CN106248204B - A kind of apparatus for measuring quality of laser beam of optical fiber output - Google Patents
A kind of apparatus for measuring quality of laser beam of optical fiber output Download PDFInfo
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 27
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- G—PHYSICS
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- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
- G01J1/4257—Photometry, e.g. photographic exposure meter using electric radiation detectors applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam
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Abstract
The invention discloses a kind of apparatus for measuring quality of laser beam of optical fiber output and method, mainly including one-dimensional electricity driving displacement platform, three-dimensional lifting platform, fixture, focusing lens, collimation lens, photo-thermal sensor, thermal infrared imager, darkroom and computer etc..Apparatus of the present invention are automatic measuring system, are controlled by the assisted focused regulation of thermal infrared imager and Computer Visualization, easy to operate, simple in construction, and it is few that error introduces factor, can light-metering it is strong it is higher, beam sizes are larger, the beam quality of any wavelength laser.Compared to the problems such as detector damage threshold is low, dynamic range is smaller present in conventional method, the present invention can measure more power, bigger beam sizes, the laser beam quality of wider wave-length coverage, it is very suitable for scientific research institution or enterprise carries out laser activity test or laser performance evaluation and optimization analysis, have a wide range of application, device is cost-effective.
Description
Technical field
The invention belongs to the e measurement technology of laser performance parameters, and infrared imagery technique pair is based on more particularly, to one kind
The device that the laser beam quality of optical fiber output measures.
Background technology
The invention belongs to the e measurement technology of laser performance parameters, and infrared imagery technique pair is based on more particularly, to one kind
The device that the laser beam quality of optical fiber output measures.
Laser, there is the characteristics of monochromaticjty, coherence, good directionality and high intensity, with the continuous development of laser technology
And people's continually developing with perfect to high-tech product, laser technology are applied in the field such as military, civilian, scientific research and medical science
It is increasingly extensive.And laser beam quality is the important parameter for weighing laser activity.Research, the dimensional energy point of measuring laser beam
Cloth, the scientific evaluation of laser beam quality is provided, there is extremely important guidance to anticipate laser design, manufacture and its application
Justice.The evaluation method of traditional laser beam quality mainly has focused spot size method, far-field divergence angle method, β value method and Si Te
Lie Erbifa etc..These methods respectively have advantage and disadvantage, fail to form the standard of unified evaluation laser beam quality.90 years 20th century
The theory of a set of beam intensity square is proposed for first A.E.Siegman, and defines the M2 factors of laser on this basis, is used
To characterize the beam quality of laser.This M2 factor evaluations method is recognized by international light circle, and by International standardization group
Knit (ISO) and recommended [D.Right, P.Greve, J.Fleischer, L.Austin, " Laserbeam width,
divergence and beam propagation factor-an international standardization
approach,”Optical and Quantum Electronics 24(1992)$993-S1000].Based on light intensity second moment
Theoretical M2Factorization method, the laser beam quality evaluation of any optical field distribution is applicable not only to, also overcomes conventional light beam matter
The limitation of evaluation method is measured, either laser beam converts in free space transmission, or by optical system, M2The factor is constant
Amount, so as to represent the intrinsic transmission characteristic of laser beam.So M2Value carries out quality as evaluation criterion to Optical Maser System
The tool such as monitoring and Computer Aided Design is of great significance.
Based on M2Laser Beam Quality Analysis theory it is quite ripe, there have been corresponding measuring instrument in foreign countries.
Representational product mainly has：The M that SPIRICON companies develop2-200S；The BP-109 that THORLABA companies develop.Both
Product all employs typical measuring method, by the laser emitted from laser after an aberrationless convex lens,
Lateral beam of the laser near girdling the waist is subjected to step-by-step movement imaging using charge coupled device ccd, and shown in a computer
Show imaging effect, measured each beam sizes of the X of light beam and Y-direction by image processing techniques, by a series of surveys
Measure data and carry out data fitting, X and the M of Y-direction are calculated by formula2Value.Unlike, BP-109 is set using linear
Meter, and M2- 200S shortens light path, reduces the size of measuring instrument by speculum the reflected beams.(bibliography：It is Chinese special
20061002349) profit number is
Above product has been able to preferably evaluate laser beam quality, but also faces new difficulty and challenge.
First, as the raising of laser output power, gain media are influenceed by fuel factor, output beam quality can be by
Many-side influences and reduced, thus is necessary to carrying out beam quality measurement under laser high power conditions.Due to CCD destruction threshold
It is worth relatively low, when laser intensity is slightly larger, image caused by CCD can tend to saturation or even damage camera system, so in measurement process
In decayed using optical filter, nonetheless, measurable laser power be typically not greater than 10w.
