bluuebunny/crossref_metadata_2025 huggingface dataset:
The average soliton model and its application in soliton communications with lumped amplifiers
Authors: Blow K. J. , Doran N. J.
Published: February 2023

Here we shall show that soliton propagation in lumped amplified systems is described by the lossless NLS provided two conditions are fulfilled. The first is that the power from the amplifier is such that on average (over the amplifier link) the power is equal to the single soliton value in the lossless NLS. This we call the average soliton prescription. The second is that the amplifier spacing is short compared to the nonlinear evolution length scale.
Effect of strain on Auger processes in GaAs and InP based quantum well-lasers - applications for improved threshold current and time response
Authors: Loehr John P. , Singh Jasprit
Published: February 2023

The introduction of biaxial strain to the active region of quantum well lasers creates dramatic changes in the bandstructure of the well. The bandgaps are altered, resulting in an increased wavelength tunability, and the density of states is significantly affected. In particular, the valence band masses can be reduced by a factor of 3 with the introduction of ~2% strain (see Fig. 1).1 As is now well known, this reduced hole mass leads to improved inversion at the bandedge and results in a significantly lower threshold current density for the strained systems2−4; the strain-induced splitting between heavy and light holes also results in an improved selectivity of TE over TM modes in the emission. In addition, it is expected from the threshold conditions for Auger transitions5 that the changes in hole masses and bandgaps associated with strain will greatly reduce the rate of Auger processes in strained materials. This is extremely important for 1.55μm lasers grown on InP, since the Auger transition rate increases exponentially with the small bandgap. In this work we present a comprehensive model of the effect of strain on Auger processes, threshold current density, time response, and polarization dependence of strained quantum well lasers grown on GaAs and InP. We also include the temperature dependence of the Auger rates, threshold current density, and thermionic emission of carriers out of the quantum well; optimization results will be presented for the structure with the lowest threshold current density.
High-bandwidth lithium niobate traveling-wave modulators
Authors: Seino M. , Mekada N. , Namiki T. , Kubota Y.
Published: February 2023

The Ti:LiNbO3 modulator has started being used in advanced optical transmission experiments and is required for high-speed modulation.1−3 The modulation bandwidth Δf is mainly limited by microwave decay and the velocity mismatch between microwave and light. These are proportional to the electrode length L. The drive voltage Vπ is inversely proportional to L. Thus, decreasing the microwave decay, velocity mismatch, and Vπ are areas of concern that must be addressed when making a high-bandwidth modulator.
Integrated photonics and optical computing
Authors: Goodman Joseph W.
Published: February 2023

Many of the classical optical signal processing systems, built originally in bulk form, have recently been realized in integrated form. Included would be rf spectrum analyzers, correlators of various kinds, and matrix-vector multipliers. Integration has generally involved the combination of surface acoustic wave devices for introducing signals to the processors and discrete optical elements for focusing light. Output is usually accomplished through a separate array of detectors. The integrated versions of these processors have the advantages of small size, low weight, comparatively low power consumption, and ruggedness. With these attributes have come some problems. It is difficult to couple light efficiently into the thin planar waveguides that are used. In addition, there are reported difficulties in achieving the large dynamic ranges that are often required from these systems.
Buried proton-exchanged lithium niobate waveguides
Authors: Jackel Janet Lehr
Published: February 2023

We report the first buried proton-exchanged LiNbO3 waveguides. Buried guides, in which the mode lies below the surface of the substrate, have lower propagation losses than those with the mode at the surface, and the mode shape can be made more symmetric for better coupling to fibers. Buried modes may also eliminate the need for buffer layers in electro-optic devices.
Periodic domain inversion in lithium tantalate
Authors: Åhlfeldt Henrik , Webjörn Jonas , Arvidsson Gunnar
Published: February 2023

Substrates with periodically alternating ferroelectric domains find applications for quasi-phase-matched second-harmonic generation and acousto-optic devices. Quasi-phase-matching waveguide structures have been demonstrated in LiNbO3 when using Li2O outdiffusion1 or titanium indiffusion2 and in KTP when using ion exchange.3
Guided blue and green upconversion fluorescence in an erbium-and-ytterbium-containing silicate glass
Authors: Jackel J. L. , Yi-Yan A. , Vogel E. M. , Von Lehmen A. , Johnson J. J. , Snitzer E. , Nestorowicz A.
Published: February 2023

We report the observation of upconversion fluorescence in an erbium/ytterbium-doped silicate glass. Although upconversion fluorescence has previously been observed in rare-earth doped fluoride glasses,1,2 and recently in gallate and tellurite glasses,3 it has generally been believed that silicate glasses are unsuitable for upconversion because of large nonradiative transition probabilities between adjacent energy levels, which are associated with their higher energy phonon spectra. However, we find that the high local intensity of pump power that can be obtained in a waveguide makes upconversion possible in this glass.
New circuit models of optical logic gates for computer simulation
Authors: Morikuni J. J. , Gao D. S. , Kang S. M. , Priest J. A. , Balestra C. L.
Published: February 2023

