Optical Devices (Total 131851 Papers Found)

This paper describes the fabrication of a novel stretchable fingernail sensor prototype, mounted on the fingernail for detecting fingertip touch force direction. Fingernail sensors are optical reflectance photoplethysmograph sensors that detect the change in blood perfusion in the nail bed, as the finger pad touches a planar surface with various forces. The original fingernail sensor was rigidly attached to the human fingernail and accordingly needed to be customized to the geometry of the finge ...
We report on the design and implementation of a spectral ellipsometer at near-infrared wavelength (700-1000 nm) for samples placed in high magnetic fields (up to 14 T) at low temperatures (~4.2 K). The main optical components are integrated in a probe, which can be inserted into a conventional long-neck He dewar and has a very long free-space optical path (~1.8 m×2). A polarizer-sample-(quarter-wave plate)-rotating analyzer configuration was employed. Two dielectric mirrors, one before and one ...
In this paper we present some research results on the micro and nano-photonic structures in the visible and near infrared spectral region for optical devices that have been done within the framework of Nanoscience and Nanotechnology Program of Institute of Materials Science. In the first part, we report the design and fabrication of 1D photonic structure based on porous silicon layers fabricated by electrochemical etching method and some of their potential applications such as optical filters, m ...
We designed a new image scanner using the reflective optics of a compound eye system that can easily assemble plural imaging optical units (called imaging cells) and is compact with a large depth of field (DOF). Our image scanner is constructed from 32 reflective imaging cells, each of which takes an image of approximately a 10-mm field of view (FOV) that slightly overlap the adjacent imaging cells. The total image is rebuilt by combining the 32 images in post processing. We studied how to fold ...
The possibility of pattern recognition using optical matched filtering with noncoherent light was realized by Armitage and Lohmann. A holographic implementation of this idea was demonstrated by Lohmann, who also pointed out that a noncoherent system has several advantages over its coherent equivalent, the Vander Lugt Fourier-plane filter. The operation of the noncoherent system must be described in terms of intensity rather than complex amplitude, hence, any phase variations of the input data ca ...
The deployment of translucent optical networks is considered the most promising short term solution to decrease costs and energy consumption in optical backbone networks. Indeed, due to the technological maturity of translucent wavelength switched optical network (WSON) architectures, they have already caught close attention from the research community. Moreover, recent advances and enhancements in optical devices are now (re-)fostering research interest in sub-wavelength technologies like, amon ...
Photosensitivity in chalcogenide glass waveguide allows for a permanent refractive index change by means of light exposure [1]. This property can be usefully exploited for post-fabrication trimming of integrated optical devices in order to compensate for fabrication imperfections and alleviate the need for restrictively tight fabrication tolerances [2]. In this work, visible light trimming is exploited to optimize the performance of coupled resonator filters realized by cascading micro-ring reso ...
We present quantitative morphological analyses of 37 HST/WFPC2 counterparts of X-ray sources in the 1 Ms Chandra Deep Field–South (CDFS). We investigate: 1) one-dimensional surface brightness profiles via isophotal ellipse fitting; 2) two-dimensional, PSF-convolved, bulge+disk+nucleus profile-fitting; 3) asymmetry and concentration indices compared with all ∼ 3000 sources in our three WFPC2 fields; and 4) near-neighbor analyses comparing local environments of X-ray sources versus the field c ...
The new reactor FRM-II from the Technische Universitat Munchen will offer a professional radiography and tomography facility for industrial use. It consists of a classical setup of diaphragm plus flight tube at the cold source, with unprecedented flux and geometric resolution. However, the original plans were to set it up at a neutron guide; many other facilities also only have space for a neutron radiography setup at a neutron guide. We have therefore examined several possibilities to perform n ...
Composite materials comprised of nematic liquid crystals (LCs) and SiO(2) inverse opal films were fabricated. Their optical properties were quite different from those of inverse opal films without the LCs. The optical properties could be controlled by changing the refractive indices of the LCs, which vary with orientation, phase, and temperature. In particular, the optical properties were drastically changed by thermal or photoinduced isothermal phase transitions of the LCs. This means that the ...
In this paper, we describe confocal optoelectronic holography microscopy (COEHM) technique specifically being developed for characterizing the shape of MEMS and microelectronics. This is particularly important because shape is directly related to the functionality, performance, and integrity of the microstructures of interest. A specific feature of COEHM is that it allows characterization of high aspect ratio MEMS and microelectronics. Representative applications demonstrating the capabilities o ...
The paper reports on standard fibre optical components mounted onto the chip for single atom detection. At present, two main directions are being pursued: fluorescence detection and fibre Fabry-Perot gap cavities. Theoretical analysis has shown that both devices will have the ability to detect single atoms with the micro-cavities offering the possibility of non-destructive detection. ...
