39,794 results match your criteria Optics Express [Journal]


Ghost imaging using a large-scale silicon photonic phased array chip.

Opt Express 2019 Feb;27(3):3817-3823

We experimentally demonstrate the use of a large-scale silicon-photonic optical phased array (OPA) chip as a compact, low-cost, and potentially high-speed light illuminating device for ghost imaging (GI) applications. By driving 128 phase shifters of a newly developed silicon OPA chip using rapidly changing random electrical signals, we successfully retrieve a slit pattern with over 90 resolvable points in one dimension. We then demonstrate 2D imaging capability by sweeping the wavelength. Read More

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http://dx.doi.org/10.1364/OE.27.003817DOI Listing
February 2019
1 Read

Generalized method to design phase masks for 3D super-resolution microscopy.

Opt Express 2019 Feb;27(3):3799-3816

Point spread function (PSF) engineering by phase modulation is a novel approach to three-dimensional (3D) super-resolution microscopy, with different point spread functions being proposed for specific applications. It is often not easy to achieve the desired shape of engineered point spread functions because it is challenging to determine the correct phase mask. Additionally, a phase mask can either encode 3D space information or additional time information, but not both simultaneously. Read More

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http://dx.doi.org/10.1364/OE.27.003799DOI Listing
February 2019
3.488 Impact Factor

All-fiber-integrated Yb:YAG-derived silica fiber laser generating 6 W output power.

Opt Express 2019 Feb;27(3):3791-3798

A Yb:YAG-derived silica fiber was fabricated by a molten-core fabrication method, in which a Yb:YAG crystal was used as the core material and a silica tube was used as the cladding material. The fiber's transmission loss was measured to be 0.49 dB/m at 1. Read More

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http://dx.doi.org/10.1364/OE.27.003791DOI Listing
February 2019
3.488 Impact Factor

Hyperspectral spatially offset Raman spectroscopy in a microfluidic channel.

Opt Express 2019 Feb;27(3):3782-3790

Spatially offset Raman spectroscopy (SORS) enables one to distinguish chemical fingerprints of top and subsurface layers. In this paper, we apply SORS to a microfluidic two-layer system consisting of transparent liquid in a microchannel as the surface layer and microfluidic PDMS chip material as the sublayer. By using an imaging spectrograph connected to a microscope, we perform hyperspectral SORS acquisitions. Read More

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http://dx.doi.org/10.1364/OE.27.003782DOI Listing
February 2019

Resonant-cavity infrared detector with five-quantum-well absorber and 34% external quantum efficiency at 4 μm.

Opt Express 2019 Feb;27(3):3771-3781

We report resonant-cavity infrared detectors with 34% external quantum efficiency at room temperature at the resonant wavelength of 4.0 μm, even though the absorber consists of only five quantum wells with a total thickness of 50 nm. The full width at half maximum (FWHM) linewidth is 46 nm, and the peak absorption is enhanced by nearly a factor of 30 over that for a single pass through the absorber. Read More

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http://dx.doi.org/10.1364/OE.27.003771DOI Listing
February 2019

Circularly polarized extreme ultraviolet high harmonic generation in graphene.

Authors:
Zi-Yu Chen Rui Qin

Opt Express 2019 Feb;27(3):3761-3770

Circularly polarized extreme ultraviolet (XUV) radiation is highly interesting for investigation of chirality-sensitive light-matter interactions. Recent breakthroughs have enabled the generation of such light sources via high harmonic generation (HHG) from rare gases. There is a growing interest in extending HHG medium from gases to solids, especially to 2D materials, as they hold great promise to develop ultra-compact solid-state photonic devices and provide insights into electronic properties of the materials themselves. Read More

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http://dx.doi.org/10.1364/OE.27.003761DOI Listing
February 2019
1 Read

Designing a hydraulic support system for large monolithic mirror's precise in-situ testing-polishing iteration.