Optical logic gates are realized through tire well-known phenomena of saturable gain and saturable absorption. Saturable gain occurs when the longitudinal gain of a laser is reduced by lateral injection of photons into its cavity by a control laser. The injected photons stimulate emission in a lateral mode, reducing the longitudinal gain and decreasing output power. With this effect, a laser can be turned off by a control laser, a mechanism which is useful for constructing optical OR, NOR, and NOT functions. Saturable absorption occurs when an absorbing region of a laser is optically pumped by a control laser. The injected photons increase the electron density, which decreases the absorption. With this effect, a laser can be turned on by a control laser. This property can be used to realize optical AND and NAND functions.
A 1 x 16 lithium niobate optical switch matrix with integral TTL compatible drive electronics
Authors: O'Donnell A. C.
Published: February 2023

The realization of photonic switching circuits in future broadband communication networks depends on achieving the necessary optical functionality with system-friendly interfaces. Although lithium niobate switch matrices have progressed considerably, a critical step in the technology transfer to commercial applications is providing standard interfaces. Hybrid optoelectronic integration with these components will eliminate complex and expensive installation procedures and provide direct line-replaceable components operating under direct logic control.
Variation of Optical Constants of Se85-x Te15 Inx Glass System
Authors: D Sushama , Reddy GRC , George Achamma , Predeep P.
Published: February 2023

Films of SeTeIn Chalcogenide glasses are prepared by melt quenching followed by flash evaporation. Their optical constants and variations in refractive index, extinction and absorption coefficients with energy of incident radiation are evaluated and discussed.
A Compact Disc Compatible Digital Video Disc Pickup Using Annular Mask
Authors: Lee Chui Woo , Chung Chong Sam , Cho Kun Ho , Kim Tae Kyung , Jung Soo Yul , Choi Byoung Ho , Yoo Jang Hoon , Seo Joong Eon , Shin Dong Ho
Published: February 2023

Recently, the techniques related to DVD have been developed rapidly. Among these, several techniques[1] are proposed for achieving CD compatible DVD pickup. To reduce aberration, mainly coma, the thickness of the DVD was chosen as 0.6mm which is different from a CD. The thickness difference makes it difficult for the optical pickup which is optimized for the DVD disc, to be compatible with the CD.
Blue-green II-VI Laser Diodes: Progress in Reliability
Authors: Haase Michael A.
Published: February 2023

Blue-green laser diodes based on MgZnSSe-ZnSSe-CdZnSe separate confinement heterostructures grown lattice-matched to GaAs substrates have demonstrated performance suitable for optical data storage applications. The 3M-Philips collaboration has demonstrated index-guided devices featuring single transverse mode operation with room-temperature cw output power in excess of 40 mW per facet at wavelengths of 510-520 nm with less than 10 μm of astigmatism. Buried-ridge devices have been demonstrated with threshold currents as low as 2.5 mA. Improvements in p-type ohmic contacts have enabled threshold voltages of 3.7 V.
Status and Prospects of Blue and Green Semiconductor Lasers
Authors: Olego Diego
Published: February 2023

The development of blue and green semiconductor injection lasers for applications in high density optical recording is attracting considerable attention. Other uses for these devices in areas of displays, printing, sensing and medical instrumentation are also being envisioned. Two direct band gap semiconductor material systems are well suited for light generation in the blue and green spectral region. They are the so-called wide band gap II-VI and IB-V semiconductors represented by ZnSe and GaN, respectively. The advancement of ZnSe and GaN lasers requires an intimate interplay between improving the materials qualities and developing specific laser processing technologies for these materials. Both types of lasers rely on advanced strained-layer growth by either molecular beam epitaxy or metal organic chemical vapor deposition.
Paths To Blue Diode Lasers
Authors: Welch David F.
Published: February 2023

Recent years have brought dramatic advances in the development of blue diode lasers, leading to the development of higher density optical data storage systems. Three approaches have been heavily pursued, including compact frequency doubled diode lasers, ZnSe-based diode lasers, and most recently GaN-based diode lasers. The relative merits and current status will be discussed in detail as applied to optical data storage.
Design Principles for Media Server Systems
Authors: Kovalick Al
Published: February 2023

The purpose of this paper is to provide an overview of the architectures and principles that govern Media Server (MS) design. Until recently, the three main ingredients for building a cost effective server have not all co-existed. The three are; (1) interconnect networks with a wide bandwidth (155 Mb/s SONET), (2) video compression algorithms and hardware (MPEG1/2) and (3) large storage arrays (100’s of GBs) with high read rates (>5MB/s per disc). During the last several years all three of these technologies became available at affordable prices. This paper will outline the basics of server design. There are only three different architectures in use today and these are governed by seven basic design principles.
Extension of Linear-Velocity Margin in Phase Change Optical Recording with a Variable Pulse Compensation
Authors: Mizuno H. , Takada K. , Horie M.
Published: February 2023

