60 results about "Shack–Hartmann wavefront sensor" patented technology

A beam control system and method: The inventive system includes, an arrangement for receiving a first beam of electromagnetic energy; measuring wavefront aberrations in the first beam with a wavefront sensor; and removing global tilt from the measured wavefront aberrations to provide higher order aberrations for beam control. In the illustrative embodiment, the invention uses a traditional (quad-cell) Shack-Hartmann wavefront sensor to measure wavefront aberrations. An adaptive optics processor electronically removes the global tilt (angular jitter) from this measurement leaving only the higher-order Zernike components. These higher-order aberrations are then applied to wavefront control elements, such as deformable mirrors or spatial light modulators that correct the tracker image and apply a conjugate distortion to the wavefront of the outgoing HEL beam. A track error (angular jitter) component is supplied by a separate fine track sensor. This jitter error is then applied by the adaptive optics processor to a fast steering mirror, which corrects jitter in the tracker image and applies a compensating distortion to the LOS of the HEL beam.

An apparatus for measuring the optical performance characteristics and dimensions of an optical element comprising a low coherence interferometer and a Shack-Hartmann wavefront sensor comprising a light source, a plurality of lenslets, and a sensor array is disclosed. The low coherence interferometer is configured to direct a measurement beam along a central axis of the optical element, and to measure the thickness of the center of the optical element. The light source of the Shack-Hartmann wavefront sensor is configured to emit a waveform directed parallel to and surrounding the measurement beam of the interferometer, through the plurality of lenslets, and to the sensor array. A method for measuring the optical performance characteristics and dimensions of a lens using the apparatus is also disclosed.

The invention discloses a splicing detection device of a circular Hartmann-Shack wave-front sensor based on a minor caliber. The device is characterized by comprising the Hartmann-Shack wave-front sensor, an x-z 2D electric control translation stage, a step motor controller, a computer, a mirror surface to be detected and a data acquisition card; the Hartmann-Shack wave-front sensor is positioned behind the mirror surface to be detected to detect the mirror surface to be detected, and a facula lattice is formed on the Hartmann-Shack wave-front sensor, and the data acquisition card acquires the facula data and transmits the data to the computer for storing; the computer sends an instruction to the step motor controller, and controls the 2D electric control translation stage to move along an x axis and a z axis to scan and detect the mirror surface to be detected; the data acquisition card sequentially acquires the facula data of a wavelet surface of each frame, and then a wave surface to be detected is obtained by a centroid algorithm, a splicing method and a restoration algorithm. The device and the method help improve a formula by ignoring a defocus error in theoretical analysis, eliminate a principle error of a translation error, improve splicing precision and lower computation complexity of solving splicing parameters.

The invention relates to a Hartmann wavefront sensor based on diffraction grating arrays. The sensor comprises an optical matching system, a first Fourier lens, a second Fourier lens, a charge coupled device (CCD) 1 detector, a CCD 2 detector, a spectroscope, a first diffraction grating array and a second diffraction grating array, wherein both the first diffraction grating array and the second diffraction grating array are formed by tightly arranging sub gratings with variable spatial frequency; the first diffraction grating array and the second diffraction grating array are respectively coupled with the first Fourier lens and the second Fourier lens which are attached to the front face or the back face to realize wavefront aperture cutting. The am of adjusting the measurement dynamic range of the Hartmann wavefront sensor under a high precision condition is fulfilled by selecting the diffraction series of a sub grating to control the dynamic range of each sub wavefront aperture focusing facula in the CCD detectors. The problem of irreconcilable conflict between measurement precision and dynamic range of the traditional Hartmann is solved through the Hartmann wavefront sensor; and the Hartmann wavefront sensor is simple in structure, stable in performance and high in adaptability, and is applied to fields, such as optical processing detection, detection on wavefront phase and beam quality of various high-power lasers, and the like.

The invention adopts an optical free-form surface interference detecting device and an optical free-form surface interference detecting method with high precision and a large dynamic range. The optical free-form surface interference detecting device and the optical free-form surface interference detecting method adopt a novel detection structure, utilize a self-adaptive optical component: a deformable mirror (DM) to bear low-order aberration introduced by a free-form surface, monitor deformation wavefront of the DM by means of a Shack-Hartmann wavefront sensor in real time, then utilize a specially-designed optical path structure to transmit a high-order wavefront phase containing surface-shape errors of the free-form surface into an interferometer for detection, thus reduce the detectionpressure of the interferometer, increase the detection dynamic range, ensure the detection precision of high-order aberration, and effectively solve the contradiction that the dynamic range and detection precision in free-form surface detection cannot be achieved simultaneously.

