Showing papers on "Beam splitter published in 1997"

Generating Schrödinger-cat-like states by means of conditional measurements on a beam splitter

Abstract: A scheme for generating Schr\"odinger-cat-like states of a single-mode optical field by means of conditional measurement is proposed. Feeding a squeezed vacuum into a beam splitter and counting the photons in one of the output channels, the conditional states in the other output channel exhibit a number of properties that are very similar to those of superpositions of two coherent states with opposite phases. We present analytical and numerical results for the photon-number and quadrature-component distributions of the conditional states and their Wigner and Husimi functions. Further, we discuss the effect of realistic photocounting on the states.

Design, fabrication, and characterization of form-birefringent multilayer polarizing beam splitter

Abstract: Polarizing beam splitters that use the anisotropic spectral reflectivity (ASR) characteristic of high-spatial-frequency multilayer binary gratings have been designed, fabricated, and characterized. Using the ASR effect with rigorous coupled-wave analysis, we design an optical element that is transparent for TM polarization and reflective for TE polarization at an arbitrary incidence angle and operational wavelength. The experiments with the fabricated element demonstrate a high efficiency (97), with polarization extinction ratios higher than 220:1 at a wavelength of 1.523 m over a 20 angular bandwidth by means of the ASR characteristics of the device. These ASR devices combine many useful characteristics, such as compactness, low insertion loss, high efficiency, and broad angular and spectral bandwidth operations.

Optical quadrature Interferometer

Abstract: An optical quadrature interferometer is presented. The optical quadrature interferometer uses a different state of polarization in each of two arms of the interferometer. A light beam is split into two beams by a beamsplitter, each beam directed to a respective arm of the interferometer. In one arm, the measurement arm, the light beam is directed through a linear polarizer and a quarter wave plate to produce circularly polarized light, and then to a target being measured. In the other arm, the reference arm, the light beam is not subject to any change in polarization. After the light beams have traversed their respective arms, the light beams are combined by a recombining beamsplitter. As such, upon the beams of each arm being recombined, a polarizing element is used to separate the combined light beam into two separate fields which are in quadrature with each other. An image processing algorithm can then obtain the in-phase and quadrature components of the signal in order to construct an image of the target based on the magnitude and phase of the recombined light beam. The system may further be used for lensless imaging.

Electronic imaging apparatus

Abstract: PROBLEM TO BE SOLVED: To provide an electronic image pickup device in which a lens system can easily be exchanged to a different image pickup element and can easily deal with model change is good without the fear of wasting an expensive beam splitter and an image pickup element when the image pickup lens system breaks down. SOLUTION: The beam splitter 27 and the image pickup element 33 are incorporated in an optical finder unit with optical parts for optical finder. The optical finder unit is constituted of a finder case storing the optical parts for finder and a holding member holding the beam splitter 27 and the image pickup element 33. The image pickup face of the image pickup element 33 is slantingly arranged against the incident luminous flux of the beam splitter 27. Incident luminous flux to the image pickup element 33 is reflected twice in the beam splitter and the incident luminous flux of a finder optical system 35 to the finder passes through the beam splitter 27 without reflection.

3-dimensional micromachining with femtosecond laser pulses

Abstract: A method of treating a material by generating an ultraviolet wavelength laser beam having femtosecond pulses; splitting the ultraviolet wavelength laser beam into a plurality of separate laser beams having femtosecond pulses; directing the separate laser beams onto a target point within a sample such that the femtosecond pulses of the separate beams overlap to create an intensity sufficient to treat the sample. Apparatus for treating a material that includes an ultraviolet laser for generating an ultraviolet wavelength laser beam having femtosecond pulse and directing that ultraviolet wavelength laser beam onto a beam splitter; a beam splitter for splitting the ultraviolet wave length laser beam into a plurality of separate laser beams having femtosecond pulses; directing the separate laser beams onto a target point within a sample such that the femtosecond pulses of the separate beams overlap to create an intensity sufficient to treat the sample.

