Showing papers on "Beam splitter published in 2011"

Eyepiece with uniformly illuminated reflective display

Abstract: An eyepiece includes a mechanical frame adapted to secure a lens and an image source facility above the lens. The image source facility includes an LED, a planar illumination facility and a reflective display. The planar illumination facility converts a light beam from the LED received on a side of the planar illumination facility into a top emitting planar light source, uniformly illuminates the reflective display, and is substantially transmissive to allow reflected light to pass through towards a beam splitter. The beam splitter is positioned to receive the image light and to reflect a portion onto a mirrored surface. The mirrored surface is positioned and shaped to reflect the image light into an eye of a user of the eyepiece thereby providing an image within a field of view, the mirrored surface further adapted to be partially transmissive within an area of image reflectance.

Polarization entangled state measurement on a chip

Abstract: We report the realization of an integrated beam splitter able to support polarization-encoded qubits. Using this device, we demonstrate quantum interference with polarization-entangled states and singlet state projection.

102ℏk large area atom interferometers.

Abstract: We demonstrate atom interferometers utilizing a novel beam splitter based on sequential multiphoton Bragg diffractions. With this sequential Bragg large momentum transfer (SB-LMT) beam splitter, we achieve high contrast atom interferometers with momentum splittings of up to 102 photon recoil momenta ($102\ensuremath{\hbar}k$). To our knowledge, this is the highest momentum splitting achieved in any atom interferometer, advancing the state-of-the-art by an order of magnitude. We also demonstrate strong noise correlation between two simultaneous SB-LMT interferometers, which alleviates the need for ultralow noise lasers and ultrastable inertial environments in some future applications. Our method is intrinsically scalable and can be used to dramatically increase the sensitivity of atom interferometers in a wide range of applications, including inertial sensing, measuring the fine structure constant, and detecting gravitational waves.

Realization of a nonlinear interferometer with parametric amplifiers

Abstract: We construct an interferometer with parametric amplifiers as beam splitters. Because of the gain in the parametric amplifiers, the maximum output intensity of the interferometer can be much bigger than the input intensity as well as the intensity inside the interferometer (the phase sensing intensity). We find that the fringe intensity depends quadratically on the intensity of the phase sensing field at high gain. This type of nonlinear interferometer has better sensitivity than the traditional linear interferometer made of beam splitters with the same phase sensing intensity.

1 × 12 Unequally spaced waveguide array for actively tuned optical phased array on a silicon nanomembrane

Abstract: We present an experimental demonstration of an optical phased array implementation on silicon nanomembrane. The integrated on-chip array configuration is non-uniform and avoids grating lobes inside the field of view during beam steering while allowing the waveguide separation to be large enough to prevent optical coupling. A 1 × 12 multimode interference beam splitter uniformly excites the arrayed waveguides. Individually controllable micro-heaters modulate the optical phase in the arrayed waveguides. A beam steering angle of 10.2° in a silicon planar guide equivalent to an effective steering angle of 31.9° in air is demonstrated at 1.55 μm.

Polarization entangled states measurement on a chip

Abstract: The emerging strategy to overcome the limitations of bulk quantum optics consists of taking advantage of the robustness and compactness achievable by the integrated waveguide technology. Here we report the realization of a directional coupler, fabricated by femtosecond laser waveguide writing, acting as an integrated beam splitter able to support polarization encoded qubits. This maskless and single step technique allows to realize circular transverse waveguide profiles able to support the propagation of Gaussian modes with any polarization state. Using this device, we demonstrate the quantum interference with polarization entangled states.

Wide-angle, nonmechanical beam steering with high throughput utilizing polarization gratings

Abstract: We introduce and demonstrate a ternary nonmechanical beam steering device based on polarization gratings (PGs). Our beam steering device employs multiple stages consisting of combinations of PGs and wave plates, which allows for a unique three-way (ternary) steering design. Ultrahigh efficiency (∼100%) and polarization sensitive diffraction of individual PGs allow wide steering angles (among three diffracted orders) with extremely high throughput. We report our successful demonstration of the three-stage beam steerer having a 44° field of regard with 1.7° resolution at 1550 nm wavelength. A substantially high throughput of 78%–83% is observed that is mainly limited by electrode absorption and Fresnel losses.

Femtosecond laser fabrication of birefringent directional couplers as polarization beam splitters in fused silica.

Abstract: Integrated polarization beam splitters based on birefringent directional couplers are demonstrated. The devices are fabricated in bulk fused silica glass by femtosecond laser writing (300 fs, 150 nJ at 500 kHz, 522 nm). The birefringence was measured from the spectral splitting of the Bragg grating resonances associated with the vertically and horizontally polarized modes. Polarization splitting directional couplers were designed and demonstrated with 0.5 dB/cm propagation losses and −19 dB and −24 dB extinction ratios for the polarization splitting.

