CN107942530A - Integrated light guide super-resolution micro imaging system - Google Patents

Abstract

The invention discloses an integrated optical waveguide super-resolution microscopic imaging system, which includes: an integrated waveguide substrate, the middle part is an observation area for placing micro-nano samples, and the outward extension of the observation area is used to observe Wiener samples at different angles. Several strip waveguides for illumination, and each strip waveguide has an optical switch to control the light-through state; a coupling light source, located at the incident end of each strip waveguide, provides evanescent field illumination light coupled into each strip waveguide; a general illumination source , used to directly illuminate the micro-nano sample; the objective lens, used to focus the light emitted by the general illumination source to the micro-nano sample, and collect the sample imaging information under different evanescent field wave vector illumination and general illumination; graphics processing unit , which is used to restore the spectrum information under different lighting conditions to the corresponding position of the original spatial spectrum of the micro-nano sample, and reconstruct and obtain the real image of the micro-nano sample. The invention can realize multi-wavelength and multi-angle illumination for micro-nano samples through the combination of integrated optical waveguide and micro-nano optical fiber coupling source or LED chip.

Description

Integrated optical waveguide super-resolution microscopy imaging system

technical field

The invention relates to the fields of integrated waveguide optics and super-resolution microscopic imaging, in particular to an integrated optical waveguide super-resolution microscopic imaging system.

Background technique

At present, the development of biomedicine, micro-nano processing and other fields requires that the observed sample size has far exceeded the theoretical resolution limit of traditional optical microscopy imaging systems. In order to promote the development of related industries, it is necessary to find a method that can break through the Abbe diffraction limit. .

Since the 1990s, researchers have started in-depth research on nano-resolution technology, and first achieved a breakthrough in fluorescence imaging technology, and proposed a variety of super-resolution microscopy methods based on fluorescent labels. The first type of optical microscopy method utilizes the optical switching effect of fluorescent molecules, and uses extremely low light intensity activation light so that only a very small number of sparse fluorescent molecules are activated at the same time, and have the ability to emit fluorescence. It mainly includes photoactivated localization microscopy (PALM) and optical reconstruction microscopy (STORM). The second category is to suppress the emission of fluorescence based on nonlinear effects, reduce the size of the effective fluorescence point spread function, and thus improve the resolution of the system. Stimulated Emission Microscopy (STED) proposed by Stefan Hell is based on this principle. Additionally, Optical Waveform Imaging (SOFI) is included. With the rapid development of fluorescence microscopy, researchers have also begun to study super-resolution microscopy imaging of non-fluorescent chromophores. Such as structured illumination microscopy, microsphere contact technology, plasmon surface wave, metalens technology, etc., as well as nonlinear technologies such as coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) . At the same time, the super-resolution microscopy technology based on the frequency-shifting method has also been developed rapidly.

However, the method of fluorescent labeling faces the narrow application range of samples; the labeled fluorescent molecules are phototoxic to biological samples, etc. In non-marked far-field super-resolution microscopy imaging, structured light illumination has insufficient resolution under non-marked conditions; CARS technology has the problem of non-resonant background noise; SRS technology faces the disadvantage of weak information and needs to be combined with confocal scanning technology. The existing super-resolution imaging methods based on frequency shifting are not easy to integrate, and the operation process is complicated. A truly practical product must have both a high degree of integration and ease of use. However, the existing super-resolution requires relatively large equipment and systems, and the operation is complicated. To this end, we propose a design scheme for an integrated optical waveguide super-resolution microscopy imaging system. This method achieves a high degree of integration of the entire system by effectively combining technologies such as chip integration and metamaterials, and the size of the imaging system can be reduced. to the order of centimeters. At the same time, the super-resolution system only needs to place the sample in the working area, and the super-resolution observation of micro-nano samples can be realized through simple focusing and position adjustment operations, which greatly improves the convenience of use.

Contents of the invention

The purpose of the present invention is to provide an integrated optical waveguide super-resolution microscopic imaging system, by modulating the external micro-nano coupling optical fiber light source or side-coupled LED chip, using strip optical waveguide to provide illumination wave vectors at different angles. By selecting strip waveguide structures designed with different shapes and matching with the corresponding sample slots, it can meet the observation of micro-nano samples of different complexity; by changing the wavelength of the input light in the coupling fiber or providing a combination of LED chips, multi-wavelength illumination can be realized , and finally achieve a relatively complete reconstruction of the spectral information of micro-nano samples.

