1791 results about "Light modulation" patented technology

The embodiment of the invention provides an electro-optical modulator and a light quantum computer. The electro-optical modulator comprises an electrode assembly and an optical waveguide assembly. The electrode assembly comprises a positive signal electrode, a negative signal electrode, a first grounding electrode and a second grounding electrode, and the positive signal electrode and the negative signal electrode are arranged between the first grounding electrode and the second grounding electrode. The optical waveguide assembly is configured to bear optical signals and comprises a first optical waveguide and a second optical waveguide, the first optical waveguide is located between the positive signal electrode and the negative signal electrode and used for bearing first optical signals, and the second optical waveguide is located between the first grounding electrode and the positive signal electrode or between the second grounding electrode and the negative signal electrode and used for bearing second optical signals. The carrier is used for bearing second optical signals. Constant-amplitude voltage signals with opposite phases are applied to the positive signal electrode and the negative signal electrode which are tightly coupled, so that the modulation efficiency can be improved, and the common-mode noise can be reduced.

A wide-field dynamic magnetic imaging device and method. The wide-field dynamic magnetic imaging device comprises: a probe assembly (1), comprising a diamond (101) containing NV centers; a microwave magnetic field assembly (2) configured to generate a uniform microwave field and a uniform bias magnetic field in the vicinity of the diamond (101), so as to regulate the spin energy level of the diamond (101) and the quantum state evolution process; a laser modulation assembly (3) configured to output an initial uniform pulsed laser to excite the diamond (101) to emit fluorescence; a fringe light modulation assembly (4) configured to modulate the initial uniform pulsed laser to output a fringe pulsed laser, causing the fluorescence emitted by the diamond (101) to be fringe fluorescence, or to modulate the fluorescence emitted by the diamond (101) into fringe fluorescence; a fluorescence detection assembly (5) configured to perform spatial imaging on the fringe fluorescence to obtain magnetic field information of a sample under test (7), thereby obtaining an initial magnetic image of said sample (7); and a data processing assembly (6) configured to perform Fourier transform and inverse Fourier transform on the initial magnetic image to obtain a first magnetic image.

An adjustment method of a laser processing apparatus includes a spatial light modulator adjustment step of adjusting a spatial light modulator into a state ready for splitting a laser beam emitted from a laser oscillator and applying a plurality of laser beams such that laser beams will have a desired positional relation, a processing mark formation step of operating the laser oscillator to apply the laser beams to a wafer such that a plurality of processing marks is formed, an imaging step of stopping the laser oscillator, and imaging the processing marks formed at the wafer, and an aberration correction step of correcting aberration of the condenser by comparing the desired positional relation and a positional relation among the imaged processing marks, and adjusting the spatial light modulator such that the positional relation among the processing marks conforms to the desired positional relation.

The invention discloses a laser frequency stabilization system based on Faraday anomalous dispersion atomic filtering, which is used for carrying out frequency stabilization on phase modulation multi-sideband laser, and comprises a frequency doubling laser unit which is configured to comprise a fundamental frequency seed light source, an electro-optical modulator, a fundamental frequency amplifier and a frequency doubling crystal; the light splitting module unit is configured to split the frequency doubling light into a main output light path and a monitoring light path; the atomic optical rotation filter is located on the monitoring light path and is configured to maintain the purity of the frequency-stabilized laser spectrum through purification treatment under the control of the axial magnetic field and the temperature; the frequency stabilization unit is configured to be a frequency stabilization light path and a servo system, and the frequency stabilization light path is used for obtaining laser frequency information and generating an error signal; the servo system is used for controlling the frequency of the fundamental frequency seed light source according to the error signal feedback. According to the laser frequency stabilization system provided by the invention, the spectrum purification and frequency stabilization precision can be improved, so that high-frequency stability locking is realized.

The invention discloses a high-power picosecond pulse train laser with programmable sub-pulse energy and a method, and relates to the related technical field of lasers, the high-power picosecond pulse train laser comprises a mode-locked fiber laser, an acousto-optic modulator and a solid amplification chain which are sequentially arranged along an optical transmission path; the mode-locked fiber laser generates a mode-locked picosecond pulse sequence; the acousto-optic modulator performs pulse selection and pulse string grouping on the mode-locked picosecond pulse sequence, and performs pre-programming shaping on sub-pulse energy in a pulse string according to set intensity distribution to generate a pre-shaped pulse string; the solid amplification chain comprises at least one stage of solid amplifier, and the solid amplifier comprises a dichroscope, a laser gain crystal, a coupling optical assembly and an LD pumping source; and the dichroscope is used for focusing the pre-shaped pulse string amplified at the previous stage and the LD pump light transmitted by the coupling optical assembly into the laser gain crystal. Independent programmable regulation and control of the energy of each sub-pulse in the pulse string are realized, and the energy distribution of each sub-pulse in the pulse string can be flexibly adjusted.

