Photoacoustic detection imaging system and method based on optical waveguide resonance sensing

Abstract

The present invention discloses a photoacoustic detection imaging system and method based on optical waveguide resonance sensing. The imaging system includes a detection light source, a polarization component, a first focusing lens, a prism, an objective lens, a sensor, a spectroscope, a first polarization analyzer component, a second polarization analyzer component, a photodetector, an excitation light source, a lens component, a first reflector, a second focusing lens, a second reflector, a two-dimensional mobile platform, and an imaging processing terminal. The sensor is an optical waveguide resonance sensor. The imaging system is provided with a sensor having a tightly confined detection electric field with extremely strong optical resonance and a coupling medium combination, and has ultra-high sensitivity and wide bandwidth photoacoustic detection capabilities. The excitation light irradiates the sample to generate a photoacoustic signal, which interacts with the coupling medium to obtain a detection beam based on the change of the light beam, thereby realizing reflection mode photoacoustic microscopic imaging. Regardless of the thickness of the sample, three-dimensional microscopic imaging at the micrometer scale can be achieved, significantly improving the depth resolution and image quality.

Description

Technical Field

[0001] The present invention relates to the technical field of microscopic imaging, and in particular to a photoacoustic detection imaging system and method based on optical waveguide resonance sensing. Background Art

[0002] Photoacoustic imaging uses acoustic methods to detect the transient thermoelastic expansion of biomolecules caused by their specific, strong absorption of pulsed laser energy, directly revealing the optical absorption characteristics of different molecules. This technique reveals the molecular specificity of endogenous non-fluorescent chromophores (such as hemoglobin and melanin) in a label-free manner, showing great potential in biomedical research fields such as cancer histology, vascular anatomy, and brain activity monitoring. A key branch of this technique is optical resolution photoacoustic microscopy (OR-PAM). By focusing excitation light with a microscope objective, it achieves micrometer and submicrometer lateral resolution, revealing morphological, functional, and molecular information of biological samples at the cellular and subcellular levels. In most OR-PAM systems, piezoelectric transducers are typically used to detect the time-domain photoacoustic signals generated by the transient thermoelastic expansion of biomolecules. Due to the inherent physical properties of piezoelectric materials, piezoelectric transducers have a narrow frequency bandwidth (typically tens of megahertz), while pressure transients generated by microstructures typically have an extremely wide acoustic bandwidth, ranging from near DC to hundreds of megahertz. As a result, the depth resolution of these OR-PAM systems is affected, making it impossible to accurately obtain the depth position information of biomolecules and reducing the quality of 3D photoacoustic image rendering. Therefore, the optical resolution photoacoustic microscopy in the existing technology has the problem of low depth resolution. Summary of the Invention

[0003] The embodiments of the present invention provide a photoacoustic detection imaging system and method based on optical waveguide resonance sensing, aiming to solve the problem of low depth resolution of optical resolution photoacoustic microscopes in prior art methods.

[0004] In a first aspect, an embodiment of the present invention provides a photoacoustic detection and imaging system based on optical waveguide resonance sensing, wherein the photoacoustic detection and imaging system includes a detection light source, a polarization component, a first focusing lens, a prism, an objective lens, a sensor, a spectroscope, a first polarization analyzer component, a second polarization analyzer component, a photodetector, an excitation light source, a lens component, a first reflector, a second focusing lens, a second reflector, a two-dimensional mobile platform, and an imaging processing terminal; the sensor is an optical waveguide resonance sensor;

[0005] The polarization component is arranged between the first focusing lens and the detection light source, the first focusing lens and the beam splitter are respectively arranged on both sides of the prism, the objective lens and the second reflector are respectively arranged at opposite ends of the prism, and the sensor is arranged on the side of the objective lens away from the prism; the sensor and the two-dimensional moving platform are respectively arranged on both sides of the sample, and the two-dimensional moving platform drives the sample to move horizontally; a coupling medium is provided between the sensor and the sample;

[0006] The detection light source emits a light beam which passes through the polarization component and the first focusing lens and then enters the prism. The light beam is refracted by the prism and then enters the objective lens and illuminates the sensor. The sensor excites and generates a detection light beam which passes through the objective lens and then enters the prism. The incident detection light beam is refracted again and then enters the beam splitter.