Secondly, with the continuous development of laser technology, the laser in wider wave-length coverage is applied, such as thulium doped fiber
2 μm of laser of laser output, because the wavelength laser is to eye-safe, and hydrone has stronger absorption near 2 μm of wavelength
Peak, it is hemostatic good when being performed the operation using the wavelength laser, thus it is being widely used in medical field.Conventional beam quality is surveyed
Measuring appratus is limited to detector C CD to lambda1-wavelength susceptibility, the wave-length coverage of measurable laser generally 200nm~
Among 1800nm in the nano-width of a hop count hundred.
The content of the invention
For the disadvantages described above or Improvement requirement of prior art, the invention provides a kind of laser beam matter of optical fiber output
Measuring device, its object is to provide a kind of apparatus for measuring quality of laser beam based on infrared imagery technique, thus solve
Ccd detector damage threshold is low in the prior art, the less technical problem of dynamic range, realizes to light laser, wide wave-length coverage
The measurement of interior laser beam quality.
A kind of device of measuring laser beam quality provided by the invention, including one-dimensional electricity driving displacement platform (3), three-dimensional lifting
Platform (5), fixture (6), photo-thermal sensor (9), thermal infrared imager (10), image capture module and data processing module；Wherein：
The one-dimensional electricity driving displacement platform (3) is made up of a bar-shaped plate with the translatable base (4) being located at thereon, the bottom
Seat (4) is used to install three-dimensional lifting platform (5), collimation lens (7) and focusing lens (8)；
The three-dimensional lifting platform (5) is fixed on the one-dimensional electricity driving displacement platform base (4), and it has upper and lower, front and rear, left
Right six freedom of movement, which is provided with fiber clamp (6), for fixing optical fiber and adjusting the locus of optical fiber light outgoing；
The collimation lens (7) are fixed on base (4), and are coaxially disposed with fiber exit end, for going out to optical fiber
Laser is penetrated to be collimated；
The focusing lens (8) are fixed on base (4), and are coaxially disposed with fiber exit end, collimation lens (7),
It is focused for laser after collimation；
The photo-thermal sensor (9) is located at the laser emitting end of the one-dimensional electricity driving displacement platform (3), photo-thermal sensor (9)
Face shoot laser center line is set；Photo-thermal sensor is used to absorb laser energy, is converted into heat；
The thermal infrared imager (10) is set with photo-thermal sensor (9) face, for detecting the temperature of photo-thermal sensor (9)
；
Described image gathers the temperature field data exported with display module for gathering thermal infrared imager, and with image format
Display；
The data processing module, which is used to fall into a trap from the temperature field data of thermal infrared imager (10) output, calculates corresponding optical axis
Opening position laser beam size, a series of beam radius sized datas are subjected to data fitting, laser beam quality is calculated
Index M2。
Further, the data processing module calculates laser beam quality, carries out as the following formula：
Wherein, λ is optical maser wavelength, and coefficient A, B, C are fitted to obtain by data, and fitting formula is：
Z is coordinate of the measurement point beam cross section along optical axis direction using condenser lens center as origin in formula；Put down by left and right
The base moved on one-dimensional electricity driving displacement platform, thermal infrared imager obtains the face temperature field picture of corresponding measurement point, according to light intensity
Second order is away from the beam radius d that x, y direction on each measurement point section is calculatedσx(z)、dσy(z) two groups of light beams are obtained, and then
Beamwidth dσ(z) with z functional relation；It is fitted to obtain two system number A by datax、Bx、Cx, Ay、By、Cy；
Further, the beam quality M of x, y both direction is obtained as the following formula2：
Further, the beam radius in laser beam x, y direction is calculated as follows：
dσx(z)=4 σx(z)
dσy(z)=4 σy(z)
Wherein, σx(z)、σy(z) it is calculated as follows
In formula, for I (x, y, z) to be converted into the Energy distribution of heat after photo-thermal sensor reception laser energy, x, y are light beam
Cross section internal coordinate,For the first moment of light beam center of gravity, the i.e. energy density distribution of measurement plane inner light beam, P is optical fiber
Shoot laser power.
Further, described image collection is built in computer with display module, the data processing module, and computer leads to
Ethernet interface is crossed to be connected with the thermal infrared imager.
Further, the thermal infrared imager is located in darkroom, avoids the interference of ambient light.
