A method and device for simultaneously achieving high-precision laser direct writing and super-resolution microscopic imaging

Abstract

A method for simultaneously realizing high-precision laser direct writing and super-resolution microscopic imaging, which realizes high-precision laser direct writing by doping fluorescent dyes that can flash in photoresist, and realizes super-resolution imaging by using the double-beam edge light suppression effect and the random light reconstruction microscopic method. A device for simultaneously realizing high-precision laser direct writing and super-resolution microscopic imaging comprises two light sources for high-precision laser direct writing and another two light sources for super-resolution microscopic imaging; wherein the former two light sources are an excitation light source for causing the photoresist to generate a photopolymerization process and an inhibition light source for causing the photoresist to generate an inhibition polymerization process; and the latter two light sources are an activation light for activating the dyes and an excitation light for exciting the fluorescent dyes to emit fluorescence. The present application integrates laser direct writing and optical microscopic imaging in one system, and thus simultaneously realizes the functions of super-resolution writing and imaging, realizes non-destructive and non-invasive direct optical imaging of the written structure, is easy to operate, and saves cost.

Description

Technical Field

[0001] This invention relates to the field of ultra-high precision laser direct writing and super-resolution optical microscopy imaging, specifically, to a method and apparatus for simultaneously realizing high-precision laser direct writing and super-resolution microscopy imaging. Background Technology

[0002] Laser direct writing technology has wide applications in various scientific fields due to its flexible capabilities in fabricating three-dimensional micro and nanostructures. In recent years, with the development of femtosecond pulsed lasers, the interaction mechanism between light and matter induced by femtosecond pulses has made significant progress in laser direct writing of micro and nanostructures, and is beginning to demonstrate its potential in scientific, technological, and industrial applications. The main advantage of using femtosecond lasers for laser micro and nano processing is that it can utilize various nonlinear light-matter interaction mechanisms. By controlling the photoionization and thermal processes, it is possible to directly achieve highly precise localized photomodification in sub-100 nanometer regions, thereby forming functional structures and integrated devices. To further improve writing accuracy, a method similar to STED super-resolution microscopy has been proposed, employing edge light suppression (PPI) to achieve ultra-high precision laser direct writing, reducing the minimum feature size to sub-50 nm.

[0003] To characterize and monitor the written structures, the traditional method is to observe them using an electron microscope or an atomic force microscope after writing and developing. Electron microscopy requires gold sputtering of the structure before observation, which can affect the properties of certain structures, especially micro / nano optical devices. Furthermore, electron microscopy has a slow imaging speed, high cost, and stringent environmental requirements. Atomic force microscopy also suffers from slow imaging speed. Summary of the Invention

[0004] The present invention aims to overcome the above-mentioned shortcomings of the prior art and provide a method and apparatus for simultaneously realizing high-precision laser direct writing and super-resolution microscopic imaging, so as to perform imaging characterization of the written structure and monitor the writing process.

[0005] This invention replaces the traditional methods of imaging etched structures using electron microscopy and atomic force microscopy, employing optical microscopy for super-resolution imaging of the etched structure. By doping the photoresist with a fluorescent dye exhibiting scintillation properties, the device of this invention can perform high-precision etching of the dye-doped photoresist without affecting its performance; and the device of this invention can then be used to perform stochastic optical reconstruction (STORM) super-resolution optical microscopy imaging on the etched structure.

[0006] The specific technical solution of the present invention is as follows:

[0007] A method for simultaneously achieving high-precision laser direct writing and super-resolution microscopic imaging includes:

[0008] A scintillation-enabled fluorescent dye is doped into the photoresist, and the edge light suppression effect is used to perform high-precision laser direct writing of micro- and nano-structures on the dye-doped photoresist. Then, the written structure is developed. Finally, the written structure is characterized by STORM super-resolution microscopy.