Compact display system with two stage magnification and immersed beam splitter

Abstract: A virtual image display system is provided which is made thinner through the use of an immersed beam splitter, and in one embodiment, total internal reflection. The display system includes an imaging surface on which a source object is formed, a first optical element having a reflective function and a magnification function, a second optical element having a magnification function and an immersed beam splitting element positioned between the first and second optical elements, the immersed beam splitting element including a beam splitter surrounded by an optically transparent material having a refractive index greater than air. An illumination source projects the source object formed at the imaging surface through the optically transparent material to the beam splitter. The beam splitter reflects the projected source object to the first optical element. The first optical element magnifies the projected source object and reflects a magnified virtual image of the projected source object to the beam splitter. The magnified virtual image traverses the beam splitter to the second optical element which magnifies the magnified virtual image to produce a compound magnified virtual image of the source object.

High efficiency projection displays having thin film polarizing beam-splitters

Abstract: A projection display system includes a thin film polarizing beam splitter/combiner has first and second light transmissive substrates in the form of prisms and a plurality of thin film layers disposed between the prisms. The thin film layers and have predetermined thicknesses and refractive indices which allow unpolarized incident light to be separated into s-polarized and p-polarized light beams. Both frustrated total internal reflection and thin film interference are simultaneously employed to allow s-polarized light to be transmitted and p-polarized light to be reflected over a wide range of wavelengths and angles of incidence. The device further includes two spatial light modulators for encoding an image to be projected. By providing a different signal to each spatial light modulator, a three-dimensional display results.

Fluorescence imaging system

Abstract: A fluorescence imaging system for epi-illumination wherein the usual dichroic beamsplitter is replaced by a polarizing beamsplitter (PBS). The sample is excited with light that is linearly polarized to a significant degree, and fluorescent emission light is collected in the orthogonal linear polarization state. Excitation light that is scattered or reflected by the sample is rejected by the PBS, while the desired emission light is captured for imaging by a detector. By eliminating the usual dichroic beamsplitter member, the imaging system removes the barriers to multi-spectral imaging that such members conventionally impose. A wavelength-selective birefringent network may also be interposed between the beamsplitter and the sample for converting the polarization of either the excitation or the emission light to the orthogonal state without defeating this desirable rejection property, thus permitting measurement of the sample emissions in either or both linear polarization states for assessing fluorescence polarization.

Variable polarization beam splitter, combiner and mixer

Abstract: Collimated light from two input fibers are directed against the interface of a beam splitter cube formed by two right-angle prisms. Light transmitted through, or reflected by, depends upon the polarization of the incoming light. A collimator subassembly for an output fiber receives light from the beam splitter cube. Polarization of the incoming light is controlled by orientation of the optical axes of one or two liquid crystal cells placed between each input fiber and beam splitter cube. By controlling the optical axes of the liquid crystal cells light from the two input fibers can be sent to the output fiber in any desired ratio. By rearranging the optical fibers, right-angle prisms and liquid crystal cells, a variable polarization beam combiner can be formed. A combination of the variable polarization beam combiner and beam splitter provides a variable polarization beam mixer, in which two input light signals can be combined and then split into two different output signals by control of liquid crystal cells. Finally, birefringent crystals and laminated beam splitter plates may also be used for the right angle prisms.

Projection image display apparatus

Abstract: An object of the present invention is to provide a simple image projection apparatus which prevents color shading. First, second and third dichroic mirrors are provided in parallel which separate light from a source into red, blue, and green components. First and second polarization beam splitters are provided with operative surfaces perpendicular to the dichroic mirrors for reflecting predetermined polarization light components of two colors to two reflection type liquid crystal devices. A third polarization beam splitter having an operative surface in parallel to the dichroic mirrors is provided for reflecting a predetermined polarized light component of the third color component to a third reflection type liquid crystal device. A cross dichroic prism device is provided for combining the modulated light from the three liquid crystal devices and transmitting the synthesized light for projection.