In the history of optical disks, two flavors of usages have been proposed and implemented. The one usage is for the Audio-Visual use, such as Mini Disk, Compact Disk (CD) and their family. The other usage is for computer peripherals, such as MO disk conformable to ISO standard. One significant difference in these two usages is characterized by the linear-velocity in reading and recording. The former media is used at a low linear-velocity of less than 10m/s and suitable for real-time operation. The latter is used at higher linear-velocity of more than 10m/s to achieve high data transfer rate. Phase change optical disk (PC disk), especially Ge-Sb-Te recording film 1-2), can be applied for both of these two usages. The PC disk has the following favorable features, 1-beam overwrite, simple optical system similar with the CD family. PC disk also has capability for higher density recording by Land and Groove recording3), PWM recording4), and the recording with shorter wavelength laser.5) However, the PC disk usually poor linear-velocity margin in conventional overwriting. The composition of the recording layer and film stacks must be carefully designed for each velocity with respect to crystallization speed and ability of amorphization.6) There has been no report that demonstrates an extension of applicable linear-velocity of a PC disk with a fixed active layer and film stacks. It is desirable for a fixed PC disk to cover such a wide linear-velocity range because the above mentioned two usages are merging in recent multimedia era.
Land/Groove Recording on Reflective Media
Authors: Olson Radley W.
Published: February 2023

Land/groove optical recording has received much attention because its ability to suppress crosstalk between tracks permits a large track density increase. Here we present a simple vector picture that illustrates physically the crosstalk suppression mechanism for reflective media. It leads by natural extension to a measure of crosstalk that is proportional to the timing jitter of signal transitions, which is important for PWM recording.
High Density In-Groove Recording with Phase Change Discs
Authors: Kawakubo O. , Yasuda K. , Sugiki M. , Makino H.
Published: February 2023

As candidates for a primary package media in the coming multi-media age, the large capacity optical discs are being watched with keen interest. Following developments of high density ROM discs, discussions on rewritable discs have become animated. Apart from the traditional confrontation between magneto-optics and phase change, another methodological controversy seems to emerge in connection with capabilities toward higher capacities. That is which is promising, conventional in-groove recording technique or land / groove recording technique [1] ? We have been examining our phase change disc properties based on the in-groove recording method. We will prove in this article that 3GB or more user capacities are achievable with our phase change discs by employing simple in-groove recording method.
Grating Polarizing Beam-Splitter using Polymerized Liquid crystal
Authors: Sato Hiromasa , Hotaka Hiroki , Gunjima Tomoki , Tanabe Yuzuru , Hirano Masahiro
Published: February 2023

With a progress in optical disk memory devices that have such as writable function and higher memory density, the efficient use of laser output power is strongly required, specially for DVD. One of the most practical solution for this is to implement a polarized beam splitter in optical pick-up modules. Conventional device once used in early stage of commercialization, which utilizes evaporated multi-layer thin films on a glass prism is hard to use commercially due to its large volume, heavy weight and high cost. Thus, development for new type of polarized beam splitter devices using birefringence material become very active recently 1),2). We have fabricated "Grating type Polarized Beam Splitter" (GPBS) using fine patterned photo-polymerized liquid crystal. Because of its high performance together with inherent nature of low cost and compact size, it has a large potential to be used in optical pick-ups for the advanced optical disk memory devices.
New Focusing Error Detection Method using a Tilted Holographic Optical Element
Authors: Mori Kazushi , Tajiri Atsushi , Inoue Yasuaki , Gotoh Takenori , Ibaraki Akira , Yodoshi Keiichi
Published: February 2023

Recently, optical units, which integrate an optical disk pickup (excluding the objective lens) in a hybrid system using a holographic optical element (HOE), have been actively investigated with a view to practical use. A small holographic optical unit (HOU) enables the optical pickup to be downsized and lighter in weight. However, the downsizing of the HOU is restricted by the number of terminals which connect the respective photo-diode (PD) elements (generally more than 4-section PDs) and the laser diode (LD) with external circuits.
90 mm Magneto-Optical Disk Drive
Authors: Itoh Ken-ichi
Published: February 2023

90 mm magneto-optical disk (3.5” MO), as a large-capacity high-speed
removable file or a super-floppy for multi-media era, features itself
not only by high performance, but also by high reliability and wide
compatibility based on the ISO standards.
High Performance Magneto-Optical Disk System
Authors: Kurebayashi Masaaki , Hoshino Takashi , Ikeda Tetsuya , Yonezawa Seiji
Published: February 2023

The demand of the data storage devices for multimedia has been increasing in recent years. Especially the compact size, large capacity, a high speed transfer rate and ROM and RAM concurrent disk system was expected. One of the technical approaches to achieve these requirements is the combination of the laser pulse irradiation magnetic field modulation recording method (P-MFM method) with sampled servo method[1]. We achieve the density of 2.3Gbits/inch2 by using these technology applied for conventional disks. Table 1 shows the main specification and figure 1 shows the structure of a new developed disk system.
Feasibility Study of High Density Land/Groove Recording on Magneto-Optical Disks
Authors: Narita Kyuya , Takeshima Hideharu , Kawano Toshifumi
Published: February 2023

We report on the land and groove recording (Land/Groove recording) demonstrated on magneto-optical (MO) disks using polyolefin and polycarbonate substrates. We measured and evaluated jitter, CNR, crosstalk and effects of vertical birefringence (VB) of substrates. Wavelength of laser for write and readout is 680nm, and NA of the objective lens is 0.55. And pulse train recording was carried out.
A 130mm 4.6 Gbyte MO Disk Compatible with the 2.6 Gbyte MO Disk
Authors: Robbins Jamey , Ernst Chuck
Published: February 2023