[0007] The first polarization analyzer is arranged between the photodetector and the beam splitter, the first reflector is arranged on the side of the beam splitter, and the second polarization analyzer is arranged between the photodetector and the first reflector; the beam splitter splits the incident light beam into a first light beam and a second light beam, the first light beam passes through the first polarization analyzer and enters the first probe of the photodetector, and the second light beam is reflected by the first reflector and passes through the second polarization analyzer and enters the second probe of the photodetector;

[0008] The two-dimensional moving platform, the photodetector, the detection light source and the excitation light source are respectively communicated with the imaging processing terminal, the lens assembly is arranged in front of the beam exit port of the excitation light source, and the second focusing lens is arranged between the second reflector and the lens assembly.

[0009] In a second aspect, an embodiment of the present invention further provides a photoacoustic detection and imaging method based on optical waveguide resonance sensing, wherein the photoacoustic detection and imaging method based on optical waveguide resonance sensing is applied to the photoacoustic detection and imaging system based on optical waveguide resonance sensing as described in the first aspect; the photoacoustic detection and imaging method comprises:

[0010] The detection laser light emitted by the detection light source passes through the polarization component and the first focusing lens and then enters the prism. The light beam is refracted by the prism and enters the objective lens and illuminates the sensor.

[0011] The excitation light source emits excitation light that passes through the lens assembly and the second focusing lens, and the light beam is reflected by the second reflector and sequentially passes through the prism and the objective lens before irradiating the sensor;

[0012] The excitation light passes through the sensor and is focused onto the sample surface to generate a photoacoustic signal, and the photoacoustic signal passes through the coupling medium to cause the light beam to change and obtain a detection light beam;

[0013] The detection beam passes through the objective lens and enters the prism, and the incident detection beam is refracted again and then enters the beam splitter;

[0014] The beam splitter splits the incident light beam into a first light beam and a second light beam. The first light beam passes through the first polarization analyzer assembly and then enters the first probe of the photodetector. The second light beam is reflected by the first reflector and passes through the second polarization analyzer assembly and then enters the second probe of the photodetector.

[0015] The photoelectric detector performs differential light detection on the light beams detected by the first probe and the second probe to obtain an electrical signal of the detected light change and outputs the electrical signal to the imaging processing terminal;

[0016] The imaging processing terminal controls the two-dimensional mobile platform to drive the sample to move horizontally, so as to scan and obtain electrical signals for detecting various positions in the sample and store the signals;

[0017] The imaging processing terminal performs three-dimensional reconstruction on the stored electrical signals to obtain photoacoustic three-dimensional microscopic image information with high spatial resolution.

[0018] Embodiments of the present invention provide a photoacoustic detection imaging system and method based on optical waveguide resonance sensing. The imaging system includes a detection light source, a polarization component, a first focusing lens, a prism, an objective lens, a sensor, a spectroscope, a first polarization analyzer component, a second polarization analyzer component, a photodetector, an excitation light source, a lens component, a first reflector, a second focusing lens, a second reflector, a two-dimensional mobile platform, and an imaging processing terminal. The sensor is an optical waveguide resonance sensor. The imaging system comprises a sensor with a tightly confined detection electric field having extremely strong optical resonance and a coupling medium, and has ultra-high sensitivity and wide bandwidth photoacoustic detection capabilities. The excitation light irradiates the sample to generate a photoacoustic signal, which interacts with the coupling medium to produce a change in the incident light beam to generate a detection beam. This system can achieve reflection-mode photoacoustic microscopic imaging, enabling micrometer-scale three-dimensional microscopic imaging regardless of the sample thickness, significantly improving depth resolution and image quality. Furthermore, the system can achieve a balance between photoacoustic signal detection sensitivity and bandwidth, achieving high sensitivity detection while also maintaining a bandwidth response of hundreds of megahertz. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A structural diagram of a photoacoustic detection and imaging system based on optical waveguide resonance sensing provided by an embodiment of the present invention;

