CN115014569A - Ultrafast temperature measuring device and method for transparent object based on femtosecond laser - Google Patents
Ultrafast temperature measuring device and method for transparent object based on femtosecond laser Download PDFInfo
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Abstract
The invention belongs to the technical field of high-speed temperature measurement, and discloses an ultrafast temperature measurement device and method for a light-transmitting object based on femtosecond laser. The invention obtains the function relation between the transmissivity and the temperature of the observed transparent object through calibration, generates a femtosecond pulse with first power and first wavelength through a femtosecond laser, measures the power of the incident pulse before reaching an observed object on the emergent light path of a first microscope objective to obtain the incident power, measures the power of the transmission pulse after passing through the observed object to obtain the receiving power, obtains the real-time transmissivity of the observed object based on the incident power and the receiving power, and obtains the real-time temperature distribution information of the observed object by combining the function relation and the real-time transmissivity obtained through calibration. The device has simple structure and convenient operation, and can be higher than 10 6 The sampling rate in Hz acquires the instantaneous temperature distribution of the transparent object.
Description
Technical Field
The invention belongs to the technical field of high-speed temperature measurement, and particularly relates to an ultrafast temperature measurement device and method for a light-transmitting object based on femtosecond laser.
Background
The temperature is a physical quantity representing the cold and hot degree of a substance, and is microscopically the intensity of the thermal motion of molecules of the substance, which affects certain macroscopic physical and chemical properties of the object, so that timely obtaining the temperature of the object is very important for the research process of the object. The conventional temperature measurement method mainly measures the average temperature of an object within a relatively long change time, and in some fields, a transient temperature is required to be obtained. The contact type temperature measurement realizes temperature measurement through heat balance between the temperature sensitive element and the measured object. Taking the most traditional thermocouple temperature measurement as an example, temperature measurement is realized by converting a temperature signal into an electric signal, so that higher accuracy and a larger measurement range can be realized, and under a special scene, the response time of the thermocouple can reach millisecond level, but in the process of drastic temperature change, transient temperature measurement requirements cannot be met, and the integrity of a temperature field can be damaged during contact temperature measurement. Non-contact thermometry is generally based on infrared radiation properties of a substance to achieve thermometry or indirectly reflect temperature by measuring thermal properties of a medium. The temperature measuring method has the characteristics that the temperature measuring method does not need to be in contact with a measured object, the temperature field of the measured object cannot be damaged, but the measuring precision is not as high as that of the contact type temperature measuring method, and the temperature response time of the related temperature measuring method can also reach millisecond level. The transient temperature measurement process can be realized by a method of indirectly measuring the temperature through a measuring medium. For example, the temperature measurement process can be realized based on the temperature effect of the magnetic characteristics, the magnetic temperature measurement can realize non-contact measurement of the intensity and direction of an external magnetic field, and the temperature sensitivity characteristics of the magnetic nanoparticles are used to reversely deduce the ambient temperature of the particles, so that higher accuracy can be realized, but the measurement frequency is not high enough. How to achieve higher order thermometry rates is one problem that needs to be addressed in the art.
Disclosure of Invention
The invention provides an ultrafast temperature measurement device and method for a transparent object based on femtosecond laser, and solves the problem that the temperature measurement rate of non-contact temperature measurement in the prior art is low.
The invention provides an ultrafast temperature measuring device for a transparent object based on femtosecond laser, which comprises: the device comprises a femtosecond laser, a time domain stretching component, a space dispersion component, a first microscope objective, a second microscope objective, a high-speed free space photoelectric detector of MHz level or above, a high-speed oscilloscope of MHz level or above and a computer;
the femtosecond laser is used for generating femtosecond pulses with first power and first wavelength;
the time domain stretching assembly is connected with the femtosecond laser and is used for performing time domain stretching on the femtosecond pulse;
the space dispersion assembly is arranged on an emergent light path of the time domain stretching assembly and is used for carrying out dispersion on pulses;
the first microscope objective is arranged on an emergent light path of the space dispersion assembly and used for focusing pulses on a transparent object serving as an observation object, and the pulses are transmitted through the observation object;
the second microscope objective is used for collecting transmission pulses;
the high-speed free space photoelectric detector of the MHz level and above is arranged on an emergent light path of the second microscope objective and used for converting optical pulse signals into analog electric signals;
the high-speed oscillograph of the MHz level and above is connected with the high-speed free space photoelectric detector of the MHz level and above and is used for obtaining receiving power based on the analog electric signal;
the computer is connected with the high-speed oscilloscope of the MHz level and above, and is used for calculating the real-time transmittance of the observation object according to the incident power and the received power which are obtained in advance; the computer is used for obtaining real-time temperature distribution information of the observation object by combining a first function relation obtained in advance and the real-time transmissivity;
wherein the first functional relationship is a functional relationship between the transmittance of the observation object and the temperature at the first wavelength.