Pinnacle Micro Inc. has developed a drive that lowers the cost per megabyte and increases the performance for standard MO products. The drive is called Apex and boasts a whopping 4.6 GB per cartridge. Apex maintains compatibility with 2.0 GB (Hitachi) and 2.6 GB ISO MO drives yet also supports Pinnacle’s 4.6 GB media.
Life Time Test of MD Disc
Authors: Okino Yoshihiro , Hashimoto Hidehiko , Mizumoto Kunihiko , Kubo Takahiro , Kikawa Hayami
Published: February 2023

Since life of the optical disk was expected to be long from the very
beginning, interest in life was high. This is proved by the fact that
the special working group regarding life was established in the
optical disk standardization committee in Japan. Long life was
expected of the optical disk for data (computer), but life was not
discussed much for the optical disk for consumeraudio&video use
such as CD.
Optimizing Two-Photon 3D Data Storage in Photochromic Materials Using the Principles of Nonlinear Optics
Authors: Akimov D. A. , Koroteev N. I. , Magnitskii S. A. , Naumov A. N. , Sidorov-Biryukov D. A. , Zheltikov A. M.
Published: February 2023

Applying the principles of nonlinear optics for 3D data storage holds much promise in the context implementing an optical memory device that would be capable to store large data arrays. The possibility to use two-photon transitions in photochromic materials for this purpose was discussed and experimentally investigated in recent studies [1 - 3]. In this paper, we analyze a scheme for 3D optical data storage where data writing is performed through two-photon transitions resulting in photochromic coloring in the material. It is demonstrated that the use of a frequency-tunable laser provides the opportunity to appreciably increase the efficiency of photochromic transformations and, thus, to reduce the energies of light beams involved in the process of data writing. We analyze the advantages of two-photon optical storage schemes using laser beams with different frequencies over those using a single laser beam. We discuss the results of experimental studies devoted to two-photon coloring in photochromic materials and analyze the possibility of optimizing power and geometric parameters of the optical scheme for two-photon data writing. It is demonstrated that the cross section of two-photon absorption in a photochromic material can be completely described in terms of components of the cubic-susceptibility tensor of a medium, which provides an opportunity to apply the principles of nonlinear optics, including the technique of polarization measurements, for understanding the dependence of the cross section of two-photon absorption on the polarizations of light waves involved in the process of photocoloring.
Optical array for Video-on-Demand (VOD) system
Authors: Zhang Haichuan , Pan Longfa , Xu Duanyi
Published: February 2023

Although RAID (Redundant Array of Inexpensive Disk) technology has been widely used in HDD (Hard Disk Drive) array in the past several years, optical array just begins its steps using optical drive with higher data transfer rate and faster seeking operation1. Optical drive (especially CD-ROM) have improved sustain transfer rate by several times, and some special designed optical drives can reduce seek time near to HDD. These progresses make it possible that low cost optical array become outside memory of video server in Video-on-Demand1,2,3 system instead of expensive HDD array. A new kind of RAID form can reduce distance between different data segments. So this new data strategy reduce the seeking time too, which make optical array can be accessed by more users simultaneously than before.
Measurement of the Thermal Coefficients of Phase-change Optical Recording Films
Authors: Hsieh Yung-Chieh , Mansuripur M. , Volkmer James
Published: February 2023

We describe a method of determining the thermal parameters of the non-erasable phase-change recording media based on a set of experimental data and related numerical calculations [1]. For convenience, throughout this paper, we will omit the units of the thermal conductivity and the specific heat; their units will be [joul. °C-1 · cm-1 · sec-1] and [joul. °C-1 ·cm-3], respectively.
Deformation Effects and Recording Characteristics of CD-R
Authors: Huh Y.J. , Kim J.S. , Nam T.Y. , Kim S.C.
Published: February 2023

The recording mechanism of an organic dye based CD-R disc has been studied by many researchers.1~4) Based on their studies, three different deformation effects, a bump at the dye/PC interface, a pit in the dye at the dye/Au interface and a bubble at the dye/Au interface are generally accepted as the recording mechanism of CD-R. Even though they predicted the deformation effects by the thermal analysis and observed the effects experimentally by using various microscope techniques qualitatively, the relationship between the deformations and the recording characteristics has not been studied quantitatively.
Stabilities of Laser Pumped Magnetic Field Modulation Recording
Authors: Tanaka Yasuhito , Kurebayashi Masaaki , Yonezawa Seiji
Published: February 2023