An optical fusion gate for W-states

Abstract: We introduce a simple optical gate to fuse arbitrary-size polarization entangled W-states to prepare larger W-states. The gate requires a polarizing beam splitter (PBS), a half-wave plate (HWP) and two photon detectors. We study, numerically and analytically, the necessary resource consumption for preparing larger W-states by fusing smaller ones with the proposed fusion gate. We show analytically that resource requirement scales at most sub-exponentially with the increasing size of the state to be prepared. We numerically determine the resource cost for fusion without recycling where W-states of arbitrary size can be optimally prepared. Moreover, we introduce another strategy that is based on recycling and outperforms the optimal strategy for the non-recycling case.

Quantum correlations by four-wave mixing in an atomic vapor in a nonamplifying regime: Quantum beam splitter for photons

Abstract: We study the generation of intensity quantum correlations using four-wave mixing in a rubidium vapor. The absence of cavities in these experiments allows to deal with several spatial modes simultaneously. In the standard amplifying configuration, we measure relative intensity squeezing up to 9.2 dB below the standard quantum limit. We also theoretically identify and experimentally demonstrate an original regime where, despite no overall amplification, quantum correlations are generated. In this regime, a four-wave mixing setup can play the role of a photonic beam splitter with nonclassical properties, that is, a device that splits a coherent state input into two quantum-correlated beams.

Valley beam splitter based on strained graphene

Abstract: We investigate theoretically the lateral displacements of valley-unpolarized electron beams in graphene after traversing a strained region. Valley double refraction occurs at the interface between the incident (unstrained) region and the strained region, in analogy with optical double refraction. It is shown that the exiting positions of K and K' transmitted beams, together with their distance D, can be tuned by the strain strength and the inclusion of an electrostatic potential. In addition, D can be enhanced by the wave effect near the valley-dependent transmission resonances. The enhancement is remarkable for graphene n–p–n (or p–n–p) junctions. Thus the Goos–Hanchen effect of transmitted beams for a normal/strained/normal graphene junction can be utilized to design a valley beam splitter.

Considerations for the Design of Asymmetrical Mach–Zehnder Interferometers Used as Polarization Beam Splitters on a Submicrometer Silicon-On-Insulator Platform

Abstract: Asymmetrical Mach-Zehnder Interferometer (MZI) structures on a submicrometer silicon-on-insulator platform are designed and analyzed when used as a polarization beam splitter (PBS). The analysis shows that it is allowed to use 2×2 power splitter/combiner couplers with a balanced ratio (50:50) for only one polarization by selecting the output ports for TE and TM polarizations appropriately. This makes the design much easier and more flexible. Examples for the design of MZI-based PBSs using directional couplers as well as multimode interference couplers are given. Finally, compensating the positive or negative wavelength shifts due to fabrication errors is proposed by using a thermal-optical effect on the two MZI arms separately. The numerical calculation shows that a small temperature increase (e.g., 30°C) is enough to compensate the wavelength shift due to an arm-waveguide width deviation of 50 nm. The parameters of MZI arm waveguides are chosen appropriately in order to make the MZI wavelength shifts (due to the fabrication errors) almost polarization independent, so that the thermal compensation approach could push the central wavelengths for both polarizations back to the designed value.

Indistinguishable photon pair generation using two independent silicon wire waveguides

Abstract: We performed a Hong?Ou?Mandel interference experiment with 1.5??m band photon pairs generated through spontaneous four-wave mixing (SFWM) in two independent silicon wire waveguides (SWWs). To maintain the long-term stability of the coupling between the SWWs and optical fibers without a fiber alignment system, we employed fiber module SWWs installed in a rigid metallic case with fiber array interfaces. In addition, those signal photons that passed through a beam splitter (BS) were detected by high-speed single-photon detectors that used InGaAs avalanche photodiodes operated in a gated mode with a high gate frequency of 500?MHz. With these novel technologies, we successfully observed a quantum interference with a visibility of 73% without subtracting accidental coincidence counts in the fourfold coincidence measurement.

Current and noise correlations in a double dot Cooper pair beam splitter

Abstract: We consider a double quantum dot coupled to two normal leads and one superconducting lead, modeling the Cooper pair beam splitter studied in two recent experiments. Starting from a microscopic Hamiltonian we derive a general expression for the branching current and the noise crossed correlations in terms of a single- and two-particle Green's function of the dot electrons. We then study numerically how these quantities depend on the energy configuration of the dots and the presence of direct tunneling between them, isolating the various processes which come into play. In the absence of direct tunneling, the antisymmetric case (the two levels have opposite energies with respect to the superconducting chemical potential) optimizes the crossed Andreev reflection (CAR) process while the symmetric case (the two levels have the same energies) favors the elastic cotunneling (EC) process. Switching on the direct tunneling tends to suppress the CAR process, leading to negative noise crossed correlations over the whole voltage range for large enough direct tunneling.

