CN105157839A - Interferometer collimation status online monitoring method based on zero-crossing delay detection - Google Patents
Interferometer collimation status online monitoring method based on zero-crossing delay detection Download PDFInfo
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- CN105157839A CN105157839A CN201510263851.XA CN201510263851A CN105157839A CN 105157839 A CN105157839 A CN 105157839A CN 201510263851 A CN201510263851 A CN 201510263851A CN 105157839 A CN105157839 A CN 105157839A
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- interferometer
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Abstract
The invention discloses an interferometer collimation status online monitoring method based on zero-crossing delay detection. An interferometer comprises a laser beam expander, a beam splitter, a moving mirror, a fixed mirror and an interference plane. Three ways of laser detectors 6A, 6B and 6C are mounted on the interference plane. Output ends of the laser detectors 6A, 6B and 6C are connected with a programmable FPGA chip. The interferometer collimation status online monitoring method is characterized by comprising the steps of using a high-frequency clock signal of an FPGA for establishing counters CA, CB and CC inside, counting zero-crossing positions of the detected sinusoidal interference signals A, B and C by the three ways of laser detectors 6A, 6B and 6C, and achieving the zero-crossing delay measurement. The invention uses the zero-crossing delay among the interference signals detected by the three ways of laser detectors on the interference plane for detecting the mutual position relationship between the moving mirror and the fixed mirror in the interferometer, is simple in design and high in accuracy, and provides an effective means for quick detection of an imbalanced status of the interferometer.
Description
Technical field
The present invention relates to Michelson interferometer design field, specifically refer to the real-time detection of index glass and horizontal glass plane orthogonal relation de-synchronization state in Michelson interferometer scanning process.
Background technology
Michelson interferometer is a kind of interferometer of dual beam configuration, and it is the optical devices of core the most in Fourier transformation infrared spectrometer system.
The spectral quality of spectrometer and other performance, depend on the alignment precision in interferometer between index glass and horizontal glass to a great extent.Therefore, the soundness of its hardware emphasized by traditional Fourier transformation infrared spectrometer device when designing, and carries out antidetonation process to its structure.So, corresponding spectrometer physical size is general comparatively large, and can only work under laboratory environment condition, the alignment precision in guarantee interferometer between index glass and horizontal glass is better, and relatively stable simultaneously.But along with the application scenario of spectrometer is expanded gradually, from laboratory applications to various varying environment condition, rugged environment even more, may cause no longer keeping vertical positional relationship between index glass and horizontal glass.Sometimes also need high-resolution spectrometer to carry out measure spectrum, the index glass stroke of interferometer wants corresponding to be increased gradually, and index glass, in Long travel scanning process, is difficult to the collimation between moment guarantee index glass and horizontal glass.In view of the above problems, interferometer is being subject under external environmental interference and in Long travel scanning process, is easily causing the position between index glass and horizontal glass that deviation occurs.How to monitor and accurately the collimating status of stellar interferometer needs the key technical problem of solution in the research and development of high-performance interferometer badly.
According to interference theory, interferometer is in scanning process, and laser interference signal will be changing into sinusoidal fluctuation with optical path difference.But due to the reason such as axial dipole field of Installation and Debugging error and index glass motion, index glass plane and horizontal glass plane cannot exact vertical, and the optical path difference on interference plane in laser interference hot spot between zones of different is no longer equal.Now, the zero-acrross ing moment of the laser interference signal that three road laser detectors detect is also no longer identical, therefore, the zero propagation of crossing between laser interference signal can be utilized to carry out on-line monitoring to the collimating status of interferometer.
Summary of the invention
For the problems referred to above, the present invention proposes a kind of interferometer collimating status on-line monitoring method based on crossing zero propagation detection.The interference plane of Michelson interferometer is placed No. three laser detectors are set, Michelson interferometer is when scanning process, laser interferencefringes can make Rapid Variable Design on the laser detector of interference plane Shang No. tri-, by recording the laser interference signal on No. three laser detectors, analyze in conjunction with the high frequency clock signal of the inside of fpga chip able to programme and judging rules and cross zero propagation between three road signals that No. three laser detectors are recorded to, and then the mutual alignment relation judging between index glass and horizontal glass, and determine the angular deviation size of index glass and horizontal glass mutual alignment, realize the on-line monitoring to the collimating status of interferometer.
