CN221860749U - Bimodal three-dimensional microscopic imaging system - Google Patents

Abstract

The utility model discloses a bimodal three-dimensional microscopic imaging system, which is characterized in that part of pump light generated by a laser generating device is focused on the surface of a sample to generate an ablation structure, and the other part of pump light generated by the laser generating device is divided into a beam of detection light and a beam of reference light after optical path adjustment, and the detection light receives an interference image containing the surface morphology information of the sample generated after the interference of the detection light and the reference light. The microscopic imaging system disclosed by the embodiment can acquire interference images of the surface ablation structure of the sample at different moments, overcomes the problem of insufficient information acquisition only facing surface reflectivity imaging, and has more complete ablation process information, so that more accurate control of an ultrafast dynamic process can be realized, and the accuracy of control is improved.

Description

A dual-modal three-dimensional microscopic imaging system

Technical Field

The utility model relates to the technical field of microscopic imaging, in particular to a dual-mode three-dimensional microscopic imaging system.

Background Art

Currently, the study of ultrafast laser ablation processes is mainly carried out by pump-probe microscopy. This technique has ultrafast temporal resolution and microscopic spatial resolution. By adjusting the delay time, images of the reflective surface after irradiation are captured at different time intervals. However, the dynamic changes in the interaction between the laser and the material will not only cause changes in the optical properties, but also lead to the topographic evolution of the three-dimensional surface. In addition to the insufficient temporal and spatial resolution, all these techniques can only measure reflectivity maps for analysis, but cannot image the three-dimensional structure of the surface, which limits the application of traditional pump-probe microscopy in the field of ultrafast imaging.

Therefore, the imaging system in the prior art needs to be further improved.

Utility Model Content

In view of the deficiencies in the above-mentioned related technologies, the purpose of the present invention is to provide a dual-modal three-dimensional microscopic imaging system to overcome the defect in the prior art that the ultrafast laser ablation process can only be analyzed based on the measured reflectivity map and cannot image the three-dimensional structure of the surface.

The technical solution adopted by the utility model to solve the technical problem is as follows:

This embodiment discloses a dual-modal three-dimensional microscopic imaging system, which includes:

A laser generating device for generating pump light mixed with multiples of different wavelengths;

A first beam splitting element, disposed on an optical path of the pump light, and used for splitting the pump light into a first pump light and a first detection light according to different wavelength multiples;

A delay line and a control device, arranged on the optical path of the first detection light or the first pumping light, for adjusting the optical path difference between the first detection light and the first pumping light;

A second beam splitting element is disposed on an optical path of the first detection light and is used to split the first detection light into a second detection light and a reference light;

A first objective lens is arranged on the optical path of the first pump light and the second detection light, and is used to focus the first pump light and the second detection light on the sample surface, so that an ablation structure is generated on the sample surface under the focus of the first pump light, and after the ablation structure surface reflects the second detection light, a third detection light with ablation surface information is obtained;

A second objective lens is arranged on the optical path of the reference light and is used for converging the reference light so as to match the optical path and dispersion of the reference light with the third detection light;

The image receiving element is arranged on the optical path of the third detection light and the reference light, and is used for receiving an interference image containing sample surface morphology information generated by the interference between the third detection light and the reference light.

Optionally, the laser generating device comprises: a laser and a nonlinear crystal;

The laser is used to generate original pump laser;

The nonlinear crystal is arranged on the optical path of the original pump laser and is used to double the frequency of the original pump laser to obtain a mixture of pump light with two different wavelengths.

Optionally, the first beam splitting element is a first dichroic mirror.

Optionally, the system further comprises: a switch and a control device arranged on the optical path of the first pump light, wherein the switch and the control device are used to control the number of laser pulses in a single passing first pump light.

Optionally, the system further comprises: a carrying device and a translation stage;

The carrying device and the translation stage are arranged on the optical paths of the first pump light and the second detection light, and are used to carry the sample to be processed.

Optionally, the switch and control device includes a photoelectric switch and a first control device for controlling the opening and closing time of the photoelectric switch; wherein the first control device is connected to the photoelectric switch to control the opening and closing time of the photoelectric switch to match the repetition frequency of the laser generating device to control the number of pump pulses passing through at a single time.