Preferably, the ultrafast temperature measuring apparatus for a transparent object based on femtosecond laser further includes: an optical power meter; before the real-time temperature test is started, placing the optical power meter between the first microscope objective and the observation object, generating the first power and the femtosecond pulses with the first wavelength by the femtosecond laser, and obtaining the incident power by the optical power meter; after the real-time temperature test is started, the optical power meter is moved out of the optical path.
Preferably, the ultrafast temperature measuring apparatus for a transparent object based on femtosecond laser further includes: a temperature regulating device; the temperature regulating device is used for regulating and controlling the temperature of the observation object in the process of obtaining the first functional relation.
Preferably, the spatial dispersion component adopts a diffraction grating; the diffraction grating is used to disperse the pulses into one-dimensional spatial pulses.
Preferably, the spatial dispersion assembly employs a combination of an acousto-optic deflector and a diffraction grating; the acousto-optic deflector is used for changing the internal driving frequency and the propagation direction of the pulse, so that the two-dimensional scanning of the subsequent one-dimensional femtosecond laser on the observation object is realized; the diffraction grating is used to disperse the pulses into one-dimensional spatial pulses.
Preferably, the ultrafast temperature measuring apparatus for a transparent object based on femtosecond laser further includes: a collimator; the collimator is connected with the time domain stretching assembly and is used for enabling the pulse to be incident to the space dispersion assembly in the form of space light at a specific angle.
Preferably, the ultrafast temperature measuring apparatus for a transparent object based on femtosecond laser further includes: a first lens combination and a second lens combination;
the first lens combination is arranged between the spatial dispersion assembly and the first microscope objective and is used for adjusting the size of a pulse light spot and the angle of incidence of a pulse to the first microscope objective;
the second lens combination is arranged between the second microscope objective and the MHz-level and above high-speed free space photoelectric detector, and the second lens combination is used for converging the transmission pulse to the MHz-level and above high-speed free space photoelectric detector.
On the other hand, the invention provides an ultrafast temperature measurement method for a light-transmitting object based on femtosecond laser, which is realized by adopting the ultrafast temperature measurement device for the light-transmitting object based on the femtosecond laser, and the method comprises the following steps:
acquiring a first functional relation and storing the first functional relation in a computer;
generating a femtosecond pulse with first power and first wavelength by a femtosecond laser, and measuring the power of an incident pulse before reaching an observation object on an emergent light path of a first microscope objective to obtain incident power;
generating a femtosecond pulse with first power and first wavelength by a femtosecond laser, and measuring the power of the transmission pulse passing through the observation object to obtain received power;
the computer obtains real-time transmittance of the observation object based on the incident power and the received power; and the computer combines the first functional relation and the real-time transmissivity to obtain real-time temperature distribution information of the observed object.
Preferably, a diffraction grating is used as a spatial dispersion component, and pulses are dispersed into one-dimensional spatial pulses through the diffraction grating, so that ultrafast temperature measurement of a one-dimensional line region of an observation object is realized; or, the combination of the acousto-optic deflector and the diffraction grating is adopted as a space dispersion component, the acousto-optic deflector is used for changing the internal driving frequency and changing the propagation direction of the space pulse, so that the two-dimensional scanning of the subsequent one-dimensional femtosecond laser on the light-transmitting object is realized; dispersing the pulse into a one-dimensional space pulse through a diffraction grating; and ultrafast temperature measurement of a two-dimensional surface area of an observation object is realized.
Preferably, the spatially dispersive component is moved out of the optical path to achieve ultrafast temperature measurement of the point region of the observation object.
