223 results about "Wollaston prism" patented technology

An optical system and method configured to detect surface height variations on a mask blank. The optical system comprises a Wollaston prism, optics and first and second detectors. The Wollaston prism splits an incident beam of radiation into a first beam and a second beam. The first beam has a first polarization. The second beam has a second polarization. The optics directs the first and second beams along first and second paths onto first and second illuminated areas on a surface of the mask blank. The first and second illuminated areas reflect or transmit portions of the first and second beams to produce first and second reflected or transmitted beams. The first and second detectors detect the first and second reflected or transmitted beams and produce first and second signals in response to the first and second reflected or transmitted beams. A multiple way coupler may also be used for detecting height variation or other features on a mask blank. Two substantially parallel optical incident radiation beams are transmitted to the mask blank. The multiple way coupler mixes portions of the two beams after they have been reflected or transmitted by two different areas of said mask blank to provide three or more outputs which can be analyzed to provide information on height variation or other features on the mask blank.

The invention relates to a longitudinal magnetic field modulation based three-axis vector atom magnetometer and use method thereof and belongs to the technical field of low-intensity magnetic field detection. The longitudinal magnetic field modulation based three-axis vector atom magnetometer comprises a pumping optical path composed of a No.1 895nm DFB semiconductor laser, a No.1 convex lens, a No.2 convex lens, a No. 1 linear polarizing film and a Gamma/4 slide; a detection optical path composed of a No.2 895nm DFB semiconductor laser, a No.3 convex lens, a No.4 convex lens, a No. 2 linear polarizing film, a Wollaston prism and a balance detector; a three-dimensional magnetic field generating device composed of a No.1 Helmholtz coils, a No.2 Helmholtz coils and a No.3 Helmholtz coils in mutual orthogonality; a heating device; an atomic gas cell; a locking amplifier; and a signal processing system. According to the invention, since longitudinal magnetic field modulation is adopted, technical noise can be reduced in a comparatively large degree. Therefore, extremely high flexibility is achieved. Besides, by utilizing longitudinal magnetic field modulation, inter-axis crosstalk can be reduced, so that magnetic field direction detection becomes more accurate.

The invention relates to a device and a method for testing a nonlinear polarization coefficient and an absorption coefficient at a terahertz band. Laser is split into one path of pump light and one path of probe light by a beam splitter, wherein the probe light is reflected by a reflector group with an adjustable light path, is attenuated by a metal attenuation piece used for adjusting the beam intensity of incident laser and then is reflected to a high resistance silicon chip by the reflector; the pump light split by the beam splitter is reflected to enter a terahertz generation device so as to generate terahertz collimating light and the generated terahertz collimating light is focused on a sample rack at a focus position by a parabolic mirror by virtue of a terahertz polarizing plate, and the terahertz is converted into parallel light which is reflected to the high resistance silicon chip by another parabolic mirror; and the two paths of light are coincided at the high resistance silicon chip, are focused to a detection crystal by the parabolic mirrors, are focused to reach a Wollaston prism by virtue of a 1/4 wave plate after being scattered by using a convex lens and are respectively focused to two photoelectric detectors. A test sample only needs to be arranged at the position of the sample rack or the detection crystal in a light path, namely the nonlinear polarization coefficient and the absorption coefficient of the sample at the terahertz band can be tested.

The invention discloses a method for measuring straightness accuracy and positions thereof based on double frequency interference principle. The measuring method adopts an optical laser outputting g cross-line polarized lights, a common spectroscope, a depolarization dispersion prism, a polarization splitting prism, a Wollaston prism, three analyzers, three photodevices and a measurement reflecting mirror comprising a right-angle prism. The measuring method utilizes the dichroism and polarization property of optical devices to make up a double light path measurement structure based on the heterodyne interference principle; the simultaneous measurement of the straightness accuracy and the positions thereof is realized by measuring the optical path difference of the double path, thus having measuring accuracy of the nanometer straightness accuracy and the positions thereof. The method is mainly applied in the motion displacement measurement of an accurate work table, the straightness accuracy detection of an accurate guide rail and the like belonging to fields such as super-precision processing technology, micro-photo dynamoelectric systems, integrated circuit chip manufacturing technology, etc.