A pulse light beam quality test Hartmann wavefront sensor includes a data collection device capable of receiving and sending synchronous pulse signals, a micro-prism array, a Fourier lens and a photoelectric detector, characterizing that said sensor is composed of a micro-prism array in a variable period two-dimension saw-tooth phase grating structure, a Fourier lens close to it and the photoelectric detector, among which, the micro-prism array has a ring layout structure with a symmetrical single etching center and a double sided grating structure with double-sided etching which can either apply the micro-optical technology or binary optical technology.

Wavefront control techniques are provided for the alignment and performance optimization of optical devices. A Shack-Hartmann wavefront sensor can be used to measure the wavefront distortion and a control system generates feedback error signal to optics inside the device to correct the wavefront. The system can be calibrated with a low-average-power probe laser. An optical element is provided to couple the optical device to a diagnostic / control package in a way that optimizes both the output power of the optical device and the coupling of the probe light into the diagnostics.

An improved ophthalmic instrument including a wavefront sensor that estimates aberrations in reflections of the light formed as a spot image on the retina of the human eye, wherein the wavefront sensor includes at least one subaperture that spatially samples incident light; at least one optical element that focuses each sample to a spot; and an image sensor and image processor for measuring location of the spot. The image sensor captures image data of an pixel subaperture defined around the spot and provides the image data to the image processor. The image processor analyzes the image data to identify a subarray of pixels around a peak in the pixel subaperture, fits a predetermined function to the image data for the subarray of pixels, and derives an estimate for spot location based upon location of the fit of the predetermined function. The ophthalmic instrument may further include a phase compensator, operably coupled to the wavefront sensor, that spatially modulates the phase of incident light to compensate for the aberrations estimated by the wavefront sensor, and a display device that displays a graphical representation of aberrations of the eye based upon the aberrations estimated by the wavefront sensor. The wavefront sensor preferably includes a monolithic lenslet array having a plurality of lenslets each sampling different spatial parts of an incident light beam and focusing the samples to spots.

The invention provides an HWS (Hartmann wavefront sensor) of large dynamic range and a testing method thereof. The structure of the Hartmann wavefront sensor comprises the Hartmann wavefront sensor consisting of a plane wave reference source, a spectroscope, an optical matching system, a wave surface cutting array, a photoelectric detector array and a computer. The Hartmann wavefront sensor is characterized in that a translation platform is also arranged; the photoelectric detector array is fixed on the translation platform. When an aberrated wavefront exceeds the natural dynamic range of the Hartmann wavefront sensor, the movement of the photoelectric detector is controlled by the translation platform; furthermore, the coordinates of mass center of each facula under the initial state and off-focus state of photoactive surface are respectively measured by the photoelectric detector array. According to the off-focus quantity, the period and focal distance of the wave surface cutting array and the displacement quantity of each facula mass center under the off-focus state, the practically owned aperture area of the facula is worked out by a facula belonging sub-aperture recognition algorithm, thus realizing the correct recognition of the facula which exceeds the dynamic range. The Hartmann wavefront sensor of large dynamic range and the testing method thereof effectively improves the measured dynamic range of the traditional Hartmann wavefront sensor.

A system and method of wavefront sensing with a Shack-Hartmann wavefront sensor precisely locates focal spots on a detector array, and determines the location of the lenslet array with respect to the detector array.

There is provided a Shack-Hartmann wavefront sensor which can repetitively perform a measurement at high speed and at short measurement intervals. An illuminating optical system includes a first polarizing optical member to alternately change a polarization condition to a first polarized light or a second polarized light, and illuminates a pulse light from a laser light source part to an ocular fundus of a subject eye through a first polarizing optical member. A light receiving optical system includes a second polarizing optical member to select each polarized light component of the reflected light from the subject eye illuminated according to the polarization condition of the first polarizing optical member, and a first and a second light receiving parts to alternately receive the reflected light of the selected polarized light component. An ophthalmologic measuring apparatus measures the wavefront aberration of the subject eye at short intervals based on the output of the first and the second light receiving parts.

A beam control system and method: The inventive system includes, an arrangement for receiving a first beam of electromagnetic energy; measuring wavefront aberrations in the first beam with a wavefront sensor; and removing global tilt from the measured wavefront aberrations to provide higher order aberrations for beam control. In the illustrative embodiment, the invention uses a traditional (quad-cell) Shack-Hartmann wavefront sensor to measure wavefront aberrations. An adaptive optics processor electronically removes the global tilt (angular jitter) from this measurement leaving only the higher-order Zernike components. These higher-order aberrations are then applied to wavefront control elements, such as deformable mirrors or spatial light modulators that correct the tracker image and apply a conjugate distortion to the wavefront of the outgoing HEL beam. A track error (angular jitter) component is supplied by a separate fine track sensor. This jitter error is then applied by the adaptive optics processor to a fast steering mirror, which corrects jitter in the tracker image and applies a compensating distortion to the LOS of the HEL beam.

A wavefront sensor for measuring a wavefront contains an array of lenslets, a detector array, and a mask having a temporally fixed pattern containing one or more opaque regions that are substantially opaque to light from the wavefront. The mask comprises one or more transmissive regions that are transmissive of light from the wavefront. The mask and the array of lenslets are disposed such that light from the wavefront that is transmitted by the transmissive regions is focused by onto the detector array by the array of lenslets. The mask is adapted to be selectably disposed to any one of a plurality of predetermined positions, wherein a different group of lenslets from the array focuses light from the wavefront onto the detector array depending on which of the plurality of predetermined positions is selected.

A Shack-Hartmann aberrometer for measuring ophthalmic wavefront aberrations having improved dynamic range is described. In one embodiment, a single lenslet only of the wavefront sensor microlens array is optically or physically altered. In another embodiment, a sub-array of immediately adjacent lenslets are altered. In an alternative embodiment, preferably only two non-adjacent lenslets are altered. The alteration provides for identification of the correspondence between spot images of the unknown wavefront formed by the microlens array and the respective lenslets forming the spot images. Once all the spot images are correctly identified, analysis of the incoming wavefront is simplified even when the magnitude of aberration is increased. Thus, the dynamic range and accuracy of the Shack-Hartmann aberrometer are no longer limited by the dimensions and optical properties of the lenslets.

There is provided a Shack-Hartmann wavefront sensor which can repetitively perform a measurement at high speed and at short measurement intervals. An illuminating optical system includes a first polarizing optical member to alternately change a polarization condition to a first polarized light or a second polarized light, and illuminates a pulse light from a laser light source part to an ocular fundus of a subject eye through a first polarizing optical member. A light receiving optical system includes a second polarizing optical member to select each polarized light component of the reflected light from the subject eye illuminated according to the polarization condition of the first polarizing optical member, and a first and a second light receiving parts to alternately receive the reflected light of the selected polarized light component. An ophthalmologic measuring apparatus measures the wavefront aberration of the subject eye at short intervals based on the output of the first and the second light receiving parts.

The invention provides a Hartmann wavefront sensor with an adjustable dynamic range, which consists of an optical matching system, a wavefront division sampling array, a phase modulator and a photoelectric sensor, wherein the optical matching system is used for shrinking an incident light wave so that the size of the incident light wave is less than the size of the wavefront division sampling array and the size of the phase modulator; the phase modulator is arranged between the optical matching system and the wavefront division sampling array, and the caliber of the phase modulator is greaterthan the clear caliber of the optical matching system; the phase modulator adds aberration to the shrunk incident wave, and multiple subareas are formed in the clear caliber of the phase modulator; the subareas and the sub-apertures of the wavefront division sampling array are in one-to-one correspondence in caliber and distribution, and the generated aberration is added to the light wave passingthrough the corresponding sub-aperture; and the wavefront divisions sampling array divides the light wave processed by the phase modulator into multiple sub-beams, and focuses the sub-beams on a target surface of the photoelectric sensor on a focus surface thereof respectively. The Hartmann wavefront sensor with an adjustable dynamic range provided by the invention can be widely applied to wavefront detection in various wavefront great aberrations.