Optionally, the delay line and control device include: a piezoelectric platform provided with parallel guide rails and a plurality of first reflective mirrors arranged on the parallel guide rails.

Optionally, the switch and control device and the first objective lens are further provided with: a pinhole diaphragm, a first lens group, a second reflector and a third beam splitter element in sequence;

The pinhole aperture filters the received first pump light, and the filtered first pump light is input to the first lens group, is angle-modulated by the first lens group, is input to the second reflector, is reflected by the second reflector, is incident on the third beam splitter, and is incident on the first objective lens after passing through the third beam splitter.

Optionally, a third reflector for reflecting the reference light and a fourth reflector for reflecting the light transmitted through the second objective lens are respectively arranged on both sides of the second objective lens.

Optionally, the first lens group includes: a first convex lens and a concave lens; and a second convex lens is arranged between the image receiving element and the second beam splitting element.

Beneficial effects:

The present embodiment discloses a dual-mode three-dimensional microscopic imaging system, which includes: a laser generating device, a first spectroscopic element, a delay line and a control device, a second spectroscopic element, a first objective lens, a second objective lens and an image receiving element. On the one hand, a part of the pump light generated by the laser generating device is focused on the sample surface to generate an ablation structure. On the other hand, another part of the pump light generated by the laser generating device is divided into a detection light beam and a reference light beam after optical path adjustment. The detection light receives an interference image containing sample surface morphology information generated after the detection light and the reference light interfere with each other. The microscopic imaging system disclosed in the present embodiment can obtain interference images of the sample surface ablation structure at different times, which overcomes the problem of insufficient information acquisition faced by imaging only the surface reflectivity, and the interference image of the sample surface ablation structure has more complete ablation process information, so accurate measurement and control of ultrafast dynamic processes can be achieved based on the interference image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a dual-modality three-dimensional microscopic imaging system according to an embodiment of the present utility model;

FIG2 is an interference image of the surface reflectivity at different times in an embodiment of the present invention;

FIG3 is a flowchart of the steps of an imaging method of a dual-modal three-dimensional microscopic imaging system according to an embodiment of the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Many microscopic phenomena in physics, chemistry, biology, and materials science are not only nanometer-micrometer in spatial scale, but also ultrafast in time scale. For example, the time scale of carrier transfer in optoelectronic materials/devices, femtosecond laser micromachining, and ultrafast photosynthesis processes are all in the femtosecond to picosecond range. Pump-probe microscopy is an imaging method that combines the pump-probe technology in the field of ultrafast lasers with microscopic imaging technology. It was first used by Nobel Prize winner Zewail A. in 1987 to observe the photodecomposition reaction of iodine cyanide. Pump-probe microscopy can observe the ultrafast dynamic processes of excitation and ablation of materials at the microscopic scale, and is a powerful characterization method in the field of femtosecond laser micromachining.

Although pump-probe microscopy has made great progress in observing laser ablation, most systems currently face the problem of insufficient spatial resolution and can only image the surface reflectivity during the phase change of the material. The ablation process is usually accompanied by changes in the three-dimensional morphology of the surface, resulting in a loss of information on the ablation process.

In order to solve the above problems, this example provides a dual-modal three-dimensional microscopic imaging system, which interferes the detection light carrying the ablation structure information of the sample surface with the reference light and obtains the interference image. Since the interference image carries ultrafast information, reconstruction and analysis can be performed based on the interference image, and the three-dimensional topographic image and reflectivity image of the ablation structure on the sample surface can be obtained at the same time, so as to provide more accurate surface height measurement results, accurately reflect the changes in the ablation structure, and further achieve a more comprehensive understanding of the ablation phenomenon generated in the laser manufacturing process, thereby realizing effective control of the ultrafast dynamic process.

The following is a further description of a dual-modal three-dimensional microscopic imaging system disclosed in this embodiment in conjunction with the accompanying drawings.

As shown in Figure 1, this embodiment discloses a dual-modal three-dimensional microscopic imaging system, including: a laser generating device, a first spectroscopic element 3, a delay line and control device 22, a second spectroscopic element 12, a first objective lens 10, a second objective lens 14 and an image receiving element 23.

The laser generating device includes a laser and a nonlinear crystal, which is used to generate pump light mixed with different wavelength multiples. The femtosecond laser is used to generate the original pump laser; the nonlinear crystal is arranged on the optical path of the original pump laser and is used to double the original pump laser to obtain pump light mixed with two different wavelengths.