Direct overwriting and high density recording are key issues in optical recording. There are two optical recording methods i.e. (1) optical modulation recording and (2) magnetic field modulation recording. The optical modulation recording has more like optical oriented features to modulate laser beam with data while DC magnetic field is applied. The recorded mark size are limited by the diffraction optical spot size λ/2NA and complex media are necessary to comply with the demand of direct over writing. The magnetic field modulation recording method on the other hand has more magnetic oriented features to modulate magnetic field with data while constant waveform (DC or pulse train) laser irradiation is applied. The recorded mark size are limited by the magnetic field response applied and not limited by the optical spot size. The DC laser irradiation type has been used at Mini Disk™ and Laser pumped type has been used at HS ™ 3.5inch 650MB capacity magneto-optical drive. Moreover complex media are not necessary to comply with the demand of direct over writing, therefore the media applied magnetically induced super resolution(MSR) can be used easily.
Real-Time Recognition of Address Blocks on Mail Pieces
Authors: Soh Jung , Palumbo Paul W. , Srihari Sargur N.
Published: February 2023

In previous papers, we introduced the general problem of locating a block of text corresponding to the destination address on complex backgrounds (such as magazine covers), the architecture of ABLS (address block location system) and its performance with an image database consisting of many difficult cases [SWP87, WaS88]. ABLS has demonstrated its competence by successfully locating address blocks on mail pieces that exhibit visually complex configurations. The current phase of research is to determine how to develop a system that can perform in real-time. A real-time system must be capable of processing 12 mail pieces per second for letter mail, 5 per second for flats, and 1 per second for irregular parcels and pieces (IPP). This paper reports on evaluations of components of ABLS with a view towards developing a real-time system and discusses hardware implementation of some components.
Predictions from a computational model of texture perception compared with psychophysical data
Authors: Malik Jitendra , Perona Pietro
Published: February 2023

Major theories of preattentive human texture perception due to Julesz [5,9] and to Beck [1,2] attribute preattentive texture discrimination to differences in first-order statistics of stimulus features such as orientation, size and brightness of constituent elements. These theories have typically been constructed for black and white dot or line patterns and are not directly applicable to grey scale images. An alternative approach [6,15, 4] has been to exploit the linear mechanisms (psychophysically observed spatial frequency channels and neurophysiologically observed blob, bar- and edge- sensitive neurons) which have been used to explain a range of phenomena in early spatial vision. Some experiments [4,3] suggest that this approach may explain texture perception better than the more symbolic, feature based approach of Beck and Julesz. However no scheme in this framework has been fully specified, implemented and successfully tested. The crucial experimental tests are the following: Does the model correctly predict the texture boundaries found preattentively by human observers, both in images of natural scenes and the synthetic stimuli from psychophysics literature? Even better, does it correctly predict the degree of discriminability for different texture pairs as measured by psychophysical experiments?
Motion Estimation Using Surface Correspondences*
Authors: Sabata Bikash , Nandhakumar N. , Aggarwal J.K.
Published: February 2023

In this paper a new robust method to estimate motion from a sequence of range images is developed. This approach uses the correspondences between planar surfaces in a sequence of images instead of using the usual method where point and line correspondences are used. Rotation and translation are both determined using the properties of the planar surfaces such as the surface normals and surface intersections. Because global features are used the method is less sensitive to noise, quantization errors and partial occlusion of the surfaces. Also, the method may be applied to a scene containing several objects, each with a different motion. The algorithm has been tested on sequences of synthetic and real laser range data.
The Recovery of Motion and Depth from Optical Flow
Authors: Baraldi P. , DeMicheli E. , Radonich G. , Torre V.
Published: February 2023

The navigation of a robot in any environment requires the knowledge of the motion of the robot relative to the environment and of the three dimensional structure of the scene. These information can be obtained by using active sensors and/or by passive vision, provided by cameras mounted on the robot.
Cooperative Segmentation and Stereo Matching
Authors: Vinet Laurent , Sander Peter , Cohen Laurent , Gagalowicz André
Published: February 2023

Stereo matching based on points and lines as the entities has become a well developed industry. In this paper, we investigate region based matching as we feel that many of the shortcomings inherent in other approaches can be overcome by taking more developed entities (to cite but two examples: mismatches over pairs of line elements are to be expected frequently due to the lack of distinguishing features; and occlusion can effects points or segments more than regions). We present a novel approach to the combined problem of image segmentation and object matching, based on interaction between a segmentation component and a stereo component. We believe the combination to be better than the parts taken individually. This paper is limited to segmentation/matching results—we are not concerned with the explicit depth computations here (but see [1]).
Real-Time Analysis of Blobs in Infrared Images Using Dynamic Belief Systems
Authors: Gutfinger D. , Sklansky J.
Published: February 2023

Classical techniques of designing image analyzers work well when the data in the field are similar to the data used in the design — e.g., in optical character recognition. There are many applications however in which it is very difficult or impossible to generalize adequately from the available design data by classical techniques [1]. Furthermore, requirements of real-time image processing often demand that we exploit uncertain data in making reliable decisions. Toward overcoming these difficulties in the design of real-time image analyzers we introduce a theory of dynamic belief. We refer to the image analyzers obtained with the aid of this theory as dynamic belief systems.
Part Segmentation for Object Recognition
Authors: Pentland Alex
Published: February 2023

In order to recognize objects one must be able to compute a stable, canonical representation that can be used to index into memory. The most widely accepted theory on how people recognize objects seems to be that they first segment the object into its component parts and then recognition occurs by using this part description to classify the object. The problem of segmenting objects into parts, however, has remained unsolved despite much research.
Lip Reading: Automatic Visual Recognition of Spoken Words
Authors: Mase Kenji , Pentland Alex
Published: February 2023

