bluuebunny/crossref_metadata_2025 huggingface dataset:
Organic Thin Films on the 30-kJ OMEGA Glass Laser System
Authors: Schmid A. , Kessler T. , Marshall K. , Armstrong J.
Published: February 2023

Passive, organic thin films perform key optical-phase-control functions on the new, 30-kJ (351-nm) OMEGA glass laser system. Thin-film control-device performance requirements, material selection criteria, and in-system use experiences are reported. Performance limits and next-generation device requirements will be discussed as well.
Optical Response of a Chiral Molecule and Circular Dichroism in Second-Harmonic Generation
Authors: Maki Jeffery J. , Kauranen Martti , Verbiest Thierry , Persoons André
Published: February 2023

Surface second-harmonic generation has been found experimentally and theoretically to be capable of detecting chirality of a surface and of discriminating between the two enantiomers of a chiral molecule. ’ We calculate the second-order nonlinear optical response of a chiral molecule using a simple classical model and calculate the circular dichroism in second-harmonic generation from a thin film of chiral molecules.
The Effect of Poling Induced Polymer Film Deformation on Second-Harmonic Generation in Periodically Poled Polymer Channel Waveguides
Authors: Jäger M. , Stegeman G.I. , Brinker W. , Yilmaz S. , Bauer S. , Horsthuis W.H.G. , Möhlmann G.R.
Published: February 2023

Second-harmonic generation (SHG) in waveguides has been important for years as a method of obtaining a compact, coherent blue light source. Recently, this field has received new attention due to the possibility of using cascaded χ(2)-effects for all-optical switching, spatial solitons etc. Because some polymers have exhibited large second order non-linearities after poling, there has been a growing interest in using these materials for waveguide SHG. Besides high d-coefficients, polymers offer easy processing and are a cheap alternative to inorganic crystals. In this paper we report the fabrication of periodically poled polymer channel waveguides, the deformation of the waveguide under the electrode fingers during poling, and the demonstration of SHG by quasi-phase-matching in a channel waveguide made of 4-dimethylamino-4'-nitrostilbene (DANS) side-chain polymer.
Relaxation Processes in Nonlinear Optical Side-Chain Polyimide Polymers
Authors: Kaatz P.G. , Prêtre Ph. , Meier U. , Stalder U , Günter P. , Zysset B. , Stähelin M. , Ahlheim M. , Lehr F.
Published: February 2023

Optical, nonlinear optical and electro-optic properties of modified side-chain polyimide polymers as shown in Fig. 1 have been determined. Relaxation processes in these nonlinear optical (NLO) polymers are of considerable interest for obtaining a better understanding of the long-term stability of potential devices fabricated from these materials. The relaxation mechanisms of the side-chain chromophores have been investigated above and below the glass transition by second-harmonic decay, dielectric relaxation and differential scanning calorimetry measurements. We find that the time-temperature relaxation behavior of the NLO chromophores in a variety of polymer systems can be understood in terms of current phenomenological descriptions of the glass transition with the aid of a scaling relation.
Current flow in doped and undoped electro-optic polymer films during poling
Authors: Girton D. G. , Anderson W. W. , Marley J. A. , Van Eck T. E. , Ermer S.
Published: February 2023

Electric-field poling is used to achieve a macroscopic alignment of the chromophores responsible for the electro-optic (EO) effect in polymer films.1 In EO polymer devices this chromophore doped layer, referred to as the “core” layer, is usually stacked between two polymer “cladding” layers of lower index which confine transmitted light to the core layer. These polymer films are formed by spin coating using standard semiconductor equipment and manufacturing processes. The polymer films are amorphous as spun and cured, so the polarizable chromophores are randomly arranged, and therefore no second-order electro-optic effects occur. Electric-field poling has been used to make a variety of EO polymer devices2,3,4,5, but the process is not well understood. In electric field poling the EO polymer is heated above its glass transition temperature Tg, a voltage is applied by electrodes to align the nonlinear chromophore molecules in the direction of the field, and the material is cooled back to room temperature under the influence of the electric field. While the voltage is applied to the cladding/core/cladding stack of films, the electric field divides in some manner so that a portion of the applied voltage appears across each of the film layers, as illustrated in Figure 1.
Double Heterostructure and Multiple Quantum Well Organic Light Emitting Diodes for Flat Panel Displays
Authors: Ammermann Dirk , Böhler Achim , Rompf Christoph , Kowalsky Wolfgang
Published: February 2023

Multilayer organic light emitting diodes (OLEDs) have recently been intensively studied [1,2] for future applications in large-area flat panel color displays. The principle of operation is similar to that of inorganic light emitting diodes (LEDs). Holes and electrons are injected from opposite electrodes into the organic layer sequence and recombine generating singlet excitons that decay radiatively. The emission layer consists of highly fluorescent organic dye molecules sandwiched between separate hole and electron transport layers. This multilayer structure allows to achieve bright electroluminescent emission in the visible spectral region at low driving voltages. We discuss the growth and characterization of high brightness double heterostructure diodes in the green spectral region and present results obtained from organic multiple quantum well light emitting diodes.
Highly Scattered Optical-Transmission Polymer for the Liquid Crystal Display Backlight
Authors: Horibe Akihiro , Izuhara Megumi , Nihei Eisuke , Koike Yasuhiro
Published: February 2023