The present invention discloses a multi-component gas concentration detection system, which relates to the field of gas concentration detection, and comprises: a light source, which is used for emitting detection light covering the absorption wave band of a target gas; the light splitting assembly is used for dispersing the detection light and at least splitting the detection light into a first light beam and a second light beam; the air chamber is provided with an optical signal detection module and an acoustic signal detection module; the first light modulator is used for carrying out wavelength selection and modulation on the second light beam; wherein the first light beam is received by the light signal detection module to form an absorption spectrum detection light path; the second light beam is absorbed by the gas to be detected and then excites a sound wave signal through a photoacoustic effect, and the sound wave signal is received by the sound signal detection module to form a photoacoustic spectrum detection light path. By adopting the scheme, synchronous detection of multi-component gas, compactness of a detection structure and high-sensitivity detection of low-concentration gas can be considered.

An interface for an optical modulator and the optical modulator are described. The interface includes first and second differential line pairs. The first differential line pair has a first negative line and a first positive line arranged on opposing sides of a first waveguide. The first negative line is on a distal side of the first waveguide relative to a second waveguide. The first positive line is on a proximal side of the first waveguide relative to the second waveguide. The second differential line pair has a second negative line and a second positive line arranged on opposing sides of the second waveguide. The second negative line is on a distal side of the second waveguide relative to the first waveguide. The second positive line is on a proximal side of the second waveguide relative to the first waveguide. The first and second waveguides each include lithium niobate and / or lithium tantalate.

The invention provides an electro-optical modulator and a modulation method thereof, the electro-optical modulator comprises a substrate, a buried oxide layer and a lithium niobate waveguide layer are sequentially stacked on the substrate, and the lithium niobate waveguide layer comprises a first optical waveguide and a second optical waveguide; the electrode layer comprises a composite traveling wave electrode and a direct-current electrode, and the direct-current electrode is arranged on one side, in the signal transmission direction, of the composite traveling wave electrode; wherein the composite traveling wave electrode comprises a metal electrode and a polymer electrode, the metal electrode is embedded into the buried oxide layer, the polymer electrode is arranged on the surface of the buried oxide layer, and the composite traveling wave electrode is arranged between the first optical waveguide and the second optical waveguide and arranged on the side faces of the first optical waveguide and the second optical waveguide respectively; wherein the direct current electrode is arranged between the first optical waveguide and the second optical waveguide. The electro-optical modulator is high in electro-optical conversion efficiency, the plasma effect caused by light field coupling is effectively avoided, and the light loss of the device is remarkably reduced.

The invention relates to the technical field of liquid crystal devices, and particularly discloses a normally-on flexible liquid crystal dimming film and a preparation method thereof. The structure of the normally-on flexible liquid crystal dimming film sequentially comprises a first flexible transparent substrate, a first vertical alignment layer, a dye liquid crystal layer, a second vertical alignment layer and a second flexible transparent substrate from top to bottom, wherein the materials of the first vertical alignment layer and the second vertical alignment layer are selected from side chain type transparent polyimide materials; the dye liquid crystal layer comprises black dichroic dye and negative phase liquid crystal. By accurately controlling the orientation arrangement of liquid crystal molecules, a high-precision pretilt angle is realized, the light modulation amplitude in a visible light broadband range reaches 45% or above, and the photoelectric property is equivalent to that of a normally dark (forward) mode liquid crystal dimming film.

The invention relates to the field of image recognition, discloses an image recognition method and an image recognition system, and systematically solves the core pain point of traditional document recognition through optical-topology fusion processing and a dynamic resource allocation mechanism. The image recognition method is composed of an acquisition module, a grid module, a phase module, a setting module and a distribution module, pixel brightness is calculated and coded based on document RGB data, and a two-dimensional coding matrix is generated; constructing a geometric correction grid, forming a nonlinear constraint field, and enhancing the anti-deformation capability of the image; generating spiral phase light waves in the constraint field by using a spatial light modulator, and generating a time-varying phase map; determining a local topology index by detecting the number of phase jump times; and extracting the closed boundary region as a character block, and generating an analysis result file. The system breaks through traditional limitation, improves image geometric correction precision, feature extraction sensitivity and boundary judgment accuracy, efficiently completes document analysis, and is suitable for scenes such as document digitization and information retrieval.