An adaptive optics (AO) optical system is used, to perform accurate alignment between the AO optical system and a subject's eye. An ophthalmologic apparatus according to the present invention includes a positional relationship change unit (e.g., a driving mechanism including a stage for moving the apparatus) configured to change a positional relationship between a subject's eye and an optical system including an aberration measurement unit (e.g., a Shack-Hartmann wavefront sensor) in a first irradiation state of the subject's eye with measurement light, and an irradiation state change unit (e.g., a mechanism for changing an irradiation position) configured to change an irradiation state of the subject's eye with the measurement light from the first irradiation state to a second irradiation state for correcting an aberration of the subject's eye based on a measurement result of the aberration measurement unit.

A Shack-Hartmann wavefront sensor used for an adaptive optical system is suitable for a large-diameter astronomical telescope and comprises a beam-shrinking system and an array lens. The wavefront sensor is characterized in that a beam-dividing system, at least two sets of coupling object lens, at least two sets of CCD detectors and a signal synchronous collecting system are also adopted; after the wavefront information is divided into the wavefront sub-array by the array lens, the beam-dividing system is adopted to divide the wavefront sub-array into at least two sub zones in space and each sub-zone adopts one coupling object lens and one CCD detector for slope detection; the wavefront information of each sub-zone is collected and processed by the signal synchronous collecting system; the obtained slopes are combined and then are recovered to get a complete wavefront phase distribution; at least two sets of detector are adopted to work in parallel so as to reduce the capability requirement to the CCD detectors and effectively overcome the technical difficulties to the CCD detector by the excessive detection sub apertures; the wavefront sensor is insensitive to the optical path overall errors and the tilt errors which can not be easily overcome in the assembling-regulating process of the beam-dividing system, thus adding no the complexity to the sensor system.

An apparatus for measuring the optical performance characteristics and dimensions of an optical element comprising a low coherence interferometer and a Shack-Hartmann wavefront sensor comprising a light source, a plurality of lenslets, and a sensor array is disclosed. The low coherence interferometer is configured to direct a measurement beam along a central axis of the optical element, and to measure the thickness of the center of the optical element. The light source of the Shack-Hartmann wavefront sensor is configured to emit a waveform directed parallel to and surrounding the measurement beam of the interferometer, through the plurality of lenslets, and to the sensor array. A method for measuring the optical performance characteristics and dimensions of a lens using the apparatus is also disclosed.

The invention belongs to the field of optics, and relates to a measurement device and method for transmission wavefronts of a self-focusing lens. The measurement device for the transmission wavefronts of the self-focusing lens comprises a light source, a convergent mirror, a target plate, a collimating mirror, an aperture, a first microscope objective, a second microscope objective, a positioning reference structure, a Shack-Hartmann wavefront sensor and a control computer; the convergent mirror, the target plate, the collimating mirror, the aperture, the first microscope objective, the second microscope objective, the positioning reference structure and the Shack-Hartmann wavefront sensor are successively arranged on an emergent light path of the light source; the Shack-Hartmann wavefront sensor is connected with the control computer; the self-focusing lens to be detected is placed between the first microscope objective and the second microscope objective. The invention provides the measurement device and method for the transmission wavefronts of the self-focusing lens based on the Shack-Hartmann wavefront sensor, which is free from external environmental influences and capable of guaranteeing test precision.

The invention discloses a Shack-Hartmann wave-front sensor absolute calibration device and a Shack-Hartmann wave-front sensor absolute calibration method. The device comprises a converging mirror, a point diffraction plate, a taper hole plate, a high-precision translation table, a collection and control computer, an optical axis positioning template and a monochrometer, wherein the taper hole plate is detachably fixed at the front end of a Shack-Hartmann wave-front sensor to be calibrated; the taper hole center of the taper hole plate is overlapped with the center of a target surface of the Shack-Hartmann wave-front sensor to be calibrated; the collection and control computer is connected with the Shack-Hartmann wave-front sensor to be calibrated and the high-precision translation platform respectively; the converging mirror is arranged on an emergent light path of the monochrometer; the converging mirror, the point diffraction plate and the taper hole plate are positioned on the same optical axis in sequence; the optical axis positioning module is arranged between the point diffraction plate and the taper hole plate. The Shack-Hartmann wave-front sensor absolute calibration device disclosed by the invention has the advantages of realizing absolute calibration of a system error and a physical calibration of the Shack-Hartmann wave-front sensor and improving the system calibration precision.