In LCD application, it was thought that transparent polymer materials were necessary for optical-transmission media of light sources. Therefore, for conventional edge-light type backlight systems which have lamps on one or both edges, transparent PMMA homopolymer plate has been used as a waveguide. And, it was believed that a transparent PMMA homopolymer plate as a waveguide was indispensable. However, this conventional system has not given satisfied luminance.
Self-Assembly Approaches To Organic Second-Order Nonlinear Optical Thin Film Materials
Authors: Wong George K. , Lin Weiping , Zhou Haitian , Hahn David , Lundquist Paul M. , Lin Wenbin , Roscoe Stephen B. , Yitzchaik Shlomo , Marks Tobin J.
Published: February 2023

There is much current interest in molecule-based nonlinear optical (NLO) materials because they offer attractions such as large nonresonant response, ultrafast response times, low dielectric constants/losses, intrinsic tailorability.[1] Although considerable progress has been made in the fabrication of organic NLO materials in recent years, particularly in the areas of poled glassy polymers[2,3] and Langmuir-Blodgett films[4], significant synthetic challenges have impeded the realization of optimum materials.[1,2] These challenges include maximizing chromophore hyperpolarizability and number density as well as maximizing the degree and thermal/temporal stability of induced microstructural acentricity. An attractive and intuitively superior alternative to the above approaches[2-4] is a covalent self-assembly[5] process in which acentric chromophoric superlattices[6] are built up in a layer-by-layer fashion.[6,7] We report here a new topotactic self-assembly approach to the preparation of robust chromophoric architectures with high structural regularity and large nonlinear optical response.
Photochemical Stability and Performance of Second Order Nonlinear Optical Chromophores and Polymers
Authors: Twieg R. J. , Lee V. Y. , Miller R. D. , Moylan C. R. , Volksen W. , Knoesen A. , Hill R. A. , Yankelevich D. R.
Published: February 2023

The performance of χ(2) poled polymer nonlinear optical media is influenced by numerous intrinsic materials properties as well as the specific conditions of subsequent processing and use of the materials. The origins of microscopic optical nonlinearity have now become much better understood and some highly optimized nonlinear optical chromophores have been prepared. The processing to create polar thin polymer films containing these chromophores by application of an electric field is also now much better optimized. Once the polar order is created the influence of temperature (thermal history) on its magnitude has also been studied in great detail and much progress has been made on design of materials with enhanced temporal stability of poled order. In conjunction with this latter effort chromophores with enhanced thermal stability were identified to permit use of high glass transition temperature media.
Vertical Integration of Polymer Electro-Optic Devices on Electronic Circuits
Authors: Kalluri Srinath , Chen Antao , Ziari Mehrdad , Steier William H. , Liang Zhiyong , Dalton Larry R. , Chen Datong , Jalali Bahram , Fetterman Harold R.
Published: February 2023

A major topic of research in the opto-electronics field over the last decade has been the integration of photonic devices with electronic circuits. The major hurdle here is the fabrication incompatibility of the different material systems required for electronics and photonics. Most integrated photonic devices with applications in fiber communications are fabricated from compound semiconductors (lasers, modulators, detectors) or from crystalline dielectrics (modulators). On the other hand Si electronics (or GaAs for high speed) are highly developed and available through semiconductor foundries. To integrate this well developed electronics technology with conventional photonics technology has required techniques like flip chip bonding, epitaxial liftoff, solder bump technology and other forms of hybrid integration.
Photo excitation stability and bias voltage stability of electro-optic polymer modulators for broadband analog transmission systems
Authors: Shi Yongqiang , Olson David J. , Bechtel James H. , Kalluri Srinath , Steier William H. , Wang Wenshen , Chen Datong , Fetterman Harold R.
Published: February 2023

Broadband analog transmitters are an important part of many information delivery systems. Nonlinear optical (NLO) polymer devices have shown a great potential of playing a major role in ultra-wide bandwidth analog transmission systems due to the low dielectric constant, flexibility of processing, compatibility with semiconductor technology, and high nonlinearities. The general requirements for polymer modulators used in an externally modulated broadband transmission system were briefly discussed previously.[1] In this summary, we will focus on two practical issues for polymer modulators used in an externally modulated analog transmission system: the photo excitation stability and the quadrature bias voltage stability of electro-optic( EO) polymer modulators. The photo excitation stability is directly related to the signal-to-noise ratio of the analog signal link, device life-time, and processing conditions. The bias voltage stability will affect the fidelity of the transmitted analog signal. Using a thermally crosslinkable polyurethane with Disperse Red 19 side groups(PUR-DR19), we have tested the performance and the stability of EO polymer devices.
Photoinduced Birefringence, Holographic Surface Gratings and Photorefractive Properties of AZO Polymers
Authors: Ho Mei Sing , Barrett Chris , Rochon Paul , Natansohn Almeria
Published: February 2023

