CN112986140B - A time-resolved imaging system suitable for laser beam shaping and imaging method thereof - Google Patents
A time-resolved imaging system suitable for laser beam shaping and imaging method thereof Download PDFInfo
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- CN112986140B CN112986140B CN201911300809.5A CN201911300809A CN112986140B CN 112986140 B CN112986140 B CN 112986140B CN 201911300809 A CN201911300809 A CN 201911300809A CN 112986140 B CN112986140 B CN 112986140B
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Abstract
The invention relates to a time resolution imaging system suitable for laser beam shaping and an imaging method thereof, wherein the time resolution imaging system comprises a beam shaping system, an image acquisition system, a signal control system, a signal detection system and a light path collimation system, the beam shaping system comprises a pulse laser, a control terminal and a spatial light modulator, the time resolution imaging system suitable for laser beam shaping can set a target shape of an output laser beam required by the pulse laser according to requirements, and the target shape of the laser beam can be a circular Gaussian beam or other shape of the laser beam, so that the transient change condition of the material surface morphology of a surface material of a sample to be observed after the surface material is irradiated by the laser beams of different shapes is achieved, and the observation requirements of the Gaussian circular beam and other beams of different shapes are met.
Description
Technical Field
The invention relates to the field of laser beam shaping and time resolution, in particular to a time resolution imaging system and a time resolution imaging method suitable for laser beam shaping.
Background
In the process of preparing a functional structure of a material surface by using a pulsed laser, the laser is irradiated to the material surface in an extremely short time to cause various thermodynamic processes such as gasification, ablation, melting, oxidation, etc. to occur on the material surface. Therefore, systematically studying transient changes in the laser-substance interaction process is of great importance for improving the manufacturing process level of optoelectronic and microelectronic devices.
Recording the change of the morphology of the material caused by the laser applied to the surface of the material by using a time resolution imaging technology is an effective method, and can directly observe the transient evolution process of the morphology of the surface of the material caused by the high-energy laser after being radiated to the material in a time range of nanometer precision. Because the current laser outputs a generally circular gaussian beam, conventional time-resolved imaging systems record the transient evolution of the circular gaussian beam radiation into the material. However, in practical laser micro-nano processing, different processing requirements are required for different processing devices, which also makes more demands on the beam of laser light and the shape thereof. In order to meet the different beam shapes of the laser, a conventional time-resolved imaging system is required to record not only the transient evolution process caused by the irradiation of the current gaussian circular beam to the surface of the material, but also the transient change of the topography of the surface of the material caused by the interaction of the different-shaped beam and the surface of the material.
However, the conventional time-resolved imaging system cannot meet the requirements of observing both gaussian circular beams and other beams of different shapes.
Disclosure of Invention
The first technical problem to be solved by the present invention is to provide a time-resolved imaging system suitable for laser beam shaping in the above prior art. The time resolution imaging system can record transient morphology evolution process generated after laser beams with any shape are radiated to the surface of a sample material to be measured, and meets the observation needs of taking into account Gaussian circular beams and beams with other different shapes.
The second technical problem to be solved by the present invention is to provide an imaging method of the above time-resolved imaging system.