One or more technical schemes provided by the invention at least have the following technical effects or advantages:
in the invention, the function relation between the transmittance and the temperature of the observed light-transmitting object is obtained through calibration; generating a femtosecond pulse with first power and first wavelength by a femtosecond laser, emitting the femtosecond pulse through a first microscope objective after the femtosecond pulse passes through a plurality of optical devices such as a time domain stretching assembly and a space dispersion assembly, and measuring the power of an incident pulse before reaching an observation object on an emitting light path of the first microscope objective to obtain incident power; keeping the power and wavelength of the femtosecond laser unchanged, enabling femtosecond pulses to pass through a plurality of optical devices such as a time domain stretching assembly and a space dispersion assembly, then being emitted through a first microscope objective and focused on a light-transmitting observation object, enabling the pulses to be transmitted through the observation object, collecting the transmitted pulses through a second microscope objective and focusing the transmitted pulses in an effective range of a high-speed free space photoelectric detector of MHz level or above, and obtaining received power by combining a high-speed oscilloscope of MHz level or above; and obtaining the real-time transmittance of the observed object based on the incident power and the received power through a computer, and obtaining the real-time temperature distribution information of the observed object by combining the calibrated functional relation and the real-time transmittance. The invention utilizes the characteristic that femtosecond laser pulse waves are in femtosecond level, and maps each femtosecond laser pulse in a time domain and a sample space through time domain stretching and space dispersion, thereby realizing the measurement of the temperature distribution of the sample. The whole measurement process is non-contact, continuous instantaneous temperature measurement can be carried out on an observed object, and the sampling frequency is as high as 10 6 Hz and above. The device has simple structure and convenient operation.
Drawings
Fig. 1 is a schematic structural diagram of an ultrafast temperature measurement device for a transparent object based on femtosecond laser according to embodiment 2 of the present invention;
fig. 2 is a schematic structural diagram of an ultrafast temperature measurement device for a transparent object based on femtosecond laser according to embodiment 3 of the present invention;
fig. 3 is a schematic structural diagram of an ultrafast temperature measurement device for a transparent object based on femtosecond laser according to embodiment 5 of the present invention.
Detailed Description
Based on the fact that the transmissivity of a transparent object is a physical quantity closely related to temperature, the invention provides a non-contact type ultrahigh-speed temperature measuring device and method aiming at the transparent object by utilizing the short pulse property of femtosecond laser and based on the relation between the transmissivity and the temperature so as to realize the temperature measuring speed of higher order of magnitude and a large-area temperature measuring area.
The invention provides an ultrafast temperature measuring device for a transparent object based on femtosecond laser, which mainly comprises: the device comprises a femtosecond laser, a time domain stretching component, a space dispersion component, a first microscope objective, a second microscope objective, a high-speed free space photoelectric detector at MHz level or above, a high-speed oscilloscope at MHz level or above and a computer.
The femtosecond laser is used for generating femtosecond pulses with first power and first wavelength.
And the time domain stretching assembly is connected with the femtosecond laser and is used for performing time domain stretching on the femtosecond pulse.
The space dispersion assembly is arranged on an emergent light path of the time domain stretching assembly and used for dispersing pulses.
The first microscope objective is arranged on an emergent light path of the space dispersion assembly and used for focusing pulses on a transparent object serving as an observation object, and the pulses are transmitted through the observation object.
The second microscope objective is used for collecting transmission pulses.
The high-speed free space photoelectric detector of MHz level and above is arranged on the emergent light path of the second microscope objective and used for converting the optical pulse signal into an analog electric signal.
And the high-speed oscillograph of the MHz level or above is connected with the high-speed free space photoelectric detector of the MHz level or above and is used for obtaining receiving power based on the analog electric signal.
The computer is connected with the high-speed oscilloscope of the MHz level and above, and is used for calculating the real-time transmittance of the observation object according to the incident power and the received power which are obtained in advance; the computer is used for obtaining real-time temperature distribution information of the observation object by combining a first function relation obtained in advance and the real-time transmissivity.
Wherein the first functional relationship is a functional relationship between the transmittance of the observation object and the temperature at the first wavelength.
The time domain drawing assembly may employ a single mode optical fiber or a multimode optical fiber.
The spatial dispersion component can adopt a diffraction grating; the diffraction grating is used to disperse the pulses into one-dimensional spatial pulses. Or, the spatial dispersion component adopts a combination of an acousto-optic deflector and a diffraction grating; the acousto-optic deflector is used for changing the internal driving frequency and changing the propagation direction of the pulse, so that the two-dimensional scanning of the subsequent one-dimensional femtosecond laser on the observation object is realized; the diffraction grating is used to disperse the pulses into one-dimensional spatial pulses.
In a specific implementation manner, the method may further include: the device comprises a collimator, a first lens combination, a second lens combination, an optical power meter and a temperature regulating device.