Azo polymers are the subject of an impressive number of publications in the recent literature, due to a variety of possible applications. The main area of interest is in their nonlinear optical (NLO) properties, and azo-containing polymer films have been synthesized, poled and their second harmonic generation and waveguide properties have been investigated. The publication pace on this subject is considerable, and it would be impossible to summarize the most important trends. The general directions of the research are related to improved thermal stability and especially to methods to increased stability of orientation of the azo chromophores. Polyimides and/or crosslinked polymers are the preferred methods to achieve these goals.
Azobenzene side chain polymer films for optically induced holographic surface relief gratings
Authors: Kim D. Y. , Li Lian , Kumar J. , Tripathy S. K.
Published: February 2023

Recently we have observed the formation of large amplitude and stable surface relief gratings directly produced on epoxy-based nonlinear optical polymer films with Disperse Orange 3 azobenzene side groups.1 The surface relief gratings were produced upon exposure to an interference pattern of polarized laser beams at modest intensities without any subsequent processing steps. Very similar results of the formation of the surface relief gratings were also independently reported on an acrylate polymer with Disperse Red 1 azobenzene side groups by Rochon et al.2 A surface modulation depth of more than 1000 Å has been observed. The intensities of the writing beams were well below the power required for ablation of the polymer. The gratings could be erased by heating the polymer above its glass transition temperature (Tg) and the writing and erasing cycles could be repeated. While it was already known that irradiation of a polarized laser beam could result in orientation of the azobenzene groups leading to birefringence in the polymer film,3-7 such a large surface change on the polymer film solely due to the alignment of molecules was not expected and seems to have its origins due to new optically induced processes which have not been explained so far. Large scale molecular motion and volume change due to reorientation seemed to be occurring simultaneously.
High-frequency Demodulation of Multi-Photon Fluorescence in Hyper-Rayleigh Scattering
Authors: Clays Koen , Olbrechts Geert , Persoons André
Published: February 2023

The problem of multi-photon fluorescence in hyper-Rayleigh scattering has been realized some time ago. [1] A number of very large hyperpolarizabilities have been suspected to be caused by a fluorescence contribution to the incoherently scattered second-harmonic. Different measurement schemes have been devized to exclude this additional contribution to the signal, resulting in an overestimate for the value of the first hyperpolarizability β. The quadratic dependence is true for both hyper-Rayleigh and two-photon fluorescence. Hence, a discrimination based on intensity-dependence is not valid. Two-photon fluorescence can start from wavelengths shorter than the second-harmonic (anti-Stokes two-photon fluorescence[2]) and always extends to wavelengths longer than the second-harmonic. Spectral discrimination is, hence, not possible neither. Fluorescence is spectrally not as narrow as is scattering. Fluorescence background subtraction or correction has been shown to be feasible, but time-consuming.[3] A very elegant solution has been proposed on the single possible basis of the temporal difference between the immediate scattering and the time-delayed fluorescence.[4] This solution uses essentially the same fast photon counting equipment as is used in single photon timing. Only the photons in an early and small window are regarded as due to scattering.
Next Generation Ultra-High Frequency Integrated EO Modulators
Authors: Chen Datong , Fetterman Harold R. , Tsap Boris , Chen Antao , Steier William H. , Dalton Larry R. , Wang Wenshen , Shi Yongqiang
Published: February 2023

Measurements of traveling wave modulators made from electrooptic polymer materials have now been extended to over 110 GHz using high frequency commercial probes. An optical heterodyne detection system (figure 1) has been developed to characterize those devices at high frequencies. The use of both YAG and tunable semiconductor lasers (tunable range of 8 THz) has helped to improve the detection range and sensitivity of the system. The frequency response of the system was limited only by the operation of our coplanar connecting probes.
Nonlinear Spectroscopy and Applications of Two-Photon Absorbing Molecules
Authors: Ehrlich J. , Heikal A. , Hu Z.-Y. , Lee I.-Y. S. , Marder S. R. , Perry J. W. , Röckel H. , Wu X. L.
Published: February 2023

Molecules exhibiting strong two-photon absorption hold great potential for a wide range of applications including: two-photon fluorescence microscopy, three-dimensional (3D) optical data storage, 3D microfabrication, and optical limiting. (1-4) From a fundamental point of view, knowledge of molecular two-photon spectra and structure/property relationships are also important for a more complete understanding of the third order polarizabilities of conjugated molecules. However, very little is known or understood about two-photon states and spectra of conjugated molecules or how they correlate with structure. We have observed large two-photon absorptivities in bis-donor diphenylpolyene derivatives, that appears to be correlated to simultaneous charge transfer from the end groups to the pi-conjugated bridge in the molecule. These molecules are also excellent photoexcitable electron donors that can initiate charge-transfer reactions. In initial applications of these materials we have demonstrated their use in two-photon initiation of polymerization and optical limiting.
High Speed Polymer Optical Fiber and Related Photonics Polymer
Authors: Koike Yasuhiro
Published: February 2023

