CN106969846A - Laser moda measurement light beam M is decomposed using spatial light modulator2The device of the factor - Google Patents
Laser moda measurement light beam M is decomposed using spatial light modulator2The device of the factor Download PDFInfo
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- CN106969846A CN106969846A CN201610020060.9A CN201610020060A CN106969846A CN 106969846 A CN106969846 A CN 106969846A CN 201610020060 A CN201610020060 A CN 201610020060A CN 106969846 A CN106969846 A CN 106969846A
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- laser
- spatial light
- light modulator
- amici prism
- lens
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- 238000005259 measurement Methods 0.000 title claims description 12
- 230000003287 optical effect Effects 0.000 claims description 27
- 238000000034 method Methods 0.000 claims description 16
- 230000009466 transformation Effects 0.000 claims description 4
- 238000010276 construction Methods 0.000 abstract 1
- 101150030337 CCD7 gene Proteins 0.000 description 19
- 238000000354 decomposition reaction Methods 0.000 description 6
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J11/00—Measuring the characteristics of individual optical pulses or of optical pulse trains
Abstract
The invention discloses one kind laser beam mode measuring beam M is decomposed using spatial light modulator2The device of the factor, including air supporting optics antidetonation platform, laser, attenuator, spatial light modulator, Amici prism, lens, CCD and computer, it can enter spatial light modulator by importing the hologram completed using the device, spatial light modulator is modulated to laser beam, received again after Fourier transform lens by CCD, the weight of different mode in laser beam can be calculated to obtain by analyzing the hot spot distribution calculated on CCD, it is possible thereby to calculate the M of laser beam2The factor.The present invention is simple in construction, can easily be accommodated, can measure laser beam M in real time2The factor.
Description
Technical field
The invention belongs to laser beam quality detection field, and in particular to one kind decomposes laser moda measurement light beam M using spatial light modulator2The device of the factor.
Background technology
General laser beam M2The factor is tested by being fitted beam Propagation hyperbolic method, spot radius of this method in diverse location measuring laser beam, it is impossible to the M of real time dynamic measurement laser beam2The factor.Because laser beam is made up of different mode, the presence of high-order mode can reduce the beam quality of laser beam, then propose and decompose the M that laser beam mode carrys out measuring laser beam2The factor.Mode decomposition is to calculate the M of laser beam by measuring the weight for the different mode for constituting laser beam2The factor.Mode decomposition need not measure the laser facula radius of diverse location in principle, and the M of laser beam can be obtained in real time2The factor.
2009, Thomas.Kasier proposed a kind of based on calculating hologram sheet（CGH）Laser beam mode decomposition method.This mode decomposition is to place the hologram sheet completed in the optical path, pass through Fourier transform lens after laser beam transparent hologram sheet again, focal plane measures spot energy distribution, the weight of different mode according to contained by can calculating in laser beam Energy distribution after the lens.
2011, OliverA.Schmidt proposed the real-time measuring laser beam quality of mode decomposition, by adjusting the resonator of solid state laser, laser exit beam pattern is changed, it can be seen that to measure laser beam M2Factor real-time change.It is what pre-production was completed that hologram sheet is calculated in this experimental provision, can not be adjusted in experiment to calculating hologram sheet, if changing laser, and calculating hologram sheet needs to remake, and cycle length, cost are high.
The content of the invention
It is an object of the invention to provide one kind laser moda measurement light beam M is decomposed using spatial light modulator2The device of the factor, the problem of exiting light beam intensity fluctuation range is excessive is solved using SLM dynamic characteristic, realizes that laser beam mode decomposes measuring beam M in satisfaction2The external structure of the factor is simpler, and controllability is increased substantially, and can obtain accurate test result.
