bluuebunny/crossref_metadata_2025 huggingface dataset:
DYNAMIC 3D ANIMATION OPTIMIZING GLENOSPHERE CONFIGURATION IN REVERSE SHOULDER ARTHROPLASTY
Authors: Gupta V.K. , Van Niekerk M. , Hirner M.
Published: February 2023

Scapular notching is a common problem following reverse shoulder arthroplasty (RSA). This is due to impingement between the humeral polyethylene cup and scapular neck in adduction and external rotation. Various glenoid component strategies have been described to combat scapular notching and enhance impingement-free range of motion (ROM). There is limited data available detailing optimal glenosphere position in RSA with an onlay configuration. The purpose of this study was to determine which glenosphere configurations would maximise impingement free ROM using an onlay RSA prosthesis.

A three-dimensional (3D) computed tomography (CT) scan of a shoulder with Walch A1, Favard E0 glenoid morphology was segmented using validated software. An onlay RSA prosthesis was implanted and a computer model simulated external rotation and adduction motion of the virtual RSA prosthesis. Four glenosphere parameters were tested; diameter (36mm, 41mm), lateralization (0mm, 3mm, 6mm), inferior tilt (neutral, 5 degrees, 10 degrees), and inferior eccentric positioning (0.5mm, 1.5mm. 2.5mm, 3.5mm, 4.5mm). Eighty-four combinations were simulated. For each simulation, the humeral neck-shaft angle was 147 degrees and retroversion was 30 degrees.

The largest increase in impingement-free range of motion resulted from increasing inferior eccentric positioning, gaining 15.0 degrees for external rotation and 18.8 degrees for adduction. Glenosphere lateralization increased external rotation motion by 13. 6 degrees and adduction by 4.3 degrees. Implanting larger diameter glenospheres increased external rotation and adduction by 9.4 and 10.1 degrees respectively. Glenosphere tilt had a negligible effect on impingement-free ROM.

Maximizing inferior glenosphere eccentricity, lateralizing the glenosphere, and implanting larger glenosphere diameters improves impingement-free range of motion, in particular external rotation, of an onlay RSA prosthesis. Surgeons’ awareness of these trends can help optimize glenoid component position to maximise impingement-free ROM for RSA. Further studies are required to validate these findings in the context of scapulothoracic motion and soft tissue constraints.
O INESPECÍFICO EM PAUTA NA POESIA CONTEMPORÂNEA PRODUZIDA POR MULHERES
Authors: Pszdzimirski Brunna , Valdati Nilcéia
Published: February 2023

O presente estudo centra-se na poética de Assionara Souza (1969-2018), que publicou, até seu precoce falecimento, quatro livros de contos e apenas um de poesia, incluindo uma organização póstuma de seus poemas. Em vida, a preferência da escritora era apresentar seu trabalho no ciberespaço, utilizando de várias plataformas, dentre elas o blog pessoal Cecília não é um cachimbo. É neste espaço que publica “Sonha Hito Steyerl com ovelhas eletrônicas?”, poema que será analisado neste artigo. Assim, pretende-se observar como os gestos poéticos de Assionara apontam para o transbordamento do poema, que encontrará forças em outras artes para colocar em evidência questões políticas, sociais e estéticas. Constatar enfim que a inespecificidade aparente do objeto poema é carregada de referencialidades e atravessada por afetos. Para desenvolvimento de tais questões, serão tomadas as discussões propostas por Florencia Garramuño (2014) e Ana Kiffer (2014) sobre inespecificidade; Josefina Ludmer (2010), e a noção de pós-autonomia; Giorgio Agamben (2007), Marcos Siscar (2016) e Alberto Pucheu (2014), sobre os caminhos da poesia.
POÉTICA HILSTIANA COMO EXORTAÇÃO
Authors: Guimarães Saves Fernando , José Gonçalves Aguinaldo
Published: February 2023

Compreender a poética de Hilda Hilst é adentrar o universo inquietante do eu lírico que, à semelhança do filósofo grego, questiona a si mesmo, ao mundo e à realidade. A temporalidade na poesia hilstiana é sempre marcado, motivo de reflexões e veículo através do qual o eu lírico trafega de um espaço a outro, de um tempo a outro, revisitando momentos memoráveis, ideias e formas de pensamento. A existência na obra de Hilst é também apresentada ao leitor como um objeto de reflexão. Existência própria, existências outras, personagens fictícios ou reais que deixaram seus registros históricos no tempo. Hilst, muitas vezes classificada como expressão da metapoesia no Brasil, entretanto, não se deixa prender a rótulos, utilizando sua poética no confronto mesmo das tentativas, quaisquer que sejam elas, de solapar as asas de seu imaginário poético. Recorre a estratégias variadas de expressão linguística, traduzindo o seu fazer poético em ato político contra a opressão do homem político.  Em Júbilo, memória, noviciado da paixão, a poeta traz o cenário mítico dos heróis e deuses da antiguidade, conjugando-o à cantiga lírica medieval galego-portuguesa do século XIII. Este trabalho é o resultado de uma tentativa de se abordar a poesia de Hilda Hilst a partir de uma perspectiva mítico-histórica, perspectiva esta que é proposta pela própria autora na forma pela qual desenvolveu sua poética na obra referida.
The Music Manuscripts at the Diocesan Library in Sandomierz. A Thematic Catalogue. Vol. I. Repertoire of Church Ensemble and Keyboard Music
Authors: Walter-Mazur Magdalena , Kaźmierczak, Karolina , Wysocki Michał
Published: February 2023