We demonstrate numerically the operation of optical microelements consisting of metal-dielectric multilayers with slanted edges. We show examples of optical devices for imaging with sub-wavelength resolution, for focusing in a sub-wavelength-sized area, for manipulation of the state of polarisation, and for cross-coupling between the propagating and evanescent parts of the spatial spectrum. The multilayers that are used by us consist of silver and a high refractive index dielectric and may be re ...
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mplementing automation in the testing and assembly of photonics components is a necessary step to achieve the yield improvements and cost reductions required for future telecommunications applications. Moving from the current state of largely manual test and assembly to full automation, however, presents several challenges. One of the most significant roadblocks to progress is that few current-generation products were designed for automated manufacturing , and most manufacturers have not suffici ...
The variation of band gap energy and band structure with respect to composition of Li/sub (1-x)/K/sub x/Ba/sub (1-y)/Mg/sub y/F/sub 3/ perovskite-like fluorides is investigated. Analysis of energy chart shows the feasibility of fabricating Li/sub (1-x)/K/sub x/Ba/sub (1-y)/Mg/sub y/F/sub 3/ on either LiBaF/sub 3/ or KMgF/sub 3/. ...
A new optical device based on the photoplethysmograph (PPG) method and an innovative algorithm for the assessment of lower-extremity peripheral arterial disease was investigated prospectively in patients with type II diabetes. This new functional PPG (fPPG) technique uses a cuffless functional test to assess diabetic peripheral arterial disease without operator dependency and the incompressible arteries, issues associated with ankle brachial pressure index (ABPI) measurement. Diabetic patients ( ...
The accurate design of integrated optical S bends, power splitters, and directional couplers is described through a minimum number of normalized parameters. General design curves showing these normalized parameters for waveguides with a step refractive index profile and a quadratic core cross section are given. Thus a wide variety of integrated optical components may be designed accurately without the use of time-consuming numerical methods. ...
We introduce an elastic dielectric metasurface platform for developing ultra-slim arbitrarily shaped multifunctional and tunable optical devices. We demonstrate conformal metasurfaces for decoupling optical function and geometrical form, and elastic metasurface lenses with high tunability. ...
The transformation optics technique for designing novel electromagnetic and optical devices offers great control over wave behavior, but is difficult to implement primarily due to limitations in current metamaterial design and fabrication techniques. This paper demonstrates that restricting the spatial transformation to a conformal mapping can lead to much simpler material parameters for more practical implementation. As an example, a flat cylindrical-to-plane-wave conversion lens is presented a ...
In this paper, we propose a high precision digital image stabilization system using optical device. The proposed system consists of three parts; motion sensing with gyro-sensors, detection of large motion using sub-sampled images and refinement of stabilization with sub-pixel accuracy. Experimental results show that the proposed hybrid image stabilizer outperforms some conventional stabilization techniques. ...
Analysis of optical waveguides with thin metal films is studied by the multidomain pseudospectral frequency-domain (PSFD) method. Calculated results for both guiding and leaky modes are precise by means of the PSFD based on Chebyshev-Lagrange interpolating polynomials with modified perfectly matched layer (MPML). By introducing a suitable boundary condition for the dielectric-metallic interface, the stability and the spectrum convergence characteristic of the PSFD-MPML method can be sustained. T ...
Different models of light irradiation and collection in solar concentrators are here reported, together with a theoretical analysis that leads to new optical concepts and new optical quantities. For some of them a similarity with electrical quantities is suggested. In this paper we present a general theoretical approach to the study of solar concentrators, which are seen as generic optical components with reflectance, absorbance and transmittance properties expressed with respect to different ir ...
Tens of thousands of optical data transmission links are currently installed in all four experiments at the Large Hadron Collider (LHC) [1] for the transmission of timing, control and read-out data to and from the detector systems. Work has started on identifying new technologies and optical components which could meet the requirements of the High-Luminosity LHC (HL-LHC); an upgrade of approximately of an order of magnitude to the luminosity of the LHC planned to take place in 10 years time. Sil ...
In this paper, we propose new methodology to enhance the QoS in cost and energy efficient WDM/OFDM PON system. In this, the WDM technique supports more number of ONU and the OFDM technique provides high spectral efficiency and flexible sub-channel bandwidth allocation. Here, we have reduce BER at ONU by using the post dispersion compensation technique inorder to reduce the chromatic dispersion which is a major issue in single mode fiber, when signal travels for a long distance. Also the DCF supp ...
Device-to-device (D2D) communication is considered a promising technique to provide wireless peer-to-peer communication services. Due to increasing demand on mobile services, available spectrum for radio frequency (RF) based communications becomes scarce. Recently, visible light communications (VLC) has evolved as a high speed wireless data transmission technology for indoor environments with abundant available bandwidth. In this paper, a novel VLC based D2D communication that provides wireless ...