The technical solution for realizing the object of the invention is：One kind decomposes laser moda measurement light beam M using spatial light modulator2The device of the factor, including air supporting optics antidetonation platform, laser, attenuator, spatial light modulator, Amici prism, lens, CCD and computer；Laser, attenuator, spatial light modulator, Amici prism, lens and CCD are arranged on air supporting optics antidetonation platform；Common optical axis sets gradually laser, attenuator and Amici prism, and optical axis where above-mentioned device is primary optic axis；Common optical axis sets gradually spatial light modulator, Amici prism, lens and CCD, and optical axis is the second optical axis where above-mentioned device, and primary optic axis is vertical with the second optical axis；Spatial light modulator is located at the front focal plane of lens, and CCD is located at the back focal plane of lens, and spatial light modulator and CCD are connected with computer respectively；
Hologram is sent into spatial light modulator by computer, laser sends laser, after decaying through attenuator, Amici prism light splitting is injected, is divided into reflected light and transmitted light, wherein reflected light is injected after spatial light modulator, the reflected light for carrying hologram information is reflected back Amici prism again, lens are incident to through Amici prism, Fourier transformation is carried out through lens, is received afterwards by CCD；Refraction light of the CCD by reflected light and with hologram information is changed into electric signal feeding computer, determines to load different zlasing modes in hologram the gray value of the position of carrier frequency, obtains the weight shared by different mode, obtain the M of laser beam2The factor.
The hologram is drawn by Lohmann coding method, rich neat compiling method or Li Weihan compiling methods.
The light splitting surface of the Amici prism and primary optic axis angle are 45 °, and the reflected light that Amici prism is separated is incident to spatial light modulator.
Compared with prior art, its remarkable advantage is the present invention：（1）Can measuring laser beam M in real time2The factor.
（2）Hologram is loaded into by spatial light modulator to decompose laser beam mode to realize, it is more convenient, can adjust in real time.
Brief description of the drawings
Fig. 1 decomposes laser moda measurement light beam M for the use spatial light modulator of the present invention2The overall structure diagram of the device of the factor.
Fig. 2 is the hologram drawn by Li Weihan compiling methods in the embodiment of the present invention 1.
Embodiment
The present invention is described in further detail below in conjunction with the accompanying drawings.
With reference to Fig. 1, one kind decomposes laser moda measurement light beam M using spatial light modulator2The device of the factor, including air supporting optics antidetonation platform 1, laser 2, attenuator 3, spatial light modulator 4, Amici prism 5, lens 6, CCD7 and computer 8；Laser 2, attenuator 3, spatial light modulator 4, Amici prism 5, lens 6 and CCD7 are arranged on air supporting optics antidetonation platform 1；Common optical axis sets gradually laser 2, attenuator 3 and Amici prism 5, and optical axis where above-mentioned device is primary optic axis；Common optical axis sets gradually spatial light modulator 4, Amici prism 5, lens 6 and CCD7, and optical axis is the second optical axis where above-mentioned device, and primary optic axis is vertical with the second optical axis；Spatial light modulator 4 is located at the front focal plane of lens 6, and CCD7 is located at the back focal plane of lens 6, and spatial light modulator 4 and CCD7 are connected with computer 8 respectively.
Hologram is sent into spatial light modulator 4 by computer 8, laser 2 sends laser, after decaying through attenuator 3, the light splitting of Amici prism 5 is injected, light beam is divided into reflected light and transmitted light by Amici prism 5, and wherein reflected light is injected after spatial light modulator 4, the reflected light for carrying hologram information is reflected back Amici prism 5 again, lens 6 are incident to through Amici prism 5, Fourier transformation is carried out through lens 6, is received afterwards by CCD7；Refraction light of the CCD7 by reflected light and with hologram information is changed into electric signal feeding computer 8, determines to load different zlasing modes in hologram the gray value of the position of carrier frequency, obtains the weight shared by different mode, obtain the M of laser beam2The factor.
Hologram can be drawn by Lohmann coding method, rich neat compiling method or Li Weihan compiling methods.
The light splitting surface of the Amici prism 5 and primary optic axis angle are 45 °, and the reflected light that Amici prism 5 is separated is incident to spatial light modulator（4）, transmitted light is invalid light, does not consider transmitted light.