The Music Collection at the Diocesan Library in Sandomierz is one of the most valuable and extensive of this kind in Poland. It includes in total 807 library items (many collections among them) described in 2522 catalog records. Vast majority of the manuscripts originates from the eighteenth century, a significant number from the first three decades of the nineteenth century and single copies from the seventeenth century. Volume 1 of the Catalogue (1550 records), preceded by an extensive introduction, encompasses the repertoire of the church ensembles (vocal-instrumental and chamber music) and keyboard compositions. In preserved manuscripts there are mainly compositions of Polish, Italian, German, and Czech composers however anonymous compositions prevail. The Catalogue of music manuscripts from Sandomierz was created in cooperation of musicologists from Adam Mickiewicz University in Poznań and the RISM Catalogue of Musical Sources with its Editorial Office in Frankfurt am Main.
PCCA-Model: an attention module for medical image segmentation
Authors: Liu Linjie , Wang Guanglei , Wu Yanlin , Wang Hongrui , Li Yan
Published: February 2023

Convolutional neural networks have been increasingly employed in the field of medical image segmentation. Based on the idea that the human visual cortex differs in terms of the size of the receptive field and can sense the stimulus location, we propose the pyramid channel coordinate attention (PCCA) module to fuse multiscale features in the channel direction, aggregate local and global channel information, combine them with the location information in the spatial direction, and then integrate them into the existing semantic segmentation network. We conducted numerous experiments on the datasets, namely LiTS, ISIC-2018, and CX, and obtained state-of-the-art results.
Non-destructive evaluation and fast conductivity calculation of various nanowire-based thin films with artificial neural network aided THz time-domain spectroscopy
Authors: Zeki Güngördü M. , Kung Patrick , Kim Seongsin M.
Published: February 2023

Terahertz time-domain spectroscopy (THz-TDS) has been utilized extensively to characterize materials in a non-destructive way. However, when materials are characterized with THz-TDS, there are many extensive steps for analyzing the acquired terahertz signals to extract the material information. In this work, we present a significantly effective, steady, and rapid solution to obtain the conductivity of nanowire-based conducting thin films by utilizing the power of artificial intelligence (AI) techniques with THz-TDS to minimize the analyzing steps by training neural networks with time domain waveform as an input data instead of a frequency domain spectrum. For this purpose, Al-doped and undoped ZnO nanowires (NWs) on sapphire substrates and silver nanowires (AgNWs) on polyethylene terephthalate (PET) and polyimide (PI) substrates have been measured for dataset creation via THz-TDS. After training and testing a shallow neural network (SSN) and a deep neural network (DNN) to obtain the optimum model, we calculated conductivity in a conventional way, and the prediction based on our models matched successfully. This study revealed that users could determine a sample's conductivity without fast Fourier transform and conventional conductivity calculation steps within seconds after obtaining its THz-TDS waveform, demonstrating that AI techniques have great potential in terahertz technology.
Ultrahigh-density 3D holographic projection by scattering-assisted dynamic holography
Authors: Yu Panpan , Liu Yifan , Wang Ziqiang , Liang Jinyang , Liu Xingsi , Li Yinmei , Qiu Chengwei , Gong Lei
Published: February 2023

Computer-generated holography offers a promising route to
three-dimensional (3D) video displays. To realize a realistic-looking
3D display, the critical challenge is to create a 3D hologram that
enables high-density multi-plane projection with full depth control.
However, two long-existing issues in current digital holographic
techniques, low axial resolution and high inter-plane crosstalk,
prevent fine depth control and therefore limit the ultimate quality.
Here, we report 3D scattering-assisted dynamic holography (3D-SDH)
that further breaks the depth-control limit of the state-of-the-art
method. Our approach achieves orders of magnitude improvement in axial
resolution and greatly suppresses crosstalk, enabling
ultrahigh-density 3D holographic projection. Moreover, 3D-SDH enables
dynamic 3D vectorial projections via phase-only holograms. The concept
is validated through both simulations and experiments, where dynamic
projections of 3D point-cloud objects onto high-density successive
planes are demonstrated. Our work opens perspectives for 3D
holographic technology with ultra-fine depth control, dynamic
projection, and polarization multiplexing functionalities.
Transient Molecular Spectroscopy with a Frequency-Doubled Diode Laser
Authors: Fox R. W. , Hunter M. , Hollberg L.
Published: February 2023

A tunable cw low-amplitude noise laser is useful in the measurement of reaction rate constants of short-lived molecules. We are using an injection-locked diode laser together with a potassium niobate (KNbO3) crystal in a build-up cavity to generate tunable blue light. The blue light is then used to measure absorption due to iodine-monoxide (IO). This molecule is believed to play a role in the atmospheric ozone cycle.1 Chemical reactions involving IO are studied by monitoring transmittance through a flow cell in the wavelength range near 427 nm. IO is produced in the cell by photolysis of I2 and ozone with an excimer laser pulse; subsequent decay of the IO concentration takes place in approximately 10 ms. To accurately measure these fast reaction rates in low concentrations, optical absorptions of less than 10-4 are monitored with a 40 kHz bandwidth. Amplitude stabilization of the doubled light is necessary and is implimented with an electro-optic modulator.
Non-imaging Laser Diode Array Beam Shaper
Authors: Caffey David , Clarkson W. A.
Published: February 2023

