CN115451824A - Irregular laser spot size testing method - Google Patents
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Abstract
The invention provides an irregular laser spot size testing method, which is characterized in that a three-dimensional movable knife edge and slit testing assembly is built, an optical knife edge, a double-opening width-adjustable optical slit, a laser power meter and laser to be tested are coaxial through an adjusting system, micro stepping laser shielding is realized by using the optical knife edge, the laser power of the knife edge at different point positions is tested, light intensity percentage normalization values of each point are obtained, a normalization function curve is drawn, and the spot size is obtained. The laser to be tested is approximated to be a line light source through the double-opening width-adjustable optical slits, the laser to be tested is approximated to be a point light source through the optical knife edge, and the line light source at the strongest light intensity solves the problems that the traditional knife edge cannot be accurately tested and the light spot analyzer has a low threshold value; and the principle that the knife edge is similar to a point light source is equivalent to a facula analyzer. The invention has stronger practicability for testing the multimode irregular high-power laser facula in scientific research.
Description
Technical Field
The invention relates to the technical field of measurement and testing, in particular to a method for testing the size of an irregular laser spot.
Background
The laser of solid laser, semiconductor laser and fiber laser is no longer Gaussian beam due to mode competition, so that the traditional knife edge method is inaccurate in measuring the laser spot size.
Currently, in practical applications, the most common test method is a light spot analyzer. However, along with the development of laser technology, the output power of various lasers is greatly improved, and the corresponding detector threshold is not correspondingly improved, so that the spot analyzer has certain limitations on the test and analysis of high-power laser spots, and has the problems of high cost, large size, complexity and the like. Therefore, the method has great difficulty in testing the spot size of the laser with multimode output, irregularity and high power.
Disclosure of Invention
The invention provides a method for testing the spot size of irregular laser, aiming at solving the problem that the spot size cannot be directly measured by irregular, multimode and high-power laser, wherein laser to be tested is approximated to a line light source through a double-opening optical slit with adjustable width, the laser to be tested is approximated to a point light source through an optical knife edge, and the line light source at the strongest light intensity solves the problems that the traditional knife edge cannot be accurately tested and a spot analyzer has a low threshold value; the knife edge is similar to a point light source and is equivalent to a spot analyzer, but the cost problem is solved to a great extent. The invention has stronger practicability for testing the multimode irregular high-power laser facula in scientific research.
The invention provides a method for testing the size of an irregular laser spot, which comprises the following steps:
s1, installing a double-opening width-adjustable optical slit on a three-dimensional adjusting system, arranging a laser to be tested in the front of the double-opening width-adjustable optical slit, arranging a laser power meter in the rear of the double-opening width-adjustable optical slit, wherein the slit width of the double-opening width-adjustable optical slit is adjustable, and outputting irregular multimode facula by the laser to be tested;
s2, adjusting the width and the height of the slit of the double-opening width-adjustable optical slit to obtain the complete laser power P of the laser to be measured 0 Light spot test power P l And the spot test power P l The slit width a;
s3, the optical knife edge is installed on another three-dimensional adjusting system and is arranged close to the back of the double-opening width-adjustable optical slit under the condition that the double-opening width-adjustable optical slit and the optical knife edge can normally move, the position of the optical knife edge is adjusted, and the slit width a and the light spot testing power P are obtained l The initial position of the optical knife edge;
s4, moving the optical knife edge along the X axis by taking a fixed variable delta X as a step, and recording the laser power P before moving each time i Stopping recording until the index of the laser power meter is 0, I =1, \8230, I, P 1 ＝P l ，P I ＝0；
S5, according to the laser power P i Obtaining approximate point light spot power P' n Approximate point light spot maximum power value P' n-max And a light intensity percentile normalization function eta (x), wherein P' n ＝P i-1 ﹣P i ，n＝i-1；
S6, drawing a normalization function curve to obtain an approximate line light spot size D and an approximate point light spot size D' corresponding to eta (x), and completing the test of the irregular laser light spot size.