Correspondingly, the present invention also proposes a kind of laser beam quality measuring method, comprises the following steps：
(1) by photo-thermal sensor, beam energy is converted into heat energy, by infrared thermoviewer, measures photo-thermal sensor
Temperature field；
(2) Energy distribution I (x, y, z) is obtained by Temperature calculating, x, y are beam cross-section internal coordinate, and z is beam cross section
Coordinate of the face in optical axis direction；
(3) beam radius in light beam x, y directions is calculated as follows；
dσx(z)=4 σx(z)
dσy(z)=4 σy(z)
Wherein, σx(z)、σy(z) it is calculated as follows
In formula,For the first moment of light beam center of gravity, the i.e. energy density distribution of measurement plane inner light beam, P is laser work(
Rate；
(4) hyperbolic fit as the following formula；
By changing light beam to photo-thermal sensor distance, the plane temperature field figure of different measurement points is obtained from thermal infrared imager
Picture, so as to obtain the beam radius d in x, y direction on each measurement point sectionσx(z)、dσy(z) two groups of beam radius are obtained, and then
dσ(z) with z functional relation；It is fitted to obtain two system number A by datax、Bx、CxAnd Ay、By、Cy。
According to coefficient Ax、Bx、CxAnd Ay、By、Cy, the beam quality M of x, y both direction is obtained as the following formula2：
During work, the laser is through the optical fiber output laser, after laser is by the collimation lens and focusing lens
The photo-thermal sensor is acted on, the thermal infrared imager detects the temperature that the photo-thermal sensor is formed after laser action
, energy density distribution corresponding to the temperature field reflects the laser intensity distribution at laser action section, according to light intensity second order
Beam radius at corresponding section is calculated away from definition, passes through the movable pedestal on the one-dimensional electricity driving displacement platform of step-wise adjustment, regulation
The position of laser emitting point, so as to change photo-thermal sensor position on laser transmission axle, laser is further obtained with a tight waist attached
The beam radius in orthogonal x directions and y directions near cross section, a series of beam radius data measured are carried out
Fitting, the beam quality factor M in x directions and y directions is calculated by formula2Value.
In general, by the contemplated above technical scheme of the present invention compared with prior art, due to using based on red
The thermal infrared imager of outer Detection Techniques can obtain following beneficial effect as detector.
1. the present invention can be with direct measurement higher-wattage laser beam quality, because laser is not to directly act on detection
Device, but resistant to elevated temperatures photo-thermal sensor is acted on, then detecting its temperature field by thermal infrared imager obtains energy density distribution,
So testing laser light intensity, which can reach very high, does not cause detector saturation and damage but；
2. the present invention does not limit testing laser wavelength, by infrared heat image instrument measuring photo-thermal sensor temperature field, rather than connect
The direct effect of laser is received, so having a broader measurable laser wavelength range than typical measuring arrangements, cost performance is higher；
3. light channel structure of the present invention is simple, error component is few, because the present invention is based on infrared imagery technique, thermal infrared imager
Visual field is larger, and detectable area is much larger than traditional CCD detectable area, and optical transform is not needed for large spot laser beam
System carries out optical beam transformation and with direct measurement beam shaping system can be avoided to introduce the distortion of light field；Due to thermal infrared imager
Measuring range is larger, the temperature field of photo-thermal sensor can be acted on direct measurement relatively high power laser beam, so in light path not
Attenuator element is needed, will not also be caused to incident field distribution and the distortion of wavefront；
4. measurement accuracy of the present invention is higher, from high-melting-point, high-absorbility, low thermal conductivity photo-thermal sensor,
By image procossing, ambient noise is removed, error is less than 5%；
5. the present invention is increasingly automated measuring system, by the assisted focused regulation of thermal infrared imager, pass through Computer Visualization
Control, it is easy to operate, it is highly suitable for scientific research institution and enterprise and laser beam quality is measured and analyzed.
Brief description of the drawings
Fig. 1 is structural representation schematic diagram of the embodiment of the present invention；
Fig. 2 is electricity driving displacement platform and its table top element manipulation schematic diagram of the present invention；
Fig. 3 is darkroom structural representation of the present invention；
Fig. 4 is photo-thermal sensor mechanism schematic diagram of the present invention；
Fig. 5 is the measurement result of the embodiment of the present invention one；
Fig. 6 is the measurement result of the embodiment of the present invention two；
In all of the figs, identical reference is used for representing identical element or structure, wherein：
The one-dimensional electricity driving displacement platform of 1- laser, 2- optical fiber, 3-, 4- displacement platforms base, 5- three-dimensionals lifting platform, 6- fiber clamps,
7- collimation lens, 8- focusing lens, 9- photo-thermal sensor, 10- thermal infrared imagers, 11- darkrooms, 12- fans, 13- computers,
14- electricity driving displacement bench control systems.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.As long as in addition, technical characteristic involved in each embodiment of invention described below
Conflict can is not formed each other to be mutually combined.