[0009] The present invention also includes an apparatus for simultaneously realizing high-precision laser direct writing and super-resolution microscopic imaging, comprising: an optical path for realizing the edge light suppression effect of photoresist, including an excitation optical path for exciting the photoresist to generate polymerization and an inhibition optical path for inhibiting the polymerization process; an optical path for performing STORM imaging characterization on the written micro / nano structure, including an activation optical path and an excitation optical path for fluorescent dye; and a detection optical path for fluorescence reception.

[0010] The excitation optical path for achieving photoresist polymerization includes, in sequence, a first laser, a first acousto-optic modulator, a first beam expander, and a first half-wave plate;

[0011] The photoresist-suppressed light path sequentially passes through a second laser, a second acousto-optic modulator, a second beam expander, a first reflector, and a second half-wave plate;

[0012] The photoresist excitation light and suppression light are combined by a polarization beam combiner. The combined light path passes sequentially through a split-screen spatial light modulator module, a quarter-wave plate, a scanning galvanometer, a scanning lens, a first dichroic mirror, a field lens, a second dichroic mirror, an objective lens, and the photoresist sample.

[0013] The fluorescent dye activation optical path passes sequentially through a third laser, a third acousto-optic modulator, a second reflector, a lens, a second dichroic mirror, an objective lens, and a sample being written.

[0014] The excitation and activation light of the fluorescent dye passes through the element in a similar manner, but is incident on the sample surface at a total internal reflection angle;

[0015] The imaging detection optical path passes sequentially through the objective lens, the second dichroic mirror, the field lens, the first dichroic mirror, and the camera;

[0016] It also includes computers.

[0017] Preferably, the first laser is a picosecond or femtosecond pulsed laser with a wavelength of 532nm; used to initiate the polymerization reaction of the photoresist.

[0018] Preferably, the second laser is a continuous light laser or a picosecond pulsed laser with a wavelength of 532nm, used to suppress the polymerization reaction of the photoresist;

[0019] Preferably, the third laser is a continuous light laser with a wavelength of 405 nm, used for activating the fluorescent dye;

[0020] Preferably, the fourth laser is a continuous light laser with a wavelength of 488 nm, used to excite the dye to scintillate and fluoresce.

[0021] Preferably, the initiator of the photoresist can be DETC, ITX, or other materials that can achieve edge light suppression effect;

[0022] Preferably, the doped dye can be Alexa Fluor 488 or ATTO 488;

[0023] The preferred first dichroic mirror is a short-pass type;

[0024] As a preferred option, the second dichroic mirror is a continuous type;

[0025] A method for implementing the apparatus of the present invention to simultaneously achieve high-precision laser direct writing and super-resolution microscopic imaging includes the following steps:

[0026] (1) The laser emitted by the first laser is used as the excitation light to initiate the polymerization reaction of the photoresist. The excitation light is linearly polarized light. It passes through the first acousto-optic modulator. The intensity of the excitation light is controlled or switched by changing the voltage of the first acousto-optic modulator. Then it passes through the first beam expander to expand the beam. Then it passes through the first half-wave plate to adjust the linear polarization direction of the excitation light.

[0027] (2) The laser emitted by the second laser is used as the suppression light to suppress the polymerization of photoresist. The suppression light is linearly polarized light. It passes through the second acousto-optic modulator. The intensity of the excitation light is controlled or switched by changing the voltage of the second acousto-optic modulator. Then it passes through the second beam expander to expand the beam. Then it is reflected by the first mirror. The linear polarization direction of the suppression light is adjusted by the second half-wave plate. Then it passes through the polarization combiner to combine with the excitation light.