The invention solves the first technical problem and adopts the technical scheme that the time resolution imaging system suitable for laser beam shaping is characterized by comprising a beam shaping system, an image acquisition system, a signal control system, a signal detection system and a light path collimation system, wherein:
The beam shaping system comprises:
a pulsed laser;
The spatial light modulator is used for spatially shaping the light beam emitted by the pulse laser into a laser light beam with a target spatial shape;
the control terminal is connected with the spatial light modulator and is used for setting the modulation mode of the spatial light modulator;
the image acquisition system includes:
a flash lamp for emitting a flash signal;
The image acquisition device is connected with the control terminal and is used for recording images generated on the surface of the sample at the moment of flash lamp flickering;
the signal control system includes:
The signal generator is respectively connected with the pulse laser and the flash lamp, and is used for respectively triggering the pulse laser to output a pulse laser signal and triggering the flash lamp to emit a flash signal and controlling triggering delay time between the pulse laser and the flash lamp;
The signal detection system includes:
The first photoelectric signal detector is used for detecting pulse laser signals output by the pulse laser after being modulated by the spatial light modulator;
the second photoelectric signal detector is used for detecting a flash signal emitted when the flash lamp flashes;
The oscilloscope is respectively connected with the first photoelectric signal detector and the second photoelectric signal detector and is used for recording and obtaining the actual delay time between the pulse laser signal and the flash lamp signal according to signals sent by the first photoelectric signal detector and the second photoelectric signal detector;
The optical path collimation system comprises:
The polarizing plate is positioned in front of the pulse laser and is arranged opposite to the emitting end of the pulse laser, and is used for converting the output light beam of the pulse laser into linearly polarized light;
the half-wave plate is positioned between the polaroid and the spatial light modulator, is opposite to the emitting end of the pulse laser and is used for changing the polarization direction of linearly polarized light generated by the polaroid;
the first beam splitter is positioned between the half-wave plate and the spatial light modulator;
The second beam splitter is arranged opposite to the image acquisition device, and a notch filter is arranged between the second beam splitter and the image acquisition device;
The first convex lens is positioned between the first beam splitter and the second beam splitter, and the two convex surfaces of the first convex lens are respectively opposite to the first beam splitter and the second beam splitter;
The second convex lens is positioned between the second beam splitter and the first photoelectric signal detector, and two convex surfaces of the second convex lens are respectively opposite to photoelectric signal detection ends of the second beam splitter and the first photoelectric signal detector, wherein the second convex lens, the first beam splitter, the first convex lens and the second beam splitter are positioned on the same central line;
The first focusing objective lens is arranged opposite to the second beam splitter; the first beam splitter is used for directing the received laser beam to the spatial light modulator and emitting the reflected beam modulated by the spatial light modulator from one side of the first beam splitter; the second beam splitter is used for splitting the received laser beam signal into a laser beam signal which is emitted to the first focusing objective lens and a laser beam signal which is emitted to the second convex lens;
The second focusing objective is arranged opposite to the first focusing objective, and a space for placing a sample to be measured is formed between the second focusing objective and the first focusing objective;
the third convex lens is positioned between the flash lamp and the second photoelectric signal detector, and one convex surface of the third convex lens is opposite to the flash lamp;
The half-reflecting lens is positioned between the third convex lens and the second photoelectric signal detector, one side of the half-reflecting lens is arranged opposite to the second focusing objective lens and is used for dividing a flash light signal emitted by the flash light into a flash light beam signal emitted by the second focusing objective lens and a flash light beam signal emitted by the second photoelectric signal detector, and the half-reflecting lens, the second beam splitter, the first focusing objective lens and the second focusing objective lens are all positioned on the same central line.
In the time-resolved imaging system suitable for laser beam shaping, the trigger interval time of the signal generator for triggering the flash lamp and the pulse laser is the difference between the trigger delay time for the flash lamp and the trigger delay time for the pulse laser plus the interval time required for experiments.
In the time resolution imaging system suitable for laser beam shaping, a fourth convex lens is arranged between the first beam splitter and the first convex lens, and the fourth convex lens and the first convex lens are positioned on the same center and are opposite to each other.
In a further development, the focal length of the first convex lens is different from the focal length of the fourth convex lens.
Further, in the time-resolved imaging system suitable for laser beam shaping, a focal length of the first convex lens is different from a focal length of the second convex lens.
Still further, in the time-resolved imaging system suitable for shaping a laser beam, a fourth convex lens is disposed between the first beam splitter and the first convex lens, and the fourth convex lens and the first convex lens are located on the same center and are opposite to each other.
