Showing papers on "Beam splitter published in 2010"

Carbon nanotubes as Cooper pair beam splitters

Abstract: We report on conductance measurements in carbon nanotube based double quantum dots connected to two normal electrodes and a central superconducting finger. By operating our devices as beam splitters, we provide evidence for crossed Andreev reflections tunable in situ. This opens an avenue to more sophisticated quantum opticslike experiments with spin entangled electrons.

Transformation Electromagnetics: An Overview of the Theory and Applications

Abstract: The recently introduced transformation-electromagnetics techniques provide a new methodology for designing devices that possess novel wave-material interaction properties. They are based on the form invariance of Maxwell's equations under coordinate transformations. These methods provide an extremely versatile set of design tools that employ spatial-coordinate transformations, where the compression and dilation of space in different coordinate directions are interpreted as appropriate scalings of the material parameters. The most famous transformation-optics device is the cloak of invisibility. However, a wide variety of other devices are also possible, such as field concentrators, polarization rotators, beam splitters, beam collimators, and flat lenses. In this paper, an overview of transformation-electromagnetics device design techniques is presented. The paper begins by introducing the underlying design principle behind transformation electromagnetics. Several novel transformation-based device designs are then summarized, starting with electromagnetic cloaks that have spherical shell or cylindrical annular shapes, More general cloaking designs of noncircular annular geometries are treated, and the application of cloaking to RF/microwave antenna shielding is also discussed. Following this, device designs that employ transformations that have discontinuities .on the domain boundary are presented. Unlike those used for cloaks, this type of transformation is capable of modifying the fields outside of the device. Examples of this type of transformation-electromagnetics device are presented, which include flat near-field and far-field focusing lenses, wave collimators for embedded sources (e.g., antennas), polarization splitters and rotators, and right-angle beam benders.

A Coherent Beam Splitter for Electronic Spin States

Abstract: Rapid coherent control of electron spin states is required for implementation of a spin-based quantum processor. We demonstrated coherent control of electronic spin states in a double quantum dot by sweeping an initially prepared spin-singlet state through a singlet-triplet anticrossing in the energy-level spectrum. The anticrossing serves as a beam splitter for the incoming spin-singlet state. When performed within the spin-dephasing time, consecutive crossings through the beam splitter result in coherent quantum oscillations between the singlet state and a triplet state. The all-electrical method for quantum control relies on electron-nuclear spin coupling and drives single-electron spin rotations on nanosecond time scales.

Monolithic Polarization and Phase Diversity Coherent Receiver in Silicon

Abstract: In this paper, we realized a monolithic silicon photonic integrated circuit (PIC) for polarization and phase diversity coherent detection. The PIC includes two polarization beam splitters, two 90° optical hybrids, and four pairs of balanced photodiodes implemented as integrated germanium detectors. We tested the PIC using polarization-division multiplexed quadrature phase-shift keyed signals at 43 and at 112 Gb/s.

Zero-transmission law for multiport beam splitters.

Abstract: The Hong-Ou-Mandel effect is generalized to a configuration of n bosons prepared in the n input ports of a Bell multiport beam splitter. We derive a strict suppression law for most possible output events, consistent with a generic bosonic behavior after suitable coarse graining.

Correction method for differential phase contrast imaging

Abstract: The present invention generally refers to a correction method for grating-based X-ray differential phase contrast imaging (DPCI) as well as to an apparatus which can advantageously be applied in X-ray radiography and tomography for hard X-ray DPCI of a sample object or an anatomical region of interest to be scanned. More precisely, the proposed invention provides a suitable approach that helps to enhance the image quality of an acquired X-ray image which is affected by phase wrapping, e.g. in the resulting Moire interference pattern of an emitted X-ray beam in the detector plane of a Talbot-Lau type interferometer after diffracting said X-ray beam at a phase-shifting beam splitter grating. This problem, which is further aggravated by noise in the obtained DPCI images, occurs if the phase between two adjacent pixels in the detected X-ray image varies by more than π radians and is effected by a line integration over the object's local phase gradient, which induces a phase offset error of π radians that leads to prominent line artifacts parallel to the direction of said line integration.

Interferometer techniques for gravitational-wave detection

Abstract: Several km-scale gravitational-wave detectors have been constructed worldwide. These instruments combine a number of advanced technologies to push the limits of precision length measurement. The core devices are laser interferometers of a new kind; developed from the classical Michelson topology these interferometers integrate additional optical elements, which significantly change the properties of the optical system. Much of the design and analysis of these laser interferometers can be performed using well-known classical optical techniques; however, the complex optical layouts provide a new challenge. In this review, we give a textbook-style introduction to the optical science required for the understanding of modern gravitational wave detectors, as well as other high-precision laser interferometers. In addition, we provide a number of examples for a freely available interferometer simulation software and encourage the reader to use these examples to gain hands-on experience with the discussed optical methods.