Laser diode arrays are inexpensive, compact, efficient, and reliable light sources. However, the output beam, which is highly elliptical, is difficult to both efficiently collect and concentrate. This has limited continuous wave (CW) diode sources to power levels under 100 Watts. The fast axis of the laser diode array output tends to have good beam quality, M2~ 2, and a source size of ~ 1 um. The slow axis of laser diode broad stripes and of array bars is highly multimode, typically having an angular distribution of 10 degrees at the 1/e2 power points. The slow axis beam quality for a 500 um wide stripe is thus M2~ 70, and M2~ 1400 for a one centimeter array. One means of improving the brightness is to individually fiber couple broad stripe diodes, and then bundle the fiber ends together. Another is to collimate the fast axis of one centimeter arrays using a fiber lens1, and then fiber couple into a linear array of fibers. The output ends of the fibers are also bundled together. Both techniques are compact and relatively simple, and power is scaled by increasing the number of fibers in the bundle. M2 ~ 350 are available at 60 Watts output using the latter technique. It is difficult to scale beyond 100 Watts without increasing M2 to values greater than 500. This is due to loss of brightness in fiber coupling, as an essentially linear source is being coupled into a round fiber, or in mode mixing as light propagates through the fiber. Brightness is further reduced in fiber bundling by the presence of the fiber cladding, and by the less than unity packing factor of round fibers.
4 GHz All-Optical Clock Recovery Using a Self-Pulsating Multielectrode Distributed Feedback Laser
Authors: Landais P. , Pham G. , Duan G. H. , Chabran C. , Gallion P. , Jacquet J.
Published: February 2023

Clock recovery is a major key function of any transmission systems. All-optical devices are very attractive due to their high speed and their simplicity as electro-optic conversion is not necessary. It has been shown experimentally that the self-pulsation (SP) in a multielectrode distributed feedback (DFB) laser can be synchronised to the data clock rate of an incoming optical return to zero (RZ) signal. This property makes SP lasers (SPL) good candidates for clock recovery in transmission systems. Jinno et al. [1] have shown a clock extraction at 200 Mbit/s and Barnsley et al. [2] at 5 Gbit/s. They both have used multielectrode SPL with one section operated as saturable absorber section, which limits SP frequency due to the limitation of carrier lifetime. Feiste et al. [3] have extracted 18 GHz clock by using a SP DFB laser without saturable absorber. We can note that in these experiments, the clock recovery occurs in injection locking conditions where the wavelength of the injected optical signal is nearly identical to the SPL wavelength. Despite the fact that such configuration allows optical carrier recovery with a few µW injected, it seriously limits the application of the SPL to clock recovery. This paper reports for the first time that a 3.8 GHz clock extraction with low time-jitter can be obtained even under conditions of large wavelength difference.
Antarctic Miniature Lidar
Authors: Rail Jonathan A. R. , Abshire James B.
Published: February 2023

The Antarctic Miniature Lidar (AML) instrument has been assembled, tested, and deployed to the NOAA Clean Air Facility at the Amundsen-Scott South Pole Station. AML uses redundant commercially available, single element semiconductor lasers, operated CW, and a silicon avalanche photodiode (APD) operated in the Geiger or photon counting mode. We present preliminary lidar measurements made at both Goddard Space Flight Center, prior to deployment, and at the Clean Air Facility after installation at the South Pole Station in early February, 1995.
Accurate Growth of Submilliampere Threshold Current Vertical Cavity Surface Emitting Laser using Diode Laser Reflectometry in a Molecular Beam Epitaxy System
Authors: Li G. S. , Yuen W. , Lim S. F. , Toh K. , Eng L. E. , Chang-Hasnain C. J.
Published: February 2023

Vertical cavity surface emitting lasers (VCSELs) and resonant cavity detectors are of great interest for optical communications applications. In order to obtain high performance devices with high yield, the epilayer thickness and growth rate must be controlled to within ±1.5 %. Conventional molecular beam epitaxy calibration method such as reflection high energy electron diffraction (RHEED) and ion-gauge beam flux measurements are limited to an accuracy of a few percent. To achieve higher accuracy, various in situ optical techniques have been investigated for growth rate calibration [l]-[2] and for real time growth control [3]-[4]. The former is desirable because of its versatility and cost-effectiveness.
Low threshold current vertical-cavity surface-emitting lasers with enhanced resistance to heating
Authors: Yang Gye Mo , MacDougal Michael H. , Dapkus P. Daniel
Published: February 2023