Further, the model of the spatial light modulator is HOLOEYE PLUTO-2-NIR-080, and the image acquisition device is a CCD image sensor.
The invention solves the second technical problem by adopting the technical scheme that the imaging method of the time resolution imaging system is characterized by comprising the following steps:
step 1, setting a target shape required to be modulated by a spatial light modulator by using a control terminal;
step 2, the spatial light modulator modulates the received laser beam into a laser beam with the target shape;
step 3, the signal generator respectively sets a laser signal to be triggered of the pulse laser and a flash signal to be triggered of the flash lamp;
Step 4, setting a first trigger time interval time between a laser signal to be triggered of a pulse laser and a flash signal to be triggered of a flash lamp to be zero, and triggering the pulse laser and the flash lamp simultaneously by the signal generator according to the first trigger time interval;
Step 6, the oscilloscope records the light beam signals sent by the first photoelectric signal detector and the second photoelectric signal detector simultaneously and calculates the delay time difference between the two, wherein the delay time of the light beam signals sent by the first photoelectric signal detector is marked as tau 1, the delay time of the light beam signals sent by the second photoelectric signal detector is marked as tau 2, and the delay time difference is marked as delta tau, delta tau=tau 2-τ1;
step 7, setting a second triggering time interval time between a laser signal to be triggered of the pulse laser and a flash signal to be triggered of the flash lamp again, and triggering the pulse laser and the flash lamp simultaneously by the signal generator according to the second triggering time interval time, wherein the second triggering time interval time is marked as delta T ', and is the sum of the target time length T required to be recorded and the delay time difference delta tau calculated in the step 6, and delta T' = delta tau+t;
Step 8, the oscilloscope records the beam signals sent by the first photoelectric signal detector and the second photoelectric signal detector again at the same time, calculates the delay time difference between the beam signals and the second photoelectric signal detector, and checks the calculated delay time difference with the target time length t to be recorded:
when the delay time difference is consistent with the target time length t required to be recorded, the step 9 is carried out, otherwise, the step 6 is carried out;
Step 9, the image acquisition device shoots and records the transient change of the topography of the upper surface of the sample to be detected at the flickering moment of the flashlight, and sends the shot and recorded transient change image of the topography to the control terminal;
and 10, the control terminal displays and records the morphology transient change image sent by the image acquisition device to obtain transient morphology characteristics of a group of pulse shaping light beams after the irradiation of the material time t.
The imaging method of the time resolution imaging system further comprises the steps of changing the target time length required to be recorded and repeating the steps 7-10.
Compared with the prior art, the invention has the advantages that:
Firstly, the time resolution imaging system suitable for laser beam shaping can modulate the laser beam shape output by a pulse laser through a spatial light modulator according to the requirement, and the light beam of the target shape can be a circular Gaussian beam or other light beams, so that the situation of transient change of the material surface morphology of the surface material of the sample to be detected after being radiated by the laser beams of different shapes can be recorded and the requirements for observing the transient change of the morphology of the Gaussian circular beam and the other light beams of different shapes and the material surface are met;
Secondly, by arranging the first convex lens and the fourth convex lens with different focal lengths, a 4f system can be formed by the first convex lens and the fourth convex lens together, a zero-order diffraction point generated by the center of the light beam after spatial light modulation is eliminated, and the required light beam can be ensured to be parallel light after passing through the two lenses, so that the first focusing objective lens can focus the light beam conveniently;
Finally, by arranging the notch filter at the front end of the image acquisition device, the notch filter can be used for filtering the laser pulse signals, so that the phenomenon that the image acquisition device records the morphology transient change of the surface of the sample to be detected due to the fact that the laser pulse enters the image acquisition device after being reflected by the sample is avoided.
Drawings
FIG. 1 is a schematic diagram of a time-resolved imaging system suitable for laser beam shaping according to a first embodiment of the present invention;
fig. 2 is a schematic flow chart of an imaging method of the time-resolved imaging system shown in fig. 1.
