CN102175311B - Device for measuring laser beam parameters - Google Patents

Abstract

The invention discloses a device for measuring laser beam parameters and relates to the technical field of laser detection and application. The device consists of a measuring optical path, an optical path adjusting device, an indicator optical path, an image acquisition card 3 and a computer 7; the measuring optical path comprises a focusing lens 1, a right angle prism A8, a right angle prism B2, a right angle prism C5, a dimmer 6 and a camera 4; the optical path adjusting device comprises a sliding block 9, a one-dimensional moving table 12 and a controller 14; and the indicator optical path comprises an indicator light source 13, a reflecting mirror B11, a reflecting mirror A10, the right angle prism C5, the right angle prism B2, the right angle prism A8 and the focusing lens 1. The device has the characteristics that the measuring optical path can be conveniently adjusted by instrument operators, the measurement accuracy of the measuring device can be improved and the like, and is suitable to be used for measurement and evaluation on the beam parameters of a laser in various kinds of laser application equipment, such as optical display, optical information processing, optical communication, optical medical treatment, optical manufacturing, optical detection and the like.

Description

A kind of laser beam parameter measuring device

Technical field

The present invention relates to the laser detection applied technical field, particularly a kind of laser beam parameter measuring device.

Background technology

Along with science and technology development, laser technology plays the important and pivotal role in the development of the national economy.All have a wide range of applications in fields such as light demonstration, optical information processing, optical communication, light medical treatment, light manufacturing, light detections.At present, the level of application of laser technology has become one of important symbol of weighing a national industrial technology advance.

Laser beam quality then is a major criterion of weighing the laser product performance, provides the scientific evaluation of laser beam quality, and laser design and application are extremely important.1988, M was adopted in the Siegman suggestion ²The factor is described laser beam quality, M ²The factor has reflected the angle of divergence of beam waist with the expression far-field characteristic of laser near-field characteristic, has characterized laser high brightness, high spatial coherence and directivity again, M ²Factorization method has overcome the limitation of beam quality evaluation method commonly used, has more reasonably described laser beam quality, is generally acknowledged by international optics circle, and recommends for International Organization for Standardization.

At present, the Coherent Inc. of the U.S., Spiricon lnc., Photon Inc., Thorlabslnc., units such as DATARAY lnc. and Britain Lambdaphoto Inc. have business-like laser beam quality M ²Factor measuring instrument is like the M of Photon Inc. company development ²-200, the BP-109 of Thorlabs lnc. company development etc.Corresponding patent has also been declared by the relevant scientific research institution of China." laser beam quality M like Shanghai Optics and Precision Mechanics institute, Chinese Academy of Sciences's application ²Factor real-time detector " (number of patent application is: 200510030096.7), its formation comprises condenser lens successively, grating group, light path adjuster, the CCD with light path, and the output terminal of this CCD links to each other with computing machine through signal wire; This invention can be easily to laser beam quality M ²The factor is measured in real time, and system architecture is compact again.And for example " embedded type laser beam quality measuring device " of Changchun University of Science and Technology application (number of patent application is: 200810051666.4); Comprise optical unit, machine assembly and an electronics unit water part; Have advantages such as volume is little, work need not personal computer, and is easy to use.These existing laser beam quality measuring instruments; Usually sensitive detection parts are all away from measurement window; And need the hot spot at detector measurement light path diverse location place when measuring; This just needs operating personnel to adjust measured laser device emitting laser-bundle in whole measuring process, all to be on the test surface of detector, and guarantees that same position at test surface is to reduce measuring error.Because in most cases, the light inlet of measuring instrument seals to the light path between the detector, thereby its light path adjustment is difficulty comparatively.

Summary of the invention

Not enough to existing in prior technology, technical matters to be solved by this invention provides a kind ofly to be convenient to the instrumentation personnel adjustment and to measure light path, and can improve the laser beam parameter measuring instrument of the measuring accuracy of measurement mechanism.