With the growing interest focused on the broadband network systems, optical fiber network for high speed telecommunication becomes more important in the premise network area. Silica base single mode fiber is an ideal medium for long distance communication because of its high transparency and high bandwidth, while its much low attenuation is minor advantage in the short distance network. As many data distributions and fiber connections are required in the premises wiring and LANs, low coupling and distribution losses must be maintained. Therefore, we have proposed a large-core, high-bandwidth graded-index polymer optical fiber (GI POF) for high speed data "transmission" medium, and we succeeded in several gigabit transmission in 100 m GI POF link. However, as the GI POF was composed of poly methyl methacrylate (PMMA), its high attenuation of transmission limited the GI POF link length to approximately 100 m. Recently we proposed the low-loss perfluorinated (PF) polymer base GI POF which enables more than 300-m transmission with maintaining high data rate.
“Quadrupoling” for Second Order Nonlinear Optics
Authors: Singer K.D. , Hubbard S.F. , Petschek R.G. , D’Sidocky N. , Hudson C. , Chien L.C. , Henderson C.C. , Cahill P.A.
Published: February 2023

Achieving noncentrosymmetric order for second-order nonlinear optical materials has been a continuing focus of research. Monomolecular layer deposition and electric field poling of polymers have been favored approaches to generating noncentrosymmetric polymeric and organic materials.1 In this case, the alignment exploits the vector part of the molecular hyperpolarizability tensor which is optimized in donor and acceptor substituted conjugated molecules. The principles behind the nonlinearities, both molecular and macroscopic are well-known, and considerable work has been directed at optimizing them. More recently, it has been pointed out that the octupolar hyperpolarizability component is ubiquitous and can be as large or larger than the vector part with appropriate molecular design.2
Thiophene based Nonlinear Optical Chromophore functionalized Epoxy Polymers for Electro-Optic Applications
Authors: Chittibabu K. G. , Li L. , Wang X. , Kumar J. , Tripathy S. K.
Published: February 2023

Polymeric materials present certain advantages over inorganic crystals for second-order nonlinear optical (NLO) applications because of their low dielectric constant, large optical nonlinearity, low cost, and ease of processability. Stable NLO polymeric materials are potential candidates for electro-optic (EO) devices such as high bandwidth electro-optic modulators [1], optical interconnects [2], and fiber optic gyros [3]. Second-order NLO properties in polymers are present when the chromophores are aligned in a non-centrosymmetric manner. Chromophores with enhanced NLO susceptibilities can be obtained by increasing electron-donating and/or accepting effects [4], by extending the conjugation length between the donor and acceptor groups [5] and by replacing the phenyl moieties in the chromophores with thiophene moieties [6]. Efforts were made by our group [7] and various other groups [6, 8] to synthesize and optimize the properties of the chromophore functionalized polymers with high optical nonlinearity. Jen and coworkers synthesized a variety of thiophene based chromophores with high optical nonlinearity, 'μβ' [6, 8]. Many of these chromophores, when doped in a polymer matrix exhibited an electro-optic value greater than 20 pm/V. Marder and coworkers studied the effect of strong acceptors in NLO chromophores and have found that an 'r33' value of 55 pm/V at 1.313 μm is realizable with some of these chromophore doped polycarbonate composites. However, most of these systems are of guest-host type, which limit the chromophore solubility as well as temporal stability of the poled order in the NLO chromophore-polymer composites.
Field-Induced Spatial Deformations in Chiral Smectic A Liquid Crystals
Authors: Bartoli F. J. , Lindle J. R. , Flom S. R. , Ratna B. R. , Shashidhar R.
Published: February 2023

The application of an electric field to an electroclinic liquid crystal (ELC) causes the molecules to tilt, permitting efficient modulation of an optical signal. This electroclinic tilt also leads to a reduction of the smectic layer thickness, thus introducing strain and causing the planes to deform in order to accommodate the change in the layer thickness. When the ELC is viewed under a polarizing microscope, a spatial modulation of the transmission is observed.1-5 The resulting stripe texture is generally depicted as a triangular deformation of the smectic layer, where a deformation angle equal to the electroclinic (EC) tilt angle preserves the interlayer spacing.5 In this paper, the relationship of the deformation angle and the EC tilt angle is investigated by measuring the field dependence of the transmission of an ELC placed between crossed polarizers. The measured extinction is sensitive to the molecular alignment and is therefore a useful probe of the field induced deformation.
Spontaneously Self-Assembled Polar Multilayers With High Second-Order Optical Nonlinearity
Authors: Johal M. S. , Smilowitz L. , Robinson J. M. , McBranch D. W. , Li D.Q. , Yang W. S. , Cao Y. W. , Chai X. D. , Jiang Y. S. , Li T. J.
Published: February 2023

Ordered molecular assemblies can lead to materials with extremely high second-order non-linear optical (NLO) properties [1] with applications in technologies such as optoelectronics [2] and permanent magnetism [3]. Although organic molecules with high nonlinearities are well known, it has been difficult to design bulk materials in which the molecules are highly ordered with the same orientation. In this work, we use second harmonic generation (SHG) to determine the second-order nonlinear coefficient (d33) of a spontananeously self-assembled, polar multilayer film (Figure 1) grown by drop casting on a silica substrate. Using ellipsometry to measure film thickness, the average molecular orientation of the chromophores is also determined.
Optical Measurement of the Glass Transition Temperature of Polymer Waveguides for Integrated Optics
Authors: Bock Harald , Christian Stefan , Knoll Wolfgang , Vydra Jan
Published: February 2023