[0021] Figure 2 A partial structural diagram of a photoacoustic detection and imaging system based on optical waveguide resonance sensing provided by an embodiment of the present invention;

[0022] Figure 3 This is an application effect diagram of the photoacoustic detection and imaging system based on optical waveguide resonance sensing provided by an embodiment of the present invention;

[0023] Figure 4 Another application effect diagram of the photoacoustic detection and imaging system based on optical waveguide resonance sensing provided by an embodiment of the present invention;

[0024] Figure 5 Another application effect diagram of the photoacoustic detection and imaging system based on optical waveguide resonance sensing provided by an embodiment of the present invention;

[0025] Figure 6 A flow chart of a method for photoacoustic detection and imaging based on optical waveguide resonance sensing provided by an embodiment of the present invention;

[0026] Figure numerals: 1, detection light source; S, polarization component; 2, polarizer; 3, half-wave plate; 4, quarter-wave plate; 5, first focusing lens; 6, prism; 7, objective lens; 8, sensor; 9, spectrometer; J1, first polarizer component; 10, first polarizer; 11, first lens; J2, second polarizer component; 13, second polarizer; 14, second lens; 15, photodetector; 16, excitation light source; T, lens component; 12, first reflector; 17, third lens; 18, fourth lens; 19, second focusing lens; 20, second reflector; 23, two-dimensional moving platform; 22, imaging processing terminal; 21, signal amplifier; 81, polydimethylsiloxane film; 82, slide. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0029] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0030] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0031] The specific embodiment of the present application discloses a photoacoustic detection imaging system based on optical waveguide resonance sensing, wherein the photoacoustic detection imaging system includes a detection light source, a polarization component, a first focusing lens, a prism, an objective lens, a sensor, a spectroscope, a first polarization analyzer component, a second polarization analyzer component, a photodetector, an excitation light source, a lens component, a first reflector, a second focusing lens, a second reflector, a two-dimensional mobile platform and an imaging processing terminal; the sensor is an optical waveguide resonance sensor; the polarization component is arranged between the first focusing lens and the detection light source, the first focusing lens and the spectroscope are respectively arranged on both sides of the prism, the objective lens and the second reflector are respectively arranged at opposite ends of the prism, and the sensor is arranged on the side of the objective lens away from the prism; the sensor and the two-dimensional mobile platform are respectively arranged on both sides of the sample and the two-dimensional mobile platform drives the sample to move horizontally; a coupling medium is provided between the sensor and the sample; the detection light source emits a light beam through the polarization component and the After the first focusing lens, the light beam enters the prism, and after being refracted by the prism, it enters the objective lens and illuminates the sensor. The sensor excites the detection light beam to pass through the objective lens and enter the prism. The incident detection light beam is refracted again and enters the spectrometer; the first polarization analyzer is arranged between the photodetector and the spectrometer, the first reflector is arranged on the side of the spectrometer, and the second polarization analyzer is arranged between the photodetector and the first reflector; the spectrometer splits the incident light beam into a first light beam and a second light beam, the first light beam passes through the first polarization analyzer and enters the first probe of the photodetector, and the second light beam is reflected by the first reflector and passes through the second polarization analyzer and enters the second probe of the photodetector; the two-dimensional moving platform, the photodetector, the detection light source and the excitation light source are respectively communicated with the imaging processing terminal, the lens assembly is arranged in front of the beam exit port of the excitation light source, and the second focusing lens is arranged between the second reflector and the lens assembly.