Head-mounted display apparatus with a single image display device

Abstract: A head-mounted display apparatus includes an image display device for displaying images, a first flat reflection mirror for reflecting light from the image display device, a first and a second lenses for controlling a size of the image from the first flat reflection mirror, a first beam splitter for partially transmitting and partially reflecting the light passing through the first and the second lenses, thereby splitting two light beams, a second flat reflection mirror for reflecting the transmitted light beam, a second beam splitter for partially transmitting and partially reflecting the light beam from the second flat reflection mirror, a first reflection mirror for reflecting the light beam reflected by the second beam splitter to one eye of a viewer, a third flat reflection mirror for reflecting the light beam reflected by the first beam splitter, a fourth flat reflection mirror for reflecting the light beam from the third flat reflection mirror, a third beam splitter for partially transmitting and partially reflecting the light beam from the fourth flat reflection mirror and a second reflection mirror for reflecting the light beam reflected by the third beam splitter to the other eye of the viewer.

Multi spectral imaging system

Abstract: An optical imaging system provides automatic co-registration of a plurality of multi spectral images of an object which are generated by a plurality of video cameras or other optical detectors. The imaging system includes a modular assembly of beam splitters, lens tubes, camera lenses and wavelength selective filters which facilitate easy reconfiguration and adjustment of the system for various applications. A primary lens assembly generates a real image of an object to be imaged on a reticle which is positioned at a fixed length from a beam splitter assembly. The beam splitter assembly separates a collimated image beam received from the reticle into multiple image beams, each of which is projected onto a corresponding one of a plurality of video cameras. The lens tubes which connect the beam splitter assembly to the cameras are adjustable in length to provide automatic co-registration of the images generated by each camera.

Polarization maintaining fiber lasers and amplifiers

Abstract: A number of variations are provided of a device that provides an amplified single polarization optical signal. Each of these relies on the use of a non-polarization maintaining gain medium through which the signal is directed, and a polarization shifter and reflector that direct the signal back through the same gain medium with a shifted polarization state. An input polarization beamsplitter directs the returning optical signal away to an output, based on its shifted polarization state. The embodiments of the invention include the use of double-clad fiber. Multiple stages may be used to provide specific amplification parameters. In one embodiment, both amplification stages reside in the same polarization shifting optical path. A polarization maintaining amplifier of this type may be used as part of a master oscillator-power amplifier, in which polarization maintaining fiber is used as part of the source laser. Wavelength selective components are also used in certain embodiments of the invention, to allow for wavelength selectivity, as well as a single polarization state, in amplifiers, lasers and amplified spontaneous emission (ASE). In one embodiment, an optical circulator is used to allow the amplified, shifted polarization state signals to be directed away from the input to a desired output port. A feedback loop may also be used to control the polarization state at the amplifier output. A polarization beamsplitter at the output directs light not having the desired polarization state to a photodetector, the output of which is used by a polarization controller at the input, such that the input polarization state is adjusted until the control signal from the photodetector is minimized.

Interferometer having combined beam splitter compensator plate

Abstract: A Michelson-type interferometer which includes apparatus for producing a suitable collimated interferometer input beam; a beam splitter and recombiner for first splitting the input beam into two beams which have components arranged to travel along parallel forward paths and then to recombine them into a single output beam as they are returned along reverse paths to the beam splitter and recombiner; an OPD scanner for scanning the optical path difference between the two split beams travelling along said paths while substantially maintaining the parallelism between the components, and a beam reverser common to the parallel beam components for reversing their direction of travel along the reverse paths and returning them for recombination into the single output beam at the beam splitter and recombiner.