Simple formulas are derived for the degradation in the beam-quality factor, M(2), of an arbitrary laser beam caused by quartic phase distortions such as those that might occur in a spherically aberrated optical component, a thermally aberrated laser output window, or a divergent beam emerging from a high-index dielectric medium as in a wide-stripe, unstable-resonator diode laser. A new formula for the defocus correction that is needed to collimate optimally a beam with quartic phase aberration i ...
We investigate dispersion properties of <i>n</i>-layers unit cell metallic-dielectric stratified structures (MDSSs) for the first time to our knowledge. An efficient and flexible numerical method is applied to study optical characteristics of the MDSSs. As an example, we systematically investigate the influences of geometric parameters, operating frequency, and gain material on the dispersion properties of the <i>n</i>-layers unit cell MDSSs in the terahertz regime. The r ...
An array of nanometer-sized apertures capable of electrochemically modulating the fluorescence of a model analyte is presented. The device, which combines near-field optical methods and ultramicroelectrode properties in an array format, is based on an etched coherent optical fiber bundle. Indeed, the fabrication steps produced an ordered array where each optical nanoaperture is surrounded by a ring-shaped gold nanoelectrode. The chronoamperometric behavior of the array shows stable diffusion-lim ...
We demonstrate ultra-high speed, low-power and digital all-optical memory action in photonic nanostructures. We show how large-scale on-chip integration of all-optical devices can be achieved without any optical isolators, even in the presence of reflections ...
This communication introduces the modelling of optical and optoelectronic components and the simulation of optical circuits and links using SERENADE Suite. A specific library describing several optical components and devices has been established and integrated as User-Defined-Models into the SERENADE Suite. Then, the simulation facilities of SERENADE are used to study some integrated optical circuits and fiber links. INTRODUCTION The optical technologies based on the use of optical fibers and in ...
We report on an optical parametric oscillator that generates output idler wavelengths around 10.6 μm. On the basis of orientation-patterned gallium arsenide (OP-GaAs) as a nonlinear medium and a 1.95 μm ns-pulsed pump laser, a signal-resonant bow-tie resonator was designed in order to maximize the output power at moderate intensities well below the damage threshold of the optical components. With this setup, the average idler output power at 50 kHz and 100 ns idler pulse length was more than 8 ...
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Surface plasmon resonance (SPR) is widely used as a detection principle for many sensors operating in different application fields, such as bio and chemical sensing. When artificial receptors are used for bio/chemicals detection, the film on the metal surface (usually a gold surface) selectively recognizes and captures the analyte present in a liquid sample, so producing a local change in the refractive index at the metal surface. The value of the refractive index change depends on the structure ...
The integrated optical configuration of a Young interferometer is proposed for refractometry and chemical sensing. We coupled light into an integrated optical Ybranch by fixing a laser diode directly at the input of the optical device. We solved the problem of ambiguity in the interference order by operating the laser diode at currents below threshold, resulting in visibility modulation of the interference fringes caused by the low coherence length of the emitted light. A very compact device res ...
In this paper, we introduce a simple fabrication technique which can pattern high-aspect-ratio polymer nanowire structures of photoresist films by using a maskless one-step oxygen plasma etching process. When carbon-based photoresist materials on silicon substrates are etched by oxygen plasma in a metallic etching chamber, nanoparticles such as antimony, aluminum, fluorine, silicon or their compound materials are self-generated and densely occupy the photoresist polymer surface. Such self-maskin ...
Chromophores containing a donor-π-acceptor (D-π-A) motif have been shown to exhibit many interesting photophysical properties. The lowest electronic transition of a flavin derivative containing this motif, azobenzylflavin (ABFL), has previously been shown to be highly sensitive to solvent environment and hydrogen bonding ligands. To better understand this sensitivity, we have investigated the excited state charge redistribution and dynamics of ABFL in a low-dielectric, non-hydrogen bonding sol ...
The paper presents the results concerning the development and the implementation of a method and a device to detect in real-time the laser-induced damage of optical surfaces. The damage detection device is integrated in an automated station to measure the laser-induced damage-threshold of optical components according to the appropriate ISO standards, within the Laser Department of the National Institute for Laser, Plasma & Radiation Physics, Bucharest, Magurele. ...
A typical job in optical computing is to illuminate an array of small nonlinear optical components, separated by wide gaps to avoid crosstalk. We do this by letting a wide uniform beam fall onto a densely packed array of minifying telescopes. Each telescope produces a narrow bundle of parallel rays which illuminates one of the nonlinear optical components. The holographic telescopes can do more than change the width of the bundles of parallel rays. Their image forming capability allows the trans ...
Advances in design, materials and production technology for micro-optical components have led to strong growth in their use in today’s consumer products. In particular, micro-optical components produced by replication technologies such as UV embossing can now withstand the severe processing and environmental requirements of the consumer electronics industry, including lead-free IR reflow and thermal shock. With their small size and low weight, as well as the possibility of optical function not ...