The technical solution used in the present invention is as follows:
Based on the interferometer collimating status on-line monitoring method crossing zero propagation detection, described interferometer comprises laser beam expander, beam splitter, index glass, horizontal glass and interference plane, described interference plane is provided with No. three laser detectors 6
a, 6
b, 6
c, described laser detector 6
a, 6
b, 6
coutput terminal be connected with fpga chip processor able to programme, it is characterized in that: utilize the high frequency clock signal of FPGA to set up counter C therein
a, C
b, C
c, to three road laser detectors 6
a, 6
b, 6
cthe zero crossing position of sinusoidal interference signal A, B, C of detecting counts, and realizes the measurement of zero propagation, and specifically comprises the following steps:
(1) received by fpga chip disposable plates able to programme and process three road laser detectors 6
a, 6
b, 6
csinusoidal interference signal A, B, C of detecting, and determine the zero crossing S of sinusoidal interference signal A, B, C
a, S
b, S
c;
(2) the high frequency clock signal f in fpga chip processor able to programme is utilized to set up counter C
a, C
b, C
c, counter C
a, C
b, C
cfor recording No. three laser detectors 6
a, 6
b, 6
cthe counter of sinusoidal interference signal A, B, C zero crossing time information detected;
(3) T is established
aBfor laser detector 6
a, 6
bbetween cross zero propagation, T
aCfor laser detector 6
a, 6
cbetween cross zero propagation, in conjunction with high frequency clock signal f control counter C
a, C
b, C
ccounting:
(a) within the single interference cycle, counter C
aat S
aplace starts counting, at next S
aplace stops this time counting and counting from newly next time; Counter C
bat S
aplace starts counting, at next S
bplace stops this time counting and counting from newly next time; Counter C
cat S
aplace starts counting, at next S
cplace stops this time counting and counting from newly next time.
(4), after each interference periods terminates, the result of counter is analyzed:
Zero propagation is crossed on the occasion of, laser detector 6 during (a) supposition sinusoidal interference signal A advanced sinusoidal interference signal B
awith laser detector 6
bbetween to cross the criterion of zero propagation as follows:
1) if C
b>C
a/ 2, then the delayed B of A, zero propagation excessively is between the two (C
b-C
a)/f;
2) if C
b<C
a/ 2, then the advanced B of A, zero propagation excessively is between the two C
b/ f;
3) if C
b=C
a/ 2, then between A, B, nothing crosses zero propagation;
B during () supposition A advanced C, phase differential is on the occasion of, laser detector 6
awith laser detector 6
cbetween to cross the criterion of zero propagation as follows:
1) if C
c>C
a/ 2, then the delayed C of A, zero propagation excessively is between the two (C
c-C
a)/f;
2) if C
c<C
a/ 2, then the advanced C of A, zero propagation excessively is between the two C
c/ f;
3) if C
c=C
a/ 2, then between A, C, nothing crosses zero propagation.
Described three road laser detectors 6
a, 6
b, 6
cposition on interference plane forms isosceles right triangle, described laser detector 6
abe positioned at interference plane center P
a, described laser detector 6
b, laser detector 6
cposition on interference plane is respectively P
b, P
c, then
and
with
length be less than laser beam expander expand after laser facula radius length, namely described laser beam expander 1 is by after laser beam expanding, and its hot spot can cover completely and be positioned at interference plane Shang tri-road laser detector 6
a, 6
bwith 6
c.
The front of described laser beam expander is provided with coaxial infrared light supply and the LASER Light Source of reference.
Beneficial effect of the present invention is embodied in:
Zero propagation excessively between the laser interference signal utilizing interference plane Shang tri-road laser detector to detect, detects the mutual alignment relation of index glass and horizontal glass in interferometer, simplicity of design, easy to operate.The measuring error crossing zero propagation mostly is a standard clock cycle most, and when adopting the system clock of 40MHz, the measuring accuracy crossing zero propagation is better than 25ns.The method is that the online fast monitored of interferometer collimating status provides data supporting and effective means.
Accompanying drawing explanation
Fig. 1 is the interferometer detection schematic diagram that the present invention relates to.
Fig. 2 is three road laser detector position views on interference plane in the present invention.
Fig. 3 is the three road laser interference signal schematic representations that in the present invention, laser detector detects.
Fig. 4 is three road laser interference signal phase difference measurement procedure figure of the present invention.
Embodiment
Figure 1 shows that interferometer schematic diagram of the present invention, described interferometer comprises laser beam expander 1, beam splitter 2, index glass 3, horizontal glass 4 and interference plane 5.The front of described laser beam expander 1 is provided with coaxial infrared light supply and the LASER Light Source of reference, described interference plane 5 is provided with No. three laser detectors 6
a, 6
b, 6
c, as shown in Figure 2, if described index glass 3 and described horizontal glass 4 mutual alignment not exact vertical, be then equivalent in described index glass 3 place plane and there is angular deviation α.