Vertical-cavity surface-emitting lasers (VCSEL's) fabricated by selective oxidation are attractive to achieve ultralow threshold currents [1-3]. Efficient heat dissipation, along with low threshold, is critical for uses as optical interconnects where massive integration is required. In this paper, we report an ultralow threshold of 8.7 µA and a high output power over 1.9 mW in single quantum well VCSEL's fabricated by selective oxidation from an all epitaxial structure with intracavity p-contact layers grown by metalorganic chemical vapor deposition. The design of this structure is optimized for low thermal resistance by using distributed Bragg reflectors (DBR's) composed completely of binary materials. Fig.l shows a schematic cross-section of the fabricated VCSEL's. The epitaxial structure consists of a 30-pair n-doped AlAs/GaAs quarter-wave stacks, an Al0.22Ga0.78As/GaAs/In0.2Ga0.8As resonant λ-cavity, p-doped contact layers, and a 22-pair undoped AlAs/GaAs quarter-wave stacks. The p-doped contact layers are formed from a 0.25 λ AlAs current constriction layer and a 0.75 λ GaAs intracavity contact layer. After growth, the top DBR is selectively wet etched into 14 and 5 µm square mesas down to the p-type GaAs contact layer. Then, 50 µm square mesas, whose centers coincide with the centers of the top mesas, are formed by wet chemical etching. Current flow apertures of 10 and ~3 µm are formed below the 14 and 5 µm square top mirrors, respectively, by selective oxidation.
Robust and Wavelength Insensitive Performance of Selectively Oxidized Vertical-Cavity Lasers
Authors: Choquette Kent D. , Schneider R. P. , Lear K. L. , Crawford M. Hagerott , Geib K. M. , Figiel J. J. , Hull Robert
Published: February 2023

The unique properties of vertical-cavity surface emitting lasers (VCSELs), such as circular output beam, single longitudinal mode, and 2-dimensional array capability, make them promising light sources for a variety of applications, including optical data links, data storage, display and printing systems. Moreover, on-wafer testing and compatibility with traditional integrated circuit fabrication technologies make VCSEL manufacture feasible and potentially inexpensive. Recently, VCSELs fabricated using "wet" oxidation1 have demonstrated the lowest threshold current (91µA),2 lowest threshold voltage (45mV above photon gap),3 and highest power conversion efficiency (52%)4 ever reported in VCSELs. The latter two results were obtained from an all semiconductor VCSEL structure that utilizes selective oxidation to form buried oxide layers. The low index oxide layers form current apertures sandwiching the active region to efficiently confine injected carriers as well as transversely confine the emitted photons. In this paper we show that the fabrication uniformity we have obtained using our selective oxidation process can reproducibly yield high performance VCSELs that are attractive for potential applications. In addition, these lasers exhibit high performance over a wide emission wavelength range from a given wafer. Finally, our selectively oxidized device structure is demonstrated to be robust and amenable to a variety emission wavelengths, currently extending from the infra-red to visible.
Dynamics of electro-optical synchronization of self-pulsating laser diodes
Authors: Egan A. , Rees P. , O'Gorman J. , Hegarty J. , Farrell G. , Phelan P.
Published: February 2023

Higher speed requirements in communication systems have led to demands
for fast optical sub-systems. Important aspects of such sub-systems
will be the synchronization of self-pulsating laser diode (SP LD)
emission to electrical or optical signals and timing extraction,
aspects which have already been demonstrated experimentally.
Consequently, these devices may play important roles as functional
elements in transparent transmission systems. Effective implementation
of these functions in communications systems using these devices
depends on a more complete understanding of synchronization of SP LDs
than exists at present. In this paper we address a number of important
timing issues relating to electro-optical synchronization. We have
experimentally observed for the first time that a phase difference
exists between the input electrical signal and the output optical
signal of a synchronized SP LD and we have experimentally and
theoretically investigated the nature and behaviour of this phase
difference. We have also numerically investigated the impact of
synchronization of SP LDs on timing jitter in the emitted optical
pulses.
High Temperature Uncooled Lasers
Authors: Zah C. E. , Bhat R. , Lee T. P.
Published: February 2023

An uncooled laser transmitter is cheaper and more reliable than a
thermo-electrically cooled laser transmitter because of its simplicity
in packaging. A low-cost, highly-reliable uncooled laser may have a
strong influence on pushing fiber deployment closer to the home. For
loop applications, the laser transmitter must operate reliably over
the temperature range from -40 to 85°C. It is rather difficult to make
high performance uncooled lasers in the long wavelength region
(1.3-1.55 μm) using the conventional
GaxIn1-xASyP1-y/InP
materials system because the laser temperature performance suffers
from Auger recombination in the low bandgap material and poor electron
confinement resulting from the small conduction band offset
(ΔEc=0.4ΔEg). We will discuss the design of
uncooled lasers to minimize the changes in both threshold current and
slope efficiency over the temperature range from -40 to 85 °C. To
prevent carrier overflow under high-temperature operation, the
electron confinement energy is increased by using the
AlxGayIn1-x-yAs/InP materials system
instead of the conventional
GaxIn1-xASyP1-y/InP
materials system. Experimental results of the
AlxGayIn1-x-yAs/InP strained quantum
well lasers show superior high temperature performances as discussed
below.
Theoretical and Experimental Study on the Temperature Sensitivity of High-Efficiency 1.3-μm InP-Based Strained MQW Lasers
Authors: Seki S. , Oohasi H. , Sugiura H. , Hirono T. , Yokoyama K.
Published: February 2023

InP-based strained-layer (SL) multiple-quantum-well (MQW) lasers operating at a wavelength of 1.3 μm have attracted much interest due to their potential applications to fiber-in-the-loop (FITL) or fiber-to-the-home (FTTH) systems [1], [2]. For these applications, it becomes important to improve the temperature sensitivity of device properties over a wide range of operating temperatures. We have recently derived the basic design rule for highly-efficient operation of InP-based SL-MQW lasers at elevated temperatures [3]. The SL-MQW lasers fabricated according to this design rule have exhibited high external differential quantum efficiency over 58% in the temperature range up to 363 K [3]. In this paper, we present a theoretical and experimental study on the temperature sensitivity of the differential quantum efficiency and threshold current of 1.3-μm InP-based SL-MQW lasers.
Generating Tandem Component Correlation Filters For Programmable Spatial Light Modulators
Authors: Monroe Stanley E.
Published: February 2023