[0032] Among them, the detection light source emits a pulsed laser beam, which generates a laser output with adjustable polarization after passing through the polarization component. After the laser passes through the first focusing lens, the laser is refracted by the prism and focused on the back focal plane of the objective lens. When the parallel light passing through the objective lens is incident on the sensor, total internal reflection occurs and excites an electromagnetic field that is localized and has a reduced lateral size. At the same time, the excitation light source emits excitation light, which passes through the lens component and the second focusing lens. The light beam is reflected by the second reflector and passes through the prism and the objective lens in sequence to illuminate the sensor. Due to the optical transparency of the sensor, the objective lens can focus the excitation light through the sensor to the sample surface, thereby exciting a photoacoustic signal. The photoacoustic signal changes the light beam that passes through the objective lens and enters the sensor through the coupling medium, and the photoacoustic signal is superimposed on the reflected light beam corresponding to the light beam that passes through the objective lens and enters the sensor. The reflected light beam with the superimposed photoacoustic signal is also the detection beam. The detection beam passes through the objective lens and enters the prism. After being refracted by the prism, the detection beam enters the beam splitter. The beam splitter splits the incident beam into a first beam and a second beam. The first beam passes through the first polarization analyzer and enters the first probe of the photodetector. The second beam is reflected by the first reflector and passes through the second polarization analyzer before entering the second probe of the photodetector. The photodetector performs differential optical detection on the beams detected by the first and second probes to obtain corresponding electrical signals. The above steps can scan a position of the sample to obtain a corresponding set of electrical signals. The sample is driven horizontally by a two-dimensional mobile platform to scan multiple positions of the sample to obtain the electrical signals corresponding to each position. Three-dimensional reconstruction is then performed based on the stored electrical signals to obtain the photoacoustic three-dimensional microscopic image information of the sample.

[0033] In a more specific embodiment, the detection light source is a continuously pulsed helium-neon laser, and the laser wavelength generated by the detection light source is 615-650nm. Preferably, the laser wavelength generated by the detection light source is 632.8nm. Specifically, the polarization component includes a polarizer, a half-wave plate, and a quarter-wave plate; the polarizer is positioned near the detection light source. The excitation light source is a neodymium-doped yttrium aluminum garnet laser (Nd:YAG laser), and the excitation light generated by the excitation light source has a wavelength of 510-555nm and a pulse duration of 0.8-5ns. In a preferred embodiment, the excitation light generated by the excitation light source has a wavelength of 532nm and a pulse duration of approximately 1.2ns.

[0034] In a more specific embodiment, the first polarization analyzer assembly includes a first polarizer and a first lens; the second polarization analyzer assembly includes a second polarizer and a second lens; the first lens and the second lens are both disposed on a side proximal to the photodetector. The cross-section of the prism is an isosceles trapezoid; the first focusing lens and the beam splitter are disposed relative to the inclined side surfaces of the trapezoid; the objective lens is disposed at the end of the prism corresponding to the upper base of the isosceles trapezoid; and the second reflector is disposed at the end of the prism corresponding to the lower base of the isosceles trapezoid.

[0035] By setting a first polarizer and a first lens to form a first polarizer assembly, and setting a second polarizer and a second lens to form a second polarizer assembly, after the detection light beam generated by reflection passes through the beam splitter, the p-polarized light passes through the first polarizer with mutually orthogonal projection directions and is focused by the first lens, and the s-polarized light is reflected by the first reflector and passes through the second polarizer with mutually orthogonal projection directions and is focused by the second lens; the first probe and the second probe of the photoelectric detector can be both photodiodes, and the two paths of light passing through the first polarizer assembly and the second polarizer assembly are respectively focused on the two photodiodes of the balanced photodetector for differential light detection.

[0036] Specifically, the prism can be configured as an isosceles trapezoid, with the first focusing lens and the beam splitter positioned relative to the inclined side surfaces of the trapezoid. The objective lens and the second reflector are positioned at the upper and lower ends of the isosceles trapezoid, respectively. The incident laser is refracted on one inclined surface of the prism, while the reflected detection beam is refracted on the other inclined surface of the prism. The optical refraction of the two beams is identical, ensuring stable detection of photoacoustic signals. Furthermore, the objective lens, prism, and second reflector are aligned, allowing the excitation light reflected by the second reflector to directly enter the objective lens and focus on the sensor's imaging position, improving imaging quality.