As shown in Figure 2, three road laser detectors 6
a, 6
b, 6
cbe arranged on described interference plane 5.Described laser detector 6
abe positioned at interference plane center P
a, described laser detector 6
b, laser detector 6
cwith lay respectively at P
b, P
c, and laser detector 6
b, laser detector 6
cwith laser detector 6
aposition forms isosceles right triangle, namely
and waist long be less than laser beam expander expand after laser facula radius length, namely described laser beam expander 1 is by after laser beam expanding, and its hot spot can cover completely and be positioned at interference plane Shang tri-road laser detector 6
a, 6
bwith 6
c.
Interferometer is in scanning process, and due to the reason such as axial dipole field of Installation and Debugging error and index glass motion, index glass plane and horizontal glass plane cannot exact vertical, and the optical path difference on interference plane in laser interference hot spot between zones of different is no longer equal.Now, three road laser detectors 6
a, 6
bwith 6
cthe zero-acrross ing moment of the laser interference signal detected is also no longer identical, therefore, can utilize three road laser detectors 6
a, 6
bwith 6
czero propagation excessively between the laser interference signal detected, carries out on-line monitoring to the collimating status of interferometer.
The laser interference signal that three road laser detectors detect is crossed zero propagation detection and is used FPGA to complete, the high frequency clock signal of FPGA is utilized to set up counter therein, the zero crossing position of laser interference signal is counted, realized the high-acruracy survey of zero propagation, for the calibration of interferometer collimation provides data supporting.
As shown in Figure 3 and Figure 4, a kind of interferometer collimating status on-line monitoring method based on crossing zero propagation detection, described interferometer comprises laser beam expander, beam splitter, index glass, horizontal glass and interference plane, described interference plane is provided with No. three laser detectors 6
a, 6
b, 6
c, described laser detector 6
a, 6
b, 6
coutput terminal be connected with fpga chip processor able to programme, it is characterized in that: utilize the high frequency clock signal of FPGA to set up counter C therein
a, C
b, C
c, to three road laser detectors 6
a, 6
b, 6
cthe zero crossing position of sinusoidal interference signal A, B, C of detecting counts, and realizes the measurement of zero propagation, and specifically comprises the following steps:
(1) received by fpga chip disposable plates able to programme and process three road laser detectors 6
a, 6
b, 6
csinusoidal interference signal A, B, C of detecting, and determine the zero crossing S of sinusoidal interference signal A, B, C
a, S
b, S
c;
(2) counter C is set up according to the high frequency clock signal f in fpga chip processor able to programme
a, C
b, C
c, counter C
a, C
b, C
cfor recording No. three laser detectors 6
a, 6
b, 6
cthe counter of sinusoidal interference signal A, B, C zero crossing time information detected;
(3) T is established
aBfor laser detector 6
a, 6
bbetween cross zero propagation, T
aCfor laser detector 6
a, 6
cbetween cross zero propagation, in conjunction with high frequency clock signal f control counter C
a, C
b, C
ccounting:
If T
aBfor laser detector 6
a, 6
bbetween cross zero propagation, T
aCfor laser detector 6
a, 6
cbetween cross zero propagation, as shown in Figure 4, wherein, f is FPGA system clock frequency to its measurement procedure, C
a, C
b, C
cbe respectively the counter of three road laser interference signals.In each interference periods, counter C
aat S
aplace starts counting, at next S
aplace stops this time counting and counting from newly next time; Counter C
bat S
aplace starts counting, at next S
bplace stops this time counting and counting from newly next time; Counter C
cat S
aplace starts counting, at next S
cplace stops this time counting and counting from newly next time.
After each interference periods terminates, the result of counter is analyzed.
Assuming that cross zero propagation during the advanced B of A on the occasion of, laser detector 6
awith 6
bbetween to cross the criterion of zero propagation as follows:
4) if C
b>C
a/ 2, then the delayed B of A, zero propagation excessively is between the two (C
b-C
a)/f;
5) if C
b<C
a/ 2, then the advanced B of A, zero propagation excessively is between the two C
b/ f;
6) if C
b=C
a/ 2, then between A, B, nothing crosses zero propagation.
Assuming that phase differential is on the occasion of, laser detector 6 during A advanced C
awith 6
cbetween to cross the criterion of zero propagation as follows:
4) if C
c>C
a/ 2, then the delayed C of A, zero propagation excessively is between the two (C
c-C
a)/f;
5) if C
c<C
a/ 2, then the advanced C of A, zero propagation excessively is between the two C
c/ f;
6) if C
c=C
a/ 2, then between A, C, nothing crosses zero propagation.
Zero passage Time delay measurement error mostly is a standard clock cycle most, and when adopting the system clock of 40MHz, the measuring accuracy crossing zero propagation is better than 25ns.
This invention proposes a kind of interferometer collimating status on-line monitoring method based on crossing zero propagation detection, simplicity of design, easy to operate, utilize fpga chip to realize between interference signal that three road laser detectors detect to cross the high-acruracy survey of zero propagation, for the quick on-line monitoring of interferometer collimating status provides a kind of effective means, for the calibration of interferometer collimation provides data supporting.