The development of polymeric devices for integrated optical applications has recently received much attention [1]. The thermodynamic properties of the waveguiding materials are of vital interest in this field. In particular the fabrication of active components based on poled nonlinear chromophore functionalized polymers requires knowledge of the materials’ glass transition temperature T
g
, since the relaxation of noncentrosymmetric orientational order is strongly related to the glass transition.
Transient Photoconductivity in Thin Films of Ferrocene Carboxylic Acid
Authors: Prayaga Chandra S. , Mungan Carl E. , Chow Lee
Published: February 2023

Organic thin films have been actively studied since the early 1980s for photonic applications, due to their large, ultrafast nonlinear optical and electro-optic coefficients, as well as their stability and their ability to be molecularly engineered. Many of the most interesting applications depend on charge transport of the delocalized π electrons in the medium, and hence are influenced by the electronic mobility and the presence of optically active traps [1]. The incorporation of metal ions into the organic compounds enhances their optical nonlinearities. Photoconductivity is also directly related to the mobility of photo-excited charge carriers, their lifetimes, and the recombination mechanisms, and has applications such as in optoelectronic switching and optical detection [2].
Polarization-Independent Electro-Optic Polymer Devices with Twisted Optic-Axis Waveguide Polarization Converters
Authors: Oh M.-C. , Hwang W.-Y. , Lee H. J. , Lee M. H. , Ahn J.-H. , Park H. , Han S. G. , Won Y.-H.
Published: February 2023

Electro-optic waveguide devices are essential components for the high-speed photonic signal processings and broadband optical communications. In the lightwave signal transmission, the polarization state of the light is not maintained when a standard single-mode fibers are used. Hence, polarization independent EO devices are preferred to reduce the system complexity caused by an adaptive polarization controlling circuit. In lithium niobate substrates, there have been various investigations for the polarization-independent switches such as mode-evolution type digital switches [1], directional coupler switches with coincident coupling length for TE and TM modes [2], Mach-Zehnder (MZ) switches on x-cut, z-propagating orientation providing degenerated TE and TM modes [3], The switching voltages of these devices are 17 ~ 60 V. In this work, we propose a polarization-independent polymer waveguide modulator [4] which can be realized by integrating a polymeric polarization converters [5] in the middle of the MZ modulator. The optic-axis of the polarization converting waveguide is twisted 90 degree by poling it with specially designed electrodes.
Accordion Polymers with Aromatic Donors
Authors: Herman W.N. , Stenger-Smith J.D. , Chafin A. , Gratz R. , Hollins R. , Yee R. , Lindsay G.A.
Published: February 2023

Nonlinear optical (NLO) polymers are of considerable interest for photonics applications due to their fast NLO response time, low cost, ease of fabrication, favorable material characteristics for high-speed modulation, and potentially large nonlinear second-order susceptibility. These materials can readily be formed into thin films fabricated by standard microelectronic techniques. Photonic modulators with bandwidths as high as 110 GHz have recently been reported.1
Orientational Relaxation of NLO Dipole Moments Transversely Aligned to the Main Backbone in the Linear Polyurethane
Authors: Tsutsumi Naoto , Matsumoto Osamu , Sakai Wataru
Published: February 2023

Recently, we have synthesized a new type of linear polyurethane (T-polymer) with NLO azobenzene chromophore whose dipole moment is aligned transverse to the main chain backbone and another linear urethane polymer (L-polymer) with NLO dipole chromophore incorporated in the main chain backbone.1 The resultant poled T-polymer shows the large second order nonlinearity of d33=1.6 × 10-7 esu (67 pm/V) with good thermal stability at the ambient conditions.1 This polymer is amorphous with a high density of NLO chromophore moiety and optically transparent thin film, which can be processed by spin-casting or solvent casting.
Hyper-Rayleigh Scattering and Two-Photon Absorption-Induced Fluorescence of Chromophores with Enhanced Thermal Stability
Authors: Hsu Chia-Chen , Shu Ching-Fong , Huang Tzer-Hsiang , Lin Jiunn-Lih , Wang Yuh-Kai , Zang Yi-Liang , Wang C.H.
Published: February 2023

Hyper-Rayleigh scattering (HRS) technique has been frequently used to determine chromophore's β values.1 Comparing with the electric field induced second harmonic generation (EFISH) technique, the HRS technique offers a straightforward method for measuring the first hyperpolarizabilities of organic molecules. Recently, HRS from some molecules excited with the fundamental radiation at 1064 nm wavelength has been found to be accompanied by the two-photon absorption (TPA) induced fluorescence.2-3 Consequently, the β value determined by the HRS technique without making appropriate corrections for the contribution due to TPA induced fluorescence could be too large. To obtain the correct β value, the TPA induced fluorescence must be discriminated or removed from the HRS signal.
Nonlinear Optical Films from Pairwise-Deposited Semi-ionomeric Syndioregic Polymers
Authors: Roberts M. J. , Lindsay G. A. , Stenger-Smith J. D. , Zarras P. , Hollins R. A. , Chafin A. P. , Nadler M. P. , Wynne K. J.
Published: February 2023

Processing polymers near room temperature to produce all-polymeric nonlinear optical films has important advantages [1]. For example, the Langmuir-Blodgett-Kuhn (LBK) technique offers control over final film thickness to within one monolayer. Also, materials may be precisely located within the film to control properties for purposes such as phase matching of the fundamental and second harmonic waveguide modes [2].
Application of Highly Scattering Optical-Transmission Polymer to high quality LCDs
Authors: Horibe Akihiro , Nihei Eisuke , Koike Yasuhiro
Published: February 2023

More efficient LCD backlights have been strongly required to achieve lower electric power consumption and higher brightness on the LCD panel.
Three Dimensional Integrated Optics Using Polymers
Authors: Garner Sean , Chuyanov Vadim , Chen Antao , Kalluri Srinath , Marti-Carrera Felix Ignacio , Steier William H. , Dalton Larry R.
Published: February 2023

Two dimensional integrated optical circuits have been demonstrated with considerable complexity and size. For example, 19x19 integrated star couplers1 have shown the large-scale routing capabilities of optical waveguides. As the two dimensional area and complexity of these circuits increases, problems can arise, for example, if the signals require similar optical time delays. The vertical integration of optical devices into a three dimensional structure can offer a significant increase in the integration density without increasing the time delays or the integration area. In 3-D integrated optics, one envisions several layers of 2-D integrated optics with the various layers coupled together vertically at appropriate locations by vertical waveguide bends, vertical waveguide power splitters, or vertical voltage controlled switches.
Preparation and Characterization of Single Crystal PTS Waveguide Film
Authors: Liu M. , Hwangbo C.K. , Friedrich L. , Stegeman G. I.
Published: February 2023

Spatial optical solitons have been receiving an increasing amount of attention due to their potential application for all-optical interconnects. Bright solitons arise as a compensation of natural diffraction of an optical beam by a self-focus nonlinearity. They have been observed in semiconductor, glass and CS2 waveguides at powers of 500W, 400KW and 500KW [1,2,3]. Recently, conjugated polymer poly[2,4-hexadiyn-1, 6-diol-bis(p-toluenesulfonate)] (PTS) was reported to have large positive nonlinearity (2.2×10-12W/cm2) and a very small two-photo absorption at around 1.6μm [4]. The large off-resonant positive nonlinearity would allow the one dimensional (ID) spatial soliton at a practical power level on PTS slab waveguide. We now report the preparation and waveguiding of PTS films.
Basic Mechanisms involved in the Off-resonant Nonlinear Refractive Index of PTS-Polydiacetylene
Authors: Quintero-Torres R. , Thakur M.
Published: February 2023

Polydiacetylene single crystal, PTS, is known to have the largest off-resonant nonlinear refractive index (n2). Recently we have demonstrated picosecond all-optical switching using PTS-polydiacetylene in a Fabry-Perot cavity1. This measurement was performed using a pump-probe technique with 90ps pulses at 1.06μm wavelength. In that measurement, besides demonstrating a large modulation depth, we showed that the sign of n2 was negative. In another work, however, a positive sign for n2 was reported from a z-scan measurement2 and two photon resonances were used to explain the positive sign and the off-resonant nonlinear optical processes in PTS. In this work we have made detailed measurements of the sign using Michelson interferometry and z-scan. These and previous measurements using pump-probe technique at different off-resonant wavelengths show that the sign of n2 of PTS is negative over the wavelength of 650 - 1064nm.
Characterization of Push-Pull Polyenes of Increasing Size: Linear and Quadratic Polarizabilities in Solution
Authors: Fort Alain , Muller Jacques , Azoulay Joel , Barzoukas Marguerite , Alain Valérie , Blanchard-Desce Mireille
Published: February 2023

Push-pull molecules have been extensively studied for their properties in the field of quadratic nonlinear optics. Such molecules consist of electron-donor and electron acceptor substituents connected via a conjugation path. The partial intramolecular charge transfer (ICT) between these end groups can lead to large ground-state dipoles μ. Also, they can display huge static quadratic hyperpolarizabilities β(0) related to the occurence of the ICT transition between the ground and first-excited states [1].
One and Two Photon Induced Photodegradation of DANS Films
Authors: Zhang Qiang , Canva Michael , Stegeman George
Published: February 2023

Dye doped solids have been investigated for a decade for non-linear optical applications, especially for integrated optics. In some areas, their “single shot” performance has now reached levels which compete with the best ferroelectrics materials and thus encourages their practical usage. However, a key question remains to be answered : how stable is their performance with time when used in given devices and under operational conditions ?
Light Amplification in Polymer Optical Fibers
Authors: Kobayashi Takeyuki , Nihei Eisuke , Sasaki Keisuke , Koike Yasuhiro
Published: February 2023

Polymer optical fibers (POF) have attracted increasing attention because of their clear technical advantages over glass fibers, such as flexibility and a large core diameter, which enable efficient coupling and connection. Recently, we developed low-loss (100 dB/km) high-bandwidth (5.12 GHz for 100-m transmisson) graded index POF1. Polymer optical fibers that regenerate signal light in the visible and infrared are potentially important because of their adaptability for POF-based short span optical local distribution networks such as premise wiring and LAN.
About Traps in Displaying Optical Performances of A Progressive Addition Lens
Authors: Bourdoncle B. , Chauveau J.P. , Mercier J.L.
Published: February 2023

There are many ways of displaying optical characteristics of a Progressive Addition Lens (PAL). These characteristics are computed by ray-tracing (1).