The invention discloses a measuring-compensating device and method for a single-frequency interference linearity error and position thereof. After passing a half-wave plate, the polarization direction of a linearly polarized light beam output by a single-frequency laser is adjusted to 45 degree relative to the paper surface, the modulated linearly polarized light beam is split by a first depolarization splitting prism, a transmitted light beam enters a Wollaston prism type laser single-frequency interferometer, a reflected light beam enters a Michelson type laser single-frequency interferometer, the Wollaston prism type laser single-frequency interferometer serves as a sensing unit to process formed circularly polarized and linearly polarized interference signals, and a linearity error and a position thereof are measured. An error detection and compensation part uses the Michelson type laser single-frequency interferometer as a sensing unit, formed thickness-equivalent interference fringe images are analyzed, swing and pitch angles are measured, a measuring result of the linearity error and the position thereof is compensated according to the measured pitch angle, and the measuring precision of the linearity error and the position thereof is improved.

The invention discloses a device for measuring straightness/coaxiality by applying laser, comprising a first Wollaston prism, a second Wollaston prism and a transitional reflector which are arranged on the measuring light path in sequence, wherein the second Wollaston prism and the first Wollaston prism are positioned on the path of the light which returns after being reflected by the transitional reflector in sequence; the transitional reflector is of plane mirror structure with light path drift adaptation functions in the two mutually vertical directions; and when the incident light enters along the characteristic direction of the transitional reflector, the light which returns after being reflected by the transitional reflector is opposite and parallel to the incident light, and the distance between the light which returns and the incident light is constant. The device ensures the datum to be invariant during measuring the straightness in the horizontal and vertical directions, thus greatly simplifying the adjustment process, shortening the adjustment time and improving the adjustment efficiency.

The invention relates to a double-channel differential polarizing interference imaging spectrometer, which comprises a collimating lens, a Wollaston prism, a Savart polarizer, a linear polarizer, an imaging lens, a plane array detector, a connecting lead and a computer processing system, wherein after light emitted by a target passes through the double-channel differential polarizing interference imaging spectrometer, interference images of a parallel component and a vertical component of the target can be acquired by using the plane array detector; the interference images are input to the computer processing system through the connecting lead, and Fourier transformation and image fusion processing are respectively performed on the two interference images, so that spectral images of the parallel component and the vertical component of the target can be inversed; the difference of the two spectral images is a differential polarizing spectral image of the target; and the ratio of the difference of the two spectral images to the sum of the two spectral images is a linear polarizing spectral image of the target. The spectrometer has the advantages of simple and compact structure, high sampling precision, good stability, no rotary component, and capability of acquiring the differential polarizing spectral image and the linear polarizing spectral image of the target.

The invention discloses a laser straightness and displacement measuring device comprising a dual-frequency laser light source and a normal beam splitter. A first light path retracing reflector is arranged on a measuring light path of the normal beam splitter, a first Wollaston prism, a second Wollaston prism and a benchmark reflector are arranged on a first reflecting light path of the first light path retracing reflector in sequence, the second Wollaston prism, the first Wollaston prism and the first light path retracing reflector are further located in a light path of return light reflected from the benchmark reflector in sequence, a polarizing beam splitter is arranged on a second reflecting light path of the first light path retracing reflector and also located in a reference light path of the normal beam splitter, an analyzer and a photoelectric receiver are arranged in each of two emergent directions of the polarizing beam splitter in sequence, and the two photoelectric receivers are connected to a signal processing unit. The device is capable of completing measurement of straightness and displacement simultaneously, equipment cost is lowered, adjustment process is simplified, testing efficiency is improved, and measurement accuracy is guaranteed.

The invention relates to an atomic magnetometer, particularly relates to an atomic magnetometer under a high excitation magnetic field and a use method thereof, and belongs to the technical field of weak magnetic field detection. The magnetometer comprises a pumping light path which is composed of a 895nm DFB semiconductor laser, a first convex lens, a second convex lens, a first linear polarizer and a lambda/4 wave plate, a detection light path which is composed of a 852nm DFB semiconductor laser, a third convex lens, a fourth convex lens, a second linear polarizer, a Wollaston prism and a balance detector, a Helmholtz coil, a heating device, an atomic air chamber, a lock-in amplifier and a signal processing system. The high-sensitivity atomic magnetometer is realized by using the sag of an MR signal related to excitation magnetic field frequency response under the high excitation magnetic field so as to be applied to the Mx-MR atomic magnetometer for enhancing the sensitivity.