Lipreading is an rich source of speech information, and in noisy environments it can even be the primary source of information. In day-to-day situations lipreading is important because it provides a source of information that is largely independent of auditory signal, so that auditory and lipreading information can be combined to produce more accurate and robust speech recognition. For instance, the nasal sounds ‘n’, ‘m’, and ‘ng’ are quite difficult to distinguish acoustically, but have very different visual appearance.
Imaging hemoglobin concentration and oxygen saturation in the female breast with near-infrared diffusion tomography
Authors: Pogue Brian W. , McBride Troy O. , Poplack Steven P. , Osterberg Ulf L. , Paulsen Keith D.
Published: February 2023

Measurements of diffuse near-infrared light are used to tomographically image hemoglobin in tissue. A diffusion theory finite element solution is matches theoretical predictions to these measurements, allowing computed images of absorption and scattering coefficients to be recovered from the projection data by iteratively solving a regularized matrix equation which using the Newton-Raphson method. The diffuse measurements are recorded at wavelengths between 660 nm and 850 nm with automated data acqusition, using intensity-modulated light at 100 MHz. This prototype system is being tested on breast cancer patients to determine the utility of hemoglobin morphology for tumor diagnosis. Hemoglobin concentration and oxygen saturation images are derived from reconstructed absorption coefficient images at multiple wavelengths through a multi-parameter concentration fit at each point in the image. The chromophores assumed to be present in breast tissue are water, lipids, oxy- and deoxy-hemoglobin. This type of data acquisition system allows multi-spectral imaging which may provide the information needed to accurately recover the hemoglobin concentration and oxygen saturation images of the breast.
Optical Matching Techniques and Molecular Upconverting Reporters
Authors: Faris Gregory W. , Gerken Martina , Dyer Mark J. , Wu Xingkun
Published: February 2023

We are applying optical matching techniques to two types of applications: (1) the accurate determination of tissue optical properties and (2) improving in vivo imaging quality. With optical matching, measurement of tissue optical properties to accuracies of a few percent is possible. Accurate tissue properties are useful for physiological monitoring, modeling optical imaging and therapies, and providing a priori information for image reconstruction. For imaging, matching improves illumination uniformity and contrast, and makes better use of image dynamic range.

In a separate effort, we are developing a new class of reporters which provide upconversion from molecular labels. Advantages of these materials include no autofluorescence, multiplexing capabilities, no photobleaching, and excitation with compact and low power diode lasers. Applications include in vitro assays and in vivo imaging.
Non-Jacobian non-linear image reconstruction technique in diffuse optical tomography
Authors: Yaroslavsky Ilya , Yaroslavsky Anna , Battarbee Harold , Sisson Cynthia , Rodriguez Juan
Published: February 2023

A novel approach to the image reconstruction problem in diffuse optical tomography is proposed. This technique is free from Jacobian calculations and is based on separating the non-linear inverse problem into two steps: calculation of the volumetric source distribution and update of the estimates of the optical properties. Advantages and potential applications of the new technique are analyzed.
Multiphoton Microscopy MPM: Imaging Spectra and Dynamics of Molecular Function Deep in Living Tissues
Authors: Webb Watt W.
Published: February 2023

Multiphoton Excitation (MPE) of fluorescence provides the optimum photophysics for microscopic imaging deep in living tissue with minimal photodamage, to depths so far ~ 400 µm. Tissue autofluorescence excited by two-photon or three-photon absorption to ultra-violet energies can provide specific indications of disease. Useful autofluorescence of serotonin (5HT), melatonin, indolamine breakdown products, NADH, collagen, elastin, and a number of yet-to-be-identified molecular species, some of which identify disease states are already being imaged routinely. For research in model animals, genetic constructs that label specific molecules with mutants of Green Fluorescent Protein (GFP) can be imaged deep in tissue with MPM. MPM excitation of GFP mutants at nanomolar concentrations for Fluorescence Correlation Spectroscopy (FCS) provides a robust, internally calibrated, new measure of pH in cells and tissues. Fluorescent labels that penetrate tissue can be usefully imaged in living animals and thick tissue cultures; for example, thioflavins in the beta amyloid plaques of Alzheimer’s Disease are being imaged deep in living transgenic mouse brains. Multiphoton imaging spectroscopy and fluorescence lifetime imaging (FLIM) provides useful molecular identification diagnostics. Some applications are shown in order to illustrate capability. However, the potential of MPM for in vivoimaging has barely been explored, and this technology should be regarded as providing a fertile opportunity that is yet to be fully exploited for biomedical research and for clinical applications.
Diagnostic Imaging in Living Subjects
Authors: Webb Robert H.
Published: February 2023