Embodiment 1
With reference to Fig. 1, one kind decomposes laser moda measurement light beam M using spatial light modulator2The device of the factor, including air supporting optics antidetonation platform 1, laser 2, attenuator 3, spatial light modulator 4, Amici prism 5, lens 6, CCD7 and computer 8；All devices in addition to computer are arranged on air supporting optics antidetonation platform 1；Common optical axis sets gradually laser 2, attenuator 3 and Amici prism 5, and optical axis where above-mentioned device is primary optic axis；Common optical axis sets gradually spatial light modulator 4, Amici prism 5, lens 6 and CCD7, and optical axis is the second optical axis where above-mentioned device, and primary optic axis is vertical with the second optical axis；Spatial light modulator 4 is located at the front focal plane of lens 6, and CCD7 is located at the back focal plane of lens 6, and spatial light modulator 4 and CCD7 are connected with computer 8 respectively.
Hologram is sent into spatial light modulator 4 by computer 8, laser 2 sends laser, after decaying through attenuator 3, the light splitting of Amici prism 5 is injected, is divided into reflected light and transmitted light, wherein reflected light is injected after spatial light modulator 4, the reflected light back for carrying hologram information returns Amici prism 5, lens 6 are incident to through Amici prism 5, Fourier transformation is carried out through lens 6, is received afterwards by CCD7；Refraction light of the CCD7 by reflected light and with hologram information is changed into electric signal feeding computer 8, determines to load different zlasing modes in hologram the gray value of the position of carrier frequency, obtains the weight shared by different mode, obtain the M of laser beam2The factor.
Laser 2 uses He-Ne laser.
With reference to Fig. 2, so that Li Shi methods draw He-Ne laser hologram as an example：
The first step, the schema category for determining laser emitting light beam is Ermy-Gaussian beam.
Second step, the transmittance function formula in hologram is write according to Mode Decomposition theory.
3rd step, hologram is drawn using MATLAB softwares using Li Shi compiling methods.
Optical path modulation process is as follows：
Step 1, opening laser 2, so that laser 2 sends laser, after decaying through attenuator 3, incide Amici prism 5, light beam is divided into reflected light and transmitted light by the light splitting of Amici prism 5, Amici prism 5, and reflected light is incident to after spatial light modulator 4, the reflected light for carrying hologram information is reflected back Amici prism 5 again, and lens 6 are incident to through Amici prism 5.
Step 2, debug detection light path：
2-1, regulation laser 2 enable the light beam of the outgoing of laser 2 is parallel to incide in spatial light modulator 4 with Amici prism 5, and the luminous energy reflected through spatial light modulator 4 is parallel to be incided on CCD7.
2-2, the hot spot that observation CCD7 is received on computer 8, regulation CCD7 position make the center that hot spot is located at CCD7.
2-3, the power supply for connecting spatial light modulator 4, hologram is imported by computer 8, and the position of adjustment space optical modulator 4 makes launching spot positioned at the center of hologram.
Step 3, the time for exposure for adjusting CCD7 and gain so that obtained hot spot is observed on computer 8 will not darker or lighter.
Step 4, the position for finely tuning spatial light modulator 4 so that the hot spot distribution that CCD7 is received more can clearly tell different mode and be distributed in diverse location.
Step 5, the gray value for determining the interior position that different zlasing modes are loaded with carrier frequency of hologram, obtain the weight shared by different mode, obtain the M of laser beam2The factor.
The advantage of the invention is that can measuring laser beam M in real time by decomposing that the pattern of laser beam constitutes2The factor, is loaded into hologram by spatial light modulator and laser beam mode is decomposed to realize, more convenient, can adjust in real time.
