6 results about "Heterodyne interferometer" patented technology

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.

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.

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.

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 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.