The collimator is connected with the time domain stretching assembly and is used for enabling the pulse to be incident to the space dispersion assembly in the form of space light at a specific angle.
The first lens combination is arranged between the spatial dispersion assembly and the first microscope objective and is used for adjusting the size of a pulse light spot and adjusting the angle of incidence of a pulse to the first microscope objective.
The second lens combination is arranged between the second microscope objective and the high-speed free space photoelectric detector at the MHz level or above, and the second lens combination is used for converging the transmission pulse to the high-speed free space photoelectric detector at the MHz level or above.
Before the real-time temperature test is started, placing the optical power meter between the first microscope objective and the observation object, generating the first power and the femtosecond pulses with the first wavelength by the femtosecond laser, and obtaining the incident power by the optical power meter; after the real-time temperature test is started, the optical power meter is moved out of the optical path.
The temperature regulating device is used for regulating and controlling the temperature of the observation object in the process of obtaining the first functional relation.
Corresponding to the device, the invention also provides an ultrafast temperature measurement method for the transparent object based on the femtosecond laser, which comprises the following steps:
acquiring a first functional relation and storing the first functional relation in a computer;
generating a femtosecond pulse with first power and first wavelength by a femtosecond laser, and measuring the power of an incident pulse before reaching an observation object on an emergent light path of a first microscope objective to obtain incident power;
generating a femtosecond pulse with first power and first wavelength by a femtosecond laser, and measuring the power of the transmission pulse passing through the observation object to obtain received power;
the computer obtains real-time transmissivity of the observation object based on the incident power and the received power; and the computer combines the first functional relation and the real-time transmissivity to obtain real-time temperature distribution information of the observed object.
By specifically selecting and moving part of optical elements, the ultrafast temperature measurement method provided by the invention can realize ultrafast temperature measurement of a one-dimensional line region, a two-dimensional surface region and a point region of an observation object:
(1) the diffraction grating is used as a space dispersion component, and the pulse is dispersed into a one-dimensional space pulse through the diffraction grating, so that ultrafast temperature measurement of a one-dimensional line region of an observation object can be realized.
(2) The combination of the acousto-optic deflector and the diffraction grating is used as a space dispersion component, the acousto-optic deflector is used for changing the internal driving frequency and changing the propagation direction of space pulses, and therefore the two-dimensional scanning of the subsequent one-dimensional femtosecond laser on a light-transmitting object is realized; dispersing the pulse into a one-dimensional space pulse through a diffraction grating; and ultrafast temperature measurement of a two-dimensional surface area of an observation object is realized.
(3) And the space dispersion component is moved out of the light path, so that ultra-fast temperature measurement of a point region of an observation object can be realized.
In order to better understand the technical scheme, the technical scheme is described in detail in the following with reference to the attached drawings of the specification and specific embodiments.
Example 1:
embodiment 1 provides an ultrafast temperature measurement method for a transparent object based on a femtosecond laser, and specifically, an ultrafast temperature measurement method for a one-dimensional line region of a transparent object based on a femtosecond laser, which is divided into a reference test process and a transient temperature test (i.e., a real-time temperature test) process, and mainly includes the following steps:
step 1, regulating and controlling the temperature of a test object through a temperature regulating and controlling device, emitting monochromatic laser with a first wavelength through a femtosecond laser, obtaining a functional relation (marked as a first functional relation) between the transmittance and the temperature of an observation object by matching with the whole set of device or other instrument combination provided by the invention, calibrating according to a formula (1), and storing the functional relation to a computer.
R Transmittance of light ＝a*T 2 +b*T+c (1)
The following describes how to obtain the first functional relationship by taking the apparatus provided by the present invention as an example.
A calibration process: before formal calibration is started, the femtosecond laser is controlled to emit monochromatic laser with first power and first wavelength, and the power W of an incident pulse emitted by the first microscope objective and reaching a test object is measured by an optical power meter Incident light Recording the power W of the incident pulse at this time Incident light . The formal calibration process is started, the temperature control device controls a test object to be at a stable T0 temperature and keeps the same, the power and the wavelength of emitted monochromatic laser before the femtosecond laser calibration is started are kept unchanged, the monochromatic laser is subjected to time domain stretching through a time domain stretching assembly, the collimator emits the monochromatic laser into a space dispersion assembly in the form of space pulse for space dispersion, the space pulse is subjected to size adjustment of a light spot and an incident angle of the spatial pulse to a first microscope objective through a first plano-convex lens and a second plano-convex lens, the first microscope objective focuses the space pulse on the observation object, the pulse is transmitted through the observation object, the transmission pulse is collected through the second microscope objective, and the transmission pulse is transmitted through a third plano-convex lens and a fourth plano-convex lensThe convex lens and the fifth plano-convex lens adjust the size and the angle of convergence of the high-speed free space photoelectric detector reaching the MHz level or above, the high-speed free space photoelectric detector converts space light pulse signals into analog electric signals, and a high-speed oscilloscope at the MHz level or above obtains received power W Receiving The computer passes the formula
The transmittance of the observation object at this temperature is calculated. In the subsequent calibration step, the temperature T1, T2.. Tn of the observation object is slowly increased by the temperature control device, the calibration process is repeated, and after the computer obtains the relation between the transmissivity and the temperature in a certain temperature range, the relation is fitted according to the formula (1), and the functional relation is stored in the computer.
Transient temperature testing stage:
step 2, controlling the femtosecond laser to generate a femtosecond pulse with first power and first wavelength (namely the femtosecond pulse with the same power and wavelength as those in calibration), and measuring the power (W) of an incident pulse emitted by the first microscope objective and reaching a test object by an optical power meter in the calibration process Incident light ) Inputting the laser pulse power into a computer for storage, and moving the optical power meter out of the optical path after the test is started, so as to keep the power and wavelength of the laser pulse emitted by the femtosecond laser unchanged;
step 3, performing time domain stretching on the femtosecond pulse through a single mode fiber;
step 4, the pulse is incident to the diffraction grating in the form of space light at a specific angle through the collimator;
step 5, dispersing the space pulse into a one-dimensional space pulse through the diffraction grating;
step 6, the pulse passes through the first plano-convex lens and the second plano-convex lens to adjust the size of a light spot and the angle of incidence to the first microscope objective;
step 7, focusing the pulse on an observation object through the first microscope objective, wherein the pulse is transmitted through the observation object;
step 8, collecting transmission pulses through a second microscope objective;
step 9, changing the size and angle of the transmission pulse converged in front of a fifth plano-convex lens through a third plano-convex lens and a fourth plano-convex lens, and converging the transmission pulse to the high-speed free space photoelectric detector of MHz level and above through the fifth plano-convex lens;
step 10, converting the optical pulse signal into an analog electrical signal through the high-speed free space photoelectric detector at the MHz level and above, and transmitting the analog electrical signal to the high-speed oscilloscope at the MHz level and above;
step 11, the computer records the received power (W) acquired by the high-speed oscilloscope of MHz level and above at the moment Receiving ) The computer calculates the transmittance of the observation object at the moment through a formula (2);
and step 12, calling the first functional relation by the computer, and obtaining the temperature of the observation object at the moment through the transmissivity of the observation object at the moment.
In embodiment 1, a one-dimensional space pulse is formed by dispersing a space pulse by a diffraction grating by using the characteristic that a femtosecond laser pulse wave is in a femtosecond level, so that one-dimensional line scanning of the one-dimensional femtosecond laser on an observation object (a light-transmitting object) is realized, the transmittance of the pulse passing through the observation object is obtained ultrafast, and the real-time temperature of a one-dimensional line region of the observation object in a very short time can be obtained by matching with a pre-calibrated functional relationship between the transmittance and the temperature of the observation object. The whole measurement process is non-contact, continuous instantaneous temperature measurement can be carried out on an observation object, and the sampling frequency is as high as 10 6 Hz and above.
Example 2:
embodiment 2 provides an ultrafast temperature measuring apparatus for a transparent object based on femtosecond laser, as shown in fig. 1, including: the device comprises a femtosecond laser 101, a single-mode fiber 102, a collimator 103, a diffraction grating 104, a first plano-convex lens 105, a second plano-convex lens 106, a first microscope objective 107, an optical power meter 108, a temperature control device 109, a second microscope objective 110, a third plano-convex lens 111, a fourth plano-convex lens 112, a fifth plano-convex lens 113, a high-speed free space photoelectric detector 114 of MHz level or above, a high-speed oscilloscope 115 of MHz level or above and a computer 116.
The femtosecond laser 101 is connected to the single-mode fiber 102, the collimator 103 is connected to the single-mode fiber 102, the diffraction grating 104 is located in front of the collimator 103, the first plano-convex lens 105 is located in front of the diffraction grating 104, the second plano-convex lens 106 is located in front of the first plano-convex lens 105, the first microscope objective 107 is located in front of the second plano-convex lens 106, and an observation object is located between the first microscope objective 107 and the second microscope objective 110. The third plano-convex lens 111 is disposed in front of the second microscope objective lens 110, the fourth plano-convex lens 112 is disposed in front of the third plano-convex lens 111, and the fifth plano-convex lens 113 is disposed in front of the fourth plano-convex lens 112. The high-speed free space photoelectric detector 114 of the MHz level and above is arranged in front of the fifth planoconvex lens 113, the high-speed oscilloscope 115 of the MHz level and above is connected with the high-speed free space photoelectric detector 114 of the MHz level and above, and the computer 116 is connected with the high-speed oscilloscope 115 of the MHz level and above. The optical power meter 108 is positioned in front of the first microscope objective 107 during calibration; the temperature control device 109 is located on the side of the observation object during calibration and outside the transmission optical path of the transmission pulse.
The steps in the method provided by the embodiment 1 can be realized by using the device provided by the embodiment 2, the ultrafast temperature measurement of the one-dimensional linear region of the light-transmitting object is realized, and the device provided by the embodiment 2 has the advantages of simple structure and convenient operation.
Example 3:
embodiment 3 provides an ultrafast temperature measurement device for a transparent object based on femtosecond laser, which is different from the device provided in embodiment 2 in that the device provided in embodiment 3 further includes an acousto-optic deflector, and the device provided in embodiment 3 can perform ultrafast temperature measurement for a two-dimensional surface region of the transparent object based on femtosecond laser.
Specifically, as shown in fig. 2, the apparatus includes: the device comprises a femtosecond laser 201, a single-mode fiber 202, a collimator 203, an acousto-optic deflector 204, a diffraction grating 205, a first plano-convex lens 206, a second plano-convex lens 207, a first microscope objective 208, an optical power meter 209, a temperature control device 210, a second microscope objective 211, a third plano-convex lens 212, a fourth plano-convex lens 213, a fifth plano-convex lens 214, a MHz-level and above high-speed free space photoelectric detector 215, a MHz-level and above high-speed oscilloscope 216 and a computer 217.
Wherein the acousto-optic deflector 204 is located in front of the collimator 203, the diffraction grating 205 is located in front of the acousto-optic deflector 204, and the first plano-convex lens 206 is located in front of the diffraction grating 205. The acousto-optic deflector 204 changes the internal driving frequency and changes the propagation direction of the space pulse, thereby realizing the large-area two-dimensional scanning of the subsequent one-dimensional femtosecond laser on the light-transmitting object; the spatial pulse is dispersed into a one-dimensional spatial pulse by the diffraction grating 205.
Embodiment 3 utilizes the characteristic that femtosecond laser pulse waves are in femtosecond level, utilizes a diffraction grating to disperse spatial pulses to form one-dimensional spatial pulses, and an acoustic optical deflector realizes large-area two-dimensional scanning of the one-dimensional femtosecond laser on a transparent object by changing internal driving frequency and changing the propagation direction of the spatial pulses, obtains the transmittance of the pulses when passing through an observation object ultrafast, and obtains the real-time temperature of a two-dimensional surface region of the observation object in a very short time by matching with a pre-calibrated functional relationship between the transmittance and the temperature of the observation object. The device provided by embodiment 3 is simple in structure and convenient to operate.
Example 4:
embodiment 4 provides an ultrafast temperature measurement method for a transparent object based on femtosecond laser, which is implemented by using the device provided in embodiment 3.
Example 4 provides a thermometric method different from example 1 in that "step 4" in example 1, the pulse is incident on the diffraction grating through the collimator at a specific angle in the form of spatial light; step 5, the spatial pulse is dispersed into a one-dimensional spatial pulse through the diffraction grating, and the one-dimensional spatial pulse is adjusted as follows: step 4, enabling the pulse to enter the acousto-optic deflector in a space light mode at a specific angle through the collimator; step 5, changing the internal driving frequency and changing the propagation direction of the space pulse through the acousto-optic deflector, thereby realizing large-area two-dimensional scanning of the subsequent one-dimensional femtosecond laser on the light-transmitting object; the spatial pulse is dispersed into a one-dimensional spatial pulse by the diffraction grating.
The method provided by embodiment 4 can be used for realizing the ultra-fast temperature measurement function of the two-dimensional surface area of the light-transmitting object.
Example 5:
embodiment 5 provides an ultrafast temperature measurement device for a transparent object based on femtosecond laser, which is different from the device provided in embodiment 2 in that a diffraction grating is removed from the device provided in embodiment 5, and the device provided in embodiment 5 can perform ultrafast temperature measurement for a spot region of the transparent object based on femtosecond laser.
Specifically, as shown in fig. 3, the apparatus includes: the device comprises a femtosecond laser 301, a single-mode fiber 302, a collimator 303, a first plano-convex lens 304, a second plano-convex lens 305, a first microscope objective 306, an optical power meter 307, a temperature control device 308, a second microscope objective 309, a third plano-convex lens 310, a fourth plano-convex lens 311, a fifth plano-convex lens 312, a high-speed free space photoelectric detector 313 of MHz level or above, a high-speed oscilloscope 314 of MHz level or above and a computer 315.
The collimator 303 is connected to the single-mode optical fiber 302, and the first plano-convex lens 304 is located in front of the collimator 303. The pulse is incident to the first plano-convex lens 304 in the form of spatial light at a certain angle by the collimator 303.
In embodiment 5, by using the characteristic that the femtosecond laser pulse wave is in femtosecond level, the transmittance of the pulse passing through the observation object is obtained ultrafast, and the real-time temperature of the observation object point region in a very short time can be obtained by matching the pre-calibrated functional relationship between the transmittance and the temperature of the observation object. The device provided by embodiment 5 is simple in structure and convenient to operate.
Example 6:
embodiment 6 provides an ultrafast temperature measurement method for a transparent object based on femtosecond laser, which is implemented by using the device provided in embodiment 5. Example 6 provides a thermometric method different from example 1 in that example 6 causes the pulse to be incident on the first plano-convex lens through the collimator at a specific angle in the form of spatial light. That is, embodiment 6 removes the spatial dispersion component, and embodiment 6 does not involve a step of dispersing the spatial pulse into a one-dimensional spatial pulse by the diffraction grating.
The method provided by embodiment 6 can be used to realize the ultra-fast temperature measurement function of the point region for the light-transmitting object.
The ultrafast temperature measuring device and method for the transparent object based on the femtosecond laser provided by the embodiment of the invention at least comprise the following technical effects:
(1) the invention can perform ultrafast temperature measurement function of one-dimensional linear region on the light-transmitting object under the conventional condition, and the sampling frequency can reach 10 6 Hz and above.
(2) On the basis of a one-dimensional linear region temperature measuring device, the acousto-optic deflector is arranged in front of the diffraction grating, so that the ultra-fast temperature measuring function of a two-dimensional surface region can be realized on a light-transmitting object, the acquisition frequency of two-dimensional temperature distribution mainly depends on the actual frequency of the acousto-optic deflector and a one-dimensional temperature measuring system, and the MHz-level sampling rate can be usually achieved. The ultra-fast temperature measurement example of the two-dimensional area can acquire the transient change of the temperature along with the time at an ultra-fast speed, and the two-dimensional scanning function can acquire the specific temperature distribution of different areas in a certain transient state.
(3) The invention can also simplify the device by canceling the space dispersion assembly, and realize the ultra-fast temperature measurement function of the point region of the light-transmitting object.
Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.
Claims (10)
1. The utility model provides an ultrafast temperature measuring device to printing opacity object based on femto second laser which characterized in that includes: the system comprises a femtosecond laser, a time domain stretching component, a space dispersion component, a first microscope objective, a second microscope objective, a high-speed free space photoelectric detector at MHz level or above, a high-speed oscilloscope at MHz level or above and a computer;
the femtosecond laser is used for generating femtosecond pulses with first power and first wavelength;
the time domain stretching assembly is connected with the femtosecond laser and is used for performing time domain stretching on the femtosecond pulse;
the space dispersion assembly is arranged on an emergent light path of the time domain stretching assembly and is used for carrying out dispersion on pulses;
the first microscope objective is arranged on an emergent light path of the space dispersion assembly and used for focusing pulses on a transparent object serving as an observation object, and the pulses are transmitted through the observation object;
the second microscope objective is used for collecting transmission pulses;
the high-speed free space photoelectric detector of the MHz level and above is arranged on an emergent light path of the second microscope objective and used for converting optical pulse signals into analog electric signals;
the high-speed oscillograph of the MHz level and above is connected with the high-speed free space photoelectric detector of the MHz level and above and is used for obtaining receiving power based on the analog electric signal;
the computer is connected with the high-speed oscilloscope of the MHz level and above, and is used for calculating the real-time transmittance of the observation object according to the incident power and the received power which are obtained in advance; the computer is used for obtaining real-time temperature distribution information of the observation object by combining a first function relation obtained in advance and the real-time transmissivity;
wherein the first functional relationship is a functional relationship between the transmittance of the observation object and the temperature at the first wavelength.