The invention relates to a method for testing the size of an irregular laser spot, which is a preferable mode, and the step S2 comprises the following steps:
s21, opening the double-opening width-adjustable lightThe slit width of the learning slit is adjusted to be maximum, the slit width is adjusted to be maximum, the slit is opened by linearly moving the two slit with adjustable width up and down and left and right, the laser is observed by holding the photosensitive card, the slit is fixed when the laser output by the laser to be detected completely passes through the slit and is positioned at the visual centered position of the slit, then the laser power meter is linearly moved up and down until the laser spot is fixed when the laser spot is positioned at the visual centered position of the detection surface of the laser power meter, and the complete laser power P is obtained 0 ；
S22, adjusting the slit width of the double-opening width-adjustable optical slit to be zero, observing laser by using a photosensitive card, moving the double-opening width-adjustable optical slit up and down linearly until the laser is in visual alignment with the central line of the double-opening width-adjustable optical slit, and then slowly increasing the slit width until the numerical value of the laser power meter is a threshold value P k ，P k ＜P 0 ；
S23, moving the double-opening width-adjustable optical slit upwards until the slit is positioned right above the laser spot, wherein the numerical value of the laser power meter is 0, then slowly moving the double-opening width-adjustable optical slit downwards, and adding the maximum numerical value of the power meter of the laser power meter and P to the maximum numerical value of the power meter of the laser power meter k If greater than P k Then the slit width is slowly decreased until the count value is P k Recording the slit width a at the time; if approaching P k Directly recording the width a of the slit at the moment;
s24, moving the double-opening width-adjustable optical slit upwards again to enable the slit to be located right above the laser spot, wherein the value of the laser power meter is 0; slowly moving the double-opening width-adjustable optical slit downwards until the reading of the laser power meter is fixed when the reading is maximum, wherein the reading of the laser power meter is the facula test power P l 。
The invention relates to a method for testing the size of an irregular laser spot, which is a preferable mode, and the step S3 comprises the following steps:
s31, mounting an optical knife edge on another three-dimensional adjusting system and arranging the optical knife edge at the rear part of the double-opening width-adjustable optical slit, increasing the width of the slit until all laser output by the laser to be tested passes through the double-opening width-adjustable optical slit, then using a laser sensing card and taking the laser optical axis as a reference,the initial left and right positions of the optical knife edge are positioned at the edge of the laser spot without blocking laser, and the numerical value of the laser power meter is the complete laser power P 0 ；
S32, moving the optical knife edge back and forth through the three-dimensional adjusting system, and tightly attaching the optical knife edge to the back of the double-opening adjustable-width optical slit under the condition that the double-opening adjustable-width optical slit and the optical knife edge can normally move;
s33, adjusting the slit width of the double-opening width-adjustable optical slit to be slit width a, moving the optical knife edge leftwards until the reading of the laser power meter is reduced, stopping moving the optical knife edge rightwards slowly until the reading P of the laser power meter l Stopping the operation, and obtaining the initial position of the optical knife edge.
The invention relates to a method for testing the size of an irregular laser spot, which is a preferred mode, and in the step S5, a light intensity percentage normalization function eta (x) is as follows:
wherein, I x Is the spot light intensity, I max Eta (x) is 0 to 1 as the central light intensity.
The invention relates to a method for testing the size of an irregular laser spot, which is used as a preferred mode to test the light intensity of the spot light
Central light intensity of
The slit converts the light spots to be detected into approximate linear light spots, the knife edge approximate linear light spots are cut into a plurality of approximate point light spots, and L is the number of the approximate point light spots;
the invention relates to a method for testing the spot size of an irregular laser, which is a preferable mode, wherein the initial position of an optical knife edge in the step S3 is an X-axis 0 point, and the abscissa of eta (X) is as follows:
the invention relates to a method for testing the spot size of an irregular laser, which is a preferred mode, wherein the spot size D of an approximate line is as follows: d = x 2 -x 1 Wherein x is 1 、x 2 Is the abscissa corresponding to eta (x) in the curve of the normalization function;
the approximate spot size D' is: d' = D = x 2 -x 1 。
The invention discloses a method for testing the spot size of an irregular laser, which is used as a preferred mode and adopts a threshold value P k Is P 0 /10。
The invention relates to an irregular laser spot size testing method, which is a preferred mode, wherein a double-opening width-adjustable optical slit comprises a first slit surface arranged at the upper part, a second slit surface arranged at the lower part and a slit positioned between the first slit surface and the second slit surface, wherein the first slit surface and the second slit surface can synchronously move, the width of the slit is adjustable, and the slit is used for cutting spots;
the three-dimensional adjusting system comprises three one-dimensional linear translation tables and is used for adjusting the high and low positions, the left and right positions and the front and back positions;
the laser power meter is arranged on a two-dimensional adjusting system, the two-dimensional adjusting system comprises two one-dimensional linear translation tables, and the two-dimensional adjusting system is used for adjusting the height position and the left and right positions of the laser power meter;
the double-opening width-adjustable optical slit, the laser power meter, the optical knife edge, the laser to be measured, the three-dimensional adjusting system, the two-dimensional adjusting system and the photosensitive card are all arranged on the optical platform.
The invention relates to a method for testing the size of an irregular laser spot, which is used as a preferred mode, wherein a laser power meter is a pyroelectric optical power meter;
the optical knife edge is a metal knife edge.