A short description of a PAL is given. This lens is used for the compensation of presbyopia (2,3). The front surface is a deep non-rotationnally symmetric aspheric designed in order to vary the local power. Then, it allows the presbyope to focus at every distance by changing the gaze. For such an exotic surface, the mathematical model (4,5) is also described.
Optics and Contrast Questions Connected with the Multifocal IOL
Authors: Miller David
Published: February 2023

Multifocal IOL's of different designs are now being implanted in patients. This paper will attempt to put in perspective the early clinical results, and relate them to questions of multifocal design, implant decentration, pupillary function, contrast sensitivity, as well as describe a new design.
Image quality and photoreceptor distribution
Authors: Artal Pablo , Navarro Rafael
Published: February 2023

The two first stages in the spatial information processing performed by the human visual system are the optics of the eye and the spatial sampling in the photoreceptor mosaic. Recently, we have developed at the Instituto de Optica in Madrid, objective techniques to measure both image quality [1-4] and photoreceptors distribution [5]. In particular, we are able to determine image forming properties of the human eye and to measure cone spacing in the living fovea by using together coherent imaging and digital image processing.
The Chromatic Eye: A New Model of Ocular Chromatic Aberration
Authors: Thibos Larry N. , Ye Ming , Zhang Xiaoxiao , Bradley Arthur
Published: February 2023

The optical apparatus of the eye presents a low-pass spatial filter to the front end of the visual system which is a potential limiting factor for any visual task. In the well-focused eye, chromatic aberration and diffraction are thought to be the major optical factors limiting vision.1-3 Recent evidence indicates that ocular chromatic aberration can significantly reduce image contrast, resulting in loss of contrast sensitivity and visual acuity, and may also inject large artifacts into the retinal image of colored visual targets.4,5 Such problems are likely to be exacerbated by the use of achromatizing lenses6 or other optical apparatus such as clinical test instrumentation7 which may shift the eye's achromatic axis away from the fovea, thus exposing central vision to transverse aberration from which it is normally protected.8 Consequently, it is important to have available an accurate, mathematically tractable model of ocular chromatic aberration to help gauge the potential magnitude and significance of these optical effects for visual performance.
Change of Pupil Centration with Change of Illumination And Pupil Size
Authors: Wilson M. Anne , Campbell Melanie C.W. , Simonet Pierre
Published: February 2023

Pupil centration is important for retinal image quality. Both the principal line of sight and the optical axis of a centered optical system pass through the center of the entrance pupil. However, we know that the eye is not, in general, a centered optical system. The eye suffers from a variety of regular and irregular aberrations. Howland and Howland1 have indicated that coma, in spite of much intersubject variability, is the predominant monochromatic source of image degradation. Coma is a pupil position dependent aberration. Attempts to map the wavefront aberration across the pupil have shown local wavefront irregularities with very marked inter-subject differences. For an axial object point the wavefront aberration of the eye is rarely symmetrical about the pupil center2,3. Walsh and Charman2 reported that, although Howland and Howland could deduce no direct influence of pupil centration, asymmetry of the wavefront aberration in an eye can produce marked degradation in the modulation transfer function (MTF) even with slight decentrations of the pupil. These authors also found that in two eyes an improved MTF could be produced with an appropriately decentered pupil. Campbell et.al.3 have found both subjects with coma induced by pupil position and coma independent of pupil position.
A Comprehensive Optical Model of the Aging, Accommodating Adult Eye
Authors: Blaker J. Warren
Published: February 2023

Traditional schematic eyes as best exemplified by the Gullstrand eye model have been static.1 Gullstrand presented two distinct sets of lens parameters for a young, mature adult eye, one to describe the eye's state for distance vision and a second to describe the fully accommodated eye. In an earlier paper we used a gradient index model for the crystalline lens and were easily able to describe the optical parameters of the young, mature eye for any level of accommodation.2
Age-Related Trends of the Ocular Components and Refractive Error in Childhood
Authors: Zadnik Karla , Mutti Donald O. , Adams Anthony J.
Published: February 2023

The ocular components which influence refractive error have been investigated in an ongoing fashion for the last 50 years. The classic notions of normal distribution of the ocular components (except axial length and refractive error), the skewed, leptokurtic distribution of refractive error with its disproportionate number of emmetropes, the correlation between refractive error and axial length, and the concept of refractive error as a result of mismatched association among the ocular components in a given eye have all resulted from studies measuring human eyes in vivo . However, we believe that there is a common misconception that the growth of the eye in childhood and the development of myopia are well understood.
Comparison Between Measurements of Retinal Thickness Made Noninvasively in Vivo and by Microscopy in Vitro
Authors: Shahidi Mahnaz , Land Richard , Weinhaus Richard S. , Snodderly D. Max , Zeimer Ran
Published: February 2023