Planck Spectroscopy and Quantum Noise of Microwave Beam Splitters

Abstract: We use a correlation function analysis of the field quadratures to characterize both the blackbody radiation emitted by a 50 Ω load resistor and the quantum properties of two types of beam splitters in the microwave regime. To this end, we first study vacuum fluctuations as a function of frequency in a Planck spectroscopy experiment and then measure the covariance matrix of weak thermal states. Our results provide direct experimental evidence that vacuum fluctuations represent the fundamental minimum quantum noise added by a beam splitter to any given input signal.

Magnetically controllable unidirectional electromagnetic waveguiding devices designed with metamaterials

Abstract: We demonstrate a sharply asymmetric reflection in a geometrically symmetric magnetic metamaterial (MM) system, which originates from the coupling of electromagnetic (EM) wave to magnetic surface plasmon resonance states and the broken time reversal symmetry in MM. Based on this effect, we have designed unidirectional EM waveguide, wave bender, and beam splitter. Our simulations indicate that the designs possess the merits of robustness against strong defect and disorder, controllability with an external magnetic field, in addition to the finite working bandwidth and the high transmission efficiency.

Silicon-on-insulator polarization splitter using two horizontally slotted waveguides

Abstract: We propose and analyze a short-length silicon-on-insulator polarization splitter using two horizontally slotted silicon waveguides. A polarization splitter with a 46.7 μm length and a 22 dB extinction ratio (ER) is achieved. Around 1550 nm, it also exhibits an 18 nm bandwidth for ER>20 dB. The effects of the slot thickness, the waveguide spacing, and the refractive index of the slot on the splitting length and ER are investigated.

Light processing system and method

Abstract: A portion of a first portion of light (13, 90, 90') from a source of light (11) is masked by a mask (138), and the resulting masked first portion of light (90'') is combined using a beam splitter optic (136) with at least one second portion of the light (30) that had been subject to scattering by a medium (20, 20', 20''). The mask (138) is configured so that interference patterns (104, 47) generated from the first and at least one second portions of light are substantially mutually exclusive even though those interference patterns (104, 47) would otherwise overlap one another absent the mask (138).

Distillation of mixed-state continuous-variable entanglement by photon subtraction

Abstract: We present a detailed theoretical analysis for the distillation of one copy of a mixed two-mode continuous-variable entangled state using beam splitters and coherent photon-detection techniques, including conventional on-off detectors and photon-number-resolving detectors. The initial Gaussian mixed-entangled states are generated by transmitting a two-mode squeezed state through a lossy bosonic channel, corresponding to the primary source of errors in current approaches to optical quantum communication. We provide explicit formulas to calculate the entanglement in terms of logarithmic negativity before and after distillation, including losses in the channel and the photon detection, and show that one-copy distillation is still possible even for losses near the typical fiber channel attenuation length. A lower bound for the transmission coefficient of the photon-subtraction beam splitter is derived, representing the minimal value that still allows to enhance the entanglement.

Longitudinal coherence measurements of an extreme-ultraviolet free-electron laser

Abstract: We have measured the average single-pulse longitudinal coherence characteristics of FLASH, a self amplified spontaneous emission free electron laser, at extreme UV wavelengths Electric field autocorrelation measurements in the time domain were enabled by a wavefront division beam splitter applied to a tunable delay Mach-Zehnder interferometer These data agree with the spectral bandwidth measurements made in the frequency domain They exhibit two correlation time scales and the measured coherence curves have relevant implications for single-shot measurements

Head-mounted optical apparatus using an oled display

Abstract: A see-through head-mounted optical apparatus for a viewer has at least one display module, each display module having a display energizable to form an image and a positive field lens optically coupled to the surface of the display and disposed to direct imaged light from the display toward a first surface of a prism. A curved reflector element is in the path of the imaged light through the prism and disposed at a second surface of the prism, opposite the first surface. The curved reflector element has a refractive surface and a curved reflective surface disposed to collimate imaged light received from the display and direct this light toward a beam splitter that is disposed within the prism and that is at an oblique angle to the collimated reflected light. The beam splitter redirects the incident collimated reflected light through the prism to form an entrance pupil for the viewer.

Application of inverse, strict conformal transformation to design waveguide devices.

