238 results about "Phase conjugation" patented technology

This invention has incorporated projective optics and phase conjugate material thus eliminating the requisite use of an external phase conjugate material to provide a see-through head mounted projective display. A key component of the invention is the use of optical imaging technology in combination with projective optics to make this revolutionary technology work. In previous head mounted projective displays the phase conjugate material had to be placed in the environment to display images, but in this invention one is not limited to the use of an external phase conjugate material but further extends its use to outdoor see-through augmented reality to produce images using the see-through head mounted projective display system. Furthermore, this invention extends the use of projective head mounted displays to clinical guided surgery, surgery medical, an outdoor augmented see-through virtual environment for military training and wearable computers.

Disclosed is a generalized reconstruction method that corrects for non-linear phase errors based on least-squares estimation. An approximation of the least squares estimate utilizes refocusing reconstruction in which high-resolution data is multiplied by the phase conjugate of a navigator in image-space. The multiplication rephases the unaliased signal in the high-resolution data. The high-resolution data can then be added together coherently. The multiplication can be effected in k-space as a convolution using a gridding reconstruction of the high-resolution data using the low resolution navigator.

An optical transport system configured to transmit at least two phase-conjugated optical variants carrying the same modulated symbols, with the phase-conjugated optical variants in being different from one another in one or more of polarization of light, the time of transmission, spatial localization, optical carrier wavelength, and subcarrier frequency during transmission. The two phase-conjugated optical variants can be generated by a single polarization-diversity transmitter to be orthogonally polarized, and propagate through an optical transmission link with the same wavelength and spatial path. The optical variants are detected and processed at the receiver in a manner that enables coherent summation of the corresponding electrical signals prior to constellation de-mapping. The coherent summation tends to cancel out the deleterious effects of nonlinear distortions imparted on the individual phase-conjugated optical variants in an optical fiber transmission link because said nonlinear distortions tend to be opposite to each other.

Methods and systems are provided for obtaining a phase conjugate reconstruction beam for use in retrieving holographic information from a holographic storage medium. These methods and systems include generating a coherent light beam that is a reproduction of the reference beam used in storing the holographic information in the storage medium. This coherent light beam is then directed through the holographic storage medium at the same angle and location of the reference beam during recording of the hologram. The directed coherent beam is then reflected back through the storage medium so that the reflected coherent light beam provides a phase conjugate of the reference beam and passes through the storage medium at the same angle and location that the reference beam passed through the storage medium during recordation of the hologram.

An apparatus comprises an optical transmitter that comprises a processor and at least one optical modulator. The processor is configured to generate electronic representations of at least two pre-dispersion-compensated phase-conjugated optical variants carrying a same modulated payload data for transmission. The at least one optical modulator is configured to modulate the electronic representations, wherein an amount of dispersion induced on the pre-dispersion-compensated phase-conjugated optical variants depends on an accumulated dispersion (AD) of a transmission link through which the pre-dispersion-compensated phase-conjugated optical variants are to be transmitted. The amount of dispersion induced on the phase-conjugated optical variants may be approximately −AD/2, where AD is the accumulated dispersion of the transmission link. The pre-dispersion-compensated phase-conjugated optical variants are different from one another in one or more dimensions such as the polarization of light, the time of transmission, the spatial localization, the optical carrier wavelength, or the subcarrier frequency during transmission.

A method of employing multipath propagation in wireless radio communications uses an omnidirectional transmitting/receiving antenna at one end of a transmission link to send an interrogating signal across an environment subject to multipath disturbances to a phase-conjugating retrodirective antenna, and the retrodirective antenna returns a communication signal along the multiple pathways taken by the interrogating signal to the omnidirectional antenna despite the multipath disturbances. In a simplex communication mode, the retrodirective antenna sends a return signal mixed with a communication signal to the omnidirectional antenna. In a duplex communication mode, both an omnidirectional antenna and a phase-conjugating retrodirective antenna are operated in tandem at each end of the transmission link to provide effective two-way wireless radio transmissions.

A system and method for automatically generating a return beam in the direction of a received beam. The inventive system (10) includes a phased array antenna (12) for receiving a radio frequency signal having a first wavefront from a first direction. In response to this signal, the invention (10) provides a second signal having a second wavefront. The second signal is a phase conjugate of the first signal and is transmitted in a reverse direction relative to the direction of the first signal. In the illustrative embodiment, the invention includes a plurality of phase conjugators each of which are disposed in a transmit/receive module and coupled to an associated radiating element. Each of the phase conjugators includes a mixer (60) having the input signal as a first input thereto. The input signal has a first frequency and a first phase. A second signal having a frequency equal to twice the first frequency is input to each mixer (60) from a reference frequency module (30) such that the output of the mixer includes a component representative of the negative of the first phase. The output of each mixer (60) is filtered to extract a signal component having a negative phase relative to the input signal. These signal components are then transmitted as the phase conjugated wavefront. This process will occur for each signal when multiple signals are received within the field of regard of the phased array antenna (12).