Concrete technical scheme of the present invention is as follows:

A design of an integrated optical waveguide super-resolution microscopic imaging system, including:

Integrated waveguide substrate, the middle part is the observation area for placing micro-nano samples, and several strip waveguides for illuminating Wiener samples at different angles are set outward along the observation area, and each strip waveguide has a control light transmission state the optical switch;

An external coupling light source, located at the incident end of each strip waveguide, provides illumination light coupled into each strip waveguide;

A general illumination source for directly illuminating the micro-nano sample;

The objective lens is used to focus the light emitted by the general illumination source to the micro-nano sample, and collect the imaging information of the sample under different wave vector illumination and general illumination source illumination conditions;

The tube lens is used to image the sample imaging information from the objective lens onto the image display unit.

The graphics processing unit is used to restore the spectrum information under different lighting conditions to the corresponding position of the original spatial spectrum of the micro-nano sample, and reconstruct and obtain the real image of the micro-nano sample.

Preferably, the observation area is polygonal, the number of strip waveguides is equal to the number of sides of the polygon, and the exit ends of each strip waveguide are respectively located on different sides of the polygon; wherein, the externally coupled light source is a fiber optic light source or an LED chip light source.

In the present invention, strip-shaped integrated optical waveguide structures with specific shapes are prepared by etching technology, and the exit ends of all strip-shaped waveguides will be located on different sides of a regular polygon. When the strip-shaped waveguide substrate is placed in the system architecture device, the position of the end of the micro-nano fiber light source is adjusted through the displacement device on the system architecture device, so that the output end of the micro-nano fiber and the incident end of the strip waveguide can be effectively realized. Coupling; or attach the LED chip to the corresponding incident end of the micro-nano waveguide, and at the same time point and lead out the excitation electrode lead of the chip. When light of different wavelengths is time-divisionally coupled into different strip waveguides, the light transmitted in the strip waveguides will respectively excite evanescent fields inside the regular polygon, and these evanescent fields will interact with micro-nano samples respectively. and is scattered into the far field. By adjusting the specific position of the imaging receiving unit, the micro-nano sample on the integrated waveguide substrate is clearly imaged on the imaging display unit, such as CCD, CMOS and other imaging devices. The image processing program is used to restore the spectral information under different lighting conditions to the corresponding position of the original spatial spectrum of the micro-nano sample, and reconstruct the real image of the micro-nano sample.

The material of the micro-nano waveguide substrate in the present invention can be selected from Si-SiO ₂ -Si ₃ N ₄ /InGaAsP/InP/TiO ₂ /Al ₂ O ₃ , etc., and polymer materials can also be selected. The choice of specific material needs to match the substrate material. The etching technology of the micro-nano waveguide substrate can be selected from dry etching, wet etching or ion beam etching. In the present invention, the specific size of the strip-shaped integrated optical waveguide needs to determine the optimal value through simulation and later experiments. Here, the wavelength of the light used, the surrounding dielectric material, the expected polygonal shape formed by the exit end of the strip waveguide, etc. need to be considered. For example, the feature size of the strip waveguide needs to be reduced when more polygonal side lengths are expected without increasing the target sample area.

The evanescent field coupling light source in the present invention can be introduced into the strip waveguide in the following ways: micro-nano fiber coupling, LED chip coupling and on-chip integrated light source. In the micro-nano fiber coupling method, the micro-nano fiber can be prepared by tapering manually or on a micro-nano operating platform. The micro-nano fiber can be coupled into the strip waveguide by means of end-face coupling, or a part of the coupling aperture can be reserved when preparing the strip waveguide, and the micro-nano fiber can be directly placed in the coupling aperture in the later stage for effective coupling and transmission of light. In addition, the micro-nano fiber can also use the evanescent field coupling method on the side to provide a coupling source for the strip waveguide. By adopting the optical fiber coupling method, it is convenient to provide light of various available light bands to illuminate micro-nano samples, and there is no need to change the rest of the whole system. Using the LED chip coupling method, the patch method can be used to attach different chips to the surface or end face of the strip waveguide. After that, the electrodes of the chip are drawn out by equipment such as electric welding machine. If the on-chip integrated light source is used, the on-chip light source can be directly integrated into the strip waveguide to provide the evanescent field source for the strip waveguide.