The technical scheme that the present invention taked is a kind of laser beam parameter measuring device of invention: comprise and measure light path, image pick-up card 3 and computing machine 7; Also include the optical path regulator that constitutes by slide block 9, motion in one dimension platform 12 and controller 14;

Described measurement light path is to be made up of condenser lens 1, right-angle prism A8, right-angle prism B2, right-angle prism C5, dimmer 6 and camera 4;

Described condenser lens 1 is a positive lens;

Described right-angle prism A8 and right-angle prism B2 are isosceles right-angle prism, are coated with highly reflecting films on its two right angle faces separately;

Described right-angle prism C5 is an isosceles right-angle prism;

Right-angle prism A8 device is on slide block 9, and slide block 9 devices are on motion in one dimension platform 12; Camera 4, image pick-up card 3, computing machine 7 connect successively; Computing machine 7 also connects dimmer 6 and motion in one dimension platform 12 respectively through controller 14;

The horizontal device of the optical axis of condenser lens 1; The on-right angle face of right-angle prism A8 towards condenser lens 1, and in vertical direction the device; The on-right angle face of right-angle prism B2 relatively installs the bottom at condenser lens 1 in vertical direction and with the on-right angle face of right-angle prism A8; The corresponding lower left of the on-right angle face of right-angle prism C5 to and be the miter angle device, its underpart device dimmer 6 with horizontal direction; Camera 4 devices are in the bottom of dimmer 6.

Described dimmer 6 is the two continuous regulators of wedge light intensity intensity of absorption-type.

Described dimmer 6 is the continuous regulators of electro-optical type light intensity.

Be coated with 400-1100nm wave band highly reflecting films on the right angle face of right-angle prism A (8) and right-angle prism B (2).

Described camera 4 is CCD analogue camera or CCD digital camera or cmos digital camera.

Also include the indication light path that constitutes by indication light source 13, catoptron B11, catoptron A10, right-angle prism C5, right-angle prism B2, right-angle prism A8 and condenser lens 1; Catoptron A10 device is on the right of right-angle prism C5, the corresponding lower left of its reflecting surface to and be the miter angle device, its underpart device catoptron B11 with horizontal direction; The corresponding upper right side of the reflecting surface of catoptron B11 to and be the miter angle device, its right device indication light source 13 with horizontal direction; Measure light path and indicate light path between condenser lens 1, right-angle prism A8, right-angle prism B2 and right-angle prism C5, to be total to light path.

Described indication light source 13 is 632.8nm wavelength, TEM ₀₀The helium-neon laser of pattern output.

Laser beam parameter measuring device of the present invention; Be employed in laser beam parameter measuring device inside and insert the indication light source; And the measurement light path of indication light path and the measurement mechanism axle of sharing the same light provides reference thereby adjust light path when measuring, and is convenient to the adjustment that operating personnel carry out externally measured light path.In addition, inner two wedges of absorption-type or the continuous regulator of electro-optical type light intensity of adopting of this laser beam parameter measuring device improved the sampling precision when camera is measured, thereby improved the laser beam parameter measuring precision.

Description of drawings

Fig. 1 is a structural principle synoptic diagram of the present invention.

Among the figure: the 1st, condenser lens, the 2nd, right-angle prism B, the 3rd, image pick-up card, the 4th, camera, the 5th, right-angle prism C; The 6th, dimmer, the 7th, computing machine, the 8th, right-angle prism A, the 9th, slide block, the 10th, catoptron A; The 11st, catoptron B, the 12nd, motion in one dimension platform, the 13rd, indication light source, the 14th, controller.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the present invention is further described.Following explanation is to adopt the mode of giving an example, but protection scope of the present invention should not be limited to this.

Present embodiment is to constitute by measuring light path, optical path regulator, indication light path and image pick-up card 3 and computing machine 7.

Measure light path and comprise condenser lens 1, right-angle prism A8, right-angle prism B2, right-angle prism C5, dimmer 6 and camera 4; Optical path regulator comprises slide block 9, motion in one dimension platform 12 and controller 14, and the indication light path comprises indication light source 13, catoptron B11, catoptron A10, right-angle prism C5, right-angle prism B2, right-angle prism A8 and condenser lens 1.

Condenser lens 1 is the planoconvex positive lens; Right-angle prism A8 and right-angle prism B2 are isosceles right-angle prism; Be coated with highly reflecting films (this film is to 400-1100nm wave band highly reflecting films) on its two right angle faces separately; Right-angle prism C5 is an isosceles right-angle prism; Dimmer 6 can be the dimmer of the two continuous regulators of wedge light intensity intensity (that is: the continuous regulator of intensity that is made up of two absorption-type right angle parallel placements in wedge inclined-plane) of absorption-type or the continuous regulator of electro-optical type light intensity or other type, and camera 4 is CCD analogue camera or CCD digital camera or CMOS camera.(preferred 1/2 inch Si CCD digital camera, pixel 8.6umx8.3um, spectral response range 190-1100nm), indication light source 13 is 632.8nm wavelength, TEM ₀₀The helium-neon laser of pattern output.

