Method and device for detecting and controlling phase shift based on alternating current small-phase modulation
A technology of phase modulation and phase shift, which is applied in the field of optical testing, can solve problems such as frequency drift and output light intensity changes, and achieve the effect of strong anti-interference ability and avoiding environmental interference sensitivity
Active Publication Date: 2012-08-08
善测(天津)科技有限公司
View PDF0 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
But there are also disadvantages such as frequency drift and output light intensity changes
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0031] In order to solve the problem that the accuracy of the open-loop phase shift is not high, a closed-loop phase shift is proposed. The high-precision real-time detection of step phase shift is the key to realize this technology. AC phase modulation is a relatively mature technology at present, but the phase modulation degree required by this technology is large, such as 2.45, 2.63, etc. This type of phase modulation degree will extremely deteriorate the interference pattern in phase shift interference. The smaller the degree of phase modulation, the smaller the effect on the interference pattern.
[0032] citation[13] In the middle, the degree of phase modulation is z=0.21rad modulation, at this time J 1 (z)=0.1044, by controlling the phase difference near nπ (n is an integer), the phase sensitivity is the highest, the RMS value of the phase shift accuracy is 7.3mrad, and the influence on the fringe contrast is no more than 1%. When using large phase modulation z=2.45ra...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention belongs to an optical testing technology. In order to provide high phase shift precision, improve the signal-to-noise ratio and signal stability in a non-balance interferometer, realize high-precision locked phase shift through a low-precision phase shifter under the closed-loop situation and realize the precision measurement of phase distribution on an optical surface, the invention adopts the following technical scheme: a method for measuring phase shift interference based on alternating current small-phase modulation and phase control comprises the following steps: adopting alaser device driver to drive a laser device to generate laser, enabling the laser to sequentially pass through a focusing lens, a transflective mirror, a beam-expanding and collimating lens, a small transflective mirror and a reference mirror to reach a mirror to be tested, sending signals reflected by the small transflective mirror to a photoelectric detector PD, enabling the signals reflected by the transflective mirror to enter a video camera, and finally sending the signals to a computer for processing; performing sine modulation on the laser device driver according to the signals received by the photoelectric detector PD; and changing the phase difference alpha between the mirror to be tested and the reference mirror to realize stepping phase shift. The method is mainly applied in optical testing.
Description
technical field [0001] The invention belongs to the optical test technology, relates to the manufacture of advanced optical instruments, in particular to a detection and control method and device for phase shift based on AC small phase modulation. Background technique [0002] The invention of phase-shifting interferometry is a major breakthrough in the field of interferometry, enabling phase measurements to achieve unprecedented precision. The phase shift method is divided into time phase shift method and space phase shift method. The space phase shifting method is complex in structure and difficult to install, so the time phase shifting method is often used. The time phase shift method is divided into continuous phase shift and step phase shift. The step phase shift solves the phase by the least square method, but it is sensitive to the phase shift error, and the accuracy is mainly determined by the phase shifter. Phase shift methods include piezoelectric crystal method...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): G01J9/02
Inventor 段发阶张超胡博吕昌荣蒋佳佳
Owner 善测(天津)科技有限公司