In the fiber coupling mode, an integrated light source can be configured for each strip waveguide, and then the light transmission of each strip waveguide can be realized by controlling the on and off of each light source. It is also possible to control the light transmission of each strip waveguide by connecting a laser light source to the corresponding coupling fibers of different strip waveguides. In addition, the optical fiber beam splitter can also be used in combination with related optical switch modules to realize the control of the light passing conditions of different strip waveguides. If LED chips are used, the light transmission conditions of different strip waveguides can be directly controlled by digitally controlling the brightness of each LED chip. If the on-chip integrated light source is used, the light-emitting state of each light source can be controlled by photo-induced or electro-induced methods.

The common light source in the present invention can be selected from other lighting sources such as LED white light lighting source or single-wavelength LED lighting source and halogen lamp.

The objective lens and the tube lens in the present invention can be ultra-thin lens groups designed and processed by metamaterials or free-form surfaces. The lens group needs to correct optical parameters such as astigmatism and distortion; at the same time, the objective lens needs to have a large numerical aperture NA.

The imaging display unit in the present invention can use a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS), a photomultiplier tube (PMT) or a special imaging recording unit. The imaging display unit is required to have sufficient imaging resolution and be able to provide images with sufficiently high pixels. According to specific application scenarios, a color or black and white display device may be used.

In addition, each component unit mentioned above in the present invention will eventually be integrated into the system architecture for use. The structure of the whole system will meet the following conditions: 1. It can realize the fixation of the integrated waveguide substrate chip; 2. It can provide fixation and three-dimensional space movement for the ultra-thin lens group; 3. It can provide fixed CCD, CMOS, PMT or special The fixed interface of the display unit; 4. It provides the interface for fixing the micro-nano optical fiber coupling end, and can realize the fine control of the spatial position of each coupling end; 5. It can provide the fixation of the common lighting source.

The invention provides an integrated and miniaturized super-resolution microscopic imaging system, which can realize multi-wavelength and multi-angle illumination of micro-nano samples through the combination of integrated optical waveguide and micro-nano optical fiber coupling source or LED chip; and It can achieve a larger range of reconstruction of the spectrum space of micro-nano samples, and obtain the morphology characteristics of micro-nano samples.

Description of drawings

Fig. 1 is the scheme of the integrated optical waveguide super-resolution microscopic imaging system involved in the present invention. Among them, 11 is a support and clamping device, 12 is a slot, 13 is an integrated waveguide substrate, 14 is an observation area on the integrated waveguide substrate, 15 is a fixing hole for an external coupling light source, 16 is a three-dimensional displacement fine adjustment device, 17 is the optical switch in the integrated strip waveguide, 18 is the objective lens, 19 is the general illumination source for obtaining the fundamental frequency information from the outside, 20 is the half-mirror, 21 is the tube mirror, 22 is the circular optical component plug-in cylinder, 23 24 is a three-dimensional displacement fine adjustment device, and 25 is an image processing unit.

Fig. 2 is a scheme of the integrated optical waveguide super-resolution microscopic imaging system involved in the present invention. Among them, 31 is a support and clamping device, 32 is a slot, 33 is an integrated waveguide substrate, 34 is an observation area on the integrated waveguide substrate, 35 is a fixing hole for an external coupling light source, and 36 is a three-dimensional displacement fine adjustment device, 37 is an optical switch in the integrated strip waveguide, 38 is an objective lens, 39 is a general illumination source for obtaining fundamental frequency information from the outside, 40 is a half-mirror, 41 is a tube mirror, 42 is a square optical component insertion and removal cylinder, 43 is The display device, 44 is a three-dimensional displacement fine adjustment device, and 45 is an image processing unit.

Fig. 3 is a scheme of the integrated optical waveguide super-resolution microscopic imaging system involved in the present invention. Among them, 51 is a support frame, 52 is a slot, 53 is an integrated waveguide substrate, 54 is a strip waveguide optical switch, 55 is an observation area on a micro-nano sample, 56 is a fixing hole for an external coupling light source, and 57 is a three-dimensional displacement precision Adjusting device, 58 is the entrance of the white light source, 59 is the fixed lens barrel, 60 is the objective lens, 61 is the half mirror, 62 is the tube mirror, 63 is the image display and recording device (CCD, CMOS, etc.), 64 is the mirror The three-dimensional displacement fine adjustment device of the barrel, 65 is a graphic processing unit.