Bartelt and Horner [1,2,3] have described an iterative procedure for constructing Tandem Component (TC) filters, which are a series of phase-only, passive elements distributed through an optical system. Of the several applications considered, the one of interest to this author is that of optical correlators. Since the elements do not affect the amplitude of the optical beam (ie, there is no absorption), the optical efficiency of these systems is higher than systems using conventional matched filters. By using more than one element, more than one degree of freedom can be influenced and an iterative technique can be used to force a desired response in the correlation plane for a given input.
Optical Implementation of Association and Learning Based on Primo/Light Valve Devices
Authors: Efron U. , Owechko Y.
Published: February 2023

An outer-product associative memory system is proposed which optically implements the learning of the association weights as well as the execution of the association operation. The simplest implementation is based on the concept of the correlation matrix associative memory. The system is based on the use of two 1-D PRIMO SLM layers as the input modulator, coupled with a liquid crystal light valve which represents the Tij matrix. The system can learn the relative importance of the input vectors by self-adjusting the weights of the Tij elements. The learning as well as the association with a given input are performed optically.
Optically Addressed Spatial Light Modulators by MBE-Grown nipi/MQW Structures
Authors: Maserjian J. , Andersson P.O. , Hancock B.R. , lannelli J.M. , Eng S.T. , Grunthaner F.J. , Law K-K. , Holtz P.O. , Simes R.J. , Coldren L.A. , Gossard A.C. , Merz J.L.
Published: February 2023

The development of high performance, reliable spatial light modulators (SLMs) has been slow over past years, primarily due to the limitations of materials technology1. New opportunities have been made possible by the greatly enhanced electro-optic properties of multiple quantum well (MQW) structures2. Such MQW structures are now being incorporated into a variety of new electro-optic devices3. Approaches for SLMs using MQWs have been proposed4-8 and early results are encouraging5,6,8.
A 2-D Optically Addressed Silicon/PLZT Spatial Light Modulator Array
Authors: Lin T. H. , Wang J. , Dasgupta S. , Esener S. C. , Lee S. H.
Published: February 2023

Optically addressed spatial light modulators (OSLM) are an important component for the implementation of massively parallel high performance opto-electronic computers. Such devices are particularly useful for applications such as optical logic and memory, wavelength and coherence transformations and 2-D filtering. The technology which combines silicon for detection and computation and electro-optic PLZT (Pb0.9La0.1 [Zr0.65Ti0.35]0.97503) for optical modulation allows the realization of such SLMs. These two materials combine the computational power of silicon and the parallel communication capability of optics. In this paper we report the successful fabrication of 2 × 2 OSLM arrays using polycrystalline silicon deposited on a PLZT substrate. We detail the device design considerations, describe the experimental techniques utilized and discuss the resulting OSLM performance.
Ferroelectric Liquid Crystal Spatial Light Modulator: Materials and Addressing
Authors: Pagano-Stauffer L.A. , Handschy M.A. , Clark N.A.
Published: February 2023

Ferroelectric liquid crystal (FLC) technology is ideally suited for the making of spatial light modulators (SLMs) because of its fast, low-voltage, low-power electrooptic effect. Its bistabilty and sharp dynamic threshold further make multiplexed addressing schemes attractive, promising SLMs with a large number of elements yet with an economical number of electronic drivers. We report here results of several implementations of the most common multiplexing scheme, “matrix addressing,” and point out several properties of the FLC materials that are likely to influence the performance of matrix-addressed SLMs.
Rotatioanlly Invariant Joint Transform Correlation
Authors: Yu F.T.S. , Jutamulia S. , Li X. , Tam E. , Gregory Don. A.
Published: February 2023

Many problems in pattern recognition require the identification of an object that has an unknown rotational orientation, and many rotationally invariant correlation techniques have been proposed.1 This paper describes two rotational-invariant methods utilizing a joint transform correlator that can be implemented with liquid crystal televisions (LCTVs).2
Spatial Light Modulators in Multimode Fibers
Authors: El-Sherif Mahmoud A.
Published: February 2023

An external field applied to a modified multimode fiber induces modal power redistribution. This technique is examined for spatial light modulators, and promising results are obtained.
Pattern Recognition Utilizing Binary Light Modulators
Authors: Hill Robert E. , Fronek Donald K. , Faller Calton S. , Lane Richard A.
Published: February 2023

The Optics Laboratory at Louisiana Tech University is developing application capability for high speed image processing and pattern recogition using a three-plane Vander Lugt optical correlator.
Experimental Investigation of Photoemitter Membrane Spatial Light Modulator Performance Limit
Authors: Rolsma Peter B. , Lee John N. , Oh Tae-Kwan
Published: February 2023