The invention relates to the technical field of laser light source measurement, and discloses a wide-range narrow-linewidth laser wavelength and linewidth measurement system, which can be flexibly matched with the center frequency of laser to be measured through the arrangement of a tunable laser, breaks through the strict limitation of the existing beat frequency method on the center frequency, effectively expands the measurement range, and improves the measurement accuracy. By combining the synergistic effect of the absorption cell and the locking loop, the system stability is improved, the measurement precision of narrow linewidth laser is guaranteed, the integration time can be flexibly adapted without tedious adjustment of a delay optical path or change of parameters of acquisition equipment through the cooperation of the optical modulator and the delay optical fiber, the problem of inconsistent measurement resolution under different integration time is avoided, and the measurement accuracy is improved. And the accuracy of short-time measurement is obviously improved. The system integrates wavelength and line width measurement functions, can measure line width, center wavelength and long-time frequency stability of to-be-measured laser, is reasonable in structural design, retains the advantage of high precision of a beat frequency method, overcomes the defects that an existing method is narrow in measurement range and inconvenient to adjust integral time, and improves the measurement accuracy of the to-be-measured laser. And the measurement requirements of wide-range and narrow-linewidth laser are met.

This invention relates to a Bragg light generation system and method suitable for Bragg-type atomic interferometers. The system includes: a laser for generating a first laser beam with a frequency in a preset atomic absorption peak band; an optical circulator for propagating the first laser beam to a cascaded acousto-optic modulator and receiving two third laser beams returned from the cascaded acousto-optic modulator; a cascaded acousto-optic modulator for diffracting the first laser beam into two second laser beams with opposite propagation directions through Bragg diffraction of two acousto-optic crystals; an optical assembly for performing secondary diffraction on the two second laser beams and reflecting the two mutually perpendicular second laser beams to the cascaded acousto-optic modulator; and an output module for splitting and sampling the two third laser beams and modulating the sampled third laser beams into Bragg laser beams in the target frequency band. This invention reduces the path separation of the two Bragg laser beams by using a quasi-common optical path, thereby reducing phase noise and improving measurement accuracy.

The embodiment of the present disclosure provides an optical transceiver and a manufacturing method thereof. The manufacturing method comprises the following steps: providing a substrate, wherein the substrate comprises a substrate, a buried oxygen layer and a lithium niobate layer which are sequentially stacked; the substrate comprises a light modulation area and a light detection area; etching the lithium niobate layer located in the light modulation area to form a thin film lithium niobate waveguide; removing the lithium niobate layer and part of the buried oxygen layer located in the light detection area to form a groove; the bottom of the groove exposes the substrate; forming a light absorption layer in the groove; wherein the thin film lithium niobate waveguide is used for modulating an optical signal and outputting the modulated optical signal; and the light absorption layer is used for detecting the modulated optical signal and converting the modulated optical signal into an electrical signal.

The invention discloses a near-infrared dichroic dye, a liquid crystal composition and application of the near-infrared dichroic dye and the liquid crystal composition. The structural general formula of the disclosed dichroic dye is as shown in formula I in the specification. According to the invention, a hydrogenated quinoline ring, a hydrogenated benzopyran ring and a hydrogenated naphthalene ring are introduced into a molecular skeleton, so that the novel near-infrared dichroic dye with high light stability, high solubility, high order parameter and high light modulation capability is obtained. Compared with the near-infrared dichroic dye disclosed in the prior art, the absorption band is further subjected to red shift, and the light modulation capability is remarkably improved; ordering parameters are greatly improved, and the application bottleneck is solved.

