: February 2023

Molecular systems, in particular polymers, with π-electron donor-acceptor groups are becoming potential candidates in applications where large bandwidth and low costs are desired for electro-optical modulation of optical information. Di-Phenyl molecules including Disperse-Red-1 and Di-Amino-Nitro-Stilbene (DANS) embody most of the requirements in stability, high loading, processability and very large electro-optical figures of merit1. However little is known about their electronic structure represented by their excited state spectrum and responsible for their nonlinear optical response, for both second and third order. We present a complete spectroscopic study of the DANS molecular system and compare our theoretical predictions to the second order nonlinear spectrum and four third order nonlinear optical spectra of amorphous DANS side-chain polymers. In particular we can successfully explain shifts of the nonlinear spectrum compared to the linear absorption one by properly accounting for Frank-Condon type displacements2.
Linear and Nonlinear Spectroscopy of β-Carotene and Other Oligo-polyenes: Experimental and Theoretical Studies
Authors: Rohlfing F. , Bradley D.D.C. , Cornil J. , Beljonne D. , Brédas J. L , Eberhardt A. , Müllen K.
Published: February 2023

We report studies of linear- and electro-absorption spectra which allow new insights into the electronic structure of polyenes and their nonlinear response.
Electronic and Nonlinear Optical Properties of Organic Molecules: Assessment of the Influence of the Molecular Structure
Authors: Meyers Fabienne , Chen Chin-Ti , Beljonne David , Brédas Jean-Luc , Marder Seth R.
Published: February 2023

In a previous work, using computational approaches, we analyzed how the polarizability, α, second-order polarizability, β, and third-order polarizability, γ, are controled by the ground state polarization [1-4]. To do so, we investigated the influence of an external, static electric field upon the nonlinear optical (NLO) properties, for a set of push-pull polyenes [1]. The calculated effect of the external electric field on the molecular structure and electronic properties of the chromophores is similar to that resulting from donor-acceptor substituents on a segment of the chromophore, or from changing the dielectric properties of the environment around the molecule, e.g., increasing the polarity of the solvent. The structure/properties relationships derived from that study are summarized in Figure 1, and have allowed us to propose chemical design prescriptions for the optimization of second- and third-order optical nonlinearities in organic molecules [3].