[0037] In a more specific embodiment, the lens assembly includes a third lens and a fourth lens disposed opposite each other, the third lens and the fourth lens being combined to form a 4F lens assembly. The 4F lens assembly can collimate the incident laser light to optimize it into a pure collimated light pattern, thereby improving the quality of the excitation beam incident on the sensor.

[0038] In a more specific embodiment, Figure 2As shown, the sensor consists of a polydimethylsiloxane (PDMS) film and a glass slide. The PDMS film is deposited on the side of the glass slide facing the sample. The sensor is an optical waveguide resonance (OWR) sensor fabricated using a deposition method. The PDMS layer is 350 nm thick and is deposited on a glass slide. The objective lens can be a total internal reflection fluorescence (TIRF) lens.

[0039] The incident laser is a 632.8nm wavelength laser, which is coupled to the sensor through an objective lens at a specific incident angle (such as 62.45°), exciting a size-limited strong resonant electric field inside the PDMS film, allowing the sensor to theoretically respond to ultrasonic excitation over a bandwidth of hundreds of megahertz; the excitation light is a 532nm wavelength short-pulse laser (pulse width in nanoseconds) focused onto the sample surface through the objective lens, exciting the generation of broadband photoacoustic signals; due to the elliptical effect, the photoacoustic pressure disturbs the PDMS film, causing a drastic impact on the waveguide resonance mode, resulting in a phase shift in the orthogonal polarization components of the reflected light, and light interference will occur in the transmission direction of the polarizer used to recombine the two polarization components. By monitoring the light interference intensity that changes with time relative to the initial static conditions, broadband detection of the photoacoustic signal can be achieved, which means that the detection bandwidth of the photoacoustic signal can be improved.

[0040] In a more specific embodiment, the photoacoustic detection imaging system further includes a signal amplifier, one end of which is connected to the imaging processing terminal, and the other end of which is connected to the photodetector.

[0041] To improve the detection effect, a signal amplifier can be set up. The signal amplifier amplifies the electrical signal output by the photodetector, obtains an amplified signal and outputs it to the imaging processing terminal. The imaging processing terminal processes the amplified signal and obtains photoacoustic three-dimensional microscopic image information, which can further improve the quality of the microscopic image.

[0042] The present application also discloses a photoacoustic detection imaging method based on optical waveguide resonance sensing, wherein the photoacoustic detection imaging method is applied to the photoacoustic detection imaging system based on optical waveguide resonance sensing as described in the above embodiment; Figure 6 As shown, the photoacoustic detection imaging method includes steps S1 to S8:

[0043] S1, the detection light source emits a detection laser which passes through the polarization component and the first focusing lens and then enters the prism. The light beam is refracted by the prism and enters the objective lens and illuminates the sensor;

[0044] S2, the excitation light source emits excitation light that passes through the lens assembly and the second focusing lens, and then the light beam is reflected by the second reflector and sequentially passes through the prism and the objective lens before irradiating the sensor;

[0045] S3, the excitation light passes through the sensor and is focused onto the sample surface to generate a photoacoustic signal, and the photoacoustic signal passes through the coupling medium to cause the light beam to change and obtain a detection light beam;

[0046] S4, the detection beam passes through the objective lens and enters the prism, and the incident detection beam is refracted again and then enters the beam splitter;

[0047] S5, the beam splitter splits the incident light beam into a first light beam and a second light beam, the first light beam passes through the first polarization analyzer and enters the first probe of the photodetector, the second light beam is reflected by the first reflector and passes through the second polarization analyzer and enters the second probe of the photodetector;

[0048] S6, the photoelectric detector performs differential light detection on the light beams detected by the first probe and the second probe to obtain an electrical signal of the detected light change and outputs the electrical signal to the imaging processing terminal;

[0049] S7, the imaging processing terminal controls the two-dimensional mobile platform to drive the sample to move horizontally, so as to scan and obtain electrical signals detecting various positions in the sample and store the signals;

[0050] S8. The imaging processing terminal performs three-dimensional reconstruction on the stored electrical signal to obtain photoacoustic three-dimensional microscopic image information with high spatial resolution.

