17 results about "Heterodyne interferometer" patented technology

The present application relates to the technical field of ultra-precision measurement, and particularly relates to a heterodyne interferometer for two-dimensional angular displacement measurement and a measurement method, wherein the heterodyne interferometer comprises a dual-frequency laser source for providing a dual-frequency laser beam with orthogonal polarizations, and is characterized in that a depolarization beam splitter prism is arranged on an output light path of the dual-frequency laser source, the dual-frequency laser beam is split into a first dual-frequency beam and a second dual-frequency beam after being incident on the depolarization beam splitter prism, and the two dual-frequency beams enter a plane interference measurement group and a vertical plane interference measurement group respectively; in the present application, the interference light path of each dimension is two axes, thereby avoiding the situation that measurement errors are caused by the decrease in parallelism due to the increase in the number of axes in the multi-axis measurement mode. Meanwhile, the two beams of light of each dimension are measurement light, thereby improving the resolution while suppressing common-mode noise and enhancing the anti-interference ability of the system.

The present disclosure describes systems and methods for laser diagnostics systems (e.g., systems and methods for beam combination in heterodyne interferometers and polarimeters). For instance, a laser beam combiner, including a modulator and a wedge combiner, may be implemented in a heterodyne dispersion interferometer. In some cases, a modulator receives laser light (e.g., the laser light having a combination of a vertical polarization component and a horizontal polarization component) and the modulator shifts a frequency of the laser polarization components relative to the other. A wedge combiner having an index of refraction, and the wedge combiner comprises a mirror surface coating a and transmissive surface coating configured to effectively combine different polarization components of the laser light using transmission and reflection techniques, according to embodiments described herein.

The invention discloses a double-frequency laser heterodyne interference displacement measurement system and method based on electro-optical modulation, and mainly solves the problems that optical aliasing causes nonlinear errors and speed measurement is limited by frequency difference in the existing method. Comprising the following steps: 1) a laser generates fixed wavelength laser with stable frequency; 2) controlling the radio frequency modulation frequency through a signal generator so as to adjust the frequency difference; 3) MZM carrier suppression double-sideband modulation generates a double-sideband optical signal as double-frequency measurement light; 4) establishing a measurement light path, and converting the displacement of the target to be measured into Doppler frequency shift; according to the method, non-linear errors caused by double-optical-frequency orthogonal polarization aliasing are effectively avoided, the measurement accuracy is remarkably improved, and the requirements of different measurement scenes such as linear motion and vibration can be met.

Conformal imaging vibrometer using adaptive optics with scene-based wave front sensing. An extended object is located at the first end of a link, and a reference-free, adaptive optical, conformal imaging vibrometer using scene-based wave front sensing is located at the second end of the link. An aberrated, free space or guided-wave path exists between the ends of the link. The adaptive optical system compensates for path distortions. Using a single interrogation beam, whole-body vibrations of opaque and reflective objects can be probed, as well as transparent and translucent objects, the latter pair employing a Zernike heterodyne interferometer.

An optical heterodyne interference measurement device (1) is provided with a light beam generation unit (10), a beam splitter (21), a mirror (31), a first light detector (41), a linear polarizing plate (42), a second light detector (51), a linear polarizing plate (52), an AD conversion unit (60), and a computer (70). The first light detector (41) receives light output from the linear polarizing plate (42), detects a temporal change in light intensity thereof, and outputs a first detection signal (measurement signal). A second light detector (51) receives the light output from the linear polarizing plate (52), detects a temporal change in the light intensity thereof, and outputs a second detection signal (reference signal). The computer (70) acquires information pertaining to the object to be measured (90) on the basis of a signal obtained by fitting the measurement signals within the interval using a sine function for each interval starting from the timing at which the reference signal has reached the prescribed value. As a result, an optical heterodyne interference measurement device capable of suppressing a decrease in measurement accuracy is achieved.

A method for assembling and adjusting a Doppler asymmetric spatial heterodyne interferometer belongs to the field of interference spectroscopy technology. To address the problem of relatively large overall assembly errors in existing Doppler asymmetric spatial heterodyne interferometers, the method includes parallel assembly and calibration of the front lens, rear lens, and collimating lens, using a centering instrument to detect the lens assembly and adjustment status, and using a reference reflector to align the folding mirror. After completion, the entire system is assembled and calibrated on a load mounting plate with the folding mirror assembly, beam splitter, filter, interference module, and camera. The folding mirror assembly is fine-tuned to ensure that the signal light enters the optical path in a collimated manner. The collimating lens reflector is then adjusted to ensure that the calibration light enters the optical path in parallel. The camera position is then adjusted to obtain clear imaging. Using a system-integrated assembly and calibration method, the front lens, rear lens, and collimating lens can be assembled and calibrated in parallel, improving assembly and adjustment efficiency. After completion, the entire system is assembled and calibrated with the remaining components. The integrated optical path design ensures that the optical axes of each component are not deviated, reducing the impact of assembly errors and thus obtaining high-quality interference fringes.