Right-angle prism A8 device is on slide block 9, and slide block 9 devices are on motion in one dimension platform 12 (12 examples of motion in one dimension platform adopt electronic control translation stage, and stroke is 300mm, and repetitive positioning accuracy is ± 10um that Motion Resolution rate 10um, stepper motor step angle are 1.8 degree); Camera 4, image pick-up card 3, computing machine 7 are connected by signal wire successively; Computing machine 7 also connects dimmer 6 and motion in one dimension platform 12 by signal wire respectively through controller 14.

The horizontal device of the optical axis of condenser lens 1; The on-right angle face of right-angle prism A8 towards condenser lens 1, and in vertical direction the device; The on-right angle face of right-angle prism B2 relatively installs the bottom at condenser lens 1 in vertical direction and with the on-right angle face of right-angle prism A8; The corresponding lower left of the on-right angle face of right-angle prism C5 to and be the miter angle device, its underpart device dimmer 6 with horizontal direction; Camera 4 devices are in the bottom of dimmer 6; Catoptron A10 device is on the right of right-angle prism C5, the corresponding lower left of its reflecting surface to and be the miter angle device, its underpart device catoptron B11 with horizontal direction; The corresponding upper right side of the reflecting surface of catoptron B11 to and be miter angle device (catoptron A10 is parallel with catoptron B11) with horizontal direction, its right device is indicated light source 13; Measure light path and indicate light path between condenser lens 1, right-angle prism A8, right-angle prism B2 and right-angle prism C5, to be total to light path.

During use; Condenser lens 1, right-angle prism A8, right-angle prism B2, right-angle prism C5, dimmer 6 and camera 4 constitute the measurement light path of laser beam parameter measuring device; The laser beam of measured laser device output is along the optical axis incident of condenser lens 1; And be focused lens 1 and focus on, turn back after the light path through dimmer 6 through right-angle prism A8, right-angle prism B2 and right-angle prism C5, incide the test surface center of camera 4 at last; The representation of laser facula that image pick-up card 3 collects camera 4 sends computing machine 7 to; Controller 14 judges according to the view data that computing machine 7 obtains whether camera 4 is saturated, and according to judged result control dimmer 6, so that the intensity of incident laser hot spot is in the test specification that camera 4 is set; After measuring the hot spot of a position; Drive the right-angle prism A8 that is fixed together with slide block 9 moves along the optical axis direction of condenser lens 1 and changes the light path that condenser lens 1 arrives 4 in camera through motion in one dimension platform 12; The test surface center that guarantees camera 4 in the motion process is all the time on the optical axis of condenser lens 1; It is the test surface center that the measured laser hot spot is positioned at camera 4 all the time; Thereby realize the spot size of camera 4 measurement axis, simulate the coefficient of Hyperbolic Equation, then according to the waist radius ω of Hyperbolic Equation coefficient and laser beam according to the Hyperbolic Equation of setting to diverse location ₀, divergence half-angle θ, light beam parameters product BPP and beam quality M ²Relational expression solves corresponding value between the factor.

Concern between first moment according to hot spot light intensity center and beam intensity:

$\stackrel{\‾}{x_c}=\frac{{\∫}_{-\∞}^{+\∞}{\∫}_{-\∞}^{+\∞}I(x,y)*\mathrm{xdxdy}}{{\∫}_{-\∞}^{+\∞}{\∫}_{-\∞}^{+\∞}I(x,y)\mathrm{dxdy}},$ $\stackrel{\‾}{y_c}=\frac{{\∫}_{-\∞}^{+\∞}{\∫}_{-\∞}^{+\∞}I(x,y)*\mathrm{ydxdy}}{{\∫}_{-\∞}^{+\∞}{\∫}_{-\∞}^{+\∞}I(x,y)\mathrm{dxdy}}$

Confirm the centre coordinate of hot spot, then concern between second moment again according to the size of hot spot and light intensity:

$\left\{\begin{array}{c}{\mathrm{\ω}}_x\left(z\right)=2\sqrt{\frac{{\∫\∫(x-\stackrel{\‾}{x_c})}^{2}I(x,y)\mathrm{dxdy}}{\∫\∫I(x,y)\mathrm{dxdy}}}\\ {\mathrm{\ω}}_y\left(z\right)=2\sqrt{\frac{{\∫\∫(y-\stackrel{\‾}{y_c})}^{2}I(x,y)\mathrm{dxdy}}{\∫\∫I(x,y)\mathrm{dxdy}}}\end{array}\right.$