Claims (3)
1. one kind decomposes laser moda measurement light beam M using spatial light modulator2The device of the factor, it is characterised in that：Including air supporting optics antidetonation platform（1）, laser（2）, attenuator（3）, spatial light modulator（4）, Amici prism（5）, lens（6）、CCD（7）And computer（8）；Laser（2）, attenuator（3）, spatial light modulator（4）, Amici prism（5）, lens（6）And CCD（7）It is arranged at air supporting optics antidetonation platform（1）On；Common optical axis sets gradually laser（2）, attenuator（3）With Amici prism（5）, optical axis where above-mentioned device is primary optic axis；Common optical axis sets gradually spatial light modulator（4）, Amici prism（5）, lens（6）With CCD（7）, optical axis is the second optical axis where above-mentioned device, and primary optic axis is vertical with the second optical axis；Spatial light modulator（4）Positioned at lens（6）Front focal plane, CCD（7）Positioned at lens（6）Back focal plane, spatial light modulator（4）And CCD（7）Respectively with computer（8）Connection；
Computer（8）Hologram is sent into spatial light modulator（4）, laser（2）Laser is sent, through attenuator（3）After decay, Amici prism is injected（5）Light splitting, is divided into reflected light and transmitted light, and wherein reflected light injects spatial light modulator（4）Afterwards, the reflected light for carrying hologram information is reflected back Amici prism again（5）, through Amici prism（5）It is incident to lens（6）, through lens（6）Fourier transformation is carried out, afterwards by CCD（7）Receive；CCD（7）Refraction light by reflected light and with hologram information is changed into electric signal feeding computer（8）, determine to load different zlasing modes in hologram the gray value of the position of carrier frequency, obtain the weight shared by different mode, obtain the M of laser beam2The factor.
2. use spatial light modulator according to claim 1 decomposes laser moda measurement light beam M2The device of the factor, it is characterised in that：The hologram is drawn by Lohmann coding method, rich neat compiling method or Li Weihan compiling methods.
3.
Use spatial light modulator according to claim 1 decomposes laser moda measurement light beam M2The device of the factor, it is characterised in that：The Amici prism（5）Light splitting surface and primary optic axis angle be 45 °, Amici prism（5）The reflected light separated is incident to spatial light modulator（4）.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201610020060.9A CN106969846A (en) | 2016-01-13 | 2016-01-13 | Laser moda measurement light beam M is decomposed using spatial light modulator2The device of the factor |
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| CN201610020060.9A CN106969846A (en) | 2016-01-13 | 2016-01-13 | Laser moda measurement light beam M is decomposed using spatial light modulator2The device of the factor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112816181A (en) * | 2020-12-29 | 2021-05-18 | 中国人民解放军国防科技大学 | High-speed real-time optical fiber laser mode detection method and detection device thereof |
Citations (3)
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|---|---|---|---|---|
| CN1766531A (en) * | 2005-09-28 | 2006-05-03 | 中国科学院上海光学精密机械研究所 | Laser beam quality M 2Factor real-time detector |
| CN102419213A (en) * | 2011-12-20 | 2012-04-18 | 四川大学 | Hartmann wavefront sensor based on diffraction grating arrays |
| US20150292941A1 (en) * | 2012-10-24 | 2015-10-15 | Csir | Modal decomposition of a laser beam |
-
2016
- 2016-01-13 CN CN201610020060.9A patent/CN106969846A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1766531A (en) * | 2005-09-28 | 2006-05-03 | 中国科学院上海光学精密机械研究所 | Laser beam quality M 2Factor real-time detector |
| CN102419213A (en) * | 2011-12-20 | 2012-04-18 | 四川大学 | Hartmann wavefront sensor based on diffraction grating arrays |
| US20150292941A1 (en) * | 2012-10-24 | 2015-10-15 | Csir | Modal decomposition of a laser beam |
Non-Patent Citations (1)
| Title |
|---|
| JORGE PEREZ-VIZCAINO,..ET AL.: "free-motion beam propagation factor measurement by means of a liquid crystal spatial light modulator", 《JOURNAL OF DISPLAY TECHNOLOGY》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112816181A (en) * | 2020-12-29 | 2021-05-18 | 中国人民解放军国防科技大学 | High-speed real-time optical fiber laser mode detection method and detection device thereof |
| CN112816181B (en) * | 2020-12-29 | 2023-03-14 | 中国人民解放军国防科技大学 | High-speed real-time optical fiber laser mode detection method and detection device thereof |
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Application publication date: 20170721 |
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