Specifically, the laser can be a femtosecond laser or a picosecond laser. A femtosecond laser can generate a femtosecond laser, and the duration of the original pump pulse emitted by the femtosecond laser is in the femtosecond level. A picosecond laser can generate a picosecond laser, and the duration of the original pump pulse emitted by the picosecond laser is in the picosecond level. Therefore, using the pump pulse emitted by a femtosecond laser or a picosecond laser can obtain information generated in a faster time.

In this embodiment, the original laser pulse generated in the femtosecond laser or picosecond laser is used as the pump light of the system, and a nonlinear crystal is set in front of the laser to perform frequency doubling processing on the original pump pulse emitted from the laser to obtain a pump pulse after frequency doubling processing. The pump pulse obtained after frequency doubling processing is used as the detection light of the system. After the original pump pulse passes through the nonlinear crystal, due to the nonlinear effect, a part of the reflected light is frequency doubling and used as the illumination light of the microscopic imaging system. Specifically, the nonlinear crystal can be a BBO frequency doubling crystal.

A first spectroscopic element 3 is arranged in front of the laser generating device, and the first spectroscopic element 3 is used to split the pump light into a first pump light and a first detection light according to different wavelengths; in a specific implementation, the first spectroscopic element can be a beam splitter or other spectroscopic elements that can split a laser beam into two beams.

Furthermore, since the reflected light contains a small portion of the original light beam, the filter 16 can be used to filter the reflected light so that the detection light only contains the frequency-doubled light pulses.

In one implementation, the femtosecond laser is a femtosecond laser oscillator and amplifier with a wavelength of 800nm, a central wavelength of 120fs, a repetition frequency of 10Hz, and a maximum energy of 3mJ. The BBO frequency doubling crystal used has a 20% frequency doubling efficiency, and the pulse wavelength generated after frequency doubling is 400nm.

A delay line and a control device are provided on the optical path of the first detection light or the optical path of the first pump light, and the delay line and the control device are used to adjust the optical path difference between the first detection light and the first pump light. Specifically, the delay line and the control device control the optical path difference between the optical path of the first pump light and the optical path of the first detection light to enable the first pump light to irradiate the sample surface, so as to form an ablation structure on the sample surface.

In one embodiment, the delay line and control device 22 include: a piezoelectric platform and a delay line provided with parallel guides; the first detection light incident into the delay line and the control device is emitted after being reflected back and forth by each first reflector. Wherein, the delay line is composed of a plurality of first reflectors, and as shown in FIG1 , the first reflectors provided in the delay line include: a first delay line reflector 17 and a second delay line reflector 18 provided opposite to each other. The first detection light incident into the delay line is reflected back and forth by a plurality of first reflectors, and then is incident on the second spectroscopic element 12. The control device includes a piezoelectric platform with parallel guides, and a plurality of first reflectors are installed on the parallel guides, and the piezoelectric platform drives the parallel guides to move, so as to realize the position movement of the first reflectors.

Furthermore, the number of first reflectors is not limited to two, and can be determined based on the maximum time range of target detection in the experiment. In one implementation, the number of first reflectors used is 12, the optical path can achieve 6 round-trip reflections, and the minimum step length that can be provided by the delay line and control device used is 1 micron, so the corresponding minimum time step length is 20fs, and the maximum time detection range is 10ns.

The second beam splitter 12 is arranged on the optical path of the first detection light, and is used to split the first detection light into a second detection light and a reference light. The second detection light and the reference light constitute a Michelson interferometer, wherein the second detection light is focused on the sample surface, and is used to detect the morphology of the sample surface, and obtain a third detection light reflected from the sample surface, and another reference light interferes with the third detection light, and is photographed by a CCD camera to obtain an interference image.

The first objective lens 10 (NA=0.9, 100×) is arranged on the optical path of the first pump light and the second detection light, and is used to focus the first pump light and the second detection light on the sample surface. The sample surface generates an ablation structure under the focus of the first pump light, and the second detection light is converted into a third detection light with ablation surface information after being reflected by the ablation structure surface. The first objective lens is used to focus the incoming first pump light and second detection light, so that the first pump light and the second detection light converge on the sample surface at a certain angle. The first pump light can induce the sample surface to generate an ablation structure, and the second detection light is reflected by the ablation structure on the sample surface to obtain the third detection light carrying the ablation surface information.