After measuring the hot spot of a position; Drive the right-angle prism A8 that is fixed together with slide block 9 moves along optical axis direction and changes the light path that condenser lens 1 arrives 4 in camera through motion in one dimension platform 12; The test surface center that guarantees camera 4 in the motion process is all the time on the optical axis of condenser lens 1; Be the test surface center that the measured laser hot spot is positioned at camera 4 all the time, thereby realize the spot size of camera 4 measurement axis to diverse location, according to the Hyperbolic Equation of setting:

$\left\{\begin{array}{c}{\mathrm{\ω}}_x^2\left(z\right)=A_1{z}^2+B_{1}z+C_1\\ {\mathrm{\ω}}_y^2\left(z\right)=A_2{z}^2+B_{2}z+C_2\end{array}\right.$

With organizing the Z value and corresponding spot size is updated to the coefficient that above-mentioned Hyperbolic Equation simulates Hyperbolic Equation more.According to concerning between coefficient A, B, C and parameters of laser beam in the Hyperbolic Equation:

${\mathrm{\ω}}_{0i}=\frac{1}{2}\sqrt{C_i-\frac{B_i^2}{4A_i}}$

${\mathrm{\θ}}_i=\frac{1}{2}\sqrt{A_i}$

${\mathrm{BPP}}_i=\frac{1}{4}\sqrt{A_i{C}_i-\frac{B_i^2}{4}}$

$M_i^3=\frac{\mathrm{\π}}{4\mathrm{\λ}}\sqrt{A_i{C}_i-\frac{B_i^2}{4}}$

Can solve the parameter waist radius ω of laser beam _0i, divergence half-angle θ _i, light beam parameters product BPP _iAnd M _i ²Value (annotate: the i here be meant x and y to).

Indication light source 13, catoptron B11, catoptron A10, right-angle prism C5, right-angle prism B2, right-angle prism A8 and condenser lens 1 constitute the indication light path of laser beam parameter measuring device; Behind the light beam process catoptron B11 and catoptron A10 reflection of 13 outputs of indication light source; See through right-angle prism C5; Through right-angle prism B2 and the right-angle prism A8 light path of turning back; Along the optical axis outgoing of condenser lens 1,, operating personnel indicate light path at last, so that adjust the light beam of measured laser device output and measure light path coaxial for providing systematic optical axis.

This routine condenser lens 1 adopts the planoconvex positive lens; Its bore is ￠ 20mm; At 632.8nm wavelength focal length is 600mm; Can the light beam of measured laser device output be focused on and construct the with a tight waist of laser beam again, thereby solve the difficult problem that directly to survey with a tight waist of measured laser device output beam.

Right-angle prism A8 that this is routine and right-angle prism B2 are isosceles right-angle prism, and the light of 45 degree incidents is turned back, and have solved the big problem of system bulk that the wide variation light path is brought.

Motion in one dimension platform 12 is an electronic control translation stage; Can drive slide block 9 according to the motion control signal that controller 14 sends and do side-to-side movement with right-angle prism A8; Thereby change the light path of measuring light path, realize of the measurement of condenser lens 1 rear axis to the diverse location laser facula;

This routine right-angle prism C5 is an isosceles right-angle prism; To be divided into two-beam with measured laser bundle miter angle incident, that turn back by right-angle prism B2; A branch of light is from right-angle prism C5 transmission; A branch of optical transmission direction changes 90 degree and turns to dimmer 6, has both realized the decay to the measured laser beam intensity, realizes the indication light path again and measures separating of light path.

This routine dimmer 6 is regulated the intensity of the measured laser bundle of right-angle prism C5 reflection under the control of controller 14 continuously.

This routine camera 4 converts the laser facula of incident to electric signal, and said image pick-up card 3 becomes the electrical signal conversion of camera 4 picture signal and send computing machine 7 to process and display.

The light of these routine indication light source 13 outputs is turned back the back from right-angle prism C5 transmission through catoptron B11 and catoptron A10; As the pilot light of this laser beam parameter measuring device, realize pilot light light path and the measurement light path axle of sharing the same light through adjustment catoptron B11 and catoptron A10.