Abstract: Integration of transformation optics with development of metamaterials offers great opportunities to create exotic material with electromagnetic functionality absent from nature. It has already led to several significant advancements in physical conceptions and technological applications such as invisible cloaking. Unfortunately practical application is often restricted by the complex requirements on material properties imposed by the general optical transformation theory. It is therefore necessary to relax the stringent requirements of materials properties in order to practicably use the power of transformation optics to design exotic optical devices. Development of new coordinate transformation mathematics to compromise between the stringent materials properties and the ultimate performance required by a useful novel device is required. In this work the authors employed strict conformal transformation to design physical materials that could guide light in a predetermined way. A simple and efficient numerical approach based on unusual inverse transformation is proposed here to quickly solve partial differential equations and construct the mapping relationship. The results showed that a transformed optical device could be made by purely using isotropic dielectric materials. Two application examples were numerically proposed to verify the versatility of conformal transformation and the robustness of the inverse approach. One was a 90 degrees waveguide beam bend, and the other was a waveguide-type beam splitter or coupler.

Apparatus for head mounted image display

Abstract: Image display device having an image source generating an image, a beam splitter positioned at forty five degrees to the main optical path, to project and focus the image generated by the image source into the entrance pupil of the human eye, two achromatic standard doublet lenses positioned perpendicularly to the main optical path and placed between the image source and the beam splitter, and configured to amplify, collimate, and correct optical aberrations of said image, wherein the image source, beam splitter and the doublet lenses are in an on-axis configuration and the image display device comprises two mounting brackets parallel to the main optical axis, each having an extremity part holding an edge of the beam splitter and the other extremity pivotally attached to a housing, allowing the brackets and beam splitter to rotate in an axis perpendicular to the main optical path.

Optical image systems

Abstract: The present invention is an optical image system having at least a first camera including a first lens and at least a second sensor including a second lens. The system also includes at least one beam splitter for transmitting an incoming beam of electromagnetic radiation of at least a first band of wavelength to a focal plane array of the first camera and reflecting an incoming beam of electromagnetic radiation of at least a second band of wavelength to a focal plane array of the second camera. The first lens is positioned behind the beam splitter for focusing the beam of the first band of wavelength onto an image at the focal plane array of the first camera and the second lens is positioned behind the beam splitter for focusing the beam of the second band of wavelength onto the image at the focal plane array of the second camera.

Beam combiner for use in a head-mounted display device and beam splitter

Abstract: The invention relates to a beam combiner for combining a first beam cluster with a second beam cluster that does not extend parallel to the first, to form a common beam cluster. Said beam combiner comprises a transparent body for the first beam cluster (US), which has a superimposition region (9) that is hit by the first beam cluster (US) as it passes through the body and is split into a first section (10) and a second section (11). Only the first section (10) formed from a plurality of interspaced reflective and/or refractive deflection elements (12) causes a deflection of the second beam cluster (BS) by reflection and/or refraction, such that the first beam cluster (US) forms the common beam cluster (GS) with the deflected second beam cluster (BS) once it has left the body.

Asymmetric Mach-Zehnder filter based on self-collimation phenomenon in two-dimensional photonic crystals.

Abstract: A two-dimensional photonic crystal asymmetric Mach-Zehnder filter (AMZF) based on the self-collimation effect is studied by numerical simulations and experimental measurements in microwave region. A self-collimated beam is effectively controlled by employing line-defect beam splitters and mirrors. The measured transmission spectra at the two output ports of the AMZF sinusoidally oscillate with the phase difference of pi in the self-collimation frequency range. Position of the transmission peaks and dips can be controlled by varying the size of the defect rod of perfect mirrors, and therefore this AMZF can be used as a tunable power filter.

Reliable source of conditional states from single-mode pulsed thermal fields by multiple-photon subtraction

Abstract: We demonstrate the effect of multiple-photon subtraction on the generation of conditional states in the pulsed regime. Our experimental scheme relies on a beam splitter (BS) and a pair of linear photodetectors that are able to resolve up to tens of photons. We use a single-mode thermal field at the input port of the BS to test the reliability of our scheme, and we show good agreement with the theory by fully characterizing the conditional outgoing states in terms of photon-number statistics and non-Gaussianity.

Temperature sensing by using whispering gallery modes with hollow core fibers

Abstract: We describe temperature sensing by hollow core fibers using whispering gallery modes of a spherical microresonator. Light from a tunable laser was coupled into the input end of the hollow core fiber. Optical resonances were excited in a microsphere inserted in the modified output end. Part of the light was coupled back from the resonator into the hollow core fiber and transported back to the input end. This light was recorded via a beam splitter by a diode. The sensing principle is based on the shift of the optical resonances by changing the temperature of the resonator. This shift is monitored and leads to the temperature of the resonator and surrounding respectively.