A photoemitter membrane light modulator (PEMLM) is enhanced by adding a visible light photocathode to the basic structure [1]. The basic structure consists of four parts; a microchannel plate (MCP), a grid, a deformable membrane, and a transparent electrode as shown in Figure 1. Previously the input of the MCP was used as a photocathode to convert an ultraviolet (uv) image into an electron distribution. The MCP then amplifies this distribution by secondary emission, similar to a photomultiplier tube. At the output of the MCP the electron energies are low. The purpose of the grid that is added to the MCP output, is to control the electron energy. If the energy is low the electrons will be deposited onto the membrane. If they are high, excess secondary emission at the membrane will occur and electrons will be removed from the membrane. Thus, images are added or subtracted by changing the grid voltage. The rate at which these functions and other possible functions occur, is dependent upon the rate of electron generation by the MCP, up to the point of MCP saturation. This electron generation is the product of the light intensity and photocathode quantum efficiency. Using the MCP input as a photocathode requires a strong uv light because of a low quamtum efficiency (≃10-7), even at short wavelengths. To avoid the problems of working with uv, a cesium-antimony(Cs3Sb) photocathode for the PEMLM is being fabricated. This will allow the use of red light for a write beam. Previously, high frame rates were not achieved because of the limits of the light source. With the Cs3Sb photocathode frame rates should be increased to the MCP strip current limit.
An Application of Optical Logic on Ferroelectric Liquid Crystal Spatial Light Modulators to Neural Network Processing
Authors: Neil Mark A. A. , White Ian H.
Published: February 2023

We discuss the use of ferroelectric liquid crystal spatial light modulators as optical polarisation rotating logic elements in a direct storage implementation of the Hopfield model.
Photoaddressed Liquid-Crystal Spatial Light Modulators
Authors: Armitage D. , Thackara J. I. , Eades W. D.
Published: February 2023

Photoaddressed spatial light modulators (SLM) are an efficient means of modulating light with light and provide the benefits of optical parallelism in both write and read modes. Figure 1 shows the general form of a reflective-readout photoaddressed SLM. The input and output are optically isolated and the SLM can provide gain via an intense readout source. Incoherent-to-coherent light conversion is also readily achieved by the SLM.
Two-Beam Coupling Photorefractive Spatial Light Modulation with Positive/Negative Contrast in Sillenite Crystals
Authors: Marrakchi Abdellatif
Published: February 2023

Dynamically programmable optical processing and switching systems rely heavily on the availability and performance of spatial light modulators (SLMs). Several devices based on the refractive index change of a photosensitive material have been already demonstrated.1 However, their performance has been shown to be limited, both in terms of sensitivity and resolution. As a result, new concepts are being investigated that would perform the SLM function. One alternative is to utilize the photorefractive effect.
Highly-Parallel Holographic Integrated Planar Interconnections
Authors: Jannson Tomasz , Lin Shing-Hong
Published: February 2023

The concept of using holograms or holographic devices to realize optical interconnection has been subjects of recent investigations [1,2]. In conventional holographic architectures, the holographic optical elements (HOEs) that interconnect signals between the input sources such as laser diodes (LDs) and the output receivers such as photodiodes, fibers, etc., are generally not located in the plane of the optoelectronic and VLSI elements. This type of 3D free-space holographic interconnect has important limitations. First, alignment problems are critical. If the sources and detectors are not in exact 3D alignment with the opposing holographic elements, performance suffers possibly to the point where the interconnect becomes inoperative. Second, and more importantly, even assuming ideal conditions, conventional Bragg holographic interconnect previously proposed cannot, in theory or practice, provide the large number of interconnections (N >> 10) needed in the typical VLSI systems. In short, the interconnectability of such bulk holographic system is limited by the small hologram thickness (∼10 to 20 μm).
Insulated-Gate MQW Structures on InGaAs/InP for Discrete Optical Modulators and CCD Addressed SLMs
Authors: Chen C.W. , Han K.Y. , Iyer R. , Lee H.Y. , Hafich M. , Robinson G.Y. , Lile D.L.
Published: February 2023

Optoelectronic effects in MQW structures, for optical modulators and switches, have attracted wide interest because of their potential applications in high speed signal processing(1). Due to the Quantum Confined Stark effect, a red shift of the absorption edge is expected in such quantum well devices in the presence of an orthogonally applied electric field. This mechanism presents the possibility of high speed electrically and optically addressed switches compatible with semiconductor processing technology(2). In addition to discrete devices, GaAs based MQW SLMs with Charge Couple Device (CCD) addressing have been demonstrated, successfully operating with contrast ratios of 1.45 to 1 at room temperature(3). In these structures, CCD channels have been used to input the data, and in turn, program the electric field across the surface of the semiconductor. In this way, potentially high speed multi-giga-bit data rate light modulation could be achieved in areal arrays without the problems of directly electrically accessing each pixel.
Real-Time Construction and Reconstruction of Holograms Using an Optically-Addressable Spatial Light Modulator
Authors: Kurokawa Takashi , Fukushima Seiji
Published: February 2023

Holography technology has been applied to analogue optical processing, three-dimensional display and optical storage. Their dynamic applications, however, have been limited by the lack of real-time hologram. Rewritable hologram materials, such as photochromic and photorefractive materials1, have not sufficient speed and sensitivity for real-time operation. Real-time hologram would be very important to realize flexible optical processing systems for moving images. We have developed a high-resolution optically-addressable spatial light modulator that utilizes a ferroelectric liquid crystal and an amorphous-silicon photoconductor. We have studied the diffraction characteristics from the interference pattern recorded on the SLM and have attained the real-time construction and reconstruction of a Fresnel hologram using the SLM.
Spatial Light Modulators using Acoustic Charge Transport Controlled Stark Effect in Multiple Quantum Well Structures
Authors: Bhattacharjee K.K. , Jain F.C.
Published: February 2023