Referring to figs. 1 to Fig. 2, a kind of apparatus for measuring quality of laser beam based on infrared imaging, including laser 1, optical fiber
2nd, one-dimensional electricity driving displacement platform 3, displacement platform base 4, three-dimensional lifting platform 5, fiber clamp 6, collimation lens 7, focusing lens 8, photo-thermal
Sensor 9, thermal infrared imager 10, darkroom 11, fan 12, computer 13, electricity driving displacement bench control system 14 etc..
For reference picture 3 to Fig. 4, the clear aperature in darkroom 11 is less than the diameter of photo-thermal sensor 9, on the one hand can allow laser beam
By, photo-thermal sensor 9 is applied to, on the other hand, the interference that ambient light can be avoided to detect thermal imaging system.
The structure design of the present invention is as follows：
Laser 1 exports laser through optical fiber 2, and optical fiber 2 is fixed on three-dimensional lifting platform 5 by fiber clamp 6, three-dimensional lifting
Platform 5, collimation lens 7 and focusing lens 8 are in turn secured on the displacement platform base 4 on one-dimensional electricity driving displacement platform 3, photo-thermal sensor
9 are fixed at a certain distance from electricity driving displacement platform tail end, and thermal infrared imager 10 is placed in the rear side of photo-thermal sensor 9 and adjusted by lifting support
Section height, and ensure that its center is located on same center line with focusing lens 8, collimation lens 7, optical fiber 2.The He of photo-thermal sensor 9
Thermal infrared imager 10 is positioned in darkroom 11, on the outside of the light hole in darkroom 11 place fan 12, thermal infrared imager 10 by with
Too net connecting line is connected with computer 13, and computer 13 is built-in with image processing module and data processing module, Electronic control system
Unite displacement and translational speed of the 14 control bit moving stage bases 4 on one-dimensional electricity driving displacement platform 3.
The dynamic duty process and method of testing of the present invention is as follows：
According to the Structural Design Requirement of the present invention, after putting up each module, start laser 1, electric control system 14, red
Displacement platform base 4 on one-dimensional electricity driving displacement platform 3 is moved to by outer thermal imaging system 10 and computer 13, regulation electric control system 14
Stroke one end, regulation laser 1 export certain power, start the image processing module built in computer 13, receive infrared thermal imagery
Instrument 10 detects the thermo parameters method of photo-thermal sensor 9, adjusts the focal length of thermal infrared imager 10, makes imaging effect optimal, regulation three
Tie up the displacement in 5 three directions of lifting platform so that thermal infrared imager 10 detects the surface temperature field temperature peak of photo-thermal sensor 9 and reached
To the maximum of current location, the step-by-step movement moving displacement platform base 4 of electric control system 14 is then adjusted, said temperature peak value is most
Big value changes therewith, and when displacement platform base is moved at A, the temperature peak is maximum, shows that now laser 1 is through optical fiber 2
The laser of output focuses on the surface of photo-thermal sensor 9 after collimation, is then shut off laser 1, and starts fan 12, and regulation is electronic
The point midway of displacement platform base 4 is moved at end of travel B by control system 14 by A, so far completes system initialization.
Measurement starts, and among the one-dimensional stroke B-C of electricity driving displacement platform 3, in addition at A, regularly selects symmetrical
Beam propagation position, point 1 to be measured corresponding to formation, 2 ..., 5,6, A, 6*、5*、……、2*、1*.Wherein 1~3 and 1*~
3*Measurement point corresponds to beam propagation position outside distance girdles the waist twice of Rayleigh range, and 4~6 and 4*~6*Measurement point corresponds to light beam
Position is propagated within distance one times of Rayleigh range with a tight waist.It is to be measured that regulation electric control system 14 is moved to displacement platform base 4
Amount point 1, start image processing module, the temperature field of start recording photo-thermal sensor 9, then start laser 1 and export laser action
In photo-thermal sensor 9, after acting on 3s~5s, image processing module is closed, the temperature field of stop recording photo-thermal sensor 9, closes and swashs
Light device 1 stops laser action photo-thermal sensor 9, opens fan 12, accelerates photo-thermal sensor 9 to close fan after being cooled to room temperature,
So far, the measurement of tested point 1 is completed.
Regulation electric control system 14 makes displacement platform base 4 be moved to point 2 to be measured, starts image processing module, starts
The temperature field of recording light heat sensor 9, then start laser 1 and export laser action after photo-thermal sensor 9, effect 3s~5s,
Image processing module is closed, the temperature field of stop recording photo-thermal sensor 9, laser 1 is closed and stops laser action photo-thermal sensor
9, fan 12 is opened, accelerates photo-thermal sensor 9 to close fan after being cooled to room temperature, so far, completes the measurement of tested point 2.