The present invention relates to precise laser meat technology. The measuring mechanism includes double-frequency laser light source; telescope, spectroscope, sleeve, two Wollaston prisms and right-angle prism set successively in the emitting light path of the laser; two polarization analyzers and two photoelectronic receivers in the reflecting light path of the spectroscope and right-angle prism; and one signal processing unit comprising signal amplifier, phase device and data processor. The present invention can eliminate the heat drift and non-linear error caused by the quarter wavelength plate principally. There is a pair of glass wedges mounted on the first Wollaston prism to correct the unsymmetry of the outgoing light relative to the incident light. A rotary signal receiver is adopted.

An optical power splitter for variably splitting an arbitrarily polarized light beam into two or more light beams, is disclosed. An input light beam “A” is received and split it into two output light beams “M” and “N” where the optical power ratio of the two output light beams “M” and “N” is adjusted to a desired ratio by controlling a variable polarization rotator (liquid crystal unit). The polarization components “P” and “S” of the input light beam “A” are separated in a first polarization separator (birefringent displacer), then processed through the variable polarization rotator and a second polarization separator. Finally the processed optical components are recombined in a polarization combiner so as to constitute the desired output light beams “M” and “N” having the desired optical power ratio “R”. The polarization independence of the power split is thus achieved through the stratagem of processing the “P” and “S” polarized components of the input light beam “A” separately—resulting in four light beams “H”, “I”, “L” and “K” which appropriately combined in the polarization combiner yield the output light beams “M” and “N”. A number of embodiments are disclosed with different optical technology in the second polarization separator (Wollaston prism) and the variable polarization rotator (mechanically or electro-mechanically adjusted wave plate), with optical deflection means (for physical compactness) and photo detectors (for optical power monitoring), as well as an embodiment for a four-way split.

The invention discloses a snapshot-type multispectral image multiple-splitting spectral imaging method and a spectral imager. The related spectral imager comprises an objective lens, a collimating mirror, a light-splitting structure, an imaging lens, a filter plate array and a detector, which are mutually parallel and are arranged in sequence. The light-splitting structure is the light-splitting structure based on Wollaston prisms, and comprises a polarizer, four wave plates and four Wollaston prisms, which are arranged in parallel, wherein the four wave plates and four Wollaston prisms are arranged alternatively. According to the snapshot-type multispectral spectral imager, output images thereof can be used directly without follow-up data processing work; and meanwhile, the imager is simple in imaging principle, easy to process and low in cost, and meets requirement for miniature design.

The invention belongs to the field of laser interference measurement, and relates to a quadrature error-free double-path polarization interference and double-Wollaston prism light-splitting type homodyne laser vibration meter. An interference part generates double paths of linear polarization reference light and linear polarization measurement light whose polarization directions are orthogonal and light paths are overlapped through a quarter-wave plate and a polarization-eliminating beam splitter NBS, and in a detection part, reference light and measurement light generate four paths of photoelectric signals with a phase difference of 90 degrees through two Wollaston prisms whose spatial rotation angles around light beams form a specific relation, thereby obtaining an outstanding characteristic of inhibiting a nonlinear error from a light path structure and in principle. The quadrature error-free double-path polarization interference and double-Wollaston prism light-splitting type homodyne laser vibration meter provided by the invention adopts less optical elements to realize four-channel homodyne quadrature laser interference measurement, can effectively solve the problems in an existing technical scheme that polarization leakage and polarization aliasing exist in the light paths, a direct current biased error and a non-quadrature error exist in an output signal, and a nonlinear error of a measurement result is obvious, and thus has remarkable technical advantages in the field of ultra-precise vibration measurement.