The application of quantum confined Stark effect to realize optical modulators in multiple quantum well (MQW) structures, having p-i-n configuration to apply an external electric field, has been extensively studied by a number of investigators [1-3]. Optical modulation in MQW structures using quantum well charge-coupled devices (QWCCDs) was demonstrated by Goodhue et al [4]. In these devices, the charge packets are transported in the channel by manipulating the gate potentials of the 3-phase CCD array. Jain and Bhattacharjee [5] reported novel modulators using surface acoustic wave induced Stark Effect in the MQW structures without p-i-n device format and associated biasing electrodes.
Programmable Coherent Source Arrays Using Spatial Light Modulators
Authors: Marrakchi A. , Habiby S. F. , Wullert J. R. , Patel J. S.
Published: February 2023

With the development of addressable two-dimensional spatial light modulators, many optical elements can be synthesized in a programmable fashion. As an example, we demonstrate and characterize arrays of coherent focussed spots generated by writing multiple Fresnel zone plates on optically and electrically addressed modulators.
Liquid Crystal Integrated Silicon Spatial Light Modulator
Authors: Armitage D. , Kinell D. K.
Published: February 2023

Practical optical processing systems require compact and efficient electronically addressed spatial light modulators (EASLM). This can be achieved by integrating ferroelectric liquid crystals (FLC) with silicon-chip technology. The low voltage and power requirements of FLCs are consistent with large-scale silicon integration. A 12×12-mm silicon chip could support a 512×512-pixel array, with 100-µs frame time.1,2 We have initiated a program to investigate the issues, using an active-matrix-addressed 12×12-array chip.
The Effect of Filter Pixelation on Optical Correlation
Authors: Gheen Gregory , Washwell Edward , Armitage David
Published: February 2023

There are a number of factors that impinge upon the design of spatial light modulators (SLMs) for use in 2-dimensional optical correlators. Some of the issues that have received attention include: array size, contrast ratio, gray scale, electronic addressing, and approaches towards amplitude and phase modulation.1-3 Missing from this discussion are the problems associated with using a pixelated spatial filter and ways to remedy this problem. This is most unfortunate since most SLMs used in the filter plane have an inherent pixelated structure. The objective of this paper is to draw attention to this problem and propose a solution.
Novel electron trapping (ET) spatial light modulator
Authors: Jutamulia Suganda , Storti George M. , Lindmayer Joseph , Seiderman William
Published: February 2023

The parallelism and interconnection provided by an optical system is a major potential advantage for data transmission. However, a spatial light modulator (SLM) is required to process the optical information. Either amplitude, phase, or polarization would be modulated by the SLM, but coherence may not be affected. This would allow coherent or holographic processing to take place. However, information can also be carried by only the intensity in incoherent optical processing applications. The electron trapping (ET) SLM described in this paper demonstrates potential applications to both incoherent and coherent processing, although application to incoherent processing will be emphasized in this introductory demonstration.
Development and Applications of a Truly Bistable Optically Addressed Spatial Light Modulator
Authors: Chittick R. C. , Crossland W. A. , Brocklehurst J. R. , Cambon P. , Killinger M. , de Bougrenet de la Tocnaye J-L
Published: February 2023

Optically addressed spatial light modulators (OASLMs) have potential applications in a wide range of computing and processing systems. The recent advent of fast devices using ferroelectric liquid crystals 1-3 has led to a rapid expansion of interest in a number of these areas. However, some applications such as beam steering4 and cellular image processing require a device that is not only fast, but is able to retain the image in the absence of write information or drive voltage so that processing with the read beam can proceed without interference from the write beam. In this paper we report the development of such a latching device and some preliminary experiments using it.
Nonlinear spatial operators using optically addressed ferroelectric spatial light modulators
Authors: Killinger M. , Cambon P. , de Bougrenet de la Tocnaye J. L. , Chittick R. C. , Brocklehurst J. R.
Published: February 2023

Non linear operators have been proved to play a major part in optical computing particularly for neural networks or more generally for Artificial Intelligence procedures involving complex decision rules [1]. Usually a nonlinear operator (NL) gives a zero response for a low input level, a fixed saturated one for a high sufficient value and shows a monotonic transition regime. The latter is generally not considered in the literature for applications in optics, although some recent studies have demonstrated the importance of the degree of the NL characteristic for pattern recognition invariancy, based on template matching classifiers using multilinear pattern decomposition and counting networks [2], Although NL operators are generally the domain of electronics because of higher flexibility, speed and easier handling, electronics is no longer of any interest as soon as such operations have to be performed spatially, which is the case in the latter example. Optical devices exhibiting NL behaviour are numerous [3]. In this paper, we present a solution which seems promising because of its easy handling, its high spatial resolution, the presence of different NL phases as well as the possibility of adjusting these NL characteristics, hence allowing, in the short term, the evaluation of many optical implementations of complex procedures such as described in [2].
Comparison of spatial light modulators for multipath delay estimation
Authors: Ward Michael J. , Keefer Christopher W. , Grucza David J. , Welstead Stephen T.
Published: February 2023