The second objective lens 14 (NA=0.9, 100×) is arranged on the optical path of the reference light and is used to converge the reference light so that the optical path and dispersion of the reference light match those of the third detection light. The second objective lens is used to adjust the optical path difference between the third detection light and the reference light so that the third detection light and the reference light interfere with each other on the receiving surface of the image receiving element, and on the other hand, to compensate for the dispersion degree between the third detection light and the reference light to avoid pulse broadening caused by dispersion during the transmission process.

The image receiving element 23 is disposed on the optical paths of the third detection light and the reference light, and is used to receive an interference image containing sample surface morphology information generated by interference between the third detection light and the reference light.

In a specific implementation, the image receiving element may be a CCD camera, which is used to capture an interference image carrying ultrafast information, and then the three-dimensional morphology of the sample surface is reconstructed based on the interference image to obtain a three-dimensional image of the ablated structure.

In one embodiment, the first beam splitter is a first dichroic mirror. The second beam splitter is a beam splitter. Although both the first beam splitter and the second beam splitter are beam splitters, they have different functions. The first beam splitter is used to split pump pulses of different wavelengths into two beams, while the second beam splitter is only used to split a beam of light into two identical beams.

Furthermore, in order to facilitate the control of laser pulses in the optical path, the microscopic imaging system also includes: a switch and control device 4 arranged on the optical path of the first pump light, and the switch and control device are used to control the number of laser pulses in a single passing first pump light.

Specifically, the switch and control device 4 includes a photoelectric switch and a first control device for controlling the opening and closing time of the photoelectric switch; wherein the first control device is connected to the photoelectric switch to control the opening and closing time of the photoelectric switch to match the repetition frequency of the femtosecond laser generating device to control the number of pump pulses passing through at a single time.

Furthermore, the microscopic imaging system further comprises: a carrying device and a translation stage 11, which are arranged on the optical path of the first pump light and the second detection light and are used to carry the sample to be processed.

The carrying device and the translation stage are located behind the first objective lens. The first pump light and the second detection light are focused onto the sample surface after passing through the first objective lens. The first pump light is used to induce changes in the morphology of the sample surface. The second detection light is reflected by the sample surface and then reflected onto the second beam splitter to interfere with the reference light.

Specifically, the carrying device and the translation stage include a carrying device and a translation stage, and the translation stage precisely controls the position angle of the carrying device through a control device to drive the carrying device to perform X-Y-Z three-axis motion. Therefore, by adjusting the position angle of the carrying device, the sample to be processed is adjusted to the target position.

Furthermore, in order to adjust the propagation path of the first pump light so that the first pump light is focused on the surface of the sample while avoiding the broadening effect of the first pump light during the propagation process, as shown in FIG. 1 , the switch and control device 4 and the first objective lens 10 are provided with: a pinhole diaphragm 5, a first lens group (the first lens group includes a first convex lens 6 and a concave lens 7), a second reflector 8 and a third beam splitter 9 in sequence; the pinhole diaphragm 5 filters the received first pump light, and the filtered first pump light is input to the first lens group, and after angle modulation by the first lens group, is input to the second reflector 8, and after reflection by the second reflector 8, is incident on the third beam splitter 9, and then is incident on the first objective lens 10 after passing through the third beam splitter 9.

Specifically, the pulses screened by the photoelectric switch pass through the pinhole diaphragm 5, and the opening and closing degree of the pinhole diaphragm 5 is adjusted to ensure that all the screened pump pulses can completely pass through the back aperture of the first objective lens 10. Then, the light beam passes through the lens group composed of the first convex lens 6 and the concave lens 7, and the divergence angle of the light beam is changed, and is focused by the first objective lens 10 at a certain angle, thereby forming a light spot on the sample surface.