Opt Express 2019 Feb;27(3):3746-3760

In order to improve the fabrication efficiency and testing accuracy of meter-scale, large monolithic mirrors, hydraulic support units (HSUs) are commonly used. However, the challenges to reduce the disparity of the HSUs' stiffness and keep the stability of the mirrors' altitude are hard to resolve, especially for large-scale mirrors. In this paper, we found the air ratio of the working fluid for HSUs is a key factor for designing the HSUs to resolve the challenges from the analytical solution that we derived for supporting large mirrors. Read More

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http://dx.doi.org/10.1364/OE.27.003746DOI Listing
February 2019
1 Read

Lensless single-pixel imaging by using LCD: application to small-size and multi-functional scanner.

Opt Express 2019 Feb;27(3):3731-3745

Single-pixel imaging commonly uses a spatial light modulator (SLM) to encode a scene's spatial information into a one-dimensional light signal sequence so that a single-pixel detector can be used to capture a scene. Digital micromirror device, liquid crystal on silicon, or light emitted diode matrix is a common choice of SLM, but it requires a certain lens system in order to project the structured light pattern that is generated by the SLM onto the scene. Using a lens would not only lead to aberration but also result in difficulty for establishing a compact imaging system. Read More

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http://dx.doi.org/10.1364/OE.27.003731DOI Listing
February 2019

Calculation of the impulse response and phase noise of a high-current photodetector using the drift-diffusion equations.

Opt Express 2019 Feb;27(3):3717-3730

We describe a procedure to calculate the impulse response and phase noise of high-current photodetectors using the drift-diffusion equations while avoiding computationally expensive Monte Carlo simulations. We apply this procedure to a modified uni-traveling-carrier (MUTC) photodetector. In our approach, we first use the full drift-diffusion equations to calculate the steady-state photodetector parameters. Read More

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http://dx.doi.org/10.1364/OE.27.003717DOI Listing
February 2019

Controlled integration of selected detectors and emitters in photonic integrated circuits.

Opt Express 2019 Feb;27(3):3710-3716

Integration of superconducting nanowire single-photon detectors and quantum sources with photonic waveguides is crucial for realizing advanced quantum integrated circuits. However, scalability is hindered by stringent requirements on high-performance detectors. Here we overcome the yield limitation by controlled coupling of photonic channels to pre-selected detectors based on measuring critical current, timing resolution, and detection efficiency. Read More

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http://dx.doi.org/10.1364/OE.27.003710DOI Listing
February 2019

Detection of laser-induced bulk damage in optical crystals by swept-source optical coherence tomography.

Opt Express 2019 Feb;27(3):3698-3709

An approach to characterize laser-induced bulk damage in optical crystal materials was demonstrated. With a homemade swept-source optical coherence tomography (SS-OCT) system, we obtained three-dimensional images of the bulk damage produced by laser pulses with wavelength of 351 nm, pulse width of 5 ns, beam diameter of 5.5 mm and fluences from 4. Read More

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http://dx.doi.org/10.1364/OE.27.003698DOI Listing
February 2019

Corrected parabolic fitting for height extraction in confocal microscopy.

Opt Express 2019 Feb;27(3):3682-3697

Accurate and reliable peak extraction of axial response signals plays a critical role in confocal microscopy. For axial response signal processing, nonlinear fitting algorithms, such as parabolic, Gaussian or sinc fitting may cause significant systematic peak extraction errors. Also, existing error compensation methods require a priori knowledge of the full-width-at-half-maximum of the axial response signal, which can be difficult to obtain in practice. Read More

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http://dx.doi.org/10.1364/OE.27.003682DOI Listing
February 2019

High-resolution large-scale plasmonic laser color printing for jewelry applications.