The invention discloses a femtosecond pulse laser modulation-based GaN-based micro light-emitting diode test system, which comprises a femtosecond pulse laser excitation module, a first detection light path, a to-be-tested GaN-based micro light-emitting diode, a photovoltage detection and bias control module, a photoluminescence detection module and a control module, the control module is configured to control the excitation power and the external bias voltage of the femtosecond pulse laser excitation module, and synchronously collect a photoluminescence spectrum signal and a photovoltage signal; according to the excitation power, the external bias voltage, the photoluminescence spectrum signal and the photovoltage signal, the competition relation between carrier drift extraction and local radiation recombination under different bias electric field conditions is obtained, and therefore an experimental basis is provided for structural design and working bias optimization of the GaN-based micro light-emitting diode device to be tested.

A holographic near-eye display device with multi-angle simultaneous illumination comprises a light source module, a spatial light modulator, a beam splitter, an eyepiece, and a master controller. The light source module emits parallel light at different angles and simultaneously illuminates and covers effective working area of spatial light modulator which, loaded with a hologram, modulates incident parallel light at different angles to form diffracted parallel light at different angles, that is, virtual images at different viewing angles. Parallel light at different angles illuminates spatial light modulator. After modulated and diffracted by calculated hologram on spatial light modulator, the diffracted image light is converged by second lens to form different viewpoints for human eye to view. In multi-angle simultaneous illumination, additional time-sharing control of illumination unit is not needed. When size and position of human eye pupil change, clear virtual image is always seen, achieving expanding the eyebox.

The invention discloses a femtosecond optical comb large-size precision absolute distance measurement system in a complex environment. Comprising a source module, a beam splitter, a third dichroic mirror, a fundamental frequency femtosecond optical comb reference detector, a frequency doubling femtosecond optical comb reference detector, a fourth dichroic mirror, a frequency doubling femtosecond optical comb measurement detector, a fundamental frequency femtosecond optical comb measurement detector, a phase discriminator, a ranging zero point mirror and a corner reflector. The source module comprises an atomic clock, a femtosecond optical comb, an optical fiber beam splitter, a signal generator, an electro-optical modulator, a lens, a frequency multiplication module, a first collimation beam expander, a second collimation beam expander, a first dichroic mirror and a second dichroic mirror. According to the scheme, the defects that in the prior art, the measurement range is insufficient, complex industrial sites are difficult to adapt, and the real-time performance is poor are overcome, and a new way is provided for breaking through the technical bottleneck of large-range, high-precision, dead-zone-free, rapid and real-time measurement in a complex environment; and a technical support is provided for engineering application of a femtosecond optical comb precision distance measurement technology and development of a subsequent measurement prototype.

The invention relates to the technical field of optical imaging, and discloses a novel reflective dark field imaging method and system based on Fourier conjugate plane modulation, and the method comprises the steps: controlling a first spatial light modulator to load a dynamic annular illumination pattern, and projecting the dynamic annular illumination pattern to a rear focal plane of an objective lens; light field distribution formed by scattering signal light and annular reflected light is separated on a rear focal plane by using an objective lens; relaying the light field distribution to a conjugate plane where a second spatial light modulator is located through a second relay light path; and controlling the second spatial light modulator to load a dynamic blocking pattern, blocking the annular reflected light and enabling the scattered signal light to pass through, and finally imaging. According to the invention, two electronically synchronous spatial light modulators are adopted to construct a dynamic illumination light field and realize adaptive spatial filtering respectively, so that cooperative matching of an illumination pattern and a blocking pattern is realized, active compensation of optical chromatic aberration is facilitated, the problem of background leakage under wide-spectrum illumination is solved, and the illumination quality is improved. And a high-numerical aperture objective lens lacking a dark field channel is compatible.

A segmented modeling method based on symmetrical segmentation of a travelling-wave electro-optic modulator, comprising steps: performing modeling simulation on electrical properties of an electro-optic modulation material of a silicon photonic modulator, and extracting electrical parameter data; performing optical simulation on a laser waveguide formed by the preprocessed electro-optic modulation material, and extracting optical waveguide parameter data; performing modeling simulation on an unloaded traveling-wave electrode, and extracting transmission line parameter data; performing small signal modeling analysis and calculation, and performing step-by-step segmentation processing on a medium-loaded traveling-wave electrode in a symmetrical segmentation manner, and performing data analysis and extraction on a simulation result to obtain a parameter result of system design; and the like. The problems of large amount of calculation, low speed and low efficiency can be solved.