Fig. 3 is a schematic diagram of a time-resolved imaging system suitable for laser beam shaping in the second embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the embodiments of the drawings.
Example 1
As shown in fig. 1, the present embodiment provides a time-resolved imaging system suitable for laser beam shaping, including a beam shaping system, an image acquisition system, a signal control system, a signal detection system, and an optical path collimation system, wherein:
The beam shaping system comprises:
a pulse laser 1 for emitting a laser beam, which after emission will have a Gaussian circular beam;
A spatial light modulator 2 for spatially shaping the beam of light emitted by the pulse laser 1 into a laser beam having a target spatial shape, the spatial light modulator 2 being of the model HOLOEYE PLUTO-2-NIR-080 in particular to this embodiment;
A control terminal 3 connected to the spatial light modulator 2 for setting the modulation mode of the spatial light modulator 2, wherein the control terminal 3 usually adopts a computer, the laser beam is modulated into any shape by the spatial light modulator 2, and the spatial light modulator 2 is controlled by the control terminal 3. In the present embodiment, it is assumed that the shape of the laser beam is required to be a square flat-top beam;
the image acquisition system includes:
The flash lamp 4 can flash when starting to work so as to provide enough illumination to cooperate with a subsequent image acquisition device to work in an environment with darker light, namely, the light supplementing effect for the image acquisition device to work is achieved;
The image acquisition device 5 is connected with the control terminal 3, for example, the image acquisition device 5 adopts a CCD image sensor, the image acquisition device 5 records the morphology change of the material surface of the sample to be measured after the laser beam with the laser content irradiates the material surface of the sample to be measured, the morphology change of the laser pulse at different stages after the material surface of the sample to be measured irradiates can be recorded by setting different delay time, the flash lamp 4 flashes once to record the morphology feature of the surface of the sample to be measured under the time scale of 8ns, the morphology feature of the surface of the sample to be measured is incident into the image acquisition device 5, and finally, the image information is obtained;
the signal control system includes:
A signal generator 6 connected to the pulse laser 1 and the flash lamp 4, respectively, for triggering the pulse laser 1 to output a pulse laser signal and the flash lamp 4 to emit a flash signal, respectively, and controlling a trigger delay time difference for the pulse laser 1 and the flash lamp 4, for example, in the present embodiment, assuming that the trigger delay time of the pulse laser 1 is marked with τ 1,τ1 >0, the trigger delay time of the flash lamp 4 is marked with τ 2,τ2 >0, and the trigger delay time difference between the two is Δτ=τ 2-τ1, and the signal generator 6 triggers the pulse laser 1 and the flash lamp 4 simultaneously;
In this embodiment, the trigger signal interval time between the triggering of the pulse laser 1 by the signal generator 6 and the triggering of the flash lamp 4 by the signal generator 6 is marked as DeltaT, and the trigger signal interval time is the difference Deltaτ between the trigger delay time for the flash lamp 4 and the trigger delay time for the pulse laser 1 plus the target time length T to be recorded;
As will be readily appreciated by those skilled in the art, the "target time length t to record" herein refers to a time set for obtaining a morphology change image of a sample to be measured under irradiation of a laser pulse, for example, a morphology change image of the sample to be measured under irradiation of a laser pulse for 10 ns, then the target time length t to record is 10 ns, and the "target time length t to record" may also be understood as an interval time t required for the laser beam shaping experiment;
The signal detection system includes:
a first photoelectric signal detector 7 for detecting a pulse laser signal output from the pulse laser 1;
a second photoelectric signal detector 8 for detecting a flash signal emitted when the flash lamp 4 flashes;