Opt Express 2019 Feb;27(3):3672-3681

We offer to use optical features of surface plasmon resonance in Ag nanoparticles for jewelry application as a method for the well-controlled decoration of silver items. The novel approach of silver nanoparticles formation with sizes from 5 to 50 nm via nanosecond direct laser writing allows for controlling the reflectance spectra, thus creating a color image on precious metals with a high resolution of about 450 dpi without dyes or hazardous chemicals. Moreover, the large-scale color image can be applied in single-step processing with significant productivity of 2 cm per minute. Read More

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http://dx.doi.org/10.1364/OE.27.003672DOI Listing
February 2019
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Compensating for influence of laser-frequency-drift in phase-sensitive OTDR with twice differential method.

Opt Express 2019 Feb;27(3):3664-3671

The frequency-drift of laser source is a crucial factor for influencing the performance of the phase-sensitive optical time domain reflectometer (Φ-OTDR). It induces signal fluctuation and severely limits the measurement capacity for low frequency. In this paper, a twice differential method is proposed to compensate for the influence of the laser-frequency-drift in Φ-OTDR. Read More

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http://dx.doi.org/10.1364/OE.27.003664DOI Listing
February 2019

Heterogeneous silicon photonics sensing for autonomous cars.

Opt Express 2019 Feb;27(3):3642-3663

Heterogeneous silicon photonics is uniquely positioned to address the photonic sensing needs of upcoming autonomous cars and provide the necessary cost reduction for widespread deployment. This is because it allows for wafer-scale active/passive integration, including optical sources. We present our recent research and the development of interferometric optical gyroscopes and LiDAR sensors. Read More

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http://dx.doi.org/10.1364/OE.27.003642DOI Listing
February 2019

Polarization-based exploration for clear underwater vision in natural illumination.

Opt Express 2019 Feb;27(3):3629-3641

Underwater imaging provides human vision system friendly images; however, it often suffers from severe image degradation. This research developed an underwater polarization imaging model, which considers the water scattering effect, as well as absorption effect. It fully explored the polarization information of the target scene that backscattered light is partially polarized and target light is unpolarized. Read More

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http://dx.doi.org/10.1364/OE.27.003629DOI Listing
February 2019

Terahertz time-domain spectroscopy of zone-folded acoustic phonons in 4H and 6H silicon carbide.

Opt Express 2019 Feb;27(3):3618-3628

We investigate the dielectric properties of the 4H and 6H polytypes of silicon carbide in the 0.1-19 THz range, below the fundamental transverse-optical phonons. Folding of the Brillouin zone due to the specific superlattice structure of the two polytypes leads to activation of acoustic phonon modes. Read More

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http://dx.doi.org/10.1364/OE.27.003618DOI Listing
February 2019

Polarization-multiplexed nonlinear inverse synthesis with standard and reduced-complexity NFT processing: erratum.

Opt Express 2019 Feb;27(3):3617

We correct a formula for the numerical nonlinear Fourier transform in [1]. The conclusions of our work are unchanged. Read More

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http://dx.doi.org/10.1364/OE.27.003617DOI Listing
February 2019

Multi-slot photonic crystal cavities for high-sensitivity refractive index sensing.

Opt Express 2019 Feb;27(3):3609-3616

We present the design, fabrication, and characterization of a multi-slot photonic crystal (PhC) cavity sensor on the silicon-on-insulator platform. By optimizing the structure of the PhC cavity, most of the light can be distributed in the lower index region; thus, the sensitivity can be dramatically improved. By exposing the cavities to different mass concentrations of NaCl solutions, we obtained that the wavelength shift per refractive index unit (RIU) for the sensor is 586 nm/RIU, which is one of the highest sensitivities achieved in a non-suspended cavity. Read More

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http://dx.doi.org/10.1364/OE.27.003609DOI Listing
February 2019

Absorption and slow-light analysis based on tunable plasmon-induced transparency in patterned graphene metamaterial.