The present application belongs to the technical field of laser interference measurement, and provides a wide-range light-combining type fiber array three-degree-of-freedom heterodyne interference device and method, which comprises a double-frequency laser, a wide-range light-combining type heterodyne interferometer, a low-noise photoelectric conversion unit, a signal output unit and an upper computer. The present application combines two beams of light with different frequencies and mutually orthogonal polarization directions into double-frequency orthogonal polarization light through a first polarization splitting device, and forms a wide-range light-combining heterodyne interference light field in the fiber array receiving plane through a wide-range interference light-combining unit, so that the fiber array can perform multi-point receiving in the same interference light field. The present application is adapted to the power of the double-frequency light source, the collimating output conditions, the light splitting ratio, the polarization plate setting and the photoelectric conversion unit according to the characteristics of low-coupling receiving of the fiber array, which is conducive to improving the signal-to-noise ratio and stability of the heterodyne signals of each channel under weak coupling conditions.

A three-degree-of-freedom heterodyne interferometer device with angle information recovery and a method thereof belong to the technical field of laser interferometry. The device comprises a heterodyne light source, a heterodyne interference mirror group, a wavefront control target mirror, an angle information recovery optical path, an optoelectronic conversion unit and an electronic signal processing unit. The heterodyne light source outputs two beams of light with different frequencies, and the beams are divided into measurement light and reference light by the interference mirror group; the wavefront control target mirror is deflected with the measured object to ensure the effectiveness of the light beam interference under a large angle; the angle information recovery optical path converts the change of the optical axis position of the light beam into the difference in the focal plane phase distribution, and then the difference is sampled by a fiber array. The optoelectronic conversion unit completes the conversion of the optoelectronic signal, the rear-end processing unit demodulates the phase, and the displacement, pitch angle and yaw angle of the measured object are calculated. The present application solves the problem that the angle information is difficult to extract under a large angle in the existing scheme, expands the angle measurement range, and the device structure is compact and has high integration, and three-degree-of-freedom synchronous high-precision measurement can be realized.

This invention discloses a device and method for testing the dynamic performance of a pendulum based on a laser heterodyne interferometer. The pendulum driving module of this invention applies a dynamic acceleration signal with adjustable amplitude and frequency to the clamping fixture and the pendulum under test via piezoelectric ceramics. Then, the dynamic displacement response of the clamping fixture and the pendulum under test is simultaneously detected through the heterodyne interferometry optical path. Next, the theoretical displacement signal of the pendulum under test driven by the piezoelectric ceramics and the actual displacement signals of the clamping fixture and the pendulum under test are obtained through a signal acquisition system. Finally, signal processing and data comparison are performed by a terminal computer to obtain the dynamic response characteristics of the pendulum under test under applied excitation within and outside the bandwidth and range. The device of this invention is simple and reliable, has a wide measurement range, extremely high testing accuracy, and strong anti-electromagnetic interference capability.

An interferometer system comprises a light source providing a light beam; an optical system to split the light beam into measurement and reference beams each having different wavelengths, and arranged to guide the measurement beam to a reflective measurement surface, guide the reference beam to a reflective reference surface, and recombine the reflected measurement and reference beams to provide a reflected light beam. A reference detector receives the light beam and provides a reference detector signal and / or a measurement detector receives the reflected light beam and provides a measurement detector signal. A time-of-flight camera receives the reflected light beam and a demodulation signal based on the reference detector signal or the measurement detector signal and provides a camera signal representative of a wavefront difference between the reflected measurement and reference beams demodulated with the demodulation signal. The interferometer system analyzes the wavefront difference on the basis of the camera signal.

A heterodyne interferometer device and method based on wavefront regulation target mirror belong to laser interferometer measurement technical field, the present application solves the problem of insufficient system interference keeping ability under the condition of large angle deflection of target mirror. The device comprises a heterodyne interference mirror group and a wavefront regulation target mirror, the heterodyne interference mirror group separates a bundle of input light beams into a first measurement light beam and a first reference light beam, and separates another bundle of input light beams into a second measurement light beam and a second reference light beam, the wavefront regulation target mirror is installed on the measured object, and the second measurement light beam is reflected to form a return measurement light beam and returns to the heterodyne interference mirror group, when the measured object occurs angle deflection such as pitching or yawing in the movement process, the wavefront regulation target mirror deflects synchronously with the measured object, the return measurement light beam is parallel to the second measurement light beam, the change of the return measurement light beam caused by large angle deflection of the wavefront regulation target mirror is more manifested as the position translation of the optical axis, thereby weakening the angle mismatch and wavefront mismatch.

An interferometer system includes a light source providing a light beam; an optical system for splitting the light beam into a measurement beam and a reference beam, the measurement beam and the reference beam each having a different wavelength, and the optical system being arranged to direct the measurement beam to the reflective measurement surface, direct the reference beam to the reflective reference surface, and recombine the reflective measurement beam and the reflective reference beam to provide a reflective light beam. A reference detector receives the light beam and provides a reference detector signal and / or a measurement detector receives the reflected light beam and provides a measurement detector signal. A time-of-flight camera receives the reflected light beam and a demodulated signal based on the reference detector signal or the measurement detector signal, and provides a camera signal representing a wavefront difference between the reflected measurement beam and the reflected reference beam demodulated with the demodulated signal. The interferometer system analyzes the wavefront difference based on the camera signal.