Mobile telecommunications device with image sensor directed internally and externally

Abstract: The invention provides for a mobile telecommunications device that decodes tags of coded data printed on media present at points internal and external of the device. The device has an image sensor and a beam splitter for deflecting incoming light onto the image sensor. The device also includes a first infrared LED operatively directing light onto external media at the external point, with an infrared filter configured to receive light reflected from the external media onto the beam splitter. Also included is a second infrared LED operatively directing light onto media present in the internal pathway, with a mirror arrangement configured to direct light reflected from the internal media into the beam splitter.

Noise temperature and beam pattern of an NbN hot electron bolometer mixer at 5.25 THz

Abstract: We report the measured sensitivities of a superconducting NbN hot electron bolometer (HEB) heterodyne receiver at 5.25 THz. Terahertz (THz) radiation is quasioptically coupled to a HEB mixer with a lens and a spiral antenna. Using a measurement setup with black body calibration sources and a beam splitter in vacuo, and an antireflection coated Si lens, we obtained a double sideband (DSB) receiver noise temperature (TrecDSB) of 1150 K, which is nine times h?/2k, where h is the Planck constant, ? the frequency, and k the Boltzmann constant. In addition, the measured far field beam patterns of the integrated lens antenna show nearly collimated beams from 2.5 to 5.3 THz that allow reliable measurement of TrecDSB using the vacuum setup. Our experimental results in combination with an antenna-to-bolometer coupling simulation suggest that the HEB mixer can work well at least up to 6 THz, making it suitable for next generation of high-resolution spectroscopic space telescopes and, in particular, for the detection of the neutral atomic oxygen line at 4.7 THz.

Sub-shot-noise-limit discrimination of on-off keyed coherent signals via a quantum receiver with a superconducting transition edge sensor.

Abstract: We demonstrate a sub-shot-noise-limit discrimination of on-off keyed coherent signals by an optimal displacement quantum receiver in which a superconducting transition edge sensor is installed. Use of a transition edge sensor and a fiber beam splitter realizes high total detection efficiency and high interference visibility of the receiver and the observed average error surpasses the shot-noise-limit in a wider range of the signal power. Our technique opens up a new technology for the sub-shot-noise-limit detection of coherent signals in optical communication channels.

Optical beam splitter for use in an optoelectronic module, and a method for performing optical beam splitting in an optoelectronic module

Abstract: An optical beam splitter for use in an optoelectronic module and method are provided. The optical beam splitter is configured to split a main beam produced by a laser into at least first and second light portions that have different optical power levels. The first light portion, which is to be coupled into an end of a transmit optical fiber of an optical communications link, has an optical power level that is within eye safety limits and yet has sufficient optical power to avoid signal degradation problems. The optical power level of the first light portion is less than the optical power level of the second light portion. The optical beam splitter is capable of being implemented in a unidirectional or a bidirectional optical link.

Dual polarisation optical hybrid using silica-based planar lightwave circuit technology for digital coherent receiver

Abstract: Described is a compact dual polarisation optical hybrid (DPOH) that has been achieved by integrating polarisation beam splitters and 90°-hybrids fabricated with silica-based planar lightwave circuit technology. The fabricated DPOH worked completely passively without any adjustments and its optical characteristics were sufficient for the coherent detection of 111°Gbit/s DPQPSK signals.

Compact terahertz wave polarizing beam splitter

Abstract: We designed a compact terahertz (THz) wave polarizing beam splitter based on a periodic bilayer structure, which operates over a wide THz wavelength range. Within a short length (about 1 mm), this polarizing beam splitter separates THz wave TE- and TM-polarized modes into orthogonal output waveguides. Results of simulations with the finite-element method show that 99.99% of the TE-polarized THz wave is deflected by the periodic bilayer structure (with 39.9 dB extinction ratio), whereas 99.58% of the TM-polarized THz wave propagates through the structure (with a 23.7 dB extinction ratio). Tolerance analysis reveals a large tolerance to fabrication errors.

1x3 beam splitter for TE polarization based on self-imaging phenomena in photonic crystal waveguides

Abstract: Based on inspiration from multi-mode interference self-imaging and theoretical FDTD simulations, a 1x3 beam splitter was designed, fabricated and characterized. Measurements show that for TE-polarized incident light the power is distributed equally between the output ports within 1dB in the range from 1541nm to 1552nm, and the total transmission of the 1x3 splitter is equal to the corresponding length of a single-line-defect PhCW within the measurement uncertainty.