The invention discloses a berry phase metasurface-based multi-plane holographic multiplexing method, and belongs to the field of micronano optical and holographic multiplexing application. The berry phase metasurface-based multi-plane holographic multiplexing method comprises the steps of achieving phase recovery by a 3D-Fienup algorithm, taking different numerical values of reproduction positions of different images, and acquiring a computer generation holographic diagram containing all information; selecting a metal coupling polaron as a berry phase metasurface structure unit, achieving phase modulation based on a berry phase modulation principle, and enabling a polarization state to become a multiplexing path by coding a holographic phase profile conjugated with an original phase to achieve a holographic multiplexing passage selected by circular polarization; making a metasurface phase sheet for recording the computer generation holographic diagram, selecting an emergent circular polarization light orthogonal to chirality of the polarization stat, and optically reproducing a three-dimensional object or a wave surface which is recorded. The holographic multiplexing method with sub-wavelength pixel of visible light and near-infrared bands, ultrathinness, large visual angle and large capacity is provided by the invention; and moreover, the crosstalk can be effectively reduced, and the holographic multiplexing of circular polarization selectivity is achieved.

A method of and device for generating an amplified optical signal directly in an optical fiber by way of phase-sensitive amplification based on one or more four-wave mixing (FWM) processes. In one embodiment, an input signal and two pump waves are applied to a highly nonlinear fiber (HNLF). The input signal is amplified in the HNLF due to energy transfer from the pump waves to the input signal via a degenerate phase-conjugation (PC) process. In another embodiment, an input signal and first and second pump waves are applied to a first HNLF to generate, via a Bragg scattering (BS) process, an idler signal corresponding to the input signal. The second pump wave is then filtered out and the first pump wave, a third pump wave, and the input and idler signals are applied to a second HNLF, where they interact via a non-degenerate PC process to produce an amplified output signal.

The invention provides a distributed self-adaptive optical system based on optical fibers. The distributed self-adaptive optical system based on the optical fibers comprises an emitting laser, an optical fiber beam splitter, an optical fiber phase modulator, an optical fiber laser amplifier, a photoelectric detector, a three-port optical fiber circulator, a self-adaptive optical fiber collimator and coupler array, an integrated device, a multi-channel high-voltage amplifier, a wavefront controller as well as a beacon light source, a spectroscope and a far field target. The distributed self-adaptive optical system is based on the fiber laser technology in combination with a plurality of optical fiber devices, and is characterized in that a beacon light beam is divided by use of the self-adaptive optical fiber collimator and coupler array, the wavefront error of beacon light is measured in real time and the error is decomposed to each light sub-beam in a laser array, a piston for emitting the light sub-beams and a tilting phase are controlled independently and in parallel according to the principle of phase conjugation, and the influence of atmospheric turbulence effect on the quality of the light beam at the far field target is relieved. The distributed self-adaptive optical system based on the optical fibers has important application prospects in the fields such as laser atmospheric transmission, free space laser communication and laser radar.

Exemplary embodiments include a method and systems for impairment compensation in a communication system. The systems can include an electronic phase conjugation system that receives an incoming optical signal from a first section of a fiber optic link, converts the incoming optical signal to an in-phase electric signal and a quadrature electrical signal, and generates a phase conjugated outgoing optical signal from the in-phase and quadrature electrical signals. The phase conjugated outgoing optical signal compensates for impairment of the fiber in the communication system.

A fiber-optic sensor can have a Michelson sensor portion and a Mach-Zehnder sensor portion. A first splitter-coupler can be configured to split incoming light between a first fiber portion and a second fiber portion. A first polarization-phase conjugation device can be configured to conjugate a polarization phase of incident light corresponding to the first fiber portion, and a second polarization-phase conjugation device can be configured to conjugate a polarization phase of incident light corresponding to the second fiber portion. Each of the first and second polarization-phase conjugation devices can be configured to reflect light toward a detector and through the respective first and second fiber portions. A coupler can be configured to join light in the first fiber portion with light in the second fiber portion, and a third fiber portion can be configured to receive light from the coupler and to illuminate a second detector.