Method and apparatus for controlling the size of a laser beam

Abstract: A method of controlling the size of a laser beam comprises the steps of generating the laser beam with a laser, focusing the laser beam, directing the laser beam to a target, directing a portion of the laser beam to an optical detector which generates a signal representative of a fluence distribution of the laser beam, and adjusting a focal point of the laser beam based on the measured fluence distribution to control the size of the laser beam on the target. The method can be carried out with an apparatus which comprises a beam splitter which divides the laser beam into a first portion and a second portion, a lens which focuses the first portion of the laser beam for incidence on a target, a detector which receives the second portion of the laser beam and which generates a signal representative of a spatial energy distribution of the laser beam, a digitizer which digitizes the signal from the detector, a data analyzer which receives the digitized signal from the digitizer and which calculates a fluence distribution of the laser beam, and a lens controller for adjusting a position of the lens with respect to the target based on the fluence distribution.

Direct-to-digital holography and holovision

Abstract: Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made.

Temperature controlled multiple pass absorption cell for gas phase chemical kinetics studies

Abstract: The application of a Herriott-type optical multiple pass cell for absorption detection of transient species in temperature controlled laser pump-probe kinetics experiments is described. Using reaction initiation by laser photolysis in combination with reaction monitoring by absorption of a multiple pass laser allows confinement of the probed reaction volume to the temperature controlled region of a slow flow reactor. For transient measurements, this apparatus provides enhanced sensitivity from increased path length and accurate temperature control by limiting the pump-probe interaction volume. In addition, for a polarized probe laser, a simple arrangement using a polarizing beam splitter and a λ/4 plate allows doubling of the path length.

System for correction the shape of a wave-front of a laser beam

Abstract: A system for the control of light beams includes a beam splitter placed on the path of the beam to be controlled and deriving a measurement beam from this beam; a detection device receiving the measurement beam and measuring the shape of the wave front of the measurement beam; a wave-front shape correction device placed on the path of the beam to be controlled, activated by the detection device and correcting the shape of the wave front of the beam to be controlled. The detection device includes a light spatial modulator providing for the selective transmission of the portions of the measurement beam; a focusing device receiving the different portions of the measurement beam; a series of photodetectors placed along the focusing plane of the focusing device; a device for the identification of the photodetector or photodetectors, detecting a light wave and computing the shape of the wave front as a function of the photodetectors identified.

Electron Holography of Long-Range Electrostatic Fields

Abstract: Publisher Summary This chapter presents a discussion on electron holography of long-range electrostatic fields. The chapter discusses the fundamental theoretical considerations underlying the observation of electric fields. The basic tool—that is, the phase-object approximation (POA)—is applied to the case of the electron biprism to obtain its transmission function and to analyze its effect on the image wave function within an interferometric or holographic setup. The chapter presents the basic principles of holographic recording and processing, with the modifications introduced by the long-range behavior of a particular class of electric fields—namely, the perturbation of the reference wave. Although the main emphasis is on image electron holography by means of an electron biprism, Fresnel holography using a single crystal film as an amplitude beam splitter is described in brief as this method can be carried out even if the microscope is not equipped with a field emission gun. The case of charged dielectric spheres is treated and charged microtips are analyzed. The electrostatic Aharonov–Bohm effect is reviewed in brief and it is shown how nonlocal quantum effects can arise with a particular configuration of electrostatic fields.

Method of measuring thickness and refractive indices of component layers of laminated structure and measuring apparatus for carrying out the same

Abstract: A light beam emitted by a light source is projected through a collimator lens, a beam splitter and an objective on a sample having a laminated structure. The light beam reflected from the sample travels through the beam splitter to a detector and the detector provides a confocal signal. The detector provides an interference signal upon the reception of the reflected light beam and a reference light beam reflected by a reference mirror. The sample and the reference mirror are moved on the basis of the confocal signal and the interference signal, and the thickness and the refractive index of layer of the sample are determined on the basis of the respective displacements of the sample and the reference mirror.