Furthermore, the second objective lens 14 is provided with a third reflector 13 for reflecting the reference light and a fourth reflector 15 for reflecting the light transmitted through the second objective lens 14 on both sides. The reference light separated by the second beam splitter is transmitted to the third reflector, and then input into the second objective lens through the third reflector. The second objective lens 14 focuses the input reference light to the fourth reflector 15, and the fourth reflector 15 reflects the received reference light into the second objective lens. The reference light is transmitted to the third reflector after passing through the second objective lens, and then reflected into the second beam splitter 12 through the third reflector. After being reflected into the second beam splitter, the reference light interferes with the third detection light on the receiving surface of the CCD camera, so the CCD camera is used for continuous shooting to obtain an interference image carrying ultrafast information. The adjustment of the reference light by the third reflector, the second objective lens and the fourth reflector is not only to adjust the optical path difference between the reference light and the third detection light so that the reference light and the third detection light interfere with each other, but also to compensate for the broadening of the reference light caused by dispersion during the transmission process.

Furthermore, in order to achieve a better interference image shooting effect, a second convex lens 21 is provided between the CCD camera and the second beam splitter element, and the second convex lens 21 is used to focus the reference light and the third detection light onto the receiving surface of the CCD camera.

The specific embodiment of the utility model is described in more detail with reference to FIG. 1 .

As shown in FIG1 , the original pump light emitted from the femtosecond laser 1 is incident on the BBO frequency doubling crystal 2. After the frequency doubling process by the BBO frequency doubling crystal, the obtained pump pulse is input to the first dichroic mirror, and is divided into the first pump light and the first detection light by the first dichroic mirror. The first pump light is transmitted to the switch and control device 4, and the switch and control device 4 counts the number of pump pulses that pass through the input first pump light in a single time. The first detection light is filtered by the filter 16 and input to the delay line and control device 22.

After the multiple first reflectors in the delay line and control device 22 repeatedly reflect the input first detection light, the first detection light is transmitted to the fifth reflector 19, passes through the fifth reflector 19 and the third convex lens 20, and is incident on the second beam splitter 12. The second beam splitter 12 splits the first detection light into a second detection light and a reference light. Among them, the second detection light passes through the second dichroic mirror and is focused on the sample surface on the carrier and the translation stage 11 through the first objective lens. The first pump light output by the switch and control device 4 passes through the pinhole aperture 5, the first lens group (the first lens group includes the first convex lens 6 and the concave lens 7), the second reflector 8 and the third beam splitter 9 in sequence, and then enters the first objective lens, which is focused on the sample surface by the first objective lens to induce the generation of an ablation structure on the sample surface.

After being reflected by the ablation structure, the second detection light is converted into a third detection light carrying the ablation structure information. The third detection light passes through the first objective lens 10, the third spectroscopic element 9 and the second spectroscopic element 12 in sequence, and then passes through the second convex lens 21 to be transmitted to the receiving surface of the image receiving element 23. At the same time, the reference light is reflected or focused by the third reflector 13, the second objective lens 14 and the fourth reflector 15 in sequence, and then transmitted to the second spectroscopic element 12, passes through the second convex lens 21, and is transmitted to the receiving surface of the image receiving element 23. Interference occurs between the third detection light and the reference light, so the image receiving element 23 can obtain the interference image of the ablation structure on the sample surface.

In a specific embodiment, the repetition frequency of the femtosecond laser 1 is 10 Hz, so the switch of the photoelectric switch is adjusted to open for 0.01 s after a single trigger, so that a single pulse can be screened out. A plurality of polarizers, half-wave plates and continuously adjustable attenuation plates are sequentially arranged between the pinhole aperture 5 and the first convex lens 6 along the optical path direction. Through this arrangement, the energy of the pump pulse can be continuously changed, which is convenient for controlling the power when exciting the sample surface.

Furthermore, in the microscopic imaging system, since there are a series of dispersive elements in the optical path, which have a broadening effect on the original pulse, the temporal resolution of the system depends on the laser pulse width when the detection pulse reaches the sample surface and is not equal to the pulse width of the original pulse.

In a specific embodiment, considering the broadening effect of the BBO frequency doubling crystal 2, the first objective lens 10, the third convex lens 20, and the second convex lens 21 in the detection light path, it is calculated that the dual-modal three-dimensional microscopic imaging system has a time resolution of 256 fs.