This is a summary of some of the imaging work we have been doing over the last fifteen or so years, using confocal microscopes and ophthalmoscopes. Although the work I report here comes from my labs and those of my collaborators, all of the video clips for the workshop talk were taken by collaborators – I just build ‘em, other folks use ‘em. Since this paper cannot have the video, let me list here the people who have worked on all this, and whose names should be attached to the wonderful live views of the inside of both clinical and research subjects. These are: Ann Elsner, Steve Bums, Francois Delori, and Fran Rogomentich at SERI, plus Milind Rajadhyaksha, Salvador Gonzalez, Matt White, Frank Koenig, Gary Tearney, Brett Bouma, Rox Anderson at Wellman Laboratories and Jim Zavislan of Lucid, Inc.
Ultrahigh Resolution and Spectroscopic OCT Imaging of Cellular Morphology and Function
Authors: Boppart Stephen A. , Drexler Wolfgang , Morgner Uwe , Kärtner Franz X. , Fujimoto James G.
Published: February 2023

Optical coherence tomography (OCT) is a promising optical microscopy technique which enables ultrahigh-resolution, spectroscopic, in vivo imaging in transparent and non-transparent biological specimens. This is achieved by exploiting the short temporal coherence of ultrabroad bandwidth light sources to image morphological features at subcellular resolution at depths beyond that of conventional bright-field and confocal microscopes. Extraction of spatially resolved spectroscopic information is feasible to improve image contrast and to obtain functional or biochemical properties of the investigated tissue. The potential for using OCT to image the morphological expression of genes involved in normal and abnormal development has been shown in common developmental biology animal models. In vivo imaging of single cell morphology, mitosis, and migration, as well as preliminary spectroscopic imaging, is demonstrated.
Image formation in conventional fluorescence optical microscopes with structured illumination
Authors: Wilson T. , Karadaglić D.
Published: February 2023

We present a theoretical analysis of the image formation in conventional fluorescence microscopes with structured illumination. We show that optically sectioned images may be obtained with sectioning strengths comparable to those obtained in the confocal microscope. We further show that the approach leads to images exhibiting enhanced spatial frequency content and transfer function behaviour directly comparable to that of the true confocal instrument.
Single Molecule Detection in Fluid Solution
Authors: Nguyen Dinh C. , Keller Richard A. , Jett James H. , Martin John C. , Parson Jimmie D.
Published: February 2023

We are approaching single molecule detection in fluid solution. Our current limit with dissolved dye molecules is equivalent to the detection of 8 rhodamine-6G fluorophores on a single species. Documentation of this limit is given by the detection of microspheres containing the simulated equivalent of 25 rhodamine-6G fluorophores.
New Laser-Based Measurements in Analytical Spectrometry: From Remote Testing to Thomson Scattering
Authors: Hieftje Gary M.
Published: February 2023

In this presentation, several laser-based procedures and techniques for measuring chemical substances and for characterizing chemical instrumentation will be described. However, greatest emphasis will be placed on describing some new methods for determining the time-dependent characterics of molecules in condensed phase.
Simultaneous Acquisition of Pure Rotational and Vibrational Nitrogen Spectra Using Three-Laser Cars
Authors: Lucht Robert P. , Maris Mark A.
Published: February 2023

We have used three-laser coherent anti-Stokes Raman scattering to acquire simultaneously the pure rotational and vibrational spectra from the nitrogen molecule. The energy level schematic for the three-laser CARS process is shown in Figure 1. Frequency-doubled Nd:YAG laser radiation at frequency ω1 is used to pump a broadband dye laser which lases at a range of frequencies ω
s
and a narrowband dye laser with frequency ω2. The three-beams are focused to a common CARS probe volume using a three-dimensional phase-matching geometry.
Photochemical Effects in Two-Photon-Excited Fluorescence Detection of Atomic Oxygen in Flames
Authors: Goldsmith J. E. M.
Published: February 2023

Much of the recent attention on developing techniques for measuring radical concentrations in flames, and atoms in particular, has focused on the use of multiphoton excitation schemes. One of the early papers on atomic oxygen detection in flames reported photochemical production of oxygen atoms in room air,1 drawing attention to the need for caution to make sure that these optical techniques are in fact as nonintrusive as they are claimed to be. We demonstrated recently that photochemical effects can have a strong influence in 205-nm, two-photon-excited fluorescence detection of atomic hydrogen in atmospheric-pressure flames.2 In this paper we report similar effects in measuring atomic oxygen concentration in flames, and demonstrate that excess atomic oxygen concentrations can be produced by single-photon excitation of the Schumann-Runge bands of vibrationally excited oxygen molecules present in the flame.
Laser-Induced Fluorescence in Solid Propellant Flames at High Pressure
Authors: Edwards Tim , Weaver David P. , Campbell David H. , Frederick Frank , Asmuth Gordon
Published: February 2023

There is a great deal of interest in obtaining a better understanding of the important chemical mechanisms occuring in solid propellant flames [1]. Some of the best methods of obtaining this chemical information are the recently developed laser-based combustion diagnostics, such as laser-induced fluorescence (LIF)(e.g., [2]). Solid propellant flames are quite complex, so a complete description of the flame down to the level that simple flames have been analyzed is not feasible at present. What is needed is a better understanding of the flame structure and major reaction pathways in solid propellant flames as a function of pressure and propellant composition. The distribution of radicals such as CN, NH, and OH, as seen in laser-induced fluorescence, will be a key part of this improved understanding of solid propellant flame chemistry.
Analysis and Quantitation of Biomolecules by Two-Step Laser Desorption/Multiphoton Ionization Mass Spectrometry
Authors: Hahn Jong Hoon , Zenobi Renato , Engelke Friedrich , Zare Richard N.
Published: February 2023