Opt Express 2019 Feb;27(3):3598-3608

We propose a novel simple patterned monolayer graphene metamaterial structure based on tunable terahertz plasmon-induced transparency (PIT). Destructive interference in this structure causes pronounced PIT phenomenon, and the PIT response can be dynamically controlled by voltage since the existence of continuous graphene bands in the structural design. The theoretical transmission of this structure is calculated by coupled mode theory (CMT), and the results are highly consistent with the simulation curve. Read More

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http://dx.doi.org/10.1364/OE.27.003598DOI Listing
February 2019

Symmetrical illumination based extending depth of field in Fourier ptychographic microscopy.

Opt Express 2019 Feb;27(3):3583-3597

Fourier ptychographic microscopy (FPM), simply replacing the traditional light source of a microscope with a LED array, can obtain high resolution and large field of view images simultaneously. A symmetrical LED illumination FPM is presented to improve the quality of high resolution images for defocus or thick samples in this paper. It is proven theoretically that symmetrical LED illumination had higher defocus tolerance than that of single LED illumination at first. Read More

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http://dx.doi.org/10.1364/OE.27.003583DOI Listing
February 2019

Generation of pulses with sub-nanosecond duration and sub-joule energy in gain-switched Ti: Sapphire lasers.

Opt Express 2019 Feb;27(3):3574-3582

We realized the generation of pulses with a 460 ps duration, 1% pulse duration stability, and 300 mJ pulsed energy in a gain-switched Ti: Sapphire laser. We show that a flattening of the pumping beam profile and an increase of pump fluence up to the threshold of second pulse generation are the main conditions to achieve pulses with minimum duration and maximum stability. The negative influence of pump nonuniformity on laser characteristics was also studied. Read More

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http://dx.doi.org/10.1364/OE.27.003574DOI Listing
February 2019

Light-field compression using a pair of steps and depth estimation.

Opt Express 2019 Feb;27(3):3557-3573

Advanced handheld plenoptic cameras are being rapidly developed to capture information about light fields (LFs) from the 3D world. Rich LF data can be used to develop dense sub-aperture images (SAIs) that can provide a more immersive experience for users. Unlike conventional 2D images, 4D SAIs contain both the positional and directional information of light rays; the practical applications of handheld plenoptic cameras are limited by the huge volume of data required to capture this information. Read More

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http://dx.doi.org/10.1364/OE.27.003557DOI Listing
February 2019

Integrated CMOS-compatible Q-switched mode-locked lasers at 1900nm with an on-chip artificial saturable absorber.

Opt Express 2019 Feb;27(3):3542-3556

We present a CMOS-compatible, Q-switched mode-locked integrated laser operating at 1.9 µm with a compact footprint of 23.6 × 0. Read More

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https://www.osapublishing.org/abstract.cfm?URI=oe-27-3-3542
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http://dx.doi.org/10.1364/OE.27.003542DOI Listing
February 2019
4 Reads

All-sky polarization imaging of cloud thermodynamic phase.

Opt Express 2019 Feb;27(3):3528-3541

Knowing the cloud thermodynamic phase (if a cloud is composed of ice crystals or liquid droplets) is crucial for many cloud remote sensing measurements. Further, this knowledge can help in simulating and interpreting cloud radiation measurements to better understand the role of clouds in climate, weather, and optical propagation. Knobelspiesse et al. Read More

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http://dx.doi.org/10.1364/OE.27.003528DOI Listing
February 2019

Nanotube mode-locked, wavelength and pulsewidth tunable thulium fiber laser.

Opt Express 2019 Feb;27(3):3518-3527

Mode-locked oscillators with highly tunable output characteristics are desirable for a range of applications. Here, with a custom-made tunable filter, we demonstrate a carbon nanotube (CNT) mode-locked thulium fiber laser with widely tunable wavelength, spectral bandwidth, and pulse duration. The demonstrated laser's wavelength tuning range reached 300 nm (from 1733 nm to 2033 nm), which is the widest-ever that was reported for rare-earth ion doped fiber oscillators in the near-infrared. Read More

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http://dx.doi.org/10.1364/OE.27.003518DOI Listing
February 2019

Analysis of terahertz generation using tilted pulse fronts.