Fig. 4 is an alternative scheme of using a micro-nano fiber light source coupled with a strip optical waveguide to provide an evanescent field illumination source in the present invention. Among them, 71 is the integrated waveguide substrate, 72 is the micro-nano coupling fiber light source fixing device, 73 is the micro-nano fiber coupling source, 74 is the strip waveguide etched on the integrated waveguide substrate, 75 is the optical switch in the optical fiber path, and 76 is Three-dimensional displacement fine adjustment device, 77 is the observation area on the integrated waveguide substrate.

Fig. 5 is a schematic diagram of an evanescent field illumination source provided by using an LED chip light source coupled with a strip optical waveguide in the present invention. Among them, 81 is the etched integrated optical waveguide substrate, 82 is the LED chip, 83 is the pin of the LED chip, 84 is the strip waveguide on the integrated waveguide substrate, and 85 is the observation area on the integrated optical waveguide substrate.

Detailed ways

The present invention will be described in detail below in conjunction with the embodiments and accompanying drawings, but the present invention is not limited thereto.

The integrated optical waveguide super-resolution microscopic imaging system shown in Figure 1 includes a support and clamping device 11 for placing an integrated optical waveguide substrate, a slot 12 for placing an integrated waveguide chip, and is used for micro-nano samples. An integrated optical waveguide substrate 13 that provides evanescent field illumination, an observation area 14 for placing micro-nano samples, a fixing hole 15 for fixing external micro-nano fiber-coupled light sources, and a position for adjusting the position of the exit end of the micro-nano fiber-coupled source The three-dimensional displacement fine adjustment device 16, the optical switch 17 used to control the light-passing state of the strip waveguide, the objective lens 18 used to collect imaging information, the general illumination source 19 used to obtain fundamental frequency information, the half mirror 20, For imaging the signal from the objective lens 18 to the ultra-thin lens group 21 of the receiving surface of the image collection unit, for fixing the lens barrel 22 of optical components such as the ultra-thin lens group half-transparent mirror, for receiving the signal from the ultra-thin lens group A display device 23 for imaging information, a three-dimensional displacement fine adjustment device 24 for adjusting the integrated waveguide substrate, and an image processing unit 25 for performing spectrum processing on images obtained from the display device.

In this example, Si-SiO ₂ -Si ₃ N ₄ , InGaAsP, InP, TiO ₂ , Al ₂ O ₃ and the like can be selected as the material of the integrated optical waveguide. Among them, the high refractive index material layer Si ₃ N ₄ , InGaAsP, InP, TiO ₂ , Al ₂ O ₃ etc. will be prepared into strips with specific properties by etching techniques such as dry etching, wet etching or ion beam etching. Shaped waveguide, as shown in Figure 2, but not limited to the shape shown in Figure 2. The size of the strip waveguide needs to be determined according to the simulation of the actual situation, such as the wavelength of light, the refractive index of the surrounding materials and other information.

As shown in Figure 1, the micro-nano fiber will be efficiently coupled with the strip waveguide through the fixing hole 15 of the micro-nano fiber and the three-dimensional displacement fine adjustment device, and the optical switch 17 is used to control the light-passing state of different strip waveguides, so as to realize the two-dimensional different angles of illumination for nano-samples. By changing the optical fiber input light source, the wavelength of the evanescent field illumination source can be easily changed.

When the evanescent field from different strip waveguides and the general illumination source respectively illuminate the micro-nano sample, the far-field scattering field from the micro-nano sample is collected by the objective lens 18 in Fig. For imaging, the focus needs to be adjusted by the three-dimensional displacement fine adjustment device 24 in FIG. 1 , and then the image is clearly imaged on the display device 23 and saved. The ultra-thin lens group requires correction of related optical aberrations and astigmatism. Moreover, the optical numerical aperture should be as large as possible, so as to achieve a wider range of spatial spectrum information acquisition of micro-nano samples, and it is also conducive to the convergence of the program in the later spectrum stitching process. Afterwards, the algorithm is used to process the frequency-shifted imaging results under different wave vector illumination and white light illumination conditions, and restore the corresponding spectral information to the corresponding position in the micro-nano sample spectral space. Finally, through the iterative reconstruction of the spectrum, the spectrum of the micro-nano sample can be obtained in a wide range, so as to restore the morphology characteristics of the micro-nano sample.