It is sequentially completed the record in temperature field after laser action photo-thermal sensor 9 under each tested point.Close thermal infrared imager
10, image processing module amounts to the temperature field of 180 frames according to 3s before each measurement point laser action photo-thermal sensor 9 of 60Hz export
Data, data processing module is imported, according to the resolution ratio and the angle of visual field of thermal infrared imager 10, calculate detection viewing field, obtain each
Space physics size corresponding to pixel, so as to obtain energy density distribution I (x, y, z) corresponding to temperature field, wherein (x, y) is light
Beam cross section internal coordinate, z are beam cross section by origin of condenser lens center along the coordinate of optical axis direction.
By the second-order moments beamwidth of laser beam.International standard ISO11146 and China《Laser term》National standard all
Provide that the width of laser beam can be by its light intensity second-order moments：
dσx(z)=4 σx(z)
dσy(z)=4 σy(z)
Wherein, light intensity second moment of the laser beam on x and y：
In formula, to be converted into the energy density distribution of heat after photo-thermal sensor reception laser energy, x, y are I (x, y, z)
Beam cross-section internal coordinate, z be beam cross section by origin of condenser lens center along the coordinate of optical axis direction,For light beam
The first moment of center of gravity, the i.e. energy density distribution of measurement plane inner light beam, P are fiber exit laser powers；
Measurement result is fitted with hyperbola
(dσxi(z), z (i)), wherein i=1,2 ... 5,6, A, 6*,5*...3*,2*,1*
(dσyi(z), z (i)), wherein i=1,2 ... 5,6, A, 6*,5*...3*,2*,1*
Hyperbolic fit formula：Coefficient A, B, C are obtained, then can be obtained：
Embodiment one：
Laser 1 is semiconductor laser, and Output of laser wavelength 976nm, optical fiber 2 is 105/125 passive fiber, is swashed
Light device 1 is by exporting 976nm laser after being coupled with optical fiber 2.In measurement process, power output is set as 4W, data and its fitting
As a result if Fig. 5 a are the beam quality factor in laser x directions in beam cross section of optical fiber outputFig. 5 b are optical fiber output
The beam quality factor in laser y directions in beam cross sectionWherein, abscissa z is that beam cross section is sat in the position of optical axis
Mark, ordinate Laser beam width are beam radius, and curve is the matched curve of beam radius.The beam quality of laser
Measurement result is：
Embodiment two：
Laser 1 is optical fiber laser, defeated for the 976nm Yb dosed optical fiber 2 of diode-end-pumped 20/400 by wavelength
Go out the laser that wavelength is 1070nm, in measurement process, power output is set as 4W, and data and its fitting result such as Fig. 6 a are optical fiber
The beam quality factor in the laser of output x directions in beam cross sectionFig. 6 b are the laser of optical fiber output in beam cross section
The beam quality factor in y directionsWherein, abscissa z is beam cross section in the position coordinates of optical axis, ordinate Laser
Beam width are beam radius, and curve is the matched curve of beam radius.The beam quality measurement result of laser is：
Compared with existing product, this implementation process, light path is simple, and without decay, easy to operate, repeated measuring results are steady
Fixed, measurement period is significantly shorten to 20 minutes, according to laser product parameter, M2Measuring result error is less than 5%.
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to
The limitation present invention, all any modification, equivalent and improvement made within the spirit and principles of the invention etc., all should be included
Within protection scope of the present invention.
Claims (7)
1. a kind of device of measuring laser beam quality, it is characterised in that including one-dimensional electricity driving displacement platform (3), three-dimensional lifting platform
(5), fixture (6), photo-thermal sensor (9), thermal infrared imager (10), image capture module and data processing module；Wherein：
The one-dimensional electricity driving displacement platform (3) is made up of a bar-shaped plate with the translatable base (4) being located at thereon, the base
(4) it is used to three-dimensional lifting platform (5), collimation lens (7) and focusing lens (8) are installed；
The three-dimensional lifting platform (5) is fixed on the base (4), its have up and down, six freedom of movement around,
Fiber clamp (6) is which is provided with, for fixing optical fiber and adjusting the locus of optical fiber light outgoing；
The collimation lens (7) are fixed on base (4), and are coaxially disposed with fiber exit end, for swashing to fiber exit
Light is collimated；
The focusing lens (8) are fixed on base (4), and are coaxially disposed with fiber exit end, collimation lens (7), are used for
Laser is focused after collimation；
The photo-thermal sensor (9) is located at close to the laser emitting end of the one-dimensional electricity driving displacement platform (3), photo-thermal sensor (9)
Face shoot laser center line is set；Photo-thermal sensor is used to absorb laser energy, is converted into heat；
The thermal infrared imager (10) is set with photo-thermal sensor (9) face, for detecting the temperature field of photo-thermal sensor (9)；
Described image is gathered with display module for gathering the temperature field data of thermal infrared imager output, and is shown with image format
Show；
The data processing module, which is used to fall into a trap from the temperature field data of thermal infrared imager (10) output, calculates corresponding optical axis position
Locate laser beam size, a series of beam radius sized datas are subjected to data fitting, laser beam quality index is calculated
M2。
2. device according to claim 1, it is characterised in that the data processing module presses formula
Laser beam quality index is tried to achieve, wherein, λ is optical maser wavelength, and coefficient A, B, C press beam radiusFitting
Obtain；In formula z be using condenser lens center as origin, coordinate of the measurement point beam cross section along optical axis direction, dσ(z) according to light intensity
Second order is away from obtaining.