The invention discloses a phase conjugate reflection bi-pass lighting confocal microscopic device, belonging to an optics measuring microtechnique. A collimation beam expander and a spectroscope are configured on a laser direct light path in sequence; a focusing objective lens and a three-dimensional micrometric displacement objective table are configured on a spectroscope reflecting light path; a collecting objective lens is configured on a spectroscope transmission light path; a collecting objective lens converging light is conducted to a photoelectric detector through conduction optical fibers; an ellipsoid reflecting lens is also configured on the spectroscope reflecting light path; a near focus of the ellipsoid reflecting lens is located on a surface of a sample put on the three-dimensional micrometric displacement objective table; and a phase conjugate reflecting lens is configured at a remote focus of the ellipsoid reflecting lens. According to the device, bi-pass lighting to a large curvature convex surface is carried out by adopting a characteristic that a reflection ray as a phase conjugate light wave of an incidence light of the phase conjugate reflecting lens can go back along an original way in combination with a characteristic that the ellipsoid reflecting lens is provided with a pair of isoplanatic image formation conjugate focuses, so that the device has a measurement ability of the large curvature convex surface and a characteristic of a high axial resolution force.

A method is disclosed for establishing communication through free space between a pair of optical communication devices. A divergent beam is transmitted from each of the optical communication devices toward the other. A portion of the received divergent beam is used to create a phase conjugated beam that is returned to the other device. A diffraction grating is dynamically recorded at each devices so as to establish a bi-directional self-tracking optical link between the devices.

Speckle effect in imaging applications is reduced by generating additional speckle patterns on the screen such that the speckle patterns are overlapped and the overlapped speckle patterns average out on the screen to appear as a noise background to the viewers. The speckle patterns are generated by discrete optical signals of a visible frequency comb. A visible frequency comb having discrete optical signals is generated through modulation-instability processes, phase-conjugation processes, and Bragg-scattering processes using a non-linear optical material and a wavelength converter.

A method for irradiating scattering medium, including modifying a particle's response to electromagnetic radiation irradiating the particle in a scattering medium, wherein the electromagnetic radiation is scattered by the scattering medium, and modulated by the modifying, into scattered electromagnetic radiation comprising a scattered field; forming a phase conjugate field, wherein the phase conjugate field is a phase conjugate of the scattered field; and irradiating the scattering medium with the phase conjugate field, wherein the phase conjugate field forms a focus at a target defined by the particle.

The invention discloses a high-precision distributed optical fiber frequency transfer method. Local transferred frequency signals are subjected to frequency halving and then serve as detection signals, the signals are transmitted back and forth between the local end and a remote end through bidirectional wavelength division multiplexing, and detection signals comprising optical fiber link phase noise are obtained at the local end; the returned detection signals and the local transferred frequency signals are subjected to frequency mixing and filtering to obtain phase conjugation signals, and the phase conjugation signals are transmitted to the optical fiber link through another wavelength channel; all users detect forward conjugation signals and backward detection signals, and stable frequency signals are obtained through frequency mixing; and the remote end carries out frequency mixing on the received forward phase conjugation signals and the forward detection signals to obtain stable frequency signals. Influences on frequency transfer short-term stability by backscattering noise can be avoided; the users share the same wavelength, and the fiber frequency long-term stability influences and the cost due to increasing of users can be reduced; and by adopting passive compensation, the method has the advantages of relatively simple and unlimited dynamic range and quick compensation.

A method of performing closed loop correction of phase aberrations, including the steps of directing an incoming light beam into a black fringe wavefront sensor via an adaptive optical device (“AOD”), dividing the incoming light beam into measurement and reference beams, altering the path length of the measurement beam and the location of the black fringe by modulating a ramp voltage of a modulator, combining the measurement and reference beams into a common output beam, detecting the black fringe in the common output beam using detectors mapped to the AOD, storing, as tagged ramp voltages, a corresponding ramp voltage for each detector when it detects black fringe, calculating phase errors based upon the tagged ramp voltages and modulator scaling, calculating adaptive optics correction voltages based upon the phase errors, transmitting and applying the correction voltages to the AOD to correct phase aberrations of the incoming light beam via phase conjugation.

A four-wave mixing squeezed light source includes: a mixing medium having chi(3) non-linear characteristics including two atomic ground states coupled to each other by transitions through optically-excited states; a pump beam having a polarization and a frequency, said frequency being near the ground-to-excited atomic transition but far enough from the atomic transition such that the pump beam is substantially unabsorbed; and a probe beam having a polarization that is orthogonal with respect to the pump beam polarization, the probe beam having a frequency of the pump beam frequency plus or minus a frequency splitting of the two atomic ground states. The mixing medium, the pump beam and the probe beam interact to produce a phase conjugate beam having a polarization that is orthogonal to the pump beam polarization, such that the beams are non-degenerate with the pump beam, and the probe beam is amplified.