The technical scheme of the invention is as follows: a testing device for the size of an irregular laser spot is arranged on an optical platform and comprises an optical knife edge, a double-opening width-adjustable optical slit, a one-dimensional linear translation table, a laser sensing card, a laser power meter and a laser to be tested;
the optical knife edge and the double-opening width-adjustable optical slit are both assembled on a three-dimensional adjusting system formed by combining 3 one-dimensional linear translation tables, and the two optical knife edges and the double-opening width-adjustable optical slit are in unlimited approach to each other in physical positions in the laser transmission direction; the laser power meter is assembled on an adjusting system which is formed by combining 2 one-dimensional linear translation tables and can adjust the height and the left and right positions;
the one-dimensional linear translation table can realize linear position adjustment up and down, left and right and front and back; the width-adjustable optical slit is opened in two ways, and two faces of the slit can move in the same step by rotating the adjusting part of the slit, so that the width of the slit is adjusted; the optical knife edge is composed of a high-absorption and low-reflection metal knife edge; the laser power meter is a common pyroelectric optical power meter; the laser sensitive card is a sensitive material card which converts invisible wave band laser into visible light spots;
the laser output to be measured is an irregular multi-mode facula, and the optical knife edge, the double-opening adjustable-width optical slit, the laser power meter and the laser to be measured are coaxial through the adjusting system; micro stepping laser shielding is realized by utilizing the optical knife edge, and the laser power of the knife edge at different point positions is tested; and processing the laser power data to finally obtain the spot size of the laser to be detected.
Preferably, the installation and positioning steps of the double-opening adjustable-width slit and the laser power meter are as follows:
(1) According to the test requirement of the laser facula to be tested, holding a laser sensing optical card by hand, and preliminarily mounting a double-opening width-adjustable optical slit and a laser power meter in sequence by referring to a laser optical axis, wherein a space for mounting an optical knife edge is required to be reserved between the double-opening width-adjustable optical slit and the laser power meter;
(2) Rotating the slit adjusting member so that the slit width is maximized; the hand-held light sensitive card observes laser and moves linearly up and down and left and right through the one-dimensional translation tableA slit, such that the laser passes completely through the slit and is in a visually centered position with respect to the slit; the handheld photosensitive card observes the laser, linearly moves the laser power meter up and down, left and right, enables the laser spot to be located at the visual centered position of the detection surface of the power meter, and records the complete laser power P at the moment 0 ；
(3) Rotating the slit adjusting member so that the slit width is zero; the handheld photosensitive card observes the laser, and the slit is moved linearly up and down, so that the laser and the central line of the slit are centered visually; slowly rotating the slit adjusting component to increase the slit width, and measuring the laser power by about P 0 Stopping rotation at the time of/10;
(4) Moving the position of the slit upwards to enable the slit to be positioned right above the laser spot, wherein the indication number of the laser power meter is 0; slowly moving the slit downwards to find the position with the maximum power meter reading, so that the laser power is higher than P 0 The slit width can be slowly reduced until the laser power meter indicates about P 0 /10, as in P 0 Near 10, optionally not adjusting the slit width, and recording the value a of the slit width micrometer;
(5) Moving the position of the slit upwards again to enable the slit to be positioned right above the laser spot, wherein the reading of the laser power meter is 0; slowly moving the slit downwards, finding the position with the maximum power meter reading to fix the upper and lower positions of the slit, and recording the power meter reading P at the moment l ；
Preferably, the steps of installing and positioning the optical knife edge are as follows:
(1) The knife edge is arranged behind the slit, and the slit adjusting part is rotated to increase the width of the slit so that the laser to be measured can completely pass through the slit; the laser light sensing card is held by hand, an optical knife edge is installed by referring to a laser optical axis, so that the left and right positions of the initial installation of the knife edge are positioned at the edge of a laser spot, and no shielding is ensured, namely the power meter reading is P 0 ；
(2) The knife edge is moved back and forth through the one-dimensional linear translation table, so that the front and back physical positions are infinitely close to each other under the condition that the optical knife edge and the slit can normally move;
(3) Restoring the width index a of the slit, slowly moving the knife edge to the left, and when the laser power meter showsWhen the number is decreased, the knife edge is slowly moved to the right until the power meter shows that the number is P l When the knife edge is moved, the moving of the knife edge is stopped, and the left and right initial positions of the knife edge are determined;
preferably, the testing steps of the spot power are as follows:
carrying out data test on the movable knife edge, taking a fixed micro variable delta X as a stepping movable optical knife edge along an X axis, recording the laser power before each movement, and stopping recording until the indication number of a laser power meter is 0; recording laser power value of P 1…i Apparently, P 1 ＝P l ，P i ＝0。
Preferably, the laser power data is processed to finally obtain the spot size of the laser to be measured, and the steps are as follows:
referring to the laser principle, the relation between the laser intensity I and the power P is I = P/A; wherein A represents the spot area; as shown in the abstract figure 2, the light spot to be measured is converted into an approximate line light spot through a slit, the line light spot is cut into a plurality of approximate point light spots through knife edge micro variables, and the area of the point light spot is S = L x delta x;
(1) Calculating and obtaining the power P 'of each approximate point light spot according to the recorded data' 1...n ＝P i-1 -P i Then P is 1 '＝P l -P 2 ，P' n ＝P i-1 And reading approximate point light spot maximum power value P 'from the same' n-max ；
(2) Spot light intensity
Central light intensity of
Get the light intensity percentage normalized function as
Eta (x) is 0 to 1; the starting position of the knife edge is regarded as an X-axis 0 point,
eta (x) should be plotted on the abscissa of
Drawing a normalized function curve;
(3) Attenuation of light intensity to 1/e of central light intensity according to laser spot size 2 When the spot size is taken as eta (x) =13.5%, the abscissa of the function curve is x 1 And x 2 Obtaining an approximate line spot size D = x through the slit 2 -x 1 (ii) a The slit is positioned at the center of the light spot to be detected, and the X-axis direction dimension of the light spot to be detected is equivalent to D' = D = X 2 -x 1 。
The invention solves the problem that the size of the light spot can not be directly measured by irregular multimode laser, and is particularly suitable for measuring the size of the light spot of a fast and slow axis at a fixed position of laser output.