The oscilloscope 9 is respectively connected with the first photoelectric signal detector 7 and the second photoelectric signal detector 8 and is used for recording and obtaining the actual delay time between the pulse laser signal and the flash lamp signal according to the signals sent by the first photoelectric signal detector 7 and the second photoelectric signal detector 8, wherein the actual delay time obtained by the oscilloscope 9 can be used for determining the actual time of the morphological evolution process when the pulse laser irradiates to the surface of the sample material to be detected;
The optical path collimation system comprises:
a polarizing plate 100, which is disposed in front of the pulse laser 1 and is disposed opposite to the emitting end of the pulse laser 1, for converting the output beam of the pulse laser 1 into linearly polarized light;
a half-wave plate 10 located between the polarizing plate 100 and the spatial light modulator 2, the half-wave plate 10 being disposed opposite to the emission end of the pulse laser 1;
A first beam splitter 11 located between the half-wave plate 10 and the spatial light modulator 2;
A second beam splitter 12 disposed opposite to the image pickup device 5, a notch filter 13 being disposed between the second beam splitter 12 and the image pickup device 5;
The first convex lens 14 is positioned between the first beam splitter 11 and the second beam splitter 12, and the two convex surfaces of the first convex lens 14 are respectively opposite to the first beam splitter 11 and the second beam splitter 12;
The second convex lens 15 is positioned between the second beam splitter 12 and the first photoelectric signal detector 7, and two convex surfaces of the second convex lens 15 are respectively opposite to photoelectric signal detection ends of the second beam splitter 12 and the first photoelectric signal detector 7, wherein the second convex lens 15, the first beam splitter 11, the first convex lens 14 and the second beam splitter 12 are all positioned on the same central line;
the first focusing objective lens 16 is arranged opposite to the second beam splitter 12, wherein the first beam splitter 11 is used for splitting a received laser signal into a laser beam signal emitted to the first convex lens 14 and a laser beam signal emitted to the spatial light modulator 2, specifically, the pulse laser 1 is split into two beams by the first beam splitter 11, one beam is emitted to the spatial light modulator 2 in fig. 1, the other beam is emitted to the left side (not shown in fig. 1) of the first beam splitter 11, one beam emitted to the spatial light modulator 2 is modulated and then reflected, and the light is again emitted to the right through the first beam splitter 11 (but only emitted to the right) and is emitted to the right through the spatial light modulator 2;
the second beam splitter 12 is used for splitting the received laser beam signal into a laser beam signal which is directed to the first focusing objective lens 16 and a laser beam signal which is directed to the second convex lens 15;
a second focusing objective lens 17 disposed opposite to the first focusing objective lens 16, a space for placing a sample 18 to be measured being formed between the second focusing objective lens 17 and the first focusing objective lens 16;
a third convex lens 19 located between the flash lamp 4 and the second photoelectric signal detector 8, wherein one convex surface of the third convex lens 19 is arranged opposite to the flash lamp 4;
The half reflecting and half transmitting lens 20 is located between the third convex lens 19 and the second photoelectric signal detector 8, one side of the half reflecting and half transmitting lens 20 is opposite to the second focusing objective lens 17, and is used for dividing the flash light signal emitted by the flash lamp 4 into a flash light beam signal emitted to the second focusing objective lens 17 and a flash light beam signal emitted to the photoelectric signal detecting end of the second photoelectric signal detector 8, wherein the half reflecting and half transmitting lens 20, the second beam splitter 12, the first focusing objective lens 16 and the second focusing objective lens 17 are all located on the same central line.