A spatial light modulator (SLM) may be used to variably tap and weight an acousto-optic (AO) delay line. This SLM application occurs in the optical signal processing of multipath delays from radar or other communication sources, as has been demonstrated with various electro-optic processing architectures1.2,3. These multipath delays signal must be estimated and suppressed to ensure optimal system performance. In the architecture presented here, the SLM must accurately select and weight various delays of a signal that propagate across an acousto-optic modulator. This paper reports the relative performance characteristics of the following spatial light modulators used in this application: an AO deflector used as an SLM (AOSLM), a liquid crystal television display (LCD) and a magneto-optic SLM (MOSLM).
Electro-Optic Thin Film Spatial Light Modulator using an Epitaxial Film of Bi12SiO20
Authors: Nagao Yasuyuki , Mimura Yoshinori
Published: February 2023

We have newly developed a thin film-spatial light modulator (TF-SLM) using an epitaxial film of Bi12SiO20 (BSO) which is capable of a high resolution and a fast voltage-controlled erasure operation. In this paper, its structure, operation, and preliminary experimental results are described.
A New Type of Spatial Light Modulator with Binary Phase Gratings
Authors: Buydens L. , Demeester P.
Published: February 2023

During the last decade a lot of designs have been proposed for the fabrication in different material systems of optical free space modulators for use in optical processing systems1,2.
Amorphous Silicon Carbide Multilayer Modulators for Silicon Smart Pixels
Authors: Neifeld Mark A.
Published: February 2023

Smart spatial light modulators represent a class of device which combines optical detectors, simple processing electronics and optical modulators or sources to facilitate the high speed processing of 2-D arrays of optical data.
"Smectic A and C* liquid crystal light valves: application to parallel information processing"
Authors: de Bougrenet de la Tocnaye J.L.
Published: February 2023

Optically addressable imaging devices, often referred to as light valves, have played a crucial role in adaptive optics and optical processing during the two last decades [1].
Phase Characteristics of Reflection Electro-Absorption Modulators
Authors: Liu Daxin , Lord S.M. , Larson M. , Trezza J.A. , Harris J.S. , Pezeshki B. , Watson T.J.
Published: February 2023

Asymmetric Fabry-Perot(F-P) reflection modulators1 with multi-quantum well cavities perform as excellent intensity modulators with high contrasts and large reflectivity changes. In addition to the intensity modulation caused by the absorption changes in the cavity, an accompanying phase modulation results from the refractive index changes that correlate with the absorption change through the Kramers-Kronig transformation2-3.
Active Anti-Reflection Coating Electro-Optic Modulator
Authors: Obeidat Amjad , Khurgin Jacob , Li Shaozhong
Published: February 2023

Electro-optical switches and modulators based on multiple quantum wells (MQW) have been receiving increasing attention due to their potential applications in optical logic, interconnects, and all optical signal processing [1], [2]
Implementation of a Polarization Sensitive Silicon Retinula Array
Authors: Bar-Tana Ido , Johnson Kristina M.
Published: February 2023

This paper describes the implementation of a polarization sensitive silicon retinula array.
Optical Characterization of Stripe Deformation in an Electroclinic Liquid Crystal
Authors: Lindle J. R. , Flom S. R. , Bartoli F. J. , Shashidhar R. , Ratna B. R. , Crawford G. P.
Published: February 2023

Recently the electroclinic effect in chiral smectic A (Sm A) liquid crystals has been the subject of increased study because of its potential for spatial light modulators with fast response and greyscale operation. For this application, a large contrast ratio is desirable and often essential. However, it has been observed1 that, when smectic A liquid crystals are subjected to an electric field and viewed between crossed polarizers, they exhibit distinctive periodic stripe domains due to a voltage deformation (kink) of the bookshelf geometry.2 The molecular alignment is reported to alternate between stripes, reducing the contrast ratio and imposing performance limitations on electrooptic devices based on these materials. In this investigation, we report spatially resolved measurements on a smectic A liquid crystal, performed using a novel technique to probe the optical properties with micron resolution. The effect of the stripe formation on the electrooptic properties of the Sm A liquid crystal KN125 is investigated.
Properties and Application of Liquid Crystal Spatial Light Modulators in JENOPTIK Optical Signal Processing Systems
Authors: Reichel Frank
Published: February 2023

Spatial Light Modulators (SLM) used as components in optical signal processing systems are gaining ever greater importance. The application of SLM for performing optical Fourier transformations or optical correlations in real time pattern recognition are worth speaking of. Additionally, a new scope of application has been opened up by SLM in creating optical neuronal networks and optical memories.
Surface Normal Optical Modulation in Thin Film Silicon: Is It feasible?
Authors: Estes Michael , Moddel Garret
Published: February 2023

Unlike direct band gap materials such as GaAs, which exhibit very sharp and strong absorption at the band edge, indirect gap crystalline silicon has relatively weak band edge absorption and hence weak band edge nonlinearities[1]. Even hydrogenated amorphous silicon (a-Si:H) with its quasi-direct bandgap shows only moderate electro-optic modulation at its nominally 1.7 eV band edge[2, 3] due to disorder-induced tail states. In addition, both a-Si:H and c-Si are centrosymmetric materials so that there are no χ(2) optical nonlinearities.
Nematic liquid crystal analog modulators fabricated on VLSI circuitry
Authors: Drolet Jean-Jacques P. , Psaltis Demetri , Patel Jay S.
Published: February 2023

A new, simple process for fabricating light, modulator on integrated circuits is presented. The modulators are capable of video-rate analog amplitude or phase modulation.