[0028] (3) The combined beam is subjected to wavefront phase modulation by the spatial light modulator module with left and right screens. The excitation light and the suppression light are distinguished by their mutually perpendicular linear polarization states. The phase of the excitation light is adjusted on the left screen and a solid phase diagram is loaded. The phase of the suppression light is adjusted on the right screen and a hollow phase diagram is loaded. The beam then passes through a quarter-wave plate to adjust the polarization states of the excitation light and the suppression light to circular polarization states. The beam is then scanned by a scanning galvanometer, converged by a scanning lens, reflected by a first dichroic mirror, collimated by a field mirror, transmitted by a second dichroic mirror, and converged onto the photoresist sample by an oil immersion objective. The photoresist sample is placed on a cover glass, which is placed on a sample slot, which is placed on a high-precision sample displacement stage.

[0029] (4) The computer controls the first and second acousto-optic modulators in the excitation and suppression light optical paths to adjust their switching and light intensity control, and controls the scanning of the galvanometer and the displacement of the high-precision sample stage to realize the PPI writing of the high-precision structure on the photoresist. After the writing is completed, the development process is carried out, and the developed sample is put back on the high-precision sample displacement stage for STORM super-resolution microscopy characterization.

[0030] (5) The laser emitted by the third laser is used as the activation light of the doped fluorescent dye. The activation light passes through the third acousto-optic modulator in sequence to adjust its light intensity and switch, then is reflected by the second mirror, then converged by the lens and reflected by the second dichroic mirror, to the center position of the entrance pupil of the oil immersion objective, and then collimated by the objective to become parallel light that is perpendicularly incident on the written structure sample to activate the fluorescent dye to emit light.

[0031] (6) The laser emitted by the fourth laser is used as the excitation light of the doped fluorescent dye. The excitation light passes through the fourth acousto-optic modulator in sequence to adjust its light intensity and switch, then is reflected by the third mirror, then converged by the lens and reflected by the second dichroic mirror to the edge of the entrance pupil of the oil immersion objective, and then collimated by the objective into parallel light with a total internal reflection angle and incident on the patterned sample.

[0032] (7) The fluorescence emitted by the inscribed structure is collected by the oil immersion objective, then transmitted through the second dichroic mirror, then focused by the field lens, transmitted through the first dichroic mirror, and enters the camera for imaging.

[0033] (8) During imaging, the activation light and intensity of the dye are controlled by the third and fourth acousto-optic modulators controlled by the computer. First, the excitation light is turned on to excite the fluorescent dye to start flashing. When the fluorescence brightness gradually decreases, the activation light is added to activate the fluorescent sample. Each frame of the image captured by the camera is fitted by the computer reconstruction algorithm, and finally a super-resolution image of the inscribed structure is reconstructed.

[0034] This invention integrates laser direct writing and optical microscopy imaging into one system, simultaneously achieving both super-resolution writing and imaging functions. It enables non-destructive, non-invasive direct writing and optical imaging of the written structure. Compared to characterization methods using electron microscopy and atomic force microscopy after writing, this method is simpler to operate and saves costs.

[0035] Compared with the prior art, the present invention has the following beneficial technical effects:

[0036] (1) High-precision writing and super-resolution imaging are integrated into one system. Imaging is performed through optical methods, which has the advantages of fast imaging speed, simple operation, non-destructive and low cost.

[0037] (2) By integrating two functions into one system, timely monitoring of the inscribed structure can be achieved, and the system is simple and compact. Attached Figure Description

[0038] Figure 1 This is a flowchart of the method of the present invention;

[0039] Figure 2 This is a schematic diagram of the device for simultaneously achieving high-precision laser direct writing and super-resolution imaging according to the present invention;

[0040] Figure 3 This is a magnified schematic diagram of a portion of the device during high-precision writing.

[0041] Figure 4 This is a magnified schematic diagram of a part of the device when performing super-resolution microscopy.