In addition, the embodiment also provides an imaging method of the time resolution imaging system. Specifically, referring to fig. 1 and 2, the imaging method of the time-resolved imaging system includes the following steps:
Step 1, setting a target shape required to be modulated by a spatial light modulator 2 by using a control terminal 3;
Step 2, the spatial light modulator 2 modulates the received laser beam into a laser beam having a target shape;
Step 3, the signal generator 6 respectively sets a laser signal to be triggered of the pulse laser 1 and a flash signal to be triggered of the flash lamp 4;
Step 4, setting a first triggering time interval time between a to-be-triggered laser signal of the pulse laser 1 and a to-be-triggered flash signal of the flash lamp 4 to be zero, and triggering the pulse laser 1 and the flash lamp 4 by the signal generator 6 according to the first triggering time interval;
Step 5, the first photoelectric signal detector 7 and the second photoelectric signal detector 8 respectively receive the laser beam signal and the flash beam signal, and send the respectively received beam signals to the oscilloscope 9;
Step 6, the oscilloscope 9 records the light beam signals sent by the first photoelectric signal detector 7 and the second photoelectric signal detector 8 at the same time and calculates the delay time difference between the two, wherein the delay time of the light beam signals sent by the first photoelectric signal detector 7 is marked as tau 1, the delay time of the light beam signals sent by the second photoelectric signal detector 8 is marked as tau 2, and the delay time difference is marked as Deltatau and Deltatau=tau 2-τ1;
Step 7, setting a second triggering time interval time between the laser signal to be triggered of the pulse laser 1 and the flash signal to be triggered of the flash lamp again, and triggering the pulse laser 1 and the flash lamp 4 by the signal generator 6 according to the second triggering time interval time, wherein the second triggering time interval time is marked as delta T ', and the second triggering time interval time is the sum of the target time length T required to be recorded and the delay time difference delta tau calculated in the step 6, wherein the delta T' = delta tau+t;
Step 8, the oscilloscope 9 records the beam signals sent by the first photoelectric signal detector 7 and the second photoelectric signal detector 8 again simultaneously, calculates the delay time difference delta tau '"between the beam signals and the second photoelectric signal detector, and checks the calculated delay time difference delta tau'" with the target time length t to be recorded:
When the delay time difference Δτ '"is consistent with the target time length t of the required record, i.e., Δτ'" =t, step 9 is shifted, otherwise, the time checked by the oscilloscope 9 is described as having a problem, step 6 is shifted, wherein the person skilled in the art easily knows that the "target time length t of the required record" herein refers to the time set for obtaining the morphology change image of the sample to be measured under the irradiation of the laser pulse, for example, the target time length t of the required record is 10 seconds for obtaining the morphology change image of the sample to be measured under the irradiation of the laser pulse for 10 seconds;
Step 9, the image acquisition device 5 shoots and records the transient change of the topography of the upper surface of the sample 18 to be detected at the flickering moment of the flashlight 4, and sends the shot and recorded transient change image of the topography to the control terminal 3;
And step 10, the control terminal 3 displays and records the morphology transient change image sent by the image acquisition device 5 to obtain transient morphology features of a group of pulse shaping light beams after the irradiation of the material for time t.
Of course, in order to obtain more accurate images, after the step 10 is performed, the target time length t recorded in the experiment may be changed again, so as to repeat the steps 7-10, so as to obtain transient morphology features of the multiple groups of pulse shaping light beams after the irradiation of the material time t.
Example two
As shown in fig. 3, this embodiment provides another time-resolved imaging system suitable for laser beam shaping. Specifically, the difference from the first embodiment is that a fourth convex lens 21 is provided between the first beam splitter 11 and the first convex lens 14 in the second embodiment, and the fourth convex lens 21 and the first convex lens 14 are located on the same center and are disposed opposite to each other. Wherein the focal length of the first convex lens 14 is different from the focal length of the fourth convex lens 21. By disposing the fourth convex lens 21 between the first beam splitter 11 and the first convex lens 14, a 4f system can be formed by the first convex lens 14 and the fourth convex lens 21 together, which can effectively filter out the zero-order diffraction point generated by the spatial light modulator 2 and change the shaped light beam into a parallel light beam. As for the imaging method of the time-resolved imaging system in this embodiment, reference may be made to the first embodiment, and details thereof are omitted here.