The invention has the following advantages:
the laser beam is no longer a gaussian beam due to mode competition in laser generation. Currently, two methods are commonly used for measurement: knife edge methods or spot analyzers. The traditional knife edge method measurement can only test Gaussian spots substantially, and the test algorithm of the traditional knife edge method measurement aims at Gaussian beams, so that large errors exist in experimental measurement for multimode irregular spots. For a spot analyzer, firstly, the light energy accepted by a detector of the spot analyzer is very limited, so that the spot analyzer is usually tested under low power, and for high-power laser, a spot under low output is different from a high-power spot, so that the test for a high-power irregular spot has errors; secondly, the cost is high, and the device cannot be matched with a light spot analyzer in some scientific research scenes. The laser to be measured is approximated to a linear light source through the double-opening width-adjustable optical slits and approximated to a point light source through the optical knife edge. The line light source at the strongest light intensity solves the problems that the traditional knife edge cannot be accurately tested and the light spot analyzer has a low threshold value; the principle that the knife edge is similar to a point light source is equivalent to a facula analyzer, but the cost problem is solved to a great extent. The testing device is simple and clear, and has stronger practicability for testing the multimode irregular high-power laser facula in scientific research.
Drawings
FIG. 1 is a flow chart of a method for testing the spot size of an irregular laser;
FIG. 2 is a schematic view of a testing apparatus for an irregular laser spot size testing method;
FIG. 3 is a structural diagram of a one-dimensional linear translation stage of the irregular laser spot size test method;
FIG. 4 is a schematic diagram of a light spot test analysis principle of an irregular laser light spot size test method;
FIG. 5 is a 976nm collimated semiconductor laser fast axis spot normalization function graph tested by an irregular laser spot size testing method.
Reference numerals:
1. double-opening width-adjustable optical slits; 11. a first slit surface; 12. a second slit surface; 13. a slit; 2. a laser power meter; 3. an optical edge.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Example 1
As shown in fig. 1, a method for testing the spot size of an irregular laser comprises the following steps:
s1, as shown in figures 2-3, a double-opening width-adjustable optical slit 1 is installed on a three-dimensional adjusting system, a laser to be tested is arranged in front of the double-opening width-adjustable optical slit 1, a laser power meter 2 is arranged at the rear of the double-opening width-adjustable optical slit 1, the width of the double-opening width-adjustable optical slit 1 is adjustable, and the laser to be tested outputs irregular multi-mode light spots;
s2, adjusting the width and the height of the slit of the double-opening width-adjustable optical slit 1 to obtain the complete laser power P of the laser to be measured 0 Light spot test power P l Sum spot test power P l The slit width a;
s21, adjusting the slit width of the double-opening width-adjustable optical slit 1 to the maximum,linearly moving the double-opening width-adjustable optical slit 1 up and down and left and right, observing laser by the aid of the handheld photosensitive card, fixing the slit when the laser output by the laser to be detected completely passes through the slit and is positioned at the visual centered position of the slit, and then linearly moving the laser power meter 2 up and down until a laser spot is positioned at the visual centered position of the detection surface of the laser power meter 2, so that complete laser power P is obtained 0 ；
S22, adjusting the slit width of the double-opening width-adjustable optical slit 1 to be zero, observing laser by using a photosensitive card, moving the double-opening width-adjustable optical slit 1 up and down linearly until the laser is in visual alignment with the central line of the double-opening width-adjustable optical slit 1, and then slowly increasing the slit width until the numerical value of the laser power meter 2 is the threshold value P k ，P k ＜P 0 Threshold value P k Is P 0 /10；
S23, moving the double-opening width-adjustable optical slit 1 upwards until the slit is positioned right above the laser spot, wherein the numerical value of the laser power meter 2 is 0, then slowly moving the double-opening width-adjustable optical slit 1 downwards, and counting the maximum value of the power meter of the laser power meter 2 and the maximum value of the power meter and the maximum value P k If greater than P k Then the slit width is slowly decreased until the count value is P k Recording the slit width a at this time; if approaching P k Directly recording the width a of the slit at the moment;