3. device according to claim 2, it is characterised in that the data processing module obtains x, y both direction as the following formula
Beam quality M2：
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<mn>2</mn>
</msup>
<mo>=</mo>
<mfrac>
<mi>&pi;</mi>
<mrow>
<mn>8</mn>
<mi>&lambda;</mi>
</mrow>
</mfrac>
<mo>&CenterDot;</mo>
<msqrt>
<mrow>
<mn>4</mn>
<msub>
<mi>A</mi>
<mi>x</mi>
</msub>
<msub>
<mi>C</mi>
<mi>x</mi>
</msub>
<mo>-</mo>
<msup>
<msub>
<mi>B</mi>
<mi>x</mi>
</msub>
<mn>2</mn>
</msup>
</mrow>
</msqrt>
<mo>;</mo>
</mrow>
<mrow>
<msup>
<msub>
<mi>M</mi>
<mi>y</mi>
</msub>
<mn>2</mn>
</msup>
<mo>=</mo>
<mfrac>
<mi>&pi;</mi>
<mrow>
<mn>8</mn>
<mi>&lambda;</mi>
</mrow>
</mfrac>
<mo>&CenterDot;</mo>
<msqrt>
<mrow>
<mn>4</mn>
<msub>
<mi>A</mi>
<mi>y</mi>
</msub>
<msub>
<mi>C</mi>
<mi>y</mi>
</msub>
<mo>-</mo>
<msup>
<msub>
<mi>B</mi>
<mi>y</mi>
</msub>
<mn>2</mn>
</msup>
</mrow>
</msqrt>
<mo>;</mo>
</mrow>
In formula, dσx(z)、dσy(z) be according to beam radius of the light intensity second order away from x, y direction on obtained each measurement point section,
And then obtain two groups of beam radius dσ(z) with z functional relationIt is fitted by data
To two system number Ax、Bx、Cx, Ay、By、Cy。
4. device according to claim 2, it is characterised in that in the data processing module, the light beam in laser beam x, y directions
Beamwidth calculation formula is：
dσx(z)=4 σx(z)
dσy(z)=4 σy(z)
Wherein, σx(z)、σy(z) it is calculated as follows
<mrow>
<msubsup>
<mi>&sigma;</mi>
<mi>x</mi>
<mn>2</mn>
</msubsup>
<mrow>
<mo>(</mo>
<mi>z</mi>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<mi>P</mi>
</mfrac>
<msubsup>
<mo>&Integral;</mo>
<mrow>
<mo>-</mo>
<mi>&infin;</mi>
</mrow>
<mrow>
<mo>+</mo>
<mi>&infin;</mi>
</mrow>
</msubsup>
<msubsup>
<mo>&Integral;</mo>
<mrow>
<mo>-</mo>
<mi>&infin;</mi>
</mrow>
<mrow>
<mo>+</mo>
<mi>&infin;</mi>
</mrow>
</msubsup>
<msup>
<mrow>
<mo>(</mo>
<mi>x</mi>
<mo>-</mo>
<mover>
<mi>x</mi>
<mo>&OverBar;</mo>
</mover>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
<mi>I</mi>
<mrow>
<mo>(</mo>
<mi>x</mi>
<mo>,</mo>
<mi>y</mi>
<mo>,</mo>
<mi>z</mi>
<mo>)</mo>
</mrow>
<mi>d</mi>
<mi>x</mi>
<mi>d</mi>
<mi>y</mi>
</mrow>
<mrow>
<msubsup>
<mi>&sigma;</mi>
<mi>y</mi>
<mn>2</mn>
</msubsup>
<mrow>
<mo>(</mo>
<mi>z</mi>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<mi>P</mi>
</mfrac>
<msubsup>
<mo>&Integral;</mo>
<mrow>
<mo>-</mo>
<mi>&infin;</mi>
</mrow>
<mrow>
<mo>+</mo>
<mi>&infin;</mi>
</mrow>
</msubsup>
<msubsup>
<mo>&Integral;</mo>
<mrow>
<mo>-</mo>
<mi>&infin;</mi>
</mrow>
<mrow>
<mo>+</mo>
<mi>&infin;</mi>
</mrow>
</msubsup>
<msup>
<mrow>
<mo>(</mo>
<mi>y</mi>
<mo>-</mo>
<mover>
<mi>y</mi>
<mo>&OverBar;</mo>
</mover>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
<mi>I</mi>
<mrow>
<mo>(</mo>
<mi>x</mi>
<mo>,</mo>
<mi>y</mi>
<mo>,</mo>
<mi>z</mi>
<mo>)</mo>
</mrow>
<mi>d</mi>
<mi>x</mi>
<mi>d</mi>
<mi>y</mi>
</mrow>
In formula, for I (x, y, z) to be converted into the Energy distribution of heat after photo-thermal sensor reception laser energy, x, y are beam cross section
Face internal coordinate,For the first moment of light beam center of gravity, the i.e. energy density distribution of measurement plane inner light beam, P is fiber exit
Laser power.