The invention discloses an anti-polarization mixing single-path circular polarization interference and single wollaston prism splitting-type homodyne laser vibrometer, which belongs to the field of laser interference measurement. According to an interference part, circular polarization reference lights and circular polarization measurement lights with orthogonal single-path polarization directions and coincident light paths are generated through two quarter wave plates and a non-polarization beam splitter (NBS); according to a detection part, after the reference lights and the measurement lights are split, four paths of photoelectric signals with a phase difference of 90 DEG are generated via the same wollaston prism, and outstanding characteristics for suppressing nonlinear errors can be acquired in aspects of the light path structure and the principle. Four-channel homodyne orthogonal laser interference measurement can be realized, problems that polarization leakage and polarization mixing exist in the light path in the prior technical scheme, an output signal has DC bias errors and non-orthogonal errors, the measurement result has a significant nonlinear error and the like can be effectively solved, and significant technical advantages are provided in the field of ultra precision vibration measurement.

The invention discloses a device and a method for quantitatively analyzing mine environment gas based on a terahertz time-domain spectroscopy system. The device comprises a femtosecond laser, a beam splitter, an optical delay device, a reflecting mirror, a polarizer, a focusing lens, a terahertz emitter, a gas sampling tank, indium tin oxide conductive glass, a zinc telluride electro-optical crystal, a high-power amplifier, a data acquiring and processing system, a quarter-wave plate, a Wollaston prism, a balance detector, a phase-locked amplifier and a computer. The method for quantitatively analyzing the mine environment gas, provided by the invention, comprises the following steps: firstly, establishing a quantitative analysis model of the mine environment gas; secondly, acquiring a terahertz spectrum of gas to be measured through the device provided by the invention; thirdly, determining the content of each component in the mine environment gas by using the established quantitative analysis model. The method has the characteristics of simple structure, operability, high analysis speed, high accuracy and the like. The method provided by the invention can be applied to mixture analysis in other fields.

The present invention relates to an optical scanning device that comprises a light source to emit a beam of light, and a beam splitter to split that beam into several beamlets, and further a first objective lens to direct said beamlets onto a focal plane wherein each of said beamlets impinges on the focal plane spacially separated from each other, wherein the beam splitter comprises several birefringent elements for splitting said beam, preferably a stack of Wollaston prisms.

The invention discloses an imaging method and an imaging spectrometer based on Wollaston prism light splitting. The imaging method based on the Wollaston prism light splitting comprises the following steps: changing a light polarization direction of light by a first polarizing film and carrying out light splitting by a first Wollaston prism to obtain two bundles of the light; changing the light polarization direction of the light by an nth polarizing film and carrying out the light splitting by an nth Wollaston prism to obtain 2n bundles of the light, wherein n is equal to 2 or 3; penetrating through an imaging mirror and compensating an optical path of the 2n bundles of the light by an imaging mirror and imaging on a detector. The imaging spectrometer based on the Wollaston prism light splitting has a coaxial optical path, high stability, high energy utilization rate and good imaging quality, and is applicable to the civil use fields of biomedicines, food rapid detection and the like.

The invention discloses a device for measuring linearity/coaxiality of a two-dimensional transverse dual-frequency Zeeman laser, which comprises a dual-frequency laser source; a telescope, a light splitter, a parallel light splitter, a first two-dimensional Wollaston prism, a second two-dimensional Wollaston prism and a two-dimensional rectangular prism, which are arranged in order on a light path axial line at an emission end of the laser; a second analyzer, a second photoelectric receiver, a third analyzer and a third photoelectric receiver, which are all arranged between the light splitter and the first two-dimensional Wollaston prism; a first analyzer and a first photoelectric receiver both arranged on the reflection light path of the light splitter; and a two-way signal processing unit and a display unit both connected with the three photoelectric receivers. The invention employs the two-dimensional optical elements to replace the conventional one-dimensional optical elements, so as to realize the simultaneous operation of installation, regulation and measurement of the linearity device in horizontal and vertical directions. Therefore, the invention shortens the measurement time, increases the accuracy of installation, and can accurately evaluate the error in linearity/coaxiality of an object to be measured.

The invention discloses a novel polarization interference imaging spectrum system. The multilayer wollaston prism sets are formed by cutting a single wollaston prism set, thereby improving the spectral resolution; an interference image is folded on the different rows on a CCD detector to be collected, thereby overcoming the problem that the CCD can not receive enough size under some conditions; and a slit is used for leading the late image process to be more convenient and simpler, and reducing the stray light.