Reflection-mode time-reversed ultrasonically encoded optical focusing into turbid media

Abstract: Time-reversed ultrasonically encoded (TRUE) optical focusing was recently proposed to deliver light dynamically to a tight region inside a scattering medium. In this letter, we report the first development of a reflection-mode TRUE optical focusing system. A high numerical aperture light guide is used to transmit the diffusely reflected light from a turbid medium to a phase-conjugate mirror (PCM), which is sensitive only to the ultrasound-tagged light. From the PCM, a phase conjugated wavefront of the tagged light is generated and conveyed by the same light guide back to the turbid medium, subsequently converging to the ultrasonic focal zone. We present experimental results from this system, which has the ability to focus light in a highly scattering medium with a round-trip optical penetration thickness (extinction coefficient multiplied by round-trip depth) as large as 160.

Handpiece with integrated optical system for photothermal radiometry and luminescence measurements

Abstract: An apparatus is provided for performing photothermal measurements on a object. The apparatus, which may be provided as a handpiece, houses optical components including a laser, an infrared detector, a dichroic beamsplitter, and focusing and beam directing optics for the delivery of a laser beam to, and the collection of photothermal radiation from, a measured object. Some of the optical components may be provided on an optical bench that is directly attached to a thermally conductive tip portion for the passive heat sinking of internal optical components. The apparatus may further include a sampling optical element and a photodetector for the detection of luminescence, and a camera for obtaining an image of the object during a diagnostic procedure. The apparatus may be employed for the scanning of a tooth to determine an oral health status of the tooth.

Optical measuring apparatuses

Abstract: An optical measuring apparatus may include a light source, linear polarizer, polarized beam splitter, quarter wave plate, objective lens, and/or light receiver. The polarized beam splitter may be configured to transmit linearly polarized light from the linear polarizer to any one of a first and second optical path. The quarter wave plate may be configured to circularly polarize light transmitted through the first optical path from the polarized beam splitter and transmit the circularly polarized light to an object to be measured, and the quarter wave plate may be configured to linearly polarize the circularly polarized light reflected from the object to be measured and transmit the linearly polarized reflected light to the second optical path of the polarized beam splitter. The objective lens may be configured to generate light having different wavelengths by generating chromatic aberration in the circularly polarized light from the quarter wave plate.

Design of single-polarization wavelength splitter based on photonic crystal fiber

Abstract: A new single-polarization wavelength splitter based on the photonic crystal fiber (PCF) has been proposed. The full-vector finite-element method (FEM) is applied to analyze the single-polarization single-mode guiding properties. Splitting of two different wavelengths is realized by adjusting the structural parameters. The semi-vector three-dimensional beam propagation method is employed to confirm the wavelength splitting characteristics of the PCF. Numerical simulations show that the wavelengths of 1.3 μm and 1.55 μm are split for a fiber length of 10.7 mm with single-polarization guiding in each core. The crosstalk between the two cores is low over appreciable optical bandwidths.

1× N Multimode Interference Beam Splitter Design Techniques for On-Chip Optical Interconnections

Abstract: We derive an analytical relation for the maximum number of output channels for high-performance multimode interference (MMI)-based 1 × N optical beam splitters for a given MMI width. Using eigenvalue-expansion-based simulation results, we validate the analytical relation. Experimental data from MMIs fabricated on silicon nanomembrane also confirm the effectiveness of the design methodology for on-chip optical beam splitter designs.

Augmented Reality Methods and Systems Including Optical Merging of a Plurality of Component Optical Images

Abstract: The present disclosure provides augmented reality methods and systems where two or more component optical images are optically overlaid via one or more beam splitters to form composite optical images. In some embodiments a second component optical image is an electronic optical image (an image from an electronically controlled emission source) while the first component optical image is one of a physical optical image (an image of a physical object from which diffuse reflection occurs), an electronic optical image, an emission optical image (an image from a non-electronic source that emits radiation), or a hybrid optical image (composed of at least two of a physical optical image, and electronic optical image, or an emission optical image). In some embodiments the first and second component optical images are used to provide feedback concerning the quality of the overlaying and appropriate correction factors to improve the overlay quality.

Light Source Device

Abstract: A light source device includes excitation light sources integrated into a module and each emitting excitation light. A beam splitter optical system splits the excitation light from the excitation light sources into first, second, and third portions. A first fluorescent member emits red light in response to the first portion of the excitation light through fluorescence. A second fluorescent member emits green light in response to the second portion of the excitation light through fluorescence. A third fluorescent member emits blue light in response to the third portion of the excitation light through fluorescence. A combining optical system combines the red light, the green light, and the blue light.