An apparatus for measuring the optical performance characteristics and dimensions of an optical element comprising a low coherence interferometer and a Shack-Hartmann wavefront sensor comprising a light source, a plurality of lenslets, and a sensor array is disclosed. The low coherence interferometer is configured to direct a measurement beam along a central axis of the optical element, and to measure the thickness of the center of the optical element. The light source of the Shack-Hartmann wavefront sensor is configured to emit a waveform directed parallel to and surrounding the measurement beam of the interferometer, through the plurality of lenslets, and to the sensor array. A method for measuring the optical performance characteristics and dimensions of a lens using the apparatus is also disclosed.

The invention relates to a virtual-aperture complex-amplitude splicing super resolution astronomical telescope system which comprises the components of a Cassegrain astronomical telescope system, a relay optical path system, a pupil plane complex amplitude measurement splicing and image processing system. The Cassegrain astronomical telescope system amplifies a spatial target. The relay optical path system conjugates an exit pupil of the Cassegrain astronomical telescope system to the pupil plane complex amplitude measurement splicing and image processing system at the back end. In the pupil plane complex amplitude measurement splicing and image processing system, a beam splitter mirror splits light into two parts which are respectively emitted to a micro-array lens and a Shack-Hartmann wavefront sensor; the micro-array lens at an exit pupil conjugate plane and an array photon counter realize measurement for a wavefront amplitude together; the Shack-Hartmann wavefront sensor is also arranged at the exist pupile conjugate plane and realizes measurement for a wavefront phase; and finally splicing of multiple complex amplitudes on the virtual aperture is realized through complex amplitude splicing by an image processing computer. The virtual-aperture complex-amplitude splicing super resolution astronomical telescope system has high imaging precision.

A method for eliminating model error of Shack ¿C Hartman wave ¿C front transducer includes calculating error revision matrix according to type and layout of light beam dividing element used by Shack ¿C Hartman wave ¿C front transducer, calculating inverse matrix of error revision matrix, acting error revision inverse matrix on actual measured result of Shack ¿C Hartman wave ¿C front transducer for eliminating model error.

The invention discloses a stratified atmospheric turbulence intensity measurement method based on a total atmospheric coherence length constraint. The method takes subaperture slopes of multiple targets obtained by a large-field-of-view Shack-Hartmann wavefront sensor as the input and the atmospheric total coherence length measured by a total coherence length measurement device is used as a constraint to obtain a stratified atmospheric turbulence intensity parameter. The method can make up for the deficiency of underestimation of the turbulence intensity in the upper atmosphere due to the traditional solar differential image motion monitor plus (S-DIMM+) method, and improve the measurement precision of the stratified atmospheric turbulence intensity parameter.

The invention discloses a real-time controller based on a multi-visual-line related Shack-Hartmann wavefront sensor, particularly relates to a multichannel parallel processing hardware platform architecture which is put forward aiming at the multi-conjugate adaptive optical technique, and is used for detection and reconstruction of wavefront slope in multiple visual line directions within the range of a large field of view. The controller adopts a FPGA and multi-core DSP architecture, and mainly comprises a slope calculation part and a wavefront reconstruction part; as a plurality of subregions need to be divided in each subaperture of the multi-visual-line related Shack-Hartmann wavefront sensor, the platform needs subchannels to be constructed in large channels for slope extraction. The real-time controller is suitable for selecting any amount of subregions from the subaperture of the multi-visual-line related Shack-Hartmann wavefront sensor, therefore the purpose of system upgrading can be achieved by performing repeated structural treatment on the subchannels in the FPGA on the basis of not changing the hardware circuit; besides, the real-time controller has important significance on engineering realization of the multi-conjugate adaptive optical technique.

The invention discloses a Hartmann wavefront reconstruction method matched with a micro-scanning device, and relates to the field of image processing technology. Starting from the basic research of the Shack-Hartmann wavefront detection and reconstruction technology and the micro-scanning technology, a new detection method for adding a micro-scanning device before a microlens array is proposed. The micro-scanning method is used to compensate for the shortcomings of the traditional Shack-Hartmann wavefront sensor for to-be-tested wavefront sampling, and the micro-scanning technology is used toimprove the sampling rate of the tested wavefront, so that a high-resolution spot distribution image is obtained, and the tested wavefront is better recovered.