Concrete measuring process of the present invention comprises the steps:

The first step: the power supply of opening this measurement mechanism;

Second step: open the software operation interface of computing machine and this measurement mechanism, system carries out self check, jump out the self check window that finishes after self check finishes, and display system is normal;

The 3rd step: in software master interface, click adjustment light path button, indicate this moment light source to open, then can observe from a branch of red light of the inner outgoing of this measurement mechanism, this red light through condenser lens 1 the center and along the optical axis outgoing of condenser lens 1; Open and adjustment measured laser device, overlap with the pilot light light path of laser beam parameter measuring device output with the light beam that guarantees the output of measured laser device.Distinguishing rule is in light path, to insert the detecting card that has center pit that is used for auxiliary light modulation road (this detecting card also belongs to the thing outside the measurement mechanism; Be mainly used in auxiliary light modulation road); Let of the center outgoing of pilot light spot center from the detecting card center pit; The measured laser bundle shines the another side of detecting card, if any two position measured laser spot center all overlap with the detecting card center pit in the light path, shows that then the light beam of measured laser device output overlaps with the pilot light light path of laser beam parameter measuring device output; Otherwise, the light path of adjustment laser instrument output.For avoiding error, can judge more through in light path, looking for several position, and guarantee that the adjacent position spacing is more than 20mm.After light path adjustment finishes, click once more at software master interface and to close the adjustment light path;

The 4th step: click start button, this moment, this measurement mechanism got into test mode, jumped out a big window simultaneously, two wickets.Big window shows the laser spot size that axial diverse location is measured, and carries out hyperbolic fit; Two wickets show the light intensity Two dimensional Distribution and the light intensity distributed in three dimensions of laser facula respectively in real time.After measurement finished, system generated the test data form automatically;

The 5th step: the power supply of closing software master interface and measurement mechanism successively.

When work, require operating personnel to wear lasering protective eyeglass, in order to avoid reflect/scatter light incides people's eyes and causes damage in using.

Laser beam parameter measuring device of the present invention is applicable to that the light beam parameters of laser instrument in all kinds of laser applications equipment such as light demonstration, optical information processing, optical communication, light medical treatment, light manufacturing, light detection is measured and estimated.

Claims (4)

1. a laser beam parameter measuring device comprises and measures light path and image pick-up card (3) and computing machine (7); It is characterized in that: also include the optical path regulator that constitutes by slide block (9), motion in one dimension platform (12) and controller (14);

Described measurement light path is to be made up of condenser lens (1), right-angle prism A (8), right-angle prism B (2), right-angle prism C (5), dimmer (6) and camera (4);

Described condenser lens (1) is a positive lens;

Described right-angle prism A (8) and right-angle prism B (2) are isosceles right-angle prism, are coated with highly reflecting films on its two right angle faces separately;

Described right-angle prism C (5) is an isosceles right-angle prism;

Right-angle prism A (8) device is on slide block (9), and slide block (9) installs on motion in one dimension platform (12); Camera (4), image pick-up card (3), computing machine (7) connect successively; Computing machine (7) also connects dimmer (6) and motion in one dimension platform (12) respectively through controller (14);

The horizontal device of optical axis of condenser lens (1); The on-right angle face of right-angle prism A (8) towards condenser lens (1), and in vertical direction the device; The on-right angle face of right-angle prism B (2) relatively installs the bottom in condenser lens (1) in vertical direction and with the on-right angle face of right-angle prism A (8); The corresponding lower left of the on-right angle face of right-angle prism C (5) to and be the miter angle device, its underpart device dimmer (6) with horizontal direction; Camera (4) device is in the bottom of dimmer (6);

Also include the indication light path that constitutes by indication light source (13), catoptron B (11), catoptron A (10), right-angle prism C (5), right-angle prism B (2), right-angle prism A (8) and condenser lens (1); Catoptron A (10) device is on the right of right-angle prism C (5), the corresponding lower left of its reflecting surface to and be the miter angle device, its underpart device catoptron B (11) with horizontal direction; The corresponding upper right side of the reflecting surface of catoptron B (11) to and be the miter angle device, its right device indication light source (13) with horizontal direction; Measure light path and indicate light path between condenser lens (1), right-angle prism A (8), right-angle prism B (2) and right-angle prism C (5), to be total to light path.

2. laser beam parameter measuring device according to claim 1 is characterized in that: described dimmer (6) is the two continuous regulators of wedge light intensity intensity of absorption-type.

3. laser beam parameter measuring device according to claim 1 is characterized in that: described dimmer (6) is the continuous regulator of electro-optical type light intensity.

4. according to claim 2 or 3 described laser beam parameter measuring devices, it is characterized in that: be coated with 400-1100nm wave band highly reflecting films on the right angle face of right-angle prism A (8) and right-angle prism B (2).