In many ocular diseases the retinal thickness is altered due to edema or atrophy. We have developed a method to measure the retinal thickness and thus provide earlier diagnosis and improve therapy monitoring. The application in humans has provided encouraging results. (1,2) To establish the method further, comparison between in vivo and in vitro thickness measurements in the same eye are desirable. The layers from which light is reflected and detected by the in vivo method can be identified and more information about the presence of tissue distortions arising from the in vitro method during preparation can be acquired. We present the comparison between locally measured thickness values in a cynomolgus monkey and measurements made by light microscopy of the whole mounted retina.
Battery-Powered Head-Mounted Binocular Video Magnifier for the Visually Impaired
Authors: Massof Robert , O’Shea Donald , Raasch Thomas , Clark Peter , Londono Carmina , Severns Matthew , Ferg Arthur , Gilmore Arthur , Lalle Peter , Abts Leigh
Published: February 2023

An estimated 3 million people in the U.S. suffer severe visual impairments that cannot be corrected medically, surgically, or with conventional eyeglasses. People with this type of visual impairment are described as having "low vision", because in most cases the visual impairment can be attributed to reduced visual acuity. The most common complaints of people with low vision are the loss of reading, the inability to recognize faces and objects, and difficulty watching television.
Spectacles with Adjustable Power
Authors: Regener Victor
Published: February 2023

Spectacles with manually adjustable power are intended for persons who need a single corrective device for all distances. The design of these spectacles employs two lenses for each eye, one lens of positive power and one lens of negative power. When the lenses are in contact or in close proximity their combined power is designed to be zero for an emmetropic eye, or else it is designed to conform to the prescription for distant vision of a myopic or a hyperopic eye. By mechanically adjusting the spacing between the lenses the wearer achieves visual acuity for any distance.
The Correction of Presbyopia
Authors: Freeman M H
Published: February 2023

The physiology of accommodation is well understood. The optics of accommodation and its diminution with presbyopia is not well understood. Our eyes produce relatively poor images and the optics of poor images is much more complex than the optics of good images.
Zonal-Progressive Design: New Multifocal Ophthalmic Lens to Correct Presbyopia
Authors: Portney Valdemar
Published: February 2023

Optical design of a multifocal intraocular lens is limited to the simultaneous vision principle which features two or more lens powers within the pupillary area at the same time. The principle is applied as well to contact lenses though some design requirements are different due to contact lens fitting constrains, wearer's residual accommodation and IOL's safety considerations. The simultaneous principle can be divided into two basic designs: Bifocal lens specified by two levels of diopter powers and Progressive Aspheric with continuous range of diopter powers (Charman and Saunders, 1990; Morrison, 1986; Freeman and Stones, 1987; Charm et al., 1987; Charman and Walsh, 1988; Evans and Morrison, 1983; Evans, 1983; Charman and Walsh, 1986; Erickson et al., 1988).
Clinical Significance of in - vitro MTF: Phenomenological Model
Authors: Lang Alan , Portney Valdemar
Published: February 2023

In 1965, Campbell and Green made use of the concept that the MTF of the human dioptric could be inferred from the ratio of sign-wave to interferometric contrast sensitivity measurements1. Below, we employ the same procedure, in reverse, to suggest a phenomenological algorithm for predicting the "clinical significance" (e.g., letter or sign-wave contrast sensitivity) of changes made to the human dioptric (e.g., multifocal IOL implant). This algorithm can also be used to predict the Through- Focus-Capability (acuity v.s. defocus), with the potential for studying expected changes with light intensity and object contrast. A comparison of predictions to early clinical data derived from Allergan's randomized AMO ArrayTM multifocal clinical study, demonstrates the plausibility of this approach.
Artificial Pupils and Maxwellian Viewing Systems
Authors: Jacobs Robert J. , Bailey Ian L. , Bullimore Mark A.
Published: February 2023

In vision research and in some clinical tests and instruments, the effective pupil size may be controlled by the use of artificial pupils. The artificial pupils may be real (such as a pinhole aperture placed in the spectacle plane) or they may be virtual (such as a small exit pupil of a Keplerian telescope or an image of a small source as is used in Maxwellian view systems). The purpose of artificial pupil systems may be to increase the depth of focus, to channel light around opacities or irregularities in the media, to maintain constant retinal illuminance or in some Maxwellian view systems it may be to provide a large uniformly-illuminated field of high luminance. If artificial pupil systems are used to present spatial resolution tasks to the observer, then critical differences between the alternative artificial pupil systems should be be recognized. Here we compare retinal image qualities obtained with real artificial pupils and with virtual artificial pupils in a Maxwellian viewing system.
Interrelationships of the Ocular Components in Emmetropia and Myopia
Authors: Goss David A. , VanVeen Hank G.
Published: February 2023

The refractive error distribution in the general population is leptokurtic with a peak near emmetropia, and is skewed toward myopia. Part of the high frequency of emmetropia may be accounted for by an intercorrelation of the components of ocular refraction. An inverse correlation of axial length of the eye and its refractive power would reduce the variability of refractive error. A posteriorward movement of the retina would produce a tendency toward myopia, while a reduction in corneal and/or crystalline lens power would produce a tendency toward hyperopia.(1) Statistically significant inverse correlations of axial length with corneal anterior surface power and axial length with crystalline lens power have been reported.(2) The magnitudes of these correlations are greater for groups of persons near emmetropia than for groups with wider ranges of refractive error. (2)