[0051] By carefully calibrating the optical illumination and acoustic detection, a coaxial configuration ensures optimal photoacoustic measurement results. A few drops of deionized water are placed between the sensor and the sample to serve as a coupling medium for the photoacoustic signal. During sample microscopy, the sample is mounted on a two-dimensional translation stage controlled by the imaging processing terminal via a LabVIEW program. As the two-dimensional translation stage drives the sample in XY translation, single-axis point scanning of the sample is achieved. The excitation light continuously stimulates photoacoustic signals at different locations on the sample, which are converted by the sensor into changes in the detection light. A balanced photodetector converts the detected light intensity changes into electrical signals, which are then transmitted to the imaging processing terminal via a signal amplifier. The imaging processing terminal includes a high-performance data acquisition card that continuously stores the photoacoustic signals. After a single scan, the resulting data is reconstructed in three dimensions by the imaging processing terminal, enabling high-spatial-resolution photoacoustic three-dimensional microscopy of the sample.

[0052] The photoacoustic detection imaging system and method based on optical waveguide resonance sensing disclosed in this application have the following advantages in application: (1) The preparation process of the optical waveguide resonance photoacoustic sensor is simple, and no advanced technologies such as photolithography and nanoimprinting are required. Only a spin coater and a heat curing table are required to prepare the device. The preparation of nano-scale elastic polymer material films can be achieved with a simple process and low cost. (2) The optical waveguide resonance photoacoustic sensing method can achieve a balance between the sensitivity and bandwidth of photoacoustic signal detection. While detecting with high sensitivity, it also takes into account the bandwidth response of hundreds of megahertz, and can achieve high-sensitivity detection and broadband response of broadband photoacoustic signals. (3) The optical transparency of the optical waveguide resonance photoacoustic sensor can realize a reflection mode photoacoustic microscopic imaging system. Therefore, regardless of the thickness of the sample, a three-dimensional microscopic imaging effect at the micrometer scale can be achieved, and three-dimensional imaging with a spatial resolution of micrometer level can be achieved for the sample.

[0053] The feasibility of the optical waveguide resonance (OWR) photoacoustic detection method in principle has been verified through simulation. The calculation shows that the detection bandwidth of this method is hundreds of megahertz, and it has higher detection sensitivity than optical surface wave technology. The principle simulation results are as follows: Figure 3 and Figure 4 As shown. Figure 3 As shown, the principle simulation diagram shows that the sensor has an excellent local effect on detecting the electric field excited by light. Most of the energy is confined in the PDMS film, and the layered detection intensity in the x-axis direction (corresponding to p-polarization) and the y-axis direction (corresponding to s-polarization, the s-polarization direction is perpendicular to the p-polarization direction) is basically equal. Therefore, the detection sensitivity in the x-axis direction and the y-axis direction has good uniformity, which can achieve micron-level spatial resolution imaging. The z-axis is the detection depth (the z-axis is perpendicular to the detection plane), the blue dotted box is the polydimethylsiloxane (PDMS) layer, and the upper part of the blue dotted box is the coupling medium. Since the bandwidth response is inversely proportional to the optical penetration depth, this shows that the OWR sensor has an acoustic bandwidth response capability of hundreds of megahertz. Compared with surface wave technology, the detection sensitivity of the OWR sensor has been greatly improved, nearly twice as much. Figure 4 shown.

[0054] The wavelength of the laser generated by the detection light source is set to 632.8nm, the wavelength of the excitation light generated by the excitation light source is set to 532nm, and the pulse time is about 1.2ns. The small sample and the large sample are imaged respectively. The results are as follows Figure 5 As shown. Figure 5 The experiments shown in the figure verify that the above-mentioned reflection-mode photoacoustic microscopy system based on optical waveguide resonance can achieve high spatial resolