244 results about "Diffraction order" patented technology

The present disclosure provides an optical component, which may be a metasurface grating, including (a) a substrate; and (b) an array of subwavelength-spaced phase-shifting elements, which are tessellated on the substrate to produce, when illuminated with a polarized incident light, a diffracted light beam with a distinct polarization state for each of a finite number of diffraction orders, wherein the finite number is 2 or more.

The invention relates to a multi-degree-of-freedom motion synchronous measurement system and method based on time-space domain information fusion, which utilize a heterodyne interference phenomenon generated by a double-frequency light source to realize accurate measurement of displacement and angle by analyzing phase change of an interference signal generated by interaction of a measurement grating and a reference grating. The system comprises a double-frequency light source, an optical element, a measuring grating, a reference grating and a photoelectric detector, and the photoelectric detector comprises an array detector and a common photoelectric detector and is used for receiving interference light signals of different diffraction orders. The processing device at least comprises an angle measuring module. The angle module is used for resolving by fusing phase spatial-temporal characteristics and light spot displacement of signals on the array detector; a displacement module can be further included, calculation is carried out through the phase change of heterodyne interference signals on the detector along with time, and finally synchronous measurement of six-degree-of-freedom motion parameters can be achieved. The system has the advantages of being accurate, compact in size, high in light source efficiency and the like, and is suitable for multiple fields of photoetching machine wafer table positioning, ultra-precision machine tool machining and the like.

A metrology method, and associated metrology apparatus, for determining one or more parameters of a periodic target on an object is disclosed. The periodic target is adjacent to a reference mark having a pitch equal to that of the periodic target. The method comprises projecting radiation onto the object such that a first portion of the radiation is incident on the periodic target and a second portion of the radiation is incident on the reference mark. The method further comprises measuring at least one interference pattern formed by contributions to a single diffraction order from both the first and second portions of radiation. The method further comprises determining the one or more parameters in dependence on the at least one interference pattern.

The invention provides a three-dimensional imaging method, an imaging system and a computer readable storage medium. The three-dimensional imaging method comprises the following steps: acquiring a plurality of diffraction order images of a target object through the imaging system; calculating a parallax value between the images of different diffraction orders, and converting the parallax value into a corresponding depth value; constructing a three-dimensional point cloud image of the target object by using the depth value; the imaging system is used for obtaining the multiple diffraction order images of the target object, the multiple diffraction order images can serve as parallax images shot at different positions, the parallax values between the different diffraction order images are used for obtaining the corresponding depth values, and therefore generation of the three-dimensional point cloud image can be completed without using two cameras to shoot two images; the hardware requirement and the arrangement requirement of the imaging system are reduced, and the difficulty of three-dimensional imaging is small.

The invention discloses a color hologram optical reproduction method and system based on conjugate diffraction orders, and relates to the technical field of light modulation.The method comprises the steps that firstly, color holographic data bearing phase and amplitude information of a three-dimensional object is obtained through a computer data transmission interface; loading the color holographic data on the spatial light modulator; then light beams emitted by the laser light sources of various colors are irradiated to the surface of the spatial light modulator after being expanded and collimated, and holograms of corresponding colors are generated; different from the traditional means of selecting the same diffraction order in the prior art, the holograms of all colors are synthesized into the high-fidelity color hologram by aligning the conjugate diffraction orders of the laser light sources of all colors. According to the scheme, the number of complex optical elements can be reduced, the cost and the experiment operation difficulty are reduced, and meanwhile interference fringes and optical loss existing in the dichroscope set can be avoided.

The invention discloses a metasurface based on a nano resonator and a design method for realizing wavelength classification deflection. The metasurface is formed by periodically arranging three unit silicon nano resonators, wherein the widths of middle layers of the unit silicon nano resonators change in a gradient mode along the x axis, and the metasurface is of the sub-wavelength scale. The substrate of the unit resonator is a silver substrate, the surface of the silver substrate is provided with a silicon nanometer strip, and the top of the silicon nanometer strip and the top of the silver substrate are respectively deposited and covered with a layer of silver film; by adjusting the thickness of the middle silicon layer of the resonator, the working wavelength of a near-infrared band can be regulated and controlled, normal incident y polarized light with a specific wavelength is deflected to a diffraction order, light with other wavelengths is vertically reflected, and meanwhile, a phase modulation function is achieved. The device has the remarkable advantages of simple structure and convenience in preparation, has the advantages of high throughput and large-area preparation, and has important application prospects in new technologies such as optical imaging, spectrum detection and machine vision.

A diffraction grating includes a plurality of diffraction features and a plurality of grooves. Each groove of the plurality of grooves is adjacent to at least one diffraction feature of the plurality of diffraction features. One or more apodization features include apodization by a varied ratio of the filled region of one or more diffractive gratings to the total period, typically known as the grating fill factor to a gradually alter one or more edges of the plurality if diffraction features of at least one optical element of a waveguide. The one or more apodization features reduce a diffraction efficiency of at least one diffraction order of the diffraction grating.

A programmable 3D light beam shaping device based on the beamlet printing technology comprises a laser source, the laser source emits initial laser, the polarization state of the initial laser is adjusted through a rotatable half-wave plate, and then the initial laser is separated into an s component light beam and a p component light beam through a first polarization splitting prism, the p-component light beam enters a Dammann grating after being expanded, and a diffracted light beam containing a plurality of diffraction orders is generated; the diffracted light beam sequentially passes through a second polarization splitting prism, a quarter-wave plate and a first focusing element and is introduced into focal shift by a multi-stage phase plate array, and the spatial light modulator is used for adjusting the angle and position offset of subgroups of the light beam of the sub-beam array to generate a working light beam; the working light beam returns to the second polarization splitting prism through the original light path and enters the working area through the second focusing element, and a three-dimensional light field is generated; according to the device, the three-dimensional irradiance distribution in a machining area can be accurately controlled, so that multi-layer and depth-adjustable energy deposition is realized, and the machining quality, efficiency and consistency are remarkably improved.

The application provides a laser processing brittle material multi-focus cracking device, which comprises a laser, a beam expanding and collimating system, a diffraction element and a beam focusing system; the laser is used for emitting laser; the beam expanding and collimating system is arranged on a light path of laser transmission, and is used for expanding the laser emitted by the laser; the diffraction element is used for making the laser generate multiple diffraction orders; and the beam focusing system is used for focusing the laser, so that the laser forms multiple focuses in the longitudinal position of the brittle material. The application controls the focusing sequence of the focuses in the material by introducing a specific diffraction optical element and adding a high-frequency oscillation filter on the focusing light path, and multiple modified layers are formed in the longitudinal position of the material through one-time scanning of the laser, so that the cold cracking efficiency is greatly improved.

The invention discloses a space customization three-dimensional column vector light beam array generation method based on a metasurface, and belongs to the field of micro-nano optics, diffraction optics and structured light field regulation and control. The implementation method comprises the following steps of: independently regulating and controlling left-hand circular polarization and right-hand circular polarization components of incident light based on geometric and propagation phase joint modulation of the metasurface; a metasurface, a phase distribution coding lens factor of a polarization channel, a Dammann vortex grating with opposite basic topological charges and a spiral Dammann zone plate are independently optimized, and left-handed and right-handed circular polarization components generate a three-dimensional vortex beam array with opposite spatial topological charges in a near-field Fresnel domain; the left-handed circular polarization vortex array and the right-handed circular polarization vortex array with opposite topological charges are coherently superposed to form a spatially customized three-dimensional column vector light beam array, and the vector characteristic of each light beam in the array depends on the amplitude ratio, the phase difference and the topological charges of the left-handed circular polarization component and the right-handed circular polarization component on each diffraction order. According to the invention, the regulation dimension of the column vector light beam can be expanded.

The invention discloses an optical chip, a spectrum sensing device and method, a spectrometer and equipment. The optical chip comprises an encoder with a non-periodic diffraction unit, and is used for enabling different light in a light beam to enter different diffraction units in the non-periodic diffraction unit for modulation so as to obtain optical signals in different diffraction directions. Therefore, spectral information corresponding to the light beam can be determined subsequently according to the light signal. In the application, different light in the light beam enters different diffraction units in the non-periodic diffraction units to be modulated to obtain light in different diffraction directions, and every two adjacent light signals in the light signals corresponding to the light are different in phase and phase difference, so that the space separation distance of different wavelengths is relatively large; and a relatively high resolution can be obtained. Meanwhile, along with the increase of the diffraction order, the light of each wavelength in different diffraction directions is not easy to overlap, so that the effective wavelength detection area is relatively large, and the bandwidth is relatively wide. Therefore, the problem of restriction between the resolution and the bandwidth is eliminated.

The polarization diffraction spectrometer comprises a substrate and a plurality of rectangular nano-columns arranged on the substrate, the rectangular nano-columns are periodically stacked or arranged in the height direction to form a periodic superlattice unit, and the substrate layer is made of a nanoscale transparent medium material; according to a grating equation, the optimal diffraction series, the period length and the incident light wavelength of the super grating are selected through experimental simulation, and optimal structural parameters are determined by combining an electromagnetic simulation tool and an optimization algorithm; the heights, the widths and the intervals of the rectangular nanocolumns serve as parameters of a particle swarm optimization algorithm, a fitness function with target diffraction order energy concentration ratio and target order overall diffraction efficiency optimization serving as core indexes is constructed, full-wave optical simulation software is combined, and geometric distribution in periodic units of the rectangular nanocolumns is optimized and adjusted. According to the invention, under the incident condition of 45-degree linearly polarized light, the S polarization component and the P polarization component are respectively concentrated at the preset target diffraction order, and an efficient diffraction light splitting effect is achieved.

The present invention provides an optimization method for a grating structure to reduce position measurement errors, including: establishing an evaluation method for a phase grating structure according to the intensities of signals of different diffraction orders to describe the quality of the structure; then selecting one or more grating structures with better results as the initial grating structure according to this evaluation method; generating corresponding deformed grating structures according to the deformations that may be introduced during the manufacturing process; then comparing the above initial grating structure and the deformed grating structure to give multiple groups of grating arrangement combinations for comparison, and making plates for them to process a marked measurement plate for experiments; then establishing a corresponding relationship between the deformation of the grating structure and the introduced position error based on the comparison measurement results; and finally optimizing the initial grating structure according to this corresponding relationship to obtain an optimized grating structure. The optimized grating structure can offset or alleviate the influence of the deformation introduced during the manufacturing process on the position measurement accuracy and reduce the position measurement error.

An optical metrology system can include an overlay metrology tool for characterizing an overlay target on a sample, where the overlay target includes first direction periodic features in a first set of layers of the sample and second direction periodic features in a second set of layers of the sample. The overlay metrology tool can simultaneously illuminate the overlay target using first and second illumination beams and can further generate an image of the overlay target based on diffraction of the first and second illumination beams through the overlay target, where diffraction orders of the first illumination beam contribute to resolved image formation of only the first direction periodic features, and where diffraction orders of the second illumination beam contribute to resolved image formation of only the second direction periodic features. The system can further generate overlay measurements along first and second measurement directions based on the image.

A diffractive optical waveguide and a display device having the same are disclosed. The diffractive optical waveguide includes a grating structure formed on a surface of a waveguide substrate, the grating structure including a plurality of grating lines arranged in a plane, the grating lines each extending along a first direction in the plane and arranged at a predetermined interval in a second direction perpendicular to the first direction; at least one sidewall of each grating line having a periodic structure along the first direction; and the grating structure configured to diffract light incident thereon at a non-zero angle with respect to the plane out of the plane through a predetermined diffraction order. The grating structure employed in the above-described diffractive optical waveguide can be used to adjust the diffraction efficiency at different angles and / or different diffraction orders, thereby providing a new effective and flexible means for improving the angular uniformity and / or the out-coupling efficiency of the diffractive optical waveguide.

An optical alignment system including an illumination system configured to condition a radiation beam to form a first off-axis monopole, a marker configured to diffract the first off-axis monopole to form zeroth and first diffraction orders, a projection system configured to collect the zeroth and first diffraction orders and form an image of the marker, and a sensor apparatus configured to detect the image of the marker.

An eyewear device includes a lightguide having a world-side surface and an eye-side surface, a display oriented to emit light toward the lightguide, and a beam steering element that includes a first polarization grating positioned along an optical path between the display. The first polarization grating diffracts light emitted by the display into orders having different polarizations and the orders are selectively conveyed into different eyeboxes. The eyewear device also includes a frame that supports the lightguide, the display, and the first polarization grating. In some cases, the different polarizations include a right circular polarization or a left circular polarization and the beam steering element includes a polarization dependent filter that filters right circularly polarized light in a first state and left circularly polarized light in a second state.

A diffractive multifocal lens is disclosed, comprising an optical element having at least one diffractive surface, the surface profile comprising a plurality of annular concentric zones. The optical thickness of the surface profile changes monotonically with radius within each zone, while a distinct step in optical thickness at the junction between adjacent zones defines a step height. The step heights for respective zones may differ from one zone to another periodically so as to tailor diffraction order efficiencies of the optical element. In one example of a trifocal lens, step heights alternate between two values, the even-numbered step heights being lower than the odd-numbered step heights. By plotting a topographical representation of the diffraction efficiencies resulting from such a surface profile, step heights may be optimized to direct a desired level of light power into the diffraction orders corresponding to near, intermediate, and distance vision, thereby optimizing the lens performance.

The invention discloses a field-of-view expansion type sun sensor based on diffraction order multiplexing, which comprises a dual-band band-pass optical filter, a diffraction type light introducer and a color CMOS (Complementary Metal Oxide Semiconductor) image sensor, and is characterized in that the dual-band band-pass optical filter is used for selecting two pieces of separated sunlight with a preset wave band for incidence; the diffractive light introducer diffracts transmitted sunlight into multi-level light beams; the color CMOS image sensor is used for acquiring a diffraction spot image containing spectral information of two wave bands; the current effective diffraction order can be determined through the mass center positions of the light spots in the two corresponding wave band channels and the mapping relation between the light spot distance and the diffraction order, and finally the sun vector is obtained through calculation in combination with a diffraction optical model. According to the invention, the inherent contradiction that a large view field and high precision of a traditional digital sun sensor cannot be considered is solved, the problem of level ambiguity in a diffraction extended view field is effectively overcome, the lightweight design of the sun sensor adapts to the high-density integration requirement, and technical support is provided for spacecraft attitude measurement.

Embodiments of the present disclosure relate to measurement systems and methods of measuring efficiency of optical devices. In one example, the measurement systems include a light source, a mirror, an illumination source, and a sensor. The light source provides a light beam to the optical device to be diffracted into diffraction beams having diffraction orders. The diffractions beams form a diffraction pattern. The method includes positioning the optical device in the measurement system and directing the diffraction beams to the sensor. The sensor is operable to measure the efficiency of the optical device by measuring the diffraction pattern.

This document describes systems and techniques directed at mitigating display diffraction flares for under-display sensing. In aspects, an equation may be derived that models the effects of a display in producing a diffraction phenomenon at an image plane of a sensing region for an under-display light-sensing device. The equation may be used to determine an arrangement (e.g., an optimized arrangement) of components (e.g., sub-pixels) within the display that minimizes a diffraction efficiency for at least one diffraction order and, thereby, mitigates an intensity and / or a prevalence of optical artifacts in light-sensing data. In implementations, an image intensity point-spread-function is utilized to calculate diffraction efficiencies for respective diffraction orders (e.g., the lowest diffraction orders, the diffraction orders with the greatest brightness).

An optical metrology system may include illumination optics to direct pairs of mutually-coherent illumination beams to an optical metrology target, where the optical metrology target includes sets of periodic features having features with periodicity along different measurement directions. A pair of mutually-coherent illumination beams has opposing azimuth incidence angles and a common altitude incidence angle, where the azimuth incidence angles are rotated with respect to the measurement directions. The system may further generate dark-field images of the optical metrology target, where an image of a periodic structures is formed as a sinusoidal interference pattern generated by interference of a single non-zero diffraction order of light from each of the illumination beams within a pair of mutually-coherent illumination beams. A controller may generate optical metrology measurements along the measurement directions based on the images. The system may mitigate an impact of zero-order side lobes through blocking or image filtering.

The invention provides a plasma photoetching imaging method and device and a computer readable medium, and the method comprises the steps: obtaining the axial direction of an imaging structure of plasma photoetching imaging, the imaging structure comprises a plurality of mask patterns which change periodically in one dimension, and irradiating the plurality of mask patterns in one-dimensional periodical change by light in a target direction forming a preset off-axis angle with the axial direction to obtain plasma photoetching images corresponding to the plurality of mask patterns in one-dimensional periodical change. That is to say, the diffraction order of the light can be influenced by irradiating the mask pattern in the target direction of the preset off-axis angle, so that the transmission efficiency of the light in the prohibited period range is improved, the contrast of the light intensity of the mask image in the prohibited period range during imaging is improved, and the imaging quality of the mask image in the prohibited period range is improved. And finally, realizing exposure imaging of the mask pattern in the prohibition period range.

A multi-focal ophthalmic lens using suppressed diffraction orders. A multi-focal ophthalmic lens includes an ophthalmic lens and a diffractive element. The ophthalmic lens has a base curvature corresponding to a base power. The diffractive element produces constructive interference in at least four consecutive diffraction orders corresponding to a range of vision between near vision and distance vision. The constructive interference produces a near focus point, a distance focus point, and an intermediate focus point between the near focus point and the distance focus point corresponding to the base power of the ophthalmic lens. The diffraction efficiency of at least one of the diffraction orders is suppressed to less than 10%.