The application provides a Y-shaped thin film lithium niobate electro-optical modulator and a manufacturing method. A lithium niobate layer on an electro-optical modulator chip is etched into a corresponding curved waveguide structure, and two curved waveguide structures are symmetrically arranged on both sides of the Y-shaped waveguide structure, so that the heights of two light paths are consistent. The curved waveguide structure reduces the space size required by the waveguide while ensuring the waveguide length. For the waveguide with the same length, a chip with a smaller length can be used for mounting. The signal electrode and the ground electrode are arranged on both sides of each straight waveguide in the curved waveguide structure, the optical signal in the waveguide is modulated, and the modulation requirement of the electro-optical modulator is realized.

The optical module provided by the invention comprises a circuit board, a modulation driving chip, a transimpedance amplification chip and an optical chip. The optical chip comprises an optical modulation unit, an optical demodulation unit, a first optical switch assembly and a second optical switch assembly. According to the invention, the golden finger is directly and electrically connected with the modulation driving chip and the transimpedance amplification chip. The first optical switch assembly is located between the optical modulation unit and the optical chip optical port. The second optical switch assembly is located between the optical demodulation unit and the optical port of the optical chip. By changing the on-off state of the first optical switch assembly, the output path of the optical signal in the first optical switch assembly can be regulated and controlled. By changing the on-off state of the second optical switch assembly, the optical signal input path of the second optical switch assembly can be regulated and controlled. On the basis, the optical module can be switched between a normal working mode and a loopback mode by switching the on-off states of the first optical switch assembly and the second optical switch assembly. And in the loopback mode, the optical module reports an electric signal to the upper computer, so that the upper computer performs fault diagnosis.

The present application relates to the technical field of optical communication. Disclosed are an optical chip and a preparation method therefor, and an electronic device. The preparation method comprises: acquiring a substrate, wherein the substrate comprises a first base and a first device layer that are stacked, and the first device layer comprises a detection portion for preparing a photoelectric detector; forming a first waveguide on the substrate, removing the first base, and bonding a second base, wherein the first device layer and the first waveguide are located on the same side of the second base, and the resistivity of the second base is greater than the resistivity of the first base; and forming a first electrode of an electro-optic modulator on the first waveguide, and forming a second electrode of the photoelectric detector on the detection portion. By means of the preparation method and an optical chip obtained thereby, the process compatibility of the optical chip can be enhanced, the loss of optical signals is reduced, the communication bandwidth of the optical chip is increased, and the communication performance of an electronic device is thus improved.

The invention relates to the technical field of computer display, and discloses an intelligent display optimization method and system for a notebook computer, and the method comprises the steps: detecting an environment illumination change signal, an application scene switching signal, a battery electric quantity change signal and a user interaction signal, and triggering a display optimization process; executing a display optimization process, and performing coupling relationship analysis on the backlight PWM modulation frequency, the RGB three-primary-color gain value, the liquid crystal driving voltage amplitude and the display module power consumption value to obtain a display coupling influence matrix; constructing a display system dynamic association model; performing nonlinear power consumption constraint boundary calculation on the current battery charge state value to obtain a display parameter dynamic constraint range; and performing display quality and power consumption balance solution based on the display parameter dynamic constraint range to obtain a display control instruction set, so that real-time dynamic control on display hardware can be realized, and compared with an off-line optimization or periodic adjustment mode in the prior art, the method has better real-time performance and adaptability.

The invention relates to the technical field of optical communication, and discloses an optical chip, a preparation method thereof and electronic equipment. The preparation method comprises the steps that a substrate is obtained, the substrate comprises a first base and a first device layer which are stacked, and the first device layer comprises a detection part used for preparing the photoelectric detector; a first waveguide is formed on the substrate, the first substrate is removed, a second substrate is bonded, the first device layer and the first waveguide are located on the same side of the second substrate, and the resistivity of the second substrate is larger than that of the first substrate; a first electrode of an electro-optical modulator is formed on the first waveguide, and a second electrode of a photodetector is formed on the detection section. According to the preparation method and the obtained optical chip, the process compatibility of the optical chip can be improved, the loss of optical signals is reduced, the communication bandwidth of the optical chip is improved, and the communication performance of electronic equipment is further improved.