s24, moving the double-opening width-adjustable optical slit 1 upwards again to enable the slit to be located right above the laser spot, wherein the value of the laser power meter 2 is 0; slowly moving the double-opening width-adjustable optical slit 1 downwards until the readings of the laser power meter 2 are fixed when the maximum, wherein the readings of the laser power meter 2 are the facula test power P l ；
S3, the optical knife edge 3 is installed on another three-dimensional adjusting system and is arranged close to the back of the double-opening width-adjustable optical slit 1 under the condition that the double-opening width-adjustable optical slit 1 and the optical knife edge 3 can normally move, the position of the optical knife edge 3 is adjusted, and the slit width a and the light spot testing power P are obtained l The initial position of the optical knife edge;
s31, mounting the optical blade 3 on another bladeThe three-dimensional adjusting system is arranged at the rear part of the double-opening width-adjustable optical slit 1, the width of the slit is increased until all laser output by the laser to be detected passes through the double-opening width-adjustable optical slit 1, then a laser light sensing card is used, the laser optical axis is taken as a reference, the initial left and right positions of the optical knife edge 3 are positioned at the edge of a laser spot and do not shield the laser, and the numerical value of the laser power meter 2 is the complete laser power P 0 ；
S32, moving the optical knife edge 3 back and forth through a three-dimensional adjusting system, and enabling the optical knife edge 3 to be tightly attached to the back of the double-opening width-adjustable optical slit 1 under the condition that the double-opening width-adjustable optical slit 1 and the optical knife edge 3 can normally move;
s33, adjusting the slit width of the double-opening width-adjustable optical slit 1 to be a slit width a, moving the optical knife edge 3 leftwards until the reading of the laser power meter 3 is reduced, stopping moving the optical knife edge 3 rightwards slowly until the reading P of the laser power meter 3 is reduced l Stopping the operation to obtain the initial position of the optical knife edge;
s4, moving the optical knife edge 3 along the X axis by taking a fixed variable delta X as a step, and recording the laser power P before moving each time i Stopping recording until the index of the laser power meter 2 is 0, I =1, \ 8230;, I, P 1 ＝P l ，P I ＝0；
S5, according to the laser power P i Obtaining the power P of the approximate point light spot n ', maximum power value P ' of approximate point light spot ' n-max And a light intensity percentage normalization function eta (x), where P n '＝P i-1 ﹣P i ，n＝i-1；
The light intensity percentage normalization function η (x) is:
wherein, I x Is the spot light intensity, I max Eta (x) is 0-1 as central light intensity;
spot light intensity
Central light intensity of
The slit converts the light spots to be detected into approximate linear light spots, the knife edge approximate linear light spots are cut into a plurality of approximate point light spots, and L is the number of the approximate point light spots;
in the step S3, the initial position of the optical knife edge is an X-axis 0 point, and the abscissa of η (X) is:
s6, drawing a normalization function curve to obtain an approximate line light spot size D and an approximate point light spot size D' corresponding to eta (x), and completing the test of the irregular laser light spot size;
the approximate line spot size D is: d = x 2 -x 1 Wherein x is 1 、x 2 Is the abscissa corresponding to eta (x) in the curve of the normalization function;
the approximate spot size D' is: d' = D = x 2 -x 1 ；
The double-opening width-adjustable optical slit 1 comprises a first slit surface 11 arranged at the upper part, a second slit surface 12 arranged at the lower part and a slit 13 positioned between the first slit surface 11 and the second slit surface 12, wherein the first slit surface 11 and the second slit surface 12 can move synchronously, the width of the slit 13 is adjustable, and the slit 13 is used for cutting light spots;
the three-dimensional adjusting system comprises three one-dimensional linear translation tables and is used for adjusting the high and low positions, the left and right positions and the front and back positions;
the laser power meter 2 is arranged on a two-dimensional adjusting system, the two-dimensional adjusting system comprises two one-dimensional linear translation tables, and the two-dimensional adjusting system is used for adjusting the height position and the left and right positions of the laser power meter 2;
the double-opening width-adjustable optical slit 1, the laser power meter 2, the optical knife edge 3, the laser to be measured, the three-dimensional adjusting system, the two-dimensional adjusting system and the photosensitive card are all arranged on the optical platform;
the laser power meter 2 is a pyroelectric light power meter;
the optical knife edge 3 is a metal knife edge.
Example 2
As shown in fig. 1, a method for testing the size of an irregular laser spot;
as shown in fig. 2 to 3, the test apparatus includes: double-opening width-adjustable optical slit 1: the adjusting part is rotated to realize synchronous movement of two surfaces of the slit, the width of the slit is adjusted, and cutting of light spots is realized, and the test device adopts a Thorlabs VA100 adjustable mechanical slit;
laser power meter 2: a common pyroelectric optical power meter 2;
the optical knife edge 3: the common single-side black blade adopted by the testing device can receive high-power laser and has low laser reflectivity;
laser sensitive card: in the embodiment, VRC2 of Thorlabs is adopted as a photosensitive material card for converting invisible-waveband laser into visible light spots;
the laser device to be tested: outputting irregular, high-power and multi-mode laser, wherein the laser to be tested is 976nm collimated semiconductor multi-mode laser, the laser spot size at a position 15cm away from a light outlet is tested, and the average power is 4.5W;
one-dimensional linear translation stage: the laser power meter is assembled on a three-dimensional adjusting system which is composed of 3 one-dimensional linear translation tables and can adjust the height, the left position, the right position and the front position, and the laser power meter is assembled on an adjusting system which is composed of 2 one-dimensional linear translation tables and can adjust the height, the left position and the right position; the whole set of test device is arranged on the optical platform.
The invention relates to a laser spot size testing method, which comprises the following implementation modes:
firstly, installing and positioning a double-opening width-adjustable slit 1 and a laser power meter 2 according to laser to be detected: the slit adjusting system 1 and the laser power meter 2 are preliminarily installed on the optical platform by referring to a laser optical axis and according to the light spot test requirement of the 15cm laser to be tested, and a space for installing the optical knife edge 3 is reserved between the slit adjusting system 1 and the laser power meter. Adjusting the front and back positions of the slit by a one-dimensional translation table until the distance between the slit and the slit is 15cm; the slit adjusting member is rotated so that the slit width is maximized, which is 6.4mm in this embodiment. The handheld photosensitive card observes laser, and the slit is linearly moved up and down and left and right through the one-dimensional translation table, so that the laser completely passes through the slit and is positioned at a visual centered position of the slit; the hand-held light sensing card observes the laser, the laser power meter 2 is moved linearly up, down, left and right, the laser spot is positioned at the vision centered position of the detection surface of the power meter, and the complete laser power is recorded to be 4.5W; rotating the slit adjusting component to make the slit width zero, observing laser by holding the photosensitive card, moving the slit up and down linearly to make the laser and the slit central line be in the center visually, slowly rotating the slit adjusting component to increase the slit width, and the indication number of the laser power meter 2 is about P 0 At/10, 450mw in this example, the rotation is stopped.
Moving the position of the slit upwards to enable the slit to be positioned right above the laser spot, wherein the index of the laser power meter 2 is 0; slowly moving the slit downwards to find the position with the maximum reading of the power meter 2, so that the laser power is compared with P 0 The slit width is slowly reduced until the laser power meter shows 450mw, and the value a of the slit width micrometer is recorded, wherein the value a of the slit width is 248 mu m; moving the position of the slit upwards again to enable the slit to be positioned right above the laser spot, wherein the number indicated by the laser power meter 2 is 0; slowly moving the slit downwards, finding the position with the maximum reading of the power meter 2 to fix the upper and lower positions of the slit, and recording the reading P of the power meter at the moment l This embodiment is 455mw.
And (3) carrying out installation and positioning of the optical knife edge 3: the knife edge is arranged behind the slit 1, and the slit adjusting part is rotated to increase the width of the slit so that the laser to be measured can completely pass through the slit; the hand-held laser sensitive card is provided with an optical knife edge 3 by referring to the laser optical axis, so that the knife edge is justThe left and right positions of the laser device are positioned at the edge of the laser facula and ensure no shielding, namely the power meter reading is P 0 In this example, 4.5W; the knife edge is moved back and forth through the one-dimensional linear translation table, so that the front and back physical positions are infinitely close to each other under the condition that the optical knife edge 3 and the slit 1 can normally move;
the index a of the width of the recovery slit is 248 μm in this embodiment; slowly moving the knife edge 3 leftwards, and slowly moving the knife edge 3 rightwards when the reading of the laser power meter is reduced until the reading of the power meter is P l At this time, 455mw in this embodiment, the movement of the knife edge 3 is stopped, and the left and right initial positions of the knife edge 3 are determined.
Carrying out a light spot power test: the movable knife edge 3 is used for carrying out data testing, the optical knife edge 3 is moved in a stepping mode by taking a fixed tiny variable along the X axis, the laser power at the moment is recorded before each movement, the recording is stopped until the index of the laser power meter 2 is 0, and the value of delta X in the embodiment is 100 micrometers; recording laser power value of P 1…i Apparently, P 1 ＝P l ＝455mw，P i =0, the present embodiment totals 43 power points, i.e., i =43.