The application provides a liquid crystal grating which can realize three diffraction modes by orthogonal orientation, comprising an upper glass substrate, an upper strip electrode I, an upper strip electrode II, a liquid crystal layer, a lower strip electrode I, a lower strip electrode II and a lower glass substrate. The diffraction mode of the liquid crystal grating is controlled by controlling the driving voltage V1 and V2 applied to the upper strip electrode I and the lower strip electrode I. When the driving voltage V1=0V and V2>0V, the incident light will be diffracted in the y direction through the liquid crystal layer. When the driving voltage V1>0V and V2=0V, the incident light will be diffracted in the x direction through the liquid crystal layer. When the driving voltage V1>0V and V2>0V, the incident light will be diffracted in the x and y directions through the liquid crystal layer. In addition, the diffraction order number and the diffraction efficiency of the liquid crystal grating can be adjusted by changing the size of the driving voltage V1 and V2.

Systems and methods for providing variable spot size and variable focus at a substrate are described. Sets of variable focal length lenses can be added to an alignment system to allow for adjustment of the spot size and focus. A variable focal length lens is a liquid lens that is tunable based on application of voltage across the lens. Toggling the voltage changes the water-oil interface in the liquid lens, which in turn changes the direction of light passing through. For example, turning on the voltage across the lens shifts the light output direction to converging at a focal point. As a result, variable focal length lenses provide adjustment to compensate for the fixed spot size and focus shortcomings of the prior art. Furthermore, variable focal length lenses can also be applied to compensate for spot shift and higher order diffraction orders.

This invention relates to the field of optical detection technology, specifically a multifocal parallel phase extraction and alignment system based on a spatial light modulator, comprising: a wavefront modulation module, a parallel detection module, an information extraction module, a parameter calculation module, and a correction and execution module. The wavefront modulation module loads a phase modulation pattern through a spatial light modulator, generating a complex wavefront containing multiple diffraction orders via the objective lens, forming multiple spatially separated detection focal spots on the sample surface. The parallel detection module receives the reflected light signals from each focal spot in parallel through an array detector. The information extraction module analyzes the signals and extracts the phase offset of each focal spot, constructing a mapping set between position and phase offset. The parameter calculation module calculates the tilt angle and field curvature distribution parameters based on this set. The correction and execution module generates a comprehensive correction signal to drive the objective lens or sample stage to perform multidimensional attitude adjustments. This system achieves multifocal parallel detection and synchronous parameter calculation, improving alignment efficiency and accuracy.

A position measurement encoder device includes a scale including a series of features readable by a read head to determine relative positions of the scale and the read head and diffract light into a plurality of diffraction orders; a readhead comprising a light source for illuminating the scale, and at least a first sensor configured to detect a signal generated at the first sensor by one or more diffraction orders generated by the scale; wherein the read head further comprises a diffraction order encoder that encodes the at least one diffraction order to have a different optical state than the optical state of the at least one other diffraction order.

A system for measuring satellite ghost efficiency of a diffractive lens is provided. The system includes: a light source configured to output a first probe beam; and the light beam fine tuning assembly is arranged between the light source and the diffraction lens and is configured to convert the first detection light beam into a second detection light beam, and the second detection light beam is a non-collimated light beam. The diffractive lens diffracts the second probe beam into a plurality of diffracted beams including a first diffracted beam of a main diffraction order and a second diffracted beam of a satellite ghost diffraction order. The beam fine tuning assembly includes one or more optical lenses and an adjustable optical power. The system also includes a detector configured to generate a beam spot pattern including a first beam spot corresponding to the first diffracted beam and a second beam spot corresponding to the second diffracted beam.

The application provides an alignment device and an alignment method. The alignment device is provided with a first polarization adjustment unit, which comprises a first wave plate and a second wave plate connected in sequence. Positive and negative orders of diffraction with the same diffraction order in diffracted light or scattered light pass through the first wave plate and the second wave plate respectively. The direction of the fast axis of the first wave plate and the direction of the fast axis of the second wave plate form a first included angle, so that the diffracted light or scattered light with any polarization state can form a first light beam with a first polarization direction and a second light beam with a second polarization direction after passing through the first polarization adjustment unit, and the alignment measurement is realized independently of the polarization state. Based on this, the application also provides an alignment device. The alignment device simultaneously processes the fifth light beam and the sixth light beam by using a second polarization adjustment unit, eliminates the phase difference of each detection signal, and reduces the risk of modulation depth reduction.