5. device according to claim 1, it is characterised in that described image gathers and display module, the data processing mould
Block is built in computer, and computer is connected by Ethernet interface with the thermal infrared imager.
6. device according to claim 1, it is characterised in that the thermal infrared imager is located in darkroom, avoids ambient light
Interference.
A kind of 7. laser beam quality measuring method, it is characterised in that comprise the following steps：
(1) by photo-thermal sensor, beam energy is converted into heat energy, passes through infrared thermoviewer, the temperature of measurement photo-thermal sensor
Spend field；
(2) Energy distribution I (x, y, z) is obtained by Temperature calculating, x, y are beam cross-section internal coordinate, and z is that beam cross-section exists
The coordinate of optical axis direction；
(3) beam radius in light beam x, y directions is calculated as follows；
dσx(z)=4 σx(z)
dσy(z)=4 σy(z)
Wherein, σx(z)、σy(z) it is calculated as follows
<mrow>
<msubsup>
<mi>&sigma;</mi>
<mi>x</mi>
<mn>2</mn>
</msubsup>
<mrow>
<mo>(</mo>
<mi>z</mi>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<mi>P</mi>
</mfrac>
<msubsup>
<mo>&Integral;</mo>
<mrow>
<mo>-</mo>
<mi>&infin;</mi>
</mrow>
<mrow>
<mo>+</mo>
<mi>&infin;</mi>
</mrow>
</msubsup>
<msubsup>
<mo>&Integral;</mo>
<mrow>
<mo>-</mo>
<mi>&infin;</mi>
</mrow>
<mrow>
<mo>+</mo>
<mi>&infin;</mi>
</mrow>
</msubsup>
<msup>
<mrow>
<mo>(</mo>
<mi>x</mi>
<mo>-</mo>
<mover>
<mi>x</mi>
<mo>&OverBar;</mo>
</mover>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
<mi>I</mi>
<mrow>
<mo>(</mo>
<mi>x</mi>
<mo>,</mo>
<mi>y</mi>
<mo>,</mo>
<mi>z</mi>
<mo>)</mo>
</mrow>
<mi>d</mi>
<mi>x</mi>
<mi>d</mi>
<mi>y</mi>
</mrow>
<mrow>
<msubsup>
<mi>&sigma;</mi>
<mi>y</mi>
<mn>2</mn>
</msubsup>
<mrow>
<mo>(</mo>
<mi>z</mi>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<mi>P</mi>
</mfrac>
<msubsup>
<mo>&Integral;</mo>
<mrow>
<mo>-</mo>
<mi>&infin;</mi>
</mrow>
<mrow>
<mo>+</mo>
<mi>&infin;</mi>
</mrow>
</msubsup>
<msubsup>
<mo>&Integral;</mo>
<mrow>
<mo>-</mo>
<mi>&infin;</mi>
</mrow>
<mrow>
<mo>+</mo>
<mi>&infin;</mi>
</mrow>
</msubsup>
<msup>
<mrow>
<mo>(</mo>
<mi>y</mi>
<mo>-</mo>
<mover>
<mi>y</mi>
<mo>&OverBar;</mo>
</mover>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
<mi>I</mi>
<mrow>
<mo>(</mo>
<mi>x</mi>
<mo>,</mo>
<mi>y</mi>
<mo>,</mo>
<mi>z</mi>
<mo>)</mo>
</mrow>
<mi>d</mi>
<mi>x</mi>
<mi>d</mi>
<mi>y</mi>
</mrow>
In formula,For the first moment of light beam center of gravity, the i.e. energy density distribution of measurement plane inner light beam, P is laser power；
(4) hyperbolic fit as the following formula；
<mrow>
<msub>
<mi>d</mi>
<mi>&sigma;</mi>
</msub>
<mrow>
<mo>(</mo>
<mi>z</mi>
<mo>)</mo>
</mrow>
<mo>=</mo>
<msqrt>
<mrow>
<mi>A</mi>
<mo>+</mo>
<mi>B</mi>
<mi>z</mi>
<mo>+</mo>
<msup>
<mi>Cz</mi>
<mn>2</mn>
</msup>
</mrow>
</msqrt>
</mrow>
By changing light beam to photo-thermal sensor distance, the face temperature field picture of different measurement points is obtained from thermal infrared imager,