[0042] Figure 5 (a) is the phase diagram loaded onto the left screen of the spatial light modulator; Figure 5 (b) is the phase diagram loaded on the right screen of the spatial light modulator. Detailed Implementation

[0043] The embodiments described in this specification are merely examples of implementations of the inventive concept. The scope of protection of this invention should not be considered as limited to the specific forms stated in the embodiments. The scope of protection of this invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

[0044] The technical solution of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] Figure 1 This invention illustrates a method for simultaneously achieving high-precision laser direct writing and super-resolution microscopic imaging, comprising: doping a photoresist with a scintillation-enabled fluorescent dye, and performing high-precision laser direct writing of micro / nano structures on the dye-doped photoresist using the edge light suppression effect; then, performing a development process on the written structure; and finally, performing STORM super-resolution microscopic imaging characterization on the written structure.

[0048] like Figure 2 As shown, a device is provided that simultaneously realizes high-precision laser direct writing and super-resolution microscopic imaging, comprising:

[0049] Simultaneously achieving high-precision laser direct writing and super-resolution microscopic imaging requires the following optical paths: the optical path for achieving the edge light suppression effect of photoresist includes the excitation optical path for exciting the photoresist to generate polymerization and the suppression optical path for inhibiting the polymerization process; the optical path for performing STORM imaging characterization of the written micro / nano structures includes the activation optical path and excitation optical path of fluorescent dyes; and the detection optical path for fluorescence reception.

[0050] The excitation optical path for achieving photoresist polymerization includes, in sequence, a 532nm wavelength femtosecond first laser 1, a first acousto-optic modulator 2, a first beam expander 3, and a first half-wave plate 4.

[0051] The photoresist-suppressed light path sequentially passes through a 532nm wavelength continuous light second laser 5, a second acousto-optic modulator 6, a second beam expander 7, a first reflector 8, and a second half-wave plate 9.

[0052] The photoresist excitation light and suppression light are combined by a polarization beam combiner 10. The combined light path passes sequentially through a screen-split spatial light modulator module 11, a quarter-wave plate 12, a scanning galvanometer 13, a scanning lens 14, a first dichroic mirror 15, a field lens 16, a second dichroic mirror 17, an objective lens 18, a high-precision sample displacement stage 19, a sample groove 20, a cover plate 21, and a photoresist sample 22.

[0053] The fluorescent dye activation optical path includes, in sequence, a third laser 25, a third acousto-optic modulator 26, a second reflector 27, a lens 28, a second dichroic mirror 17, an objective lens 18, a high-precision sample displacement stage 19, a sample groove 20, a cover plate 21, and a photoresist sample 22.

[0054] The excitation and activation light of the fluorescent dye passes through the same element, but is incident on the sample surface at a total internal reflection angle;

[0055] The imaging detection optical path passes sequentially through objective lens 18, second dichroic mirror 17, field lens 16, first dichroic mirror 15 and camera 23;

[0056] It also includes a computer 24, which is connected to a first acousto-optic modulator 2, a second acousto-optic modulator 7, a third acousto-optic modulator 26, a fourth acousto-optic modulator 30, a spatial light modulator module 11, a scanning galvanometer 13, a camera 23, and a high-precision sample moving platform 19.

[0057] The first laser 1 is a picosecond or femtosecond pulsed laser with a wavelength of 532nm, used to initiate the polymerization reaction of the photoresist.

[0058] The second laser 5 is a continuous light laser or a picosecond pulsed laser with a wavelength of 532nm, used to suppress the polymerization reaction of the photoresist.

[0059] The third laser 25 is a continuous light laser with a wavelength of 405 nm, used for activating fluorescent dyes.

[0060] The fourth laser, 29, is a continuous light laser with a wavelength of 488 nm, used to excite the dye to scintillate and fluoresce.

[0061] The initiator of the photoresist sample 22 can be DETC, ITX, or other materials that can achieve edge light suppression effect.

[0062] The dye doped in the photoresist sample can be Alexa Fluor 488 or ATTO 488.

[0063] The first dichroic mirror 15 is a short-pass type, and the second dichroic mirror 17 is a long-pass type.