The dual-modal three-dimensional microscopic imaging system disclosed in this embodiment obtains an interference image carrying the ablation structure information of the sample surface, performs Fourier transform on the interference image, and obtains its corresponding spectrum image. The spectrum image shows three spectrum orders of 0, ±1, and then the spectrum of the 0th and 1st order frequencies is inversely Fourier transformed to obtain the reflectivity image and the three-dimensional morphology image of the ablation structure, respectively. Since the reflectivity image characterizes the light absorption characteristics of the sample surface material, and the three-dimensional morphology image can provide more accurate surface height measurement results, the combined analysis of the reflectivity image and the three-dimensional morphology image can accurately reflect the changes in the sample surface structure, and also provides an imaging system for a comprehensive understanding of the physical phenomena in the laser manufacturing process, thereby achieving effective control of ultrafast dynamic processes.

In a specific embodiment, as shown in FIG2 , interference images at different times obtained through the above experimental process, surface reflectivity images reconstructed according to the above reconstruction method, and surface morphology three-dimensional images. The yellow circle in FIG2 is the influence range of the pump pulse. From FIG2 , it can be seen that the obliquely incident pump pulse has different wavefront arrival times, and its influence on the sample advances from left to right in sequence (the first row in FIG2 : reflectivity interference image; the second row: reflectivity reconstruction image; the third row: surface morphology reconstruction image).

In the specific implementation, when the reflectivity image and the three-dimensional morphology image are reconstructed according to the obtained interference image, Matlab is used to process the interference image obtained in the experiment. In terms of the reflectivity image, the interference image is Fourier transformed, and the 0th level in the transform spectrum is filtered out using a suitable filter window, and normalized to obtain a normalized intensity distribution image. In terms of the three-dimensional morphology image, the interference image carrying sample information and the interference image without sample information are Fourier transformed at the same time, and the +1 level in the Fourier transform image is filtered out. The two spectrum images are calculated to obtain the phase image of the surface morphology. And by calibrating the linear relationship between phase and height in the experiment, the phase image is converted into a height image.

In a specific embodiment, the first objective lens 10 and the second objective lens 14 use an Osparin plan achromatic microscope objective lens with a numerical aperture of 0.9 and a magnification of 100 times. In order to verify the spatial resolution of the system, the modulation transfer function (MTF) of the imaging system is calculated. Under this experimental condition, a spatial lateral resolution of 236nm and a spatial longitudinal resolution of 29nm are obtained. In a specific experiment, microscope objective lenses of different magnifications can be replaced according to the spatial scale of the observed phenomenon.

Based on the above-mentioned microscopic imaging system, this embodiment further discloses an imaging method of the microscopic imaging system, as shown in FIG3 , the imaging method comprises:

Step S1, controlling the pump light output by the laser generating device to be divided into a first pump light and a first detection light, and adjusting the optical path difference between the first pump light and the first detection light.

In this step, the switch of the femtosecond laser in the laser emitting device is first turned on to control the emission of the original pump light, which is then frequency-doubled by the BBO frequency-doubling crystal and then divided into the first pump light and the first detection light by the dichroic mirror. At the same time, the optical path difference between the first pump light and the first detection light is adjusted by the delay line and the control device.

Step S2: split the first detection light into the second detection light and the reference light.

The first detection light is divided into the second detection light and the reference light by the second light splitting element, and a Michelson interferometer is formed between the reference light and the third detection light obtained by reflecting the second detection light on the sample surface.

Step S3, controlling the first pump light and the second detection light to focus on the sample surface, so that an ablation structure is generated on the sample surface under the focus of the first pump light, and after the ablation structure surface reflects the second detection light, a third detection light with ablation surface information is obtained.

The first pump light and the second detection light are controlled to focus on the sample surface, the first pump light is used to induce an ablation structure on the sample surface, and the second detection light is used to obtain a third detection light carrying ablation structure information.

Step S4: receiving an interference image containing ablation surface information generated by interference between the third detection light and the reference light.

The reference light and the third detection light are controlled to form interference, and an interference image is captured at the same time, and the interference image is analyzed to obtain the ablation surface information. Specifically, the interference image is Fourier transformed, and three spectrum orders of 0 and ±1 are displayed in the spectrum image. The reflectivity image and the three-dimensional morphology image are obtained by inverse Fourier transform of the 0th and 1st order frequencies, respectively.

The imaging method disclosed in this embodiment is based on the principle of pump-probe microscopy to obtain ultrafast information, and based on the principle of interferometric Fourier analysis to simultaneously obtain height and reflectivity images, and establishes an imaging method for a dual-modal three-dimensional microscopic imaging system, achieving three-dimensional imaging at a spatiotemporal resolution of femtoseconds to nanometers.