So as to obtain the beam radius d in x, y direction on each measurement point sectionσx(z)、dσy(z) two groups of beam radius d are obtained, and thenσ
(z) with z functional relation；It is fitted to obtain two system number A by datax、Bx、CxAnd Ay、By、Cy；
According to coefficient Ax、Bx、CxAnd Ay、By、Cy, the beam quality M of x, y both direction is obtained as the following formula2：
<mrow>
<msup>
<msub>
<mi>M</mi>
<mi>x</mi>
</msub>
<mn>2</mn>
</msup>
<mo>=</mo>
<mfrac>
<mi>&pi;</mi>
<mrow>
<mn>8</mn>
<mi>&lambda;</mi>
</mrow>
</mfrac>
<mo>&CenterDot;</mo>
<msqrt>
<mrow>
<mn>4</mn>
<msub>
<mi>A</mi>
<mi>x</mi>
</msub>
<msub>
<mi>C</mi>
<mi>x</mi>
</msub>
<mo>-</mo>
<msup>
<msub>
<mi>B</mi>
<mi>x</mi>
</msub>
<mn>2</mn>
</msup>
</mrow>
</msqrt>
<mo>;</mo>
</mrow>
<mrow>
<msup>
<msub>
<mi>M</mi>
<mi>y</mi>
</msub>
<mn>2</mn>
</msup>
<mo>=</mo>
<mfrac>
<mi>&pi;</mi>
<mrow>
<mn>8</mn>
<mi>&lambda;</mi>
</mrow>
</mfrac>
<mo>&CenterDot;</mo>
<msqrt>
<mrow>
<mn>4</mn>
<msub>
<mi>A</mi>
<mi>y</mi>
</msub>
<msub>
<mi>C</mi>
<mi>y</mi>
</msub>
<mo>-</mo>
<msup>
<msub>
<mi>B</mi>
<mi>y</mi>
</msub>
<mn>2</mn>
</msup>
</mrow>
</msqrt>
<mo>.</mo>
</mrow>
2
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| CN107607195B (en) * | 2017-08-07 | 2019-11-15 | 南京理工大学 | A kind of beam quality measurement method obtained in real time based on complex amplitude |
| CN107991061A (en) * | 2018-01-16 | 2018-05-04 | 南京理工大学 | High-capacity optical fiber laser QBH optical cable beam quality detecting systems and its detection method |
| CN108827466A (en) * | 2018-06-14 | 2018-11-16 | 温州大学 | A kind of three-dimensional rotation laser fiber holder device |
| KR102686855B1 (en) * | 2018-09-27 | 2024-07-19 | 아이피지 포토닉스 코포레이션 | System and method for visualizing laser energy distribution provided by different near-field scanning patterns |
| CN109581672A (en) * | 2018-12-22 | 2019-04-05 | 苏州英谷激光有限公司 | Laser amplifier beam quality Automatic Optimal regulating device |
| CN109959502A (en) * | 2019-04-10 | 2019-07-02 | 深圳市计量质量检测研究院（国家高新技术计量站、国家数字电子产品质量监督检验中心） | A kind of measuring device and measurement method of hot spot key parameter |
| TWI729403B (en) * | 2019-05-31 | 2021-06-01 | 致茂電子股份有限公司 | Device for measuring optolectronic units |
| TWI724673B (en) * | 2019-12-05 | 2021-04-11 | 致茂電子股份有限公司 | Device for measuring optolectronic units |
| CN113063565B (en) * | 2021-03-17 | 2023-03-10 | 北京工业大学 | Method and device for measuring quality factor of light beam of semiconductor laser |
| CN113340419B (en) * | 2021-06-19 | 2023-03-14 | 上海国科航星量子科技有限公司 | Laser divergence angle detection system and method |
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| CN101393050B (en) * | 2008-11-07 | 2010-08-25 | 四川大学 | Laser beam M2 factor matrix measuring method and measuring instrument |
| CN101782435B (en) * | 2010-03-11 | 2011-04-06 | 中国科学院上海光学精密机械研究所 | Laser parameter comprehensive test system |
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