[0064] This embodiment simultaneously implements a high-precision laser direct writing and super-resolution imaging device, such as... Figure 2 As shown, the specific working process is as follows:

[0065] (1) The laser emitted by the first laser 1 is used as the excitation light to initiate the polymerization reaction of photoresist. The excitation light is linearly polarized light. After passing through the first acousto-optic modulator 2, the intensity of the excitation light is adjusted or switched by changing the voltage of the first acousto-optic modulator. Then, the beam is expanded by the first beam expander 3, and then the linear polarization direction of the excitation light is adjusted by passing through the first half-wave plate.

[0066] (2) The laser emitted by the second laser 5 is used as the suppression light to suppress the polymerization of photoresist. The suppression light is linearly polarized light. After passing through the second acousto-optic modulator, the intensity of the excitation light is adjusted or switched by changing the voltage of the second acousto-optic modulator 6. Then, the beam is expanded by the second beam expander 7. After being reflected by the first mirror 8, the linear polarization direction of the suppression light is adjusted by the second half-wave plate 9. Then, it is combined with the excitation light by the polarization beam combiner 10.

[0067] (3) The combined beam undergoes wavefront phase modulation via the left and right split-screen spatial light modulator modules 12. The excitation and suppression beams are distinguished by their mutually perpendicular linear polarization states. The left screen adjusts the phase of the excitation beam, and a solid light phase diagram is loaded as shown below. Figure 5 As shown in (a); adjust the right screen to suppress the light phase and load the hollow light phase diagram, as shown. Figure 4 As shown, the beam passes through a quarter-wave plate 12 to adjust the polarization state of the excitation light and the suppression light to a circular polarization state. Then, it passes through a scanning galvanometer 13 to scan the beam. After passing through a scanning lens 14 to converge, it is reflected by a first dichroic mirror 15, collimated by a field mirror 16, transmitted by a second dichroic mirror 17, and then converged onto the photoresist sample 22 by an oil immersion objective lens 18. The photoresist sample 22 is placed on a cover glass 21, which is placed on a sample groove 20. The sample groove 20 is placed on a high-precision sample displacement stage 19.

[0068] (4) Computer 24 controls the first acousto-optic modulator 2 and the second acousto-optic modulator 6 in the excitation light and suppression light optical path to adjust their switching and light intensity control, and controls the displacement of galvanometer scanning 13 and high-precision sample stage 19 to realize PPI writing or two-step absorption writing of high-precision structure on photoresist. After the writing is completed, the development process is performed, and the developed sample is put back on the high-precision sample displacement stage 19 for STORM super-resolution microscopy characterization.

[0069] (5) The laser emitted by the third laser 25 serves as the activation light for the doped fluorescent dye. The activation light passes through the third acousto-optic modulator 26 in sequence to adjust its light intensity and switch. It is then reflected by the second mirror 27, then focused by the lens 28 and reflected by the second dichroic mirror 17 to the center of the entrance pupil of the oil immersion objective lens 18. It is then collimated by the objective lens 18 into parallel light that is perpendicularly incident on the patterned sample to activate the fluorescent dye to emit light.

[0070] (6) The laser emitted by the fourth laser 29 is used as the excitation light of the doped fluorescent dye. The excitation light passes through the fourth acousto-optic modulator 30 in sequence to adjust its light intensity and switch. It is then reflected by the third mirror 30, then converged by the lens 28 and reflected by the second dichroic mirror to the edge of the entrance pupil of the oil immersion objective 18. It is then collimated by the objective 18 into parallel light and incident on the patterned sample with a total internal reflection angle.

[0071] (7) The fluorescence emitted by the inscribed structure is collected by the oil immersion objective 18, then transmitted through the second dichroic mirror 17, then converged by the field lens 16, and transmitted through the first dichroic mirror 15, and enters the camera 23 for imaging.