We report a new methodology, two-step laser desorption/multiphoton ionization mass spectrometry, for the ultrasensitive detection and quantitation of molecular adsorbates. The method has been successfully applied to a number of nonvolatile and thermally labile compounds, including the 20 primary phenylthiohydantoin (PTH)- amino acids, the 4 DNA bases, the steroid β-estradiol and the large porphyrin, protoporphyrin IX dimethylester.
Ultratrace Detection of Atmospheric Contaminants by Supersonic Molecular Beam, Multiphoton Ionization, Mass Spectroscopy
Authors: Syage Jack A. , Pollard James E. , Cohen Ronald B.
Published: February 2023

An ultratrace detection method that offers < 300 ppt and selectivity of ~ 104 is demonstrated for organophosphonate and sulfide chemical agent simulant molecules.
Laser Induced Fluorescence for Diagnostics of Biomolecules
Authors: Horvath J. J. , Semerjian H. G.
Published: February 2023

Recent advances in molecular biology have led industry and government agencies to recognize the economic potential for applying these advances in a diversity of industrial sectors, including the production of new drugs, food additives and chemicals, and conversion of biomass, etc. However, implementation of these new technologies requires measurement capabilities which do not currently exist. Bioprocesses require a very closely controlled environment, normally realizable only in batch processes. This is mainly because of the complex kinetics of most bioreactions, separate periods of growth and product formation, biocatalyst degeneration, contaminant risks, and the mechanical difficulties of handling a rheologically complex material. Therefore, development of new on-line and noninstrusive measurements are desirable to avoid difficulties associated with sampling, contamination, long response time, etc.
A New High Resolution Time-of-Flight Mass Spectrometer with UV Laser-Induced surface Ionization
Authors: Yang Mo , Reilly James P.
Published: February 2023

UV laser-induced surface ionization with prism internal reflection is demonstrated to be a useful ion source for the Time-of-Flight mass spectrometer (TOF-MS). Spraying aniline (93 amn) on the prism surface and using 2 ns UV laser pulses, mass resolutions of 3900 and 11000 have been achieved in a linear TOF-MS and a reflectron TOF-MS, respectively. Theoretical calculations indicate that mass resolution of over one million is possible, if a picosecond laser and appropriate electronics are employed.
UV Resonance Raman Studies of Aromatic Amino Acids and Proteins
Authors: Ludwig M. , Asher S. A.
Published: February 2023

The ultraviolet resonance Raman (UVRR) excitation profiles have been measured for the aromatic amino acids phenylalanine, tryptophan, tyrosine and tyrosinate. Resonance excitation enhances Raman scattering from vibrational modes that distort the ground state configuration towards the configuration of the excited state. The excitation profile maxima are red-shifted with respect to the absorption spectral maxima for each aromatic amino acid. These excitation profiles indicate the excitation required to maximally enhance a particular aromatic amino acid residue in a protein. Individual aromatic amino acids in environmentally distinguishable positions in a protein may have slightly different transition energies, and could therefore be identified and distinguished by proper tuning of the excitation frequency. For example, surface tyrosyl residues in hydrophilic environments will have lower lying excited states due to extensive hydrogen bonding. These residues will be maximally enhanced with longer wavelength excitation than residues buried in hydrophobic pockets within a protein. The frequency of certain vibrational bands, particularly those known to be influenced by substituents on the aromatic ring may also be indicative of the local environment. The relative intensities of other enhanced bands may also contain information concerning specific local environment. For example, the relative intensity of the peaks of the 830/850 cm-1 Fermi resonance doublet of tyrosine are known from normal Raman studies to be sensitive to hydgrogen bonding. Vibrational substructure is not observed in absorption spectral measurements due to the breadth of the absorption spectral features. The vibrational substructure is amplified in the resonance Raman excitation profiles.
Indirect Determination of a Local pH Change by Surface Enhanced Raman Spectroscopy
Authors: Anderson Mark R. , Evans Dennis H. , Wirth Mary J.
Published: February 2023

Surface enhanced Raman scattering (SERS) is, potentially, a very powerful technique for in situ surface analysis, particularly in an electrochemical environment. Unfortunately, few studies to date have taken advantage of the technique for the purpose of analysis. The present study, however, utilizes SERS to probe analyte molecules in the electrochemical double layer in order to obtain information about the behavior of the double layer as the electrode potential is altered.
Quantitative and Qualitative Determination of Impurities in III - V Semiconductors
Authors: Harris T. D.
Published: February 2023

Identification and determination of impurities in modern semiconductors is one of the most challenging analytical problems in materials characterization. Total impurity concentrations rarely exceed 100 parts per billion and the chemical state of the impurity is central to it's effect on semiconductor performance. The detection of these impurities is beyond almost all available analytical methods. Quantitative determination of these impurities is nearly impossible.