While the preferred embodiments of the present invention have been described in detail, it is to be clearly understood that the same may be varied in many ways by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. The time resolution imaging system suitable for laser beam shaping is characterized by comprising a beam shaping system, an image acquisition system, a signal control system, a signal detection system and an optical path collimation system, wherein:
The beam shaping system comprises:
A pulsed laser (1);
a spatial light modulator (2) for spatially shaping a light beam emitted from the pulse laser (1) into a laser beam having a target spatial shape;
a control terminal (3) connected to the spatial light modulator (2) for setting a modulation scheme of the spatial light modulator (2);
the image acquisition system includes:
A flash lamp (4) for emitting a flash signal;
The image acquisition device (5) is connected with the control terminal (3) and is used for recording images generated on the surface of the sample at the moment of flash lamp flickering;
the signal control system includes:
the signal generator (6) is respectively connected with the pulse laser (1) and the flash lamp (4) and is used for respectively triggering the pulse laser (1) to output a pulse laser signal and triggering the flash lamp (4) to emit a flash signal, wherein the signal generator (6) simultaneously triggers the pulse laser (1) and the flash lamp (4);
The signal detection system includes:
The first photoelectric signal detector (7) is used for detecting a pulse laser signal output by the pulse laser (1) after being modulated by the spatial light modulator (2);
The second photoelectric signal detector (8) is used for detecting a flash signal emitted when the flash lamp (4) flashes;
The oscilloscope (9) is respectively connected with the first photoelectric signal detector (7) and the second photoelectric signal detector (8) and is used for recording and obtaining the actual delay time between the pulse laser signal and the flash lamp signal according to signals sent by the first photoelectric signal detector (7) and the second photoelectric signal detector (8);
The optical path collimation system comprises:
A polarizing plate (100) which is positioned in front of the pulse laser (1) and is arranged opposite to the emitting end of the pulse laser (1) for converting the output light beam of the pulse laser (1) into linearly polarized light;
A half-wave plate (10) positioned between the polaroid (100) and the spatial light modulator (2), wherein the half-wave plate (10) is arranged opposite to the emitting end of the pulse laser (1) and is used for changing the polarization direction of linearly polarized light generated by the polaroid (100);
the first beam splitter (11) is positioned between the half-wave plate (10) and the spatial light modulator (2);
A second beam splitter (12) which is disposed opposite to the image acquisition device (5), and a notch filter (13) is disposed between the second beam splitter (12) and the image acquisition device (5);
the first convex lens (14) is positioned between the first beam splitter (11) and the second beam splitter (12), and two convex surfaces of the first convex lens (14) are opposite to the first beam splitter (11) and the second beam splitter (12) respectively;
The second convex lens (15) is positioned between the second beam splitter (12) and the first photoelectric signal detector (7), and two convex surfaces of the second convex lens (15) are respectively opposite to photoelectric signal detection ends of the second beam splitter (12) and the first photoelectric signal detector (7), wherein the second convex lens (15) is positioned on the same central line with the first beam splitter (11), the first convex lens (14) and the second beam splitter (12);
The device comprises a first focusing objective lens (16) and a second beam splitter lens (12), wherein the first beam splitter lens (11) is used for transmitting a received laser beam to the spatial light modulator (2) and transmitting a reflected beam modulated by the spatial light modulator (2) from one side of the first beam splitter lens (11), and the second beam splitter lens (12) is used for splitting the received laser beam signal into a laser beam signal transmitted to the first focusing objective lens (16) and a laser beam signal transmitted to the second convex lens (15);
A second focusing objective (17) which is arranged opposite to the first focusing objective (16), wherein a space for placing a sample (18) to be measured is formed between the second focusing objective (17) and the first focusing objective (16);
The third convex lens (19) is positioned between the flash lamp (4) and the second photoelectric signal detector (8), and one convex surface of the third convex lens (19) is opposite to the flash lamp (4);
The half reflecting half lens (20) is positioned between the third convex lens (19) and the second photoelectric signal detector (8), one side of the half reflecting half lens (20) is opposite to the second focusing objective lens (17) and is used for dividing a flash light signal emitted by the flash light (4) into a flash light beam signal emitted to the second focusing objective lens (17) and a flash light beam signal emitted to a photoelectric signal detection end of the second photoelectric signal detector (8), and the half reflecting half lens (20) is positioned on the same central line with the second beam splitter (12), the first focusing objective lens (16) and the second focusing objective lens (17).