Opt Express 2019 Feb;27(3):3496-3517

A spatio-temporal analysis of terahertz generation by optical rectification of tilted pulse fronts is presented. Closed-form expressions of terahertz transients and spectra in two spatial dimensions are furnished in the undepleted limit. Importantly, the analysis incorporates spatio-temporal distortions of the optical pump pulse such as angular dispersion, group velocity dispersion due to angular dispersion, spatial and temporal chirp, as well as beam curvature. Read More

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http://dx.doi.org/10.1364/OE.27.003496DOI Listing
February 2019

Experimental and theoretical investigation for surface plasmon resonance biosensor based on graphene/Au film/D-POF.

Opt Express 2019 Feb;27(3):3483-3495

A D-shape plastic optical fiber (D-POF) surface plasmon resonance (SPR) biosensor based on the graphene/Au film (G/Au) was proposed and experimentally demonstrated for detection of DNA hybridization process. To improve the detection performance of SPR sensors, the Physical Vapor Deposition (PVD) method was used to evaporate the Au film directly onto the graphene grown on copper foil, and the Au film acted as a role of traditional Polymethyl Methacrylate (PMMA). The process made graphene and Au film form seamless contact. Read More

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http://dx.doi.org/10.1364/OE.27.003483DOI Listing
February 2019

Broadband extremely close-spaced 5G MIMO antenna with mutual coupling reduction using metamaterial-inspired superstrate.

Opt Express 2019 Feb;27(3):3472-3482

A metamaterial structure, which has positive and negative permeability over a wide microwave frequency band, has a proposed structure that can be employed as a superstrate for reducing the mutual coupling of a MIMO antenna system. This MIMO antenna system consists of two extremely close-spaced antenna elements. The proposed structure's decoupling mechanism is verified by both the full-wave electromagnetic simulations and experiments, and the simulated and measured results agree very well with each other. Read More

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http://dx.doi.org/10.1364/OE.27.003472DOI Listing
February 2019

Modulation index stabilization technique of integrated optic phase modulator used in resonant integrated optic gyro.

Opt Express 2019 Feb;27(3):3460-3471

A novel modulation index stabilization technique for tracking the phase modulation index of integrated optic phase modulator (IOPM) is proposed to improve temperature performance of the resonant integrated optic gyro (RIOG). The influence mechanism of IOPM's modulation index fluctuation on the RIOG, especially the angular velocity tracking loop of RIOG, is investigated. A Mach-Zehnder Interferometer (MZI) is ingeniously added into the conventional RIOG structure for detecting the modulation index fluctuation. Read More

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http://dx.doi.org/10.1364/OE.27.003460DOI Listing
February 2019

Intraoperative OCT for surgical microscope with sensitivity drop and depth of focus correction based on variable focus and dynamic reference.

Opt Express 2019 Feb;27(3):3448-3459

We have developed a surgical microscope-integrated optical coherence tomography (MI-OCT) system based on an active feedback method to obtain uniform optimal OCT image contrast along the depth of focus (DOF) of a surgical microscope. Conventional MI-OCT systems use a shorter DOF objective lens than those of surgical microscopes for OCT imaging. The existing MI-OCT system was developed to overcome sensitivity roll-off by using an electrically tunable lens (ETL). Read More

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http://dx.doi.org/10.1364/OE.27.003448DOI Listing
February 2019

Large-area fabrication of microlens arrays by using self-pinning effects during the thermal reflow process.