The invention discloses a vacuum temperature measuring device based on heterodyne interference, which is used for measuring tiny temperature fluctuation in a closed heat insulation space in a non-contact and high-precision manner, and belongs to the technical field of precision measurement. The device comprises a double-frequency heterodyne interferometer, a heat insulation box body, a vacuum cavity for accommodating the heat insulation box body and an aluminum pipe arranged in the heat insulation box body. Double-frequency orthogonal polarized light emitted by an interferometer located outside the vacuum cavity is split into reference light and measuring light through the optical assembly, and the reference light and the measuring light are reflected by the semicircular reflectors at the two ends of the aluminum tube respectively and then are combined for interference. The optical path change caused by thermal expansion and cold contraction of the aluminum pipe is calculated by detecting the phase change of the interference signal, and the temperature change in the heat insulation box body is inversed in combination with the thermal expansion coefficient. The device operates in vacuum, avoids air refractive index interference, has common-mode noise suppression capability, and is suitable for gravitational wave detection and other high-precision temperature measurement scenes.

The invention discloses a pendulous reed dynamic performance testing device and method based on a laser heterodyne interferometer. According to the invention, a pendulous reed driving module applies a dynamic acceleration signal with adjustable amplitude and frequency to a clamping tool and a pendulous reed to be tested through piezoelectric ceramics; then, dynamic displacement responses of the clamping tool and the pendulous reed to be detected are detected at the same time through a heterodyne interference measurement light path; then, obtaining a theoretical displacement signal of the to-be-tested pendulous reed driven by the piezoelectric ceramic and an actual displacement signal of the clamping tool and the to-be-tested pendulous reed through a signal acquisition system; and finally, performing signal processing and data comparison through the terminal computer to obtain dynamic response characteristics of the pendulous reed to be measured under excitation inside and outside the bandwidth and the measuring range. The device disclosed by the invention is simple and reliable, wide in measurement range, extremely high in test precision and strong in anti-electromagnetic interference capability.

The invention discloses an image drift monitoring method for an asymmetric spatial heterodyne interferometer. The method comprises the following steps: constructing a scale pattern; acquiring a first interference image and a second interference image; a signal selection and interpolation step: selecting a plurality of rows of pixels with a scale pattern in the interference image for averaging, and taking the selected pixels as one-dimensional interference image data containing the scale pattern; calculating the characteristic amplitude of the edge of the scale pattern; a scale pattern feature matching step: aligning left and right feature edges of each scale pattern, selecting points with the same amplitude on the left and right edges of each scale pattern, and subtracting horizontal coordinates of the left and right edges under the same amplitude to obtain feature widths W1 and W2 of the scale patterns of the first interference image and the second interference image; comparing the W1 with the W2, and if a difference value between the W1 and the W2 is smaller than a set number of pixels, finishing feature matching; respectively calculating the average values of the horizontal coordinates of the left and right edges of the scale patterns of the first and second interference images after feature matching, wherein the difference between the average values is the horizontal drift distance of the two sampling images.

A heterodyne interferometer system comprising: a first light source providing a first laser beam having a first frequency f1; a second light source providing a second laser beam having a second frequency f2 different from the first frequency; a combiner for polarizing the first laser beam and the second laser beam and for providing an input beam, wherein the polarized first laser beam and the polarized second laser beam are combined; an optical resonator cavity comprising an odd number of at least partially reflecting mirrors arranged in the cavity for reflecting the input beam and circulating it in the cavity, the cavity being adapted to receive the input beam and provide an output beam comprising a first spatial mode having the first frequency f1 and a first polarization, and a second spatial mode having the second frequency f2 and a second polarization different from the first polarization; and a heterodyne interferometer for receiving the output beam.

The application discloses a high-spatial-resolution far-infrared laser interferometer and relates to the technical field of optical interferometers.The high-spatial-resolution far-infrared laser interferometer comprises an optical platform, an optical tower, an optical support and a phase comparator system, the optical platform is fixedly provided with a far-infrared laser light source, a heterodyne interferometer table light path, a single-point frequency mixer and a linear array frequency mixer, the far-infrared laser light source comprises a first far-infrared light source and a second far-infrared light source, the light signal transmitting ends of the first far-infrared light source and the second far-infrared light source are connected with the heterodyne interferometer table light path, the far-infrared laser light emitted by the two far-infrared light sources enters the single-point frequency mixer through the interferometer table light path, the linear array frequency mixer is used as a detection channel frequency mixer and is used for receiving the signals emitted by the two sources, and the application realizes the system layout of multi-position detection under a single detection channel light path and provides a reliable measurement tool for high-spatial-resolution measurement of plasma electron density.