Head mounted display eyepiece with integrated depth sensing

Abstract: An eyepiece for a head mounted display includes an imaging region and a viewing region. The imaging region includes a camera. The viewing region is aligned with an eye of a user and includes a first beam splitter and a second beam splitter. The viewing region is partially transparent to pass a first portion of ambient scene light received through an ambient scene side of the eyepiece out an eye-ward side of the eyepiece. The first BS and the second BS are partially reflective and oriented to redirect offset portions of the ambient scene light received through the ambient scene side along the eyepiece towards the imaging region. The camera is positioned to capture both of the offset portions of the ambient scene light redirected by the first beam splitter and the second beam splitter.

Micromachined array-type Mirau interferometer for parallel inspection of MEMS

Abstract: We present the development of an array type of micromachined Mirau interferometers, operating in the regime of low coherence interferometry (LCI) and adapted for massively parallel inspection of MEMS. The system is a combination of free-space micro-optical technologies and silicon micromachining, based on the vertical assembly of two glass wafers. The probing wafer carries an array of refractive microlenses, diffractive gratings to correct chromatic and spherical aberrations and reference micro-mirrors. The semitransparent beam splitter plate is based on the deposition of a dielectric multilayer, sandwiched between two glass wafers. The interferometer matrix is the key element of a novel inspection system aimed to perform parallel inspection of MEMS. The fabricated demonstrator, including 5 × 5 channels, allows consequently decreasing the measurement time by a factor of 25. In the following, the details of fabrication processes of the micro-optical components and their assembly are described. The feasibility of the LCI is demonstrated for the measurement of a wafer of MEMS sensors.

Laser processing machine

Abstract: A laser processing machine is provided which includes a chuck table adapted to hold a workpiece; and a laser beam irradiation unit for emitting a laser beam to the workpiece held by the chuck table. The laser beam irradiation unit includes a single laser beam oscillating unit for emitting a laser beam; a beam splitter which splits the laser beam emitted from the laser beam oscillating unit into a first laser beam propagating along a first path and a second laser beam propagating along a second path; a first condenser which condenses the first laser beam; and a second condenser which condenses the second laser beam.

Generation Of Quantum Codes Using Up And Down Link Optical Solition

Abstract: In this study, a system of continuous variable quantum code via a wavelength router is presented. The optical Kerr type nonlinearity in the nonlinear microring resonator (NMRR) induces the chaotic behavior. In this proposed system chaotic signals are generated by an optical soliton or Gaussian pulse within a NMRR system. Large bandwidth signals of optical soliton are generated by the input pulse propagating within the MRRs, which is allowed to form the continuous wavelength or frequency with large tunable channel capacity. Therefore, distinguished up and down links of wavelength or frequency pulses can be generated by using localized spatial soliton via a quantum router and networks. These selected up and down links pulses are more suitable to generate high secured quantum codes because of the greater free spectral range (FSR). The continuous quantum codes can be generated by using the polarization control unit and beam splitter, incorporating into the MRRs. In this work, frequency band of 10.7 MHz and 16 MHz and wavelengths of 206.9 nm, 1.448 μm, 2.169 μm and 2.489 μm can be obtained for QKD by using input optical soliton and Gaussian beam. Key words: Nonlinear microring resonator (NMRR); up and down links optical soliton, quantum codes

System for and method of catadioptric collimation in a compact head up display (HUD)

Abstract: A head up display can use a catadioptric collimating system. The head up display includes an image source. The head up display also includes a collimating mirror, and a polarizing beam splitter. The light from the image source enters the beam splitter and is reflected toward the collimating mirror. The light striking the collimating mirror is reflected through the beam splitter toward a combiner. A corrective lens can be disposed after the beam splitter.

Interrogator for a plurality of sensor fiber optic gratings

Abstract: An interrogator for a plurality of sensor fiber optic gratings. The interrogator includes a broadband optical source; at least one beam splitter directing output of the optical source to the sensor fiber optic gratings; at least one linear filter for converting changes in peak reflection wavelength to changes in intensity; at least one optical receiver; and at least one amplifier associated with each optical receiver. The interrogator also includes, alternatively, a driver/modulator for the optical source providing on/off pulses; an analog integrator following the at least one amplifier; or a mechanism compensating for masking of one sensor fiber optic grating by another.

Quantum Computation with the Jaynes-Cummings Model

Abstract: In this paper, we propose a method for building a two-qubit gate with the JaynesCummings model (JCM). In our scheme, we construct a qubit from a pair of optical paths where a photon is running. Generating Knill, Laflamme and Milburn’s nonlinear sign-shift gate by the JCM, we construct the conditional sign-flip gate, which works with small error probability in principle. We also discuss two experimental setups for realizing our scheme. In the first experimental setup, we make use of coherent lights to examine whether or not our scheme works. In the second experimental setup, an optical loop circuit made out of the polarizing beam splitter and the Pockels cell takes an important role in the cavity. Subject Index: 061