Opt Express 2019 Feb;27(3):3439-3447

Generally, the fabrication of curved structures such as microlens arrays has been regarded as an expensive and complicated process. Here, we propose a facile method to form a microlens array with controlled lens curvature by combining residue-free nanoimprint lithography (NIL) with V-shaped molds and the successive thermal reflow procedure of the printed polymeric structures. The V-shaped molds used in this study enable the bottom substrate to be exposed after the NIL process when the initial thickness is controlled. Read More

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http://dx.doi.org/10.1364/OE.27.003439DOI Listing
February 2019
3.488 Impact Factor

Compact reflective imaging optics in hard X-ray region based on concave and convex mirrors.

Opt Express 2019 Feb;27(3):3429-3438

We demonstrated that the combination of a hyperbolic convex and elliptical concave mirrors works as a compact reflective X-ray imaging system with a short optical focal length and large magnification factor. We performed an experiment to form a one-dimensional demagnified image with a demagnification factor of 321 within an approximately 2-m-long optical setup at an X-ray energy of 10 keV. The results showed that this imaging optics system is capable of providing a resolution of ~40 nm. Read More

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http://dx.doi.org/10.1364/OE.27.003429DOI Listing
February 2019

FPGA implementation of rate-adaptive spatially coupled LDPC codes suitable for optical communications.

Opt Express 2019 Feb;27(3):3422-3428

In this paper, we propose a unified field-programmable gate array (FPGA) structure for a rate-adaptive forward error correction (FEC) scheme based on spatially coupled (SC) LDPC codes derived from quasi-cyclic (QC) LDPC codes. We described the unified decoder structure in detail and showed that the rate adaptation can be achieved by a controller on-the-fly. By FPGA based emulation, the results show that, with comparable complexity, the SC codes provide larger coding gain. Read More

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http://dx.doi.org/10.1364/OE.27.003422DOI Listing
February 2019

Resonance/non-resonance doublet-based self-absorption-free LIBS for quantitative analysis with a wide measurement range.

Opt Express 2019 Feb;27(3):3409-3421

A resonance/non-resonance, doublet-based, self-absorption-free, laser-induced breakdown spectroscopy (SAF-LIBS) technique is proposed for greatly expanding the measurement range of quantitative elemental analysis by using a quasi-optically thin line. The quasi-optically thin spectral line is obtained by matching the measured doublet atomic lines' intensity ratios with the theoretical one, and the applicable measurement range is expanded by utilizing the resonance and non-resonance lines. The specific calibration process consists of two parts: the nonlinear LIBS calibration and the linear SAF-LIBS calibration. Read More

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http://dx.doi.org/10.1364/OE.27.003409DOI Listing
February 2019

Validity of the perturbation model for the propagation of MSF structure in 2D.

Opt Express 2019 Feb;27(3):3390-3408

Assessment of the performance degradation caused by the mid-spatial frequency (MSF) structure on optical surfaces often relies on a perturbation method that dovetails with the familiar sequence of models based on geometrical and physical optics. In the case of imaging systems, the perturbative step yields estimates of wavefronts in the exit pupil which are, in turn, used to extract performance measures such as MTF, PSF, and Strehl ratio. To date, the validity of that perturbation appears to be poorly understood. Read More

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http://dx.doi.org/10.1364/OE.27.003390DOI Listing
February 2019

Spatial full-duplex light communication achieved with a monolithic non-suspended multicomponent system.

Opt Express 2019 Feb;27(3):3379-3389

The multiple-quantum-well diode (MQW-diode) inherently exhibits simultaneous behavior because of the overlap between the emission spectra and spectral responsivity of the MQW-diode. This feature makes it feasible to form a full-duplex light communication system when two identical MQW-diodes separately function as a transmitter and a receiver at the same time. To verify spatial full-duplex light communication, we fabricated and characterized a monolithic multicomponent system by integrating two InGaN waveguide-based MQW-diodes into a single chip. Read More

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http://dx.doi.org/10.1364/OE.27.003379DOI Listing
February 2019

Simplified experimental scheme of quantum algorithm for solving linear equations with single photons.

Opt Express 2019 Feb;27(3):3369-3378

Linear equations play an important role in nearly all fields of research in science and engineering. Recent studies have shown that quantum algorithms for solving linear systems of algebraic equations provide exponential speedups over their classical counterparts. Here, we present a simplified experimental scheme for implementing the quantum algorithm for solving linear equations with multiple degrees of freedom (DoF) of single photon. Read More

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http://dx.doi.org/10.1364/OE.27.003369DOI Listing
February 2019

Aliasing-free optical phased array beam-steering with a plateau envelope.

Opt Express 2019 Feb;27(3):3354-3368

We investigate the feasibility of generating a plateau envelope for beam-steering with optical phased arrays (OPAs). The design guidelines are summarized from numerical simulations and verified with a fabricated chip, which incorporates both a coupling-suppressed curved waveguide array with a pitch of 0.8 μm for light emission and a 1-μm-long silica cavity for envelope tailoring. Read More

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http://dx.doi.org/10.1364/OE.27.003354DOI Listing
February 2019

Multipolar analysis of the second harmonic generated by dielectric particles.

Opt Express 2019 Feb;27(3):3337-3353

We studied the second harmonic generation (SHG) by two-dimensional dielectric particles made of a centrosymmetric high-index material. The calculated scattered fields at the fundamental and harmonic frequencies are decomposed on a multipolar basis, allowing the evaluation of the relative strengths of the multipolar resonances excited at the particle. With these tools, we studied the strength of the multipoles that produce the second harmonic field and the role played by those excited at the fundamental frequency. Read More

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http://dx.doi.org/10.1364/OE.27.003337DOI Listing
February 2019
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YO optical constants between 5 nm and 50 nm.

Opt Express 2019 Feb;27(3):3324-3336

We report optical constants of e-beam evaporated yttrium oxide Y2O3 thin films as determined from angle-dependent reflectance measurements at wavelengths from 5 to 50 nm. Samples were measured using synchrotron radiation at the Advanced Light Source. The experimental reflectance data were fit to obtain values for the index of refraction and thin film roughness. Read More

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http://dx.doi.org/10.1364/OE.27.003324DOI Listing
February 2019

Method of interpreting Mueller matrix of anisotropic medium.

Authors:
Y Chang W Gao

Opt Express 2019 Feb;27(3):3305-3323

The differential Mueller matrix is an important concept for analyzing the polarization properties of an optically homogeneous anisotropic sample, both nondepolarizing and depolarizing. In this work, we present a new method of interpreting Mueller matrix of anisotropic medium based on the relationships that exist between the components of a differential Mueller matrix and the polar components of the corresponding macroscopic Mueller matrix, and the necessary conditions are determined that guarantee the physical realizability of the generating matrices. Finally, a group of the experimental data of a sample from the literature with some known polarization properties was used to demonstrate the analysis. Read More

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http://dx.doi.org/10.1364/OE.27.003305DOI Listing
February 2019

Aberration-reduced spherical concave grating holographically recorded by a spherical wave and a toroidal wave for Rowland circle mounting.

Opt Express 2019 Feb;27(3):3294-3304

We propose a new recording system that employs a spherical wave and a toroidal wave to holographically record an aberration-reduced Rowland-circle spherical grating. Two more variables in this recording system are available for the design compared with a conventional symmetric dual-plane-wave recording system, which allows both the astigmatism and sagittal coma of the grating to be corrected to minimum. We derive the aberration coefficients of such grating and give the universal design principles for the recording system. Read More

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http://dx.doi.org/10.1364/OE.27.003294DOI Listing
February 2019

X-ray computational ghost imaging with single-pixel detector.

Opt Express 2019 Feb;27(3):3284-3293

We demonstrate computational ghost imaging at X-ray wavelengths with only one single-pixel detector. We show that, by using a known designed mask as a diffuser that induces intensity fluctuations in the probe beam, it is possible to compute the propagation of the electromagnetic field in the absence of the investigated object. We correlate these calculations with the measured data when the object is present in order to reconstruct the images of 50 μm and 80 μm slits. Read More

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http://dx.doi.org/10.1364/OE.27.003284DOI Listing
February 2019

Real-time dual-sensitive shearography for simultaneous in-plane and out-of-plane strain measurements.

Opt Express 2019 Feb;27(3):3276-3283

A real-time, dual-sensitive shearography system using a single-wavelength laser was developed for simultaneous and dynamic in-plane and out-of-plane strain measurements. The shearography system is capable of measuring crack-tip deformation fields quantitatively. A spatial multiplexing technique based on Fourier transform is employed for simultaneous and dynamic multi-component phase retrieval. Read More

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http://dx.doi.org/10.1364/OE.27.003276DOI Listing
February 2019

Thickness determination in anisotropic media with plasmon waveguide resonance imaging.

Opt Express 2019 Feb;27(3):3264-3275

This paper describes a simple procedure to determine the local thickness of a thin anisotropic layer. It also discriminates between isotropic and anisotropic regions, provided a smoothness hypothesis on the refractive index distribution is satisfied. The procedure is based on the analysis of surface plasmon resonance (SPR) data acquired in an imaging mode. Read More

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http://dx.doi.org/10.1364/OE.27.003264DOI Listing
February 2019

Weak feedback assisted random fiber laser from 45°-tilted fiber Bragg grating.

Opt Express 2019 Feb;27(3):3255-3263

We have demonstrated the realization of a high-polarization random fiber laser (RFL) output based on the hybrid Raman and Erbium gain with the tailored effect provided by a 45°-tilted fiber Bragg grating (45°-TFBG), revealing an improvement in the polarization extinction ratio (PER) and achieving a PER of ~15.3 dB. The hybrid RFL system incorporating the 45°-TFBG has been systematically characterized. Read More

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https://www.osapublishing.org/abstract.cfm?URI=oe-27-3-3255
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http://dx.doi.org/10.1364/OE.27.003255DOI Listing
February 2019
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Improvement of the intensity noise and frequency stabilization of Nd:YAP laser with an ultra-low expansion Fabry-Perot cavity.

Opt Express 2019 Feb;27(3):3247-3254

Continuous-wave, single-frequency, solid-state lasers with long-term frequency stability and low-intensity noise are an essential resource to generate squeezed and entangled states of light. In order to obtain the stable, nonclassical states of light, the frequency of the laser has to be stabilized with a stable reference. Due to the zero expansion property at a certain temperature, an ultra-low expansion (ULE) Fabry-Perot (F-P) cavity with a high finesse can be used as one of the best candidates of the frequency reference. Read More

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http://dx.doi.org/10.1364/OE.27.003247DOI Listing
February 2019
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A Kalman-based tomographic scheme for directly reconstructing activation levels of brain function.

Opt Express 2019 Feb;27(3):3229-3246

In functional near-infrared spectroscopy (fNIRS), the conventional indirect approaches first separately recover the spatial distribution of the changes in the optical properties at every time point, and then extract the activation levels by a time-course analysis process at every site. In the tomographic implementation of fNIRS, i.e. Read More

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http://dx.doi.org/10.1364/OE.27.003229DOI Listing
February 2019

Ring artefact reduction via multi-point piecewise linear flat field correction for X-ray computed tomography.

Opt Express 2019 Feb;27(3):3217-3228

X-ray computed tomography (XCT) is a well-established method for measuring and inspecting an object's internal structure in a non-destructive manner. Ring artefacts are unwanted high- or low-intensity rings that appear in CT images that influence CT-based measurements. The cause of the subtle ring artefacts found in high-resolution XCT data is found to be due to inadequate flat field detector correction. Read More

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http://dx.doi.org/10.1364/OE.27.003217DOI Listing
February 2019