2. Time-resolved imaging system suitable for laser beam shaping according to claim 1, characterized in that the trigger interval time of the signal generator (6) for triggering a flash lamp and a pulse laser is the difference between the trigger delay time for the flash lamp and the trigger delay time for the pulse laser plus the interval time required for experiments.
3. Time-resolved imaging system suitable for laser beam shaping according to claim 2, characterized in that a fourth convex lens (21) is arranged between the first beam splitter (11) and the first convex lens (14), which fourth convex lens (21) is located on the same center as the first convex lens (14) and is arranged opposite to each other.
4. A time-resolved imaging system suitable for laser beam shaping according to claim 3, characterized in that the focal length of the first convex lens (14) is different from the focal length of the fourth convex lens (21).
5. The time-resolved imaging system suitable for laser beam shaping according to any of claims 1-4, wherein the spatial light modulator (2) is of model HOLOEYE PLUTO-2-NIR-080 and the image acquisition device (5) is a CCD image sensor.
6. An imaging method of the time-resolved imaging system of claim 4, comprising the steps of:
step 1, setting a target shape required to be modulated by a spatial light modulator by using a control terminal;
step 2, the spatial light modulator modulates the received laser beam into a laser beam with the target shape;
step 3, the signal generator respectively sets a laser signal to be triggered of the pulse laser and a flash signal to be triggered of the flash lamp;
step 4, setting a first triggering time interval time between a laser signal to be triggered of a pulse laser and a flash signal to be triggered of a flash lamp to be zero, and triggering the pulse laser and the flash lamp simultaneously by the signal generator according to the first triggering time interval;
Step 5, the first photoelectric signal detector and the second photoelectric signal detector respectively receive the laser beam signal and the flash beam signal, and send the respectively received beam signals to an oscilloscope;
Step 6, the oscilloscope records the light beam signals sent by the first photoelectric signal detector and the second photoelectric signal detector simultaneously and calculates the delay time difference between the two, wherein the delay time of the light beam signals sent by the first photoelectric signal detector is marked as tau 1, the delay time of the light beam signals sent by the second photoelectric signal detector is marked as tau 2, and the delay time difference is marked as delta tau, delta tau=tau 2-τ1;
step 7, setting a second triggering time interval time between a laser signal to be triggered of the pulse laser and a flash signal to be triggered of the flash lamp again, and triggering the pulse laser and the flash lamp simultaneously by the signal generator according to the second triggering time interval time, wherein the second triggering time interval time is marked as delta T ', and is the sum of the target time length T required to be recorded and the delay time difference delta tau calculated in the step 6, and delta T' = delta tau+t;
Step 8, the oscilloscope records the beam signals sent by the first photoelectric signal detector and the second photoelectric signal detector again at the same time, calculates the delay time difference between the beam signals and the second photoelectric signal detector, and checks the calculated delay time difference with the target time length t to be recorded:
when the delay time difference is consistent with the target time length t required to be recorded, the step 9 is carried out, otherwise, the step 6 is carried out;
Step 9, the image acquisition device shoots and records the transient change of the topography of the upper surface of the sample to be detected at the flickering moment of the flashlight, and sends the shot and recorded transient change image of the topography to the control terminal;
and 10, the control terminal displays and records the morphology transient change image sent by the image acquisition device to obtain transient morphology characteristics of a group of pulse shaping light beams after the irradiation of the material time t.
7. The method of claim 6, further comprising repeating steps 7-10 by changing a target time length of the desired recording.
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