2. The ultrafast temperature measuring apparatus for a transparent object based on femtosecond laser as set forth in claim 1, further comprising: an optical power meter; before the real-time temperature test is started, placing the optical power meter between the first microscope objective and the observation object, generating the first power and the femtosecond pulses with the first wavelength by the femtosecond laser, and obtaining the incident power by the optical power meter; after the real-time temperature test is started, the optical power meter is moved out of the optical path.
3. The apparatus of claim 1, further comprising: a temperature regulating device; the temperature regulating device is used for regulating and controlling the temperature of the observation object in the process of obtaining the first functional relation.
4. The femtosecond laser-based ultrafast temperature measurement device for a transparent object as claimed in claim 1, wherein the spatially dispersive component employs a diffraction grating; the diffraction grating is used to disperse the pulses into one-dimensional spatial pulses.
5. The femtosecond laser-based ultrafast temperature measurement device for a transparent object as claimed in claim 1, wherein the spatially dispersive component employs a combination of an acousto-optic deflector and a diffraction grating; the acousto-optic deflector is used for changing the internal driving frequency and changing the propagation direction of the pulse, so that the two-dimensional scanning of the subsequent one-dimensional femtosecond laser on the observation object is realized; the diffraction grating is used to disperse the pulses into one-dimensional spatial pulses.
6. The apparatus of claim 1, further comprising: a collimator; the collimator is connected with the time domain stretching assembly and is used for enabling the pulse to be incident to the space dispersion assembly in the form of space light at a specific angle.
7. The apparatus of claim 1, further comprising: a first lens combination and a second lens combination;
the first lens combination is arranged between the spatial dispersion assembly and the first microscope objective and is used for adjusting the size of a pulse light spot and the angle of incidence of a pulse to the first microscope objective;
the second lens combination is arranged between the second microscope objective and the MHz-level and above high-speed free space photoelectric detector, and the second lens combination is used for converging the transmission pulse to the MHz-level and above high-speed free space photoelectric detector.
8. An ultrafast temperature measurement method for a transparent object based on femtosecond laser, which is implemented by using the ultrafast temperature measurement device for a transparent object based on femtosecond laser according to any one of claims 1 to 7, and comprises the following steps:
acquiring a first functional relation and storing the first functional relation in a computer;
generating a femtosecond pulse with first power and first wavelength by a femtosecond laser, and measuring the power of an incident pulse before reaching an observation object on an emergent light path of a first microscope objective to obtain incident power;
generating a femtosecond pulse with first power and first wavelength by a femtosecond laser, and measuring the power of the transmission pulse passing through the observation object to obtain received power;
the computer obtains real-time transmittance of the observation object based on the incident power and the received power; and the computer combines the first functional relation and the real-time transmissivity to obtain real-time temperature distribution information of the observed object.
9. The method for ultrafast temperature measurement of a transparent object based on femtosecond laser according to claim 8, wherein a diffraction grating is used as a spatial dispersion component, and pulses are dispersed into one-dimensional spatial pulses through the diffraction grating, so as to realize ultrafast temperature measurement of one-dimensional line region of an observation object;
or, the combination of the acousto-optic deflector and the diffraction grating is adopted as a space dispersion component, the acousto-optic deflector is used for changing the internal driving frequency and changing the propagation direction of the space pulse, so that the two-dimensional scanning of the subsequent one-dimensional femtosecond laser on the light-transmitting object is realized; dispersing the pulse into a one-dimensional space pulse through a diffraction grating; and ultrafast temperature measurement of a two-dimensional surface area of an observation object is realized.
10. The method according to claim 8, wherein the spatially dispersive component is moved out of the optical path to achieve ultrafast temperature measurement of the spot region of the object under observation.
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| CN202210200501.9A CN115014569A (en) | 2022-03-02 | 2022-03-02 | Ultrafast temperature measuring device and method for transparent object based on femtosecond laser |
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| CN202210200501.9A CN115014569A (en) | 2022-03-02 | 2022-03-02 | Ultrafast temperature measuring device and method for transparent object based on femtosecond laser |
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