[0072] (8) During imaging, the computer controls the third acousto-optic modulator 26 and the fourth acousto-optic modulator 30 to control the on-time and intensity of the activation light and excitation light of the dye. First, the excitation light is turned on to excite the fluorescent dye to start flashing, and when the fluorescence brightness gradually decreases, the activation light is added to activate the fluorescent sample. Each frame of image captured by the camera 23 is fitted by the reconstruction algorithm of the computer 24, and finally a super-resolution image of the inscribed structure is reconstructed.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for simultaneously achieving high-precision laser direct writing and super-resolution microscopic imaging, comprising: Two optical paths are used to achieve the edge light suppression effect of photoresist, the two optical paths include an excitation optical path for exciting the photoresist to produce polymerization and a suppression optical path for suppressing the polymerization process; The optical path used for random optical reconstruction imaging characterization of the inscribed micro / nano structures includes the activation optical path and excitation optical path of the fluorescent dye; and the detection optical path for fluorescence reception. The excitation optical path for generating polymerization of photoresist includes, in sequence, a first laser (1), a first acousto-optic modulator (2), a first beam expander (3), and a first half-wave plate (4). The suppression optical path for the polymerization process includes, in sequence, a second laser (5), a second acousto-optic modulator (6), a second beam expander (7), a first reflector (8), and a second half-wave plate (9). The photoresist excitation light and suppression light are combined by a polarization beam combiner (10). The combined beam passes sequentially through a split-screen spatial light modulator module (11), a quarter-wave plate (12), a scanning galvanometer (13), a scanning lens (14), a first dichroic mirror (15), a field lens (16), a second dichroic mirror (17), and an objective lens (18) before reaching the photoresist sample (22). The photoresist sample (22) is placed on a cover glass (21), which is placed on a sample slot (20). The sample slot (20) is placed on a high-precision sample displacement stage (19). The activation optical path of the fluorescent dye includes, in sequence, a third laser (25), a third acousto-optic modulator (26), a second mirror (27), a lens (28), a second dichroic mirror (17), an objective lens (18), and a photoresist sample (22). The excitation optical path of the fluorescent dye includes, in sequence, a fourth laser (29), a fourth acousto-optic modulator (30), a third mirror (31), a lens (28), a second dichroic mirror (17), an objective lens (18), and a photoresist sample (22); the light beam of the excitation optical path of the fluorescent dye is incident on the surface of the photoresist sample at a total internal reflection angle. The detection optical path includes, in sequence, an objective lens (18), a second dichroic mirror (17), a field lens (16), a first dichroic mirror (15), and a camera (23). It also includes a computer (24) which is connected to a first acousto-optic modulator (2), a second acousto-optic modulator (7), a third acousto-optic modulator (26), a fourth acousto-optic modulator (30), a split-screen spatial light modulator module (11), a scanning galvanometer (13), a camera (23), and a high-precision sample moving platform (19).

2. The apparatus as claimed in claim 1, characterized in that, The first laser (1) is a picosecond or femtosecond pulsed laser with a wavelength of 532 nm, used to initiate the photoresist polymerization reaction.

3. The apparatus as described in claim 1, characterized in that, The second laser (5) is a continuous light laser or a picosecond pulse laser with a wavelength of 532 nm, used to suppress the polymerization reaction of photoresist.

4. The apparatus as claimed in claim 1, characterized in that, The third laser (25) is a continuous light laser with a wavelength of 405 nm, used for the activation of fluorescent dyes.

5. The apparatus as claimed in claim 1, characterized in that, The fourth laser (29) is a continuous light laser with a wavelength of 488 nm, which is used to excite fluorescent dyes to scintillate and fluoresce.

6. The apparatus as claimed in claim 1, characterized in that, The initiator of the photoresist sample (22) is DETC or ITX.

7. The apparatus as claimed in claim 1, characterized in that, The photoresist sample is doped with Alexa Fluor 488 or ATTO 488 dye.

8. The apparatus as claimed in claim 1, characterized in that, The first dichroic mirror (15) is a short-pass type, and the second dichroic mirror (17) is a long-pass type.

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