This embodiment discloses a dual-modal three-dimensional microscopic imaging system and imaging method, which obtains dual-modal images of reflectivity and morphology at high time and space scales. The reflectivity image characterizes the light absorption characteristics of the material, while the three-dimensional morphology image can provide more accurate surface height measurement results and accurately reflect the changes in the structure. These two complementary imaging modes provide a method for a comprehensive understanding of the basic physical phenomena in the laser manufacturing process, thereby achieving effective control of ultrafast dynamic processes.

The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims (10)

1. A bimodal three dimensional microscopic imaging system comprising:

The laser generating device is used for generating pump light mixed with different wavelength multiples;

The first light splitting element is arranged on the light path of the pump light and is used for splitting the pump light into first pump light and first detection light according to different wavelength multiples;

The delay line and the control device are arranged on the optical path of the first detection light or the first pump light and are used for regulating and controlling the optical path difference between the first detection light and the first pump light;

The second light splitting element is arranged on the light path of the first detection light and is used for splitting the first detection light into second detection light and reference light;

The first objective lens is arranged on the light paths of the first pump light and the second probe light and is used for focusing the first pump light and the second probe light on the surface of the sample, an ablation structure is generated on the surface of the sample under the focusing of the first pump light, and after the second probe light is reflected by the surface of the ablation structure, third probe light with ablation surface information is obtained;

A second objective lens disposed on an optical path of the reference light for converging the reference light so as to match an optical path length and dispersion of the reference light and the third probe light;

And the image receiving element is arranged on the light path of the third detection light and the reference light and is used for receiving an interference image containing ablated surface information generated after the interference of the third detection light and the reference light.

2. The bimodal three dimensional microscopic imaging system according to claim 1, wherein the laser generating means comprises: lasers and nonlinear crystals;

The laser is used for generating original pumping laser;

the nonlinear crystal is arranged on the optical path of the original pump laser and is used for carrying out frequency multiplication on the original pump laser to obtain pump light mixed with two different wavelengths.

3. The bimodal three dimensional microscopic imaging system according to claim 1, wherein the first light splitting element is a first dichroic mirror.

4. The bimodal three dimensional microscopic imaging system according to claim 1, wherein the system further comprises: and the switch and control device is arranged on the optical path of the first pump light and is used for controlling the number of laser pulses in the first pump light passing through once.

5. The bimodal three dimensional microscopic imaging system according to claim 1, wherein the system further comprises: a bearing device and a displacement table;

The bearing device and the displacement table are arranged on the optical paths of the first pumping light and the second detection light and used for bearing a sample to be processed.

6. The bimodal three dimensional microscopic imaging system according to claim 4, wherein the switch and control device comprises a photoelectric switch and a first control device for controlling the switching time of the photoelectric switch; the first control device is connected with the photoelectric switch, and controls the switching time of the photoelectric switch to be matched with the repetition frequency of the laser generating device so as to control the number of pump pulses passing through once.

7. The bimodal three dimensional microscopic imaging system according to claim 1, wherein the delay line and control device comprises: a piezoelectric platform provided with parallel rails and a plurality of first mirrors provided on the parallel rails.

8. The bimodal three-dimensional microscopic imaging system according to claim 4, wherein the switch and control device and the first objective lens are further provided with: the device comprises an aperture diaphragm, a first lens group, a second reflecting mirror and a third light splitting element;

The aperture diaphragm carries out filtering treatment on the received first pump light, the first pump light after the filtering treatment is input into the first lens group, the first pump light is input into the second reflector after being subjected to angle modulation through the first lens group, the first pump light is incident into the third light-splitting element after being reflected by the second reflector, and the first pump light is incident into the first objective lens after being subjected to the third light-splitting element.

9. The bimodal three-dimensional microscopic imaging system according to claim 1, wherein both sides of the second objective lens are provided with a third mirror for reflecting the reference light and a fourth mirror for reflecting the light transmitted in the second objective lens, respectively.

10. The bimodal three dimensional microscopic imaging system according to claim 8, wherein the first lens group comprises: a first convex lens and a concave lens; a second convex lens is arranged between the image receiving element and the second light splitting element.