Module for optical communication

Abstract: Bi-directional and uni-directional optical communication and transmission modules minimize crosstalk during use by diffusing reflected and returned stray light A bi-directional module includes a transmission optical element for transmitting light into the module, a reception optical element for receiving light in the module, an optical fiber for guiding light to and from the transmission and reception optical elements, respectively, a beam splitter for allotting light received from the transmission optical element and the optical fiber, and a light non-return chamber for receiving and diffusing stray light reflected by the beam splitter from the transmission optical element and the optical fiber A uni-directional module includes a light non-return chamber for receiving and diffusing return light reflected by a beam splitter from at least one optical device arranged in the module In other aspects of the invention, a variety of optical modules are provided wherein component parts are either aligned along a central axis of a through-hole of the module, are adjustable to maintain an optimum optical axis for light transmission through the module, or are arranged to mutually correct for the axial shift of light in any given component to minimize the total axial shift of light entering and exiting the module

Laser diode gas sensor

Abstract: A laser diode gas sensor for the spectroscopic measurement of a gas sample, with a retroreflector and a concave mirror, which define between them an open measuring path with the gas to be analyzed. Laser light passes through the measuring path, is reflected at the retroreflector, and is directed toward a detector via a concave mirror in order to determine the mean concentration of the gas component to be analyzed in the optical measuring path. Optical elements, such as beam splitters, lenses, etc., which lead to losses of intensity, were used before to couple the laser light into the beam path onto the retroreflector, and to decouple the reflected light to the detector. An improved optical imaging array, which minimizes losses, is provided. The concave mirror is provided centrally with an opening transparent to the laser light, through which a weakly divergent bundle of laser light is directed onto the retroreflector, so that the retroreflector is illuminated essentially over its entire surface. The retroreflector is made with a matrix consisting of a plurality of triple mirrors, which reflect the incident, weakly divergent bundle of laser beams as a bundle of laser beams with convergent properties onto the concave mirror. The concave mirror is arranged or shaped such that the laser light reflected by the retroreflector is focused by the concave mirror directly onto the detector, which is arranged outside the principal beam path.

Optical instrument providing combined infrared and Ramen analysis of samples

Abstract: Apparatus for IR and Raman analysis of a sample includes an optical train having a common path segment that includes the sample, and a mechanism for selectively or simultaneously) subjecting the sample to analytic radiation (such as IR) or Raman excitation radiation, and selectively (or simultaneously) detecting the analytic radiation from the sample or the Raman scattered light from the sample. In a specific embodiment, the apparatus includes a sample stage for holding the sample; an infrared source; an infrared detector; a source of Raman excitation light; a Raman spectrometer; infrared and visible (Raman) light objectives selectively positionable in the common path segment; an optical train disposed in the common path segment for transferring light between the sample and a particular location; and a mechanism for selectively (or simultaneously) (a) directing analytical radiation to the sample and analytical radiation from the sample to the infrared detector, or (b) directing Raman excitation light to the sample and Raman scattered light to the Raman spectrometer. The mechanism can be a movable mirror or a fixed dichroic beam splitter.

Optical chopsticks: digital synthesis of multiple optical traps.

Abstract: Publisher Summary This chapter discusses the digital synthesis of multiple optical traps. The chapter describes how multiple optical traps may be synthesised by rapid scanning of a single laser beam. For many optical trapping applications it is advantageous to be able to produce two or more traps simultaneously. One technique is to split the trapping laser beam into two separate light paths using a polarising beam splitter and then to recombine the light using a second polarising beam splitter. This allows two, independently controllable optical traps to be produced. The method presented in the chapter allows two or more traps to be synthesised by rapidly scanning a single laser beam, using fast beam deflectors, to generate multiple traps that are not truly simultaneous but which function by time sharing the laser power between several positions. Multiple optical traps can be created by rapid scanning of a single laser beam because the viscosity of the solution is sufficiently high to provide positional persistence.