Carrying out laser power data processing to obtain the spot size of the laser to be detected: referring to the laser principle, the relation between the laser light intensity I and the power P is I = P/A; wherein A represents the spot area; as shown in fig. 2, converting the light spot to be measured into an approximate line light spot through a slit, cutting the light spot into a plurality of approximate point light spots through a knife edge tiny variable, wherein the area of the point light spot is S = L x Δ x; calculating and obtaining the power P 'of each approximate point light spot according to the recorded data' 1...n ＝P i-1 -P i Then P is 1 '＝P l -P 2 ，P n '＝P i-1 And reading approximate point light spot maximum power value P 'from the same' n-max In this embodiment, n is 42;
spot light intensity
Central light intensity of
Get the light intensity percentage normalized function as
Eta (x) is 0 to 1; as shown in FIG. 4, the starting position of the knife edge is regarded as the X-axis 0 point, and η (X) should be represented by the abscissa
Drawing a normalized function curve; attenuation of light intensity to 1/e of central light intensity according to laser spot size 2 When the spot size is taken as eta (x) =13.5%, the abscissa of the function curve is x 1 And x 2 The present embodiments are 0.5369 and 3.1328, respectively, and an approximate line spot size D = x is obtained through the slit 2 -x 1 In this example, 2.6459mm; the slit is positioned at the center of the light spot to be detected, and the X-axis direction dimension of the light spot to be detected is equivalent to D' = D = X 2 -x 1 =2.6459mm; the data processing process of this embodiment is shown in the following table, the values of the function curves are shown in fig. 5, and the light spots can be seen to be non-gaussian and irregular light spots from the normalized function curves.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (10)
1. A method for testing the spot size of irregular laser is characterized by comprising the following steps: the method comprises the following steps:
s1, installing a double-opening adjustable-width optical slit (1) on a three-dimensional adjusting system, arranging a laser to be tested at the front part of the double-opening adjustable-width optical slit (1), arranging a laser power meter (2) at the rear part of the double-opening adjustable-width optical slit (1), wherein the slit width of the double-opening adjustable-width optical slit (1) is adjustable, and outputting an irregular multi-mode light spot by the laser to be tested;
s2, adjusting the slit width and the slit height of the double-opening width-adjustable optical slit (1) to obtain the complete laser power P of the laser to be tested 0 Light spot test power P l Sum spot test power P l The slit width a;
s3, install optics edge of a knife (3) on another three-dimensional adjustment system and be in two open adjustable width optical slits (1) with but hug closely under the condition that optics edge of a knife (3) can normally move two back settings of opening adjustable width optical slits (1), the adjustment optics edge of a knife (3) the position obtains the slit width for an, facula test power is P l The initial position of the optical knife edge;
s4, moving the optical knife edge (3) along the X axis by taking a fixed variable delta X as a step, and recording the laser power P before each movement i Stopping recording until the index of the laser power meter (2) is 0, I =1, \8230, I, P 1 ＝P l ，P I ＝0；
S5, according to the laser power P i To obtain an approximate spot light power P' n And the maximum spot light power value P' n-max And a light intensity percentile normalization function eta (x), wherein P' n ＝P i-1 ﹣P i ，n＝i-1；
S6, drawing a normalization function curve to obtain an approximate line light spot size D and an approximate point light spot size D' corresponding to eta (x), and completing the test of the irregular laser light spot size.
2. The irregular laser spot size test method of claim 1, wherein: the step S2 comprises the following steps:
s21, will two slit width adjustment that open adjustable width optics slit (1) are biggest, about from top to bottom rectilinear movement two open adjustable width optics slit (1), handheld sensitization card observation laser the laser of await measuring laser output passes through the slit completely and fixes the slit when being in slit vision position placed in the middle, will again laser power meter (2) rectilinear movement about from top to bottom until the laser facula is located it is fixed when the detection face vision position placed in the middle of laser power meter (2) is fixed, obtains complete laser power P 0 ；
S22, will two slit width adjustment that open adjustable width optical slit (1) are zero, use the sensitive optical card to observe laser, linear motion from top to bottom two open adjustable width optical slit (1), until laser with two central line vision that open adjustable width optical slit (1) are placed in the middle, increase slit width slowly again, until the numerical value of laser power meter (2) is threshold value P k ，P k ＜P 0 ；
S23, moving the double-opening width-adjustable optical slit (1) upwards until the slit is positioned right above the laser spot, wherein the numerical value of the laser power meter (2) is 0, then slowly moving the double-opening width-adjustable optical slit (1) downwards, and combining the maximum numerical value of the power meter of the laser power meter (2) with the maximum numerical value of the power meter of the laser power meter (2) and the maximum numerical value of the power meter of the laser power meter and P k If greater than P k Then the slit width is slowly decreased until the count value is P k Recording the slit width a at the time; if approaching P k Directly recording the width a of the slit at the moment;
s24, moving the double-opening width-adjustable optical slit (1) upwards again to enable the slit to be positioned right above the laser spot, wherein the numerical value of the laser power meter (2) is 0; slowly moving the double-opening width-adjustable optical slit (1) downwards until the readings of the laser power meter (2) are fixed when the maximum, wherein the readings of the laser power meter (2) are the facula test power P l 。
3. The irregular laser spot size test method of claim 1, wherein: the step S3 comprises the following steps:
s31, install optics edge of a knife (3) on another three-dimensional adjustment system and set up the two rear portions that open adjustable width optics slit (1), increase slit width until the laser that awaits measuring the laser instrument output is all passed through two open adjustable width optics slit (1), reuse laser sense optical card to the laser optical axis is the benchmark, will the initial left and right sides position of optics edge of a knife (3) is located the edge of laser facula, does not shelter from laser, this moment the numerical value of laser power meter (2) does complete laser power P 0 ；
S32, moving an optical knife edge (3) back and forth through the three-dimensional adjusting system, and tightly attaching the optical knife edge (3) to the back of the double-opening adjustable-width optical slit (1) under the condition that the double-opening adjustable-width optical slit (1) and the optical knife edge (3) can normally move;
s33, adjusting the slit width of the double-opening width-adjustable optical slit (1) to be the slit width a, moving the optical knife edge (3) leftwards until the reading of the laser power meter (3) is reduced, stopping moving the optical knife edge (3) slowly rightwards until the reading P of the laser power meter (3) is reduced l Stopping the operation, and obtaining the initial position of the optical knife edge.