Claims (3)
1., based on the interferometer collimating status on-line monitoring method crossing zero propagation detection, described interferometer comprises laser beam expander, beam splitter, index glass, horizontal glass and interference plane, described interference plane is provided with No. three laser detectors 6
a, 6
b, 6
c, described laser detector 6
a, 6
b, 6
coutput terminal be connected with fpga chip disposable plates able to programme, it is characterized in that: utilize the high frequency clock signal of FPGA to set up counter C therein
a, C
b, C
c, to three road laser detectors 6
a, 6
b, 6
cthe zero crossing position of sinusoidal interference signal A, B, C of detecting counts, and realizes the measurement of zero propagation, and specifically comprises the following steps:
(1) received by fpga chip processor able to programme and process three road laser detectors 6
a, 6
b, 6
csinusoidal interference signal A, B, C of detecting, and determine the zero crossing S of sinusoidal interference signal A, B, C
a, S
b, S
c;
(2) the high frequency clock signal f in fpga chip processor able to programme is utilized to set up counter C
a, C
b, C
c, counter C
a, C
b, C
cfor recording No. three laser detectors 6
a, 6
b, 6
cthe counter of sinusoidal interference signal A, B, C zero crossing time information detected;
(3) T is established
aBfor laser detector 6
a, 6
bbetween cross zero propagation, T
aCfor laser detector 6
a, 6
cbetween cross zero propagation, in conjunction with high frequency clock signal f control counter C
a, C
b, C
ccounting:
(a) within the single interference cycle, counter C
aat S
aplace starts counting, at next S
aplace stops this time counting and counting from newly next time; Counter C
bat S
aplace starts counting, at next S
bplace stops this time counting and counting from newly next time; Counter C
cat S
aplace starts counting, at next S
cplace stops this time counting and counting from newly next time.
(4), after each interference periods terminates, the result of counter is analyzed:
Zero propagation is crossed on the occasion of, laser detector 6 during (a) supposition sinusoidal interference signal A advanced sinusoidal interference signal B
awith laser detector 6
bbetween to cross the criterion of zero propagation as follows:
1) if C
b>C
a/ 2, then the delayed B of A, zero propagation excessively is between the two (C
b-C
a)/f;
2) if C
b<C
a/ 2, then the advanced B of A, zero propagation excessively is between the two C
b/ f;
3) if C
b=C
a/ 2, then between A, B, nothing crosses zero propagation;
B during () supposition A advanced C, phase differential is on the occasion of, laser detector 6
awith laser detector 6
cbetween to cross the criterion of zero propagation as follows:
1) if C
c>C
a/ 2, then the delayed C of A, zero propagation excessively is between the two (C
c-C
a)/f;
2) if C
c<C
a/ 2, then the advanced C of A, zero propagation excessively is between the two C
c/ f;
3) if C
c=C
a/ 2, then between A, C, nothing crosses zero propagation.
2. a kind of interferometer collimating status on-line monitoring method based on crossing zero propagation detection according to claim 1, is characterized in that: described three road laser detectors 6
a, 6
b, 6
cposition on interference plane forms isosceles right triangle, described laser detector 6
abe positioned at interference plane center P
a, described laser detector 6
b, laser detector 6
cposition on interference plane is respectively P
b, P
c, then
and
with
length be less than laser beam expander expand after laser facula radius length, namely described laser beam expander 1 is by after laser beam expanding, and its hot spot can cover completely and be positioned at interference plane Shang tri-road laser detector 6
a, 6
bwith 6
c.
3. a kind of interferometer collimating status on-line monitoring method based on crossing zero propagation detection according to claim 1, is characterized in that: the front of described laser beam expander is provided with coaxial infrared light supply and the LASER Light Source of reference.
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|---|---|---|---|
| CN201510263851.XA CN105157839A (en) | 2015-08-05 | 2015-08-05 | Interferometer collimation status online monitoring method based on zero-crossing delay detection |
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Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103344609A (en) * | 2013-06-26 | 2013-10-09 | 无锡微奥科技有限公司 | Micro Fourier transform spectrometer |
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2015
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103344609A (en) * | 2013-06-26 | 2013-10-09 | 无锡微奥科技有限公司 | Micro Fourier transform spectrometer |
Non-Patent Citations (3)
| Title |
|---|
| 于立民: "傅里叶变换光谱仪自适应校正系统的研究", 《红外》 * |
| 孙方等: "一种傅里叶变换光谱仪动镜速度测量系统", 《半导体光电》 * |
| 杨琨等: "FTIR光谱仪定镜准直误差分析及动态校正", 《华中科技大学学报》 * |
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Application publication date: 20151216 |
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