As shown in Figure 2, the design scheme 2 of the integrated optical waveguide super-resolution microscopy imaging system, compared with scheme 1, the optical component insertion and removal cylinder in scheme 2 adopts a square design. The square design can be an overall square tube, or a square structure constructed by a cage structure or the like.

As shown in Figure 3, the design scheme 3 of the integrated optical waveguide super-resolution microscopy imaging system, compared with schemes 1 and 2, this scheme integrates all the components in the system inside a large support frame 51, and the overall size is larger , but can better protect related components.

As shown in Figure 4, it is an alternative coupling method of strip waveguide and micro-nano fiber coupling light source. Different strip waveguides are completely independently transmitted on the integrated waveguide chip, and are finely adjusted through different coupling interfaces 72 and three-dimensional displacement. Means 76 enable efficient coupling to the strip waveguide. In addition, the light transmission conditions of different strip waveguides can be controlled by an external optical switch 75 .

As shown in FIG. 5 , the evanescent field illumination source of the strip optical waveguide can also be provided by the LED chip 82 . At this time. As long as the pins 83 of different LED chips are connected to the corresponding control circuits, the light-emitting state control of different LED chips can be realized conveniently. Here, the LED chips can be laminated with multiple LED chips of different wavelengths to provide evanescent field illumination sources of different wavelengths.

The above descriptions are only examples of the preferred implementation of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention within.

Claims (10)

1. An integrated optical waveguide super-resolution microscopic imaging system, characterized in that it comprises: Integrated waveguide substrate, the middle part is the observation area for placing micro-nano samples, and several strip waveguides for illuminating Wiener samples at different angles are set outward along the observation area, and each strip waveguide has a control light transmission state the optical switch; An external coupling light source, located at the incident end of each strip waveguide, provides illumination light coupled into each strip waveguide; A general illumination source for directly illuminating the micro-nano sample; The objective lens is used to focus the light emitted by the illumination source to the micro-nano sample, and collect the imaging information of the sample under different wave vector illumination and direct illumination; The graphics processing unit is used to restore the spectrum information under different lighting conditions to the corresponding position of the original spatial spectrum of the micro-nano sample, and reconstruct and obtain the real image of the micro-nano sample. 2. The integrated optical waveguide super-resolution microscopic imaging system as claimed in claim 1, wherein the observation area is polygonal, the number of strip waveguides is equal to the number of sides of the polygon, and the exit ends of each strip waveguide are respectively located at The polygon is on different sides. 3. The integrated optical waveguide super-resolution microscopy imaging system according to claim 1, wherein each strip waveguide is correspondingly provided with an external coupling light source, or the same external coupling light source is connected to each strip waveguide through a corresponding coupling optical fiber. 4. The integrated optical waveguide super-resolution microscopic imaging system according to claim 1, characterized in that, the externally coupled light source is a fiber light source or an LED chip light source. 5. The integrated optical waveguide super-resolution microscopic imaging system according to claim 1, further comprising a support and clamping device, an assembly cavity for accommodating the integrated waveguide substrate is provided inside, and an integrated waveguide substrate is provided on the side. The substrate is loaded into the socket in the chamber. 6. The integrated optical waveguide super-resolution microscopic imaging system as claimed in claim 5, wherein the side of the support and clamping device is provided with a fixing hole leading into the assembly cavity and fixing the coupling light source . 7. The integrated optical waveguide super-resolution microscopic imaging system according to claim 6, wherein the fixed hole can adjust the relative position of the coupling source and the strip waveguide through a three-dimensional displacement fine adjustment device, thereby improving the coupling efficiency. 8. The integrated optical waveguide super-resolution microscopic imaging system as claimed in claim 1, further comprising a support frame, the integrated waveguide substrate, the illumination source and the objective lens are all arranged in the support frame; The relative position of the integrated waveguide substrate can be adjusted through the three-dimensional displacement fine adjustment device. 9. The integrated optical waveguide super-resolution microscopic imaging system according to claim 1, wherein the material of the integrated waveguide substrate is Si-SiO ₂ -Si ₃ N ₄ , InGaAsP, InP, TiO ₂ or Al ₂ O ₃ , using etching technology to prepare the strip waveguide. 10. The integrated optical waveguide super-resolution microscopic imaging system according to claim 1, wherein the general illumination source is a white light illumination source or a single-wavelength LED illumination source.