Organic molecular nanophotonics has emerged as an important avenue to harness molecular aggregation and crystallization on various functional platforms to obtain nano-optical devices. To this end, there is growing interest to combine organic molecular nanostructures with plasmonic surfaces and interfaces. Motivated by this, herein we introduce a unique geometry: vertically-tapered organic nanowires grown on a plasmonic thin film. A polarization-sensitive plasmon-polariton on a gold thin-film was ...
This paper presents a detailed analysis on the influence of misalignment errors of optical components in an orthogonal two-axis Lloyd's mirror interferometer, which can fabricate two-dimensional grating structures in a single exposure. In an ideal condition, defect-free two-dimensional grating structures can be fabricated by the interferometer. However, in a real case, visible stripes caused by misalignment errors of the optical components in the interferometer always appear on the fabricated gr ...
Various metallic nanostructures have been proposed to effectively utilize surface plasmon polaritons (SPPs) to improve the performance of optical devices such as solar cells, antennas, sensors, and light emission devices. With the progress in the research on SPP-based devices, the requirements for better materials have been increasing. Conventional SPP materials such as silver and gold have problems in processing; they are incompatible with reactive ion etching and they cannot be processed at hi ...
Spin of light provides a route to control photons. Spin-based optical devices which can manipulate photons with different spin states are imperative. Here we experimentally demonstrated a spin-selected metasurface lens based on the spin-orbit interaction originated from the Pancharatnam-Berry (PB) phase. The optimized PB phase enables the light with different spin states to be focused on two separated points in the preset plane. Furthermore, the metasurface lens can perform the spin-selected ima ...
702 whenever a whole number of wavelengths of the incident light fits into the resonator. Moreover, destructive interference occurs between light emerging from two coupled resonators. Early microresonators were simply aerosols containing particles of varying sizes, but modern fabrication procedures produce individual resonators with highly controllable resonance frequencies. These resonators come in various forms: ring shapes; disks or spheres, in which the light skims across the outer surface a ...
We present simulations of a novel liquid-crystal-based electro-optical device that enables a switching effect owing to a backreflection phenomenon. In the simulations, we exploit the optical properties of a liquid-crystal layer with a Freédericksz alignment in an unconventional way. The resulting switching effect of the proposed optical design can be controlled by means of an external electric field. Possible applications of the liquid-crystal device can be found in, but are not restricted to, ...
In this work we present results of an new experiment related to low energy protons bombardments on nano-structured optical coatings. Multilayer structures protected by different capping layers have been fabricated and exposed to low energy protons (1 keV). The experimental parameters have been selected considering the potential application of the coatings to solar mission instrumentation. Future solar missions will investigate the Sun from very close distances and optical components are constant ...
Up to now, many efforts have been continuously channeled toward the development of oxidation techniques on the III-V compounds for GaAs-based device application, which include thermal oxidation [1-7], chemical anodization [8-12], photochemical oxidation [13-16], plasma oxidation [17-20], Ga2O3 grown by molecular beam epitaxy (MBE) [21-23], Al2O3 grown by atomic layer deposition (ALD) [24], oxidized GaAs or InAlAs prepared by ultraviolet and ozone [25-27], and so on. Although the electrical quali ...
Metasurfaces are well known as a single-layer subwavelength structure with superior capability in wavefront shaping, and cascaded metasurfaces with multi-layer structures resulting in compact optical devices will further improve the performance and also bring in new functionalities, such as image correction, optical transformation and processing. However, in order to realize such cascaded metasurfaces, a key issue is to achieve high precision alignment of the structures in each layer usually wit ...
Recent research shows the tremendous potential for the development of optical devices viz. photo-detector, optical sources, connectors and applications etc. This is mainly because of the success of optical communication in the recent for gigabit transmission and is intended for terabits transmission in future. In this paper, mathematical model for the optical dependence of I-V, C-V characteristics of MISFET structure (to be used as photo-detector) is reported. Model is based on solution of Poiss ...
Recent progress in the fields of nanophotonics and metamaterials has enabled the development of ultrathin and flat optical components, providing physicists and optical engineers a new method to control light. According to the Huygens-Fresnel principle, light gradually propagates step by step by exciting secondary waves that then reradiate to form the next wavefront; the phase and amplitude of these secondary waves are intimately related to the incoming optical wavefront. By using the response of ...
We demonstrate the extension of the photorefractive effect in BaTiO(3) crystals to the 1.5-microm wavelength regime, which is obtained by two-photon absorption induced by intense femtosecond light pulses. The strong dependence of the effect on the light's intensity permits nondestructive readout of the photorefractively induced pattern by low-intensity light. One can thus use the photorefractive effect in the 1.5-microm regime to form optical components for communication applications. ...