Light measuring apparatus

Abstract: PROBLEM TO BE SOLVED: To make it possible to measure light at high speed by a method wherein a phase distribution modulator is installed on an optical path before a sample arrangement part, a beam of signal light is divided into a plurality of regions whose phases are different and their phase patterns are changed sequentially in terms of time. SOLUTION: A laser beam 11a is divided into a beam of signal light 11b and a beam of reference light 11c by a beam splitter 12, and the beam of signal light 11b is incident, via a beam expander 13, on a phase distribution modulator 13 which is driven by a drive circuit 141. The phase distribution modulator 14 divides the beam of signal light 11b into a plurality of regions, phases of the divided regions are made different from each other, and phase patterns of the respective divided regions are changed sequentially in terms of time. After that, the beam of signal light 11b is transmitted through a sample 10 in a sample arrangement part 15 so as to be incident on a beam splitter 16, it is superposed on the beam of reference light 11c whose frequency is shifted by an acousto-optic modulator 19 so as to interfere, it is incident on a photodetector 17, and the distribution of the transmittance of the sample 10 is found by a signal processing part 22 on the basis of beat signals of light-receiving elements 17a to 17n. Thereby, the influence of a speckle can be removed at high speed. COPYRIGHT: (C)1998,JPO

Millimeter-wave holographic power splitting/combining

Abstract: It is shown that holography offers a novel solution to the problem of millimeter-wave power splitting and combining. With the help of an approximate model, we demonstrate that a hologram will work as a beam-splitting element, provided that it records the holographic image of the beams to be generated. To verify this observation, a beam splitter consisting of a hologram and an antenna array is analyzed by means of a rigorous network model. This analysis serves to find the optimum structure of the beam splitter. Measurements on a realized prototype of the beam splitter prove the possibility of achieving a high splitting efficiency, a high inter-element isolation, and a relatively large bandwidth. Flexibility in the orientation and the number of outputs is another outstanding feature of this holographic approach.

- Matter-Wave Interferometers: A Synthetic Approach

Abstract: Publisher Summary This chapter presents a synthetic approach to matter–wave interferometers. The key element of most matter–wave interferometers is a diffractive beam splitter. Ideally, a diffractive beam splitter is a scattering potential for the incident particle. There is a general class of interferometers in which the splitters change, in general, both the external motion and the internal state in a single step. This includes, as a special case, interferometers in which the splitters change only the external motion. In another class of interferometers, the first step is to create a superposition of states (labels), either internal or external, and the second step is to separate these states in the physical space by a diagonal state (label) dependent potential. The chapter discusses the physics of the generalized beam splitter. It explains scattering matrix in the time-dependent approach and propagators among field zones. The chapter also elaborates in detail the architecture of interferometers and its sensitivity to gravitational and electromagnetic fields.

Head-mounted display including single image display device

Abstract: A head-mounted display apparatus comprises a single image display device 11, a beam splitter 12 for partially transmitting and partially reflecting light from the image display device, a reflection mirror 13, and first and second magnifying lenses 14 and 15 respectively disposed between the beam splitter and the right eye 16 and between the reflection mirror and the left eye 17 thereby enabling the observer to see enlarged virtual image formed at a certain distance from the eyes The head-mounted display apparatus can also provide a stereoscopic vision by displaying images on the image display device on the basis of the principle of binocular parallax using shutter glasses 25 and 26 In a further embodiment the apparatus includes concave mirrors and additional half mirrors (figs 6 and 7)

Optical system for miniature personal displays using reflective light valves

Abstract: An illumination system and display are disclosed that include a light for providing light, a polarizing beam splitter (PBS) having a first surface that receives the light from the backlight. The PBS passes a first polarization of the received light to a curved mirror located at a second PBS face, which second PBS face is opposite the first PBS face. The curvature of the mirror provides the optical power necessary for proper imaging, while limiting the reflecting area of the mirror provides an aperture stop that determines the numerical aperture of the optical system. The display also includes a quarter wave plate and a spatial light modulator (SLM). The quarter wave plate is located between the PBS and mirror and changes the first polarization of light, directed from the PBS to the mirror, to a second polarization which is reflected from the mirror back to the PBS. The SLM receives this second polarization of light after reflection thereof by the PBS, and selectively rotates the second polarization of light to form an image forming light having the first polarization, which is reflected back to the PBS. Through an exit face, the PBS provides the rotated image forming light to a viewer. Between the viewer and the PBS exit surface, an imaging lens system is provided that includes at least one folding mirror.