The invention relates to the technical field of wafer detection, in particular to a wafer surface defect detection system and method.The system comprises an imaging module, the imaging module comprises at least two sets of imaging channels, each imaging channel comprises an imaging camera for collecting light signals and converting the light signals into image signals, and a light modulation assembly is arranged in each imaging channel; the light modulation assembly performs polarization modulation and light intensity modulation on emergent light reflected or scattered by the surface of the wafer; the polarization control module adjusts the rotation angle of the light modulation assembly in each imaging channel; the signal processing module carries out differential operation on different image signals, light rays emitted by the multiple groups of imaging channels are set with different polarization parameters and light intensity parameters through the light modulation assembly, multiple groups of image signals are obtained, and an imaging image about scattered light of the same detection area is formed. The imaging image comprises an image with the defect signal as weak as possible and an image with the defect signal as strong as possible, and the imaging image with the defect signal enhanced can be obtained through differential operation.

Provided is an optical control element capable of arranging an input portion and an output portion of an optical waveguide on the same side of a substrate in which the optical waveguide is formed, and capable of reducing differences in the configuration of each branch waveguide while minimizing optical path differences between branch waveguides. The optical control element has a substrate (1) having an electro-optic effect, an optical waveguide (2) formed in the substrate, and a control electrode that controls an optical wave propagating in the optical waveguide, characterized in that an input portion (incident light (L1)) and an output portion (emitted light (L2)) of the optical waveguide are formed on the same side of the substrate, the optical waveguide has at least one Mach-Zehnder type optical waveguide portion (MZ) having two branch waveguides (21, 22) branched from one optical waveguide and recombining the two branch waveguides to form one optical waveguide, and the branch waveguides have an even number of return portions (A1, A2).

The invention provides an optical gain and electro-optical modulation integrated device and a preparation method thereof, and relates to the field of photoelectron, the optical gain and electro-optical modulation integrated device comprises a chip platform, and an electro-optical modulator and a gain waveguide which are integrated on the chip platform, and the chip platform is doped with rare earth ions in a region corresponding to the gain waveguide; the electro-optical modulator is used for modulating an input optical signal to obtain a modulated optical signal; and the gain waveguide is used for amplifying the modulated optical signal under the action of the pump light and the rare earth ions to obtain a target optical signal. The electro-optical modulator and the gain waveguide are integrated on the chip platform, cooperative work between the electro-optical modulator and the gain waveguide is achieved through rare earth ions, integrated design is achieved, the defects of discrete devices are overcome, and the design target of an on-chip photonic system can be met.

This application provides a spatial light modulator and a wavelength-selective shape. The spatial light modulator includes a backplane with a built-in driving circuit, a phase adjustment unit, electrodes, and an electrical connection. The phase adjustment unit includes a lower cavity mirror, a cavity layer, and an upper cavity mirror, with the lower cavity mirror located between the cavity layer and the backplane. The electrodes include a first electrode and a second electrode, located in the phase adjustment unit on the side of the lower cavity mirror facing away from the backplane. The electrical connection electrically connects the electrodes and the driving circuit to form a driving electric field between the first and second electrodes, thereby adjusting the refractive index of the phase adjustment unit. This application can achieve low insertion loss, high-efficiency light conversion while increasing the duty cycle.

The utility model provides a laser ablation device which comprises a first laser light source used for emitting treatment laser; the optical splitter is arranged at the output end of the first laser light source and is used for splitting the treatment laser into multiple paths of split laser; wherein the branch lasers are arranged in rows and columns; the optical modulator is arranged at the output end of the optical splitter and is used for performing independent power regulation and control on each branch laser; the optical fiber coupler is arranged at the output end of the optical modulator and is used for coupling the branch lasers into the optical fiber branches of the optical fiber array one by one; the optical fiber array is connected between the optical fiber coupler and the focusing micro-lens array, and each optical fiber branch corresponds to one focusing micro-lens of the focusing micro-lens array; and the focusing microlens array is used for focusing the split laser onto the diseased tissue in space through focusing microlenses for ablation treatment. The technical scheme can be used for ablation treatment of various irregular pathological tissues, and damage to surrounding healthy tissues is avoided.

An anamorphic near-eye display apparatus comprises a spatial light modulator with asymmetric pixels; an input transverse anamorphic lens; and an extraction waveguide that passes input light in a first direction to a lateral anamorphic reflector arranged to reflect the light back through the waveguide. Partially reflective extraction elements are arranged between the rear and front guide surfaces of the waveguide to extract the reflected light towards the pupil of an observer, maintaining the directionality of the fan of light rays from the spatial light modulator and anamorphic imaging system. A thin, transparent and efficient anamorphic display apparatus for Augmented Reality and Virtual Reality displays is provided.