4. The irregular laser spot size test method of claim 1, wherein: in step S5, the light intensity percentage normalization function η (x) is:
wherein, I x Is the spot light intensity, I max Eta (x) is 0 to 1.
5. The irregular laser spot size test method of claim 4, wherein:
spot light intensity
Central light intensity of
The slit converts the light spots to be detected into approximate linear light spots, the approximate linear light spots are cut into a plurality of approximate point light spots by a knife edge, and L is the number of the approximate point light spots;
6. the irregular laser spot size testing method of claim 4, wherein: in the step S3, the initial position of the optical knife edge is an X-axis 0 point, and the abscissa of η (X) is:
7. the irregular laser spot size testing method according to claim 1, wherein: the approximate line spot size D is: d = x 2 -x 1 Wherein x is 1 、x 2 The abscissa corresponding to eta (x) in the normalization function curve;
the approximate spot size D' is: d' = D = x 2 -x 1 。
8. The irregular laser spot size testing method of claim 2, wherein: threshold value P k Is P 0 /10。
9. The irregular laser spot size testing method according to claim 1, wherein: the double-opening width-adjustable optical slit (1) comprises a first slit surface (11) arranged at the upper part, a second slit surface (12) arranged at the lower part and a slit (13) positioned between the first slit surface (11) and the second slit surface (12), wherein the first slit surface (11) and the second slit surface (12) can move synchronously, the width of the slit (13) is adjustable, and the slit (13) is used for cutting light spots;
the three-dimensional adjusting system comprises three one-dimensional linear translation tables and is used for adjusting the height position, the left position, the right position and the front position and the rear position;
the laser power meter (2) is arranged on a two-dimensional adjusting system, the two-dimensional adjusting system comprises two one-dimensional linear translation tables, and the two-dimensional adjusting system is used for adjusting the height position and the left-right position of the laser power meter (2);
the two-opening width-adjustable optical slit (1), the laser power meter (2), the optical knife edge (3), the laser to be detected, the three-dimensional adjusting system, the two-dimensional adjusting system and the photosensitive card are all arranged on the optical platform.
10. The irregular laser spot size test method of claim 1, wherein: the laser power meter (2) is a pyroelectric power meter;
the optical knife edge (3) is a metal knife edge.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116753839A (en) * | 2023-08-17 | 2023-09-15 | 苏州大学 | Device and method for measuring submicron laser spot size by utilizing beam polarization |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001223413A (en) * | 2000-02-10 | 2001-08-17 | Ricoh Co Ltd | Collimate measuring device and measuring method |
| CN102243062A (en) * | 2011-04-13 | 2011-11-16 | 西安理工大学 | Measurement device and method for spot central coordinates of ultra-short pulse laser |
| CN203732020U (en) * | 2014-01-17 | 2014-07-23 | 浙江师范大学 | Device for measuring Gauss beam waist position and dimension of tunable semiconductor laser |
-
2022
- 2022-07-28 CN CN202210903597.5A patent/CN115451824A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001223413A (en) * | 2000-02-10 | 2001-08-17 | Ricoh Co Ltd | Collimate measuring device and measuring method |
| CN102243062A (en) * | 2011-04-13 | 2011-11-16 | 西安理工大学 | Measurement device and method for spot central coordinates of ultra-short pulse laser |
| CN203732020U (en) * | 2014-01-17 | 2014-07-23 | 浙江师范大学 | Device for measuring Gauss beam waist position and dimension of tunable semiconductor laser |
Non-Patent Citations (1)
| Title |
|---|
| 周鹏;王淑梅;刘强;: "测量高斯光束腰斑尺寸的实验与分析", 光学仪器, no. 05, 15 October 2009 (2009-10-15) * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116753839A (en) * | 2023-08-17 | 2023-09-15 | 苏州大学 | Device and method for measuring submicron laser spot size by utilizing beam polarization |
| CN116753839B (en) * | 2023-08-17 | 2023-11-07 | 苏州大学 | Device and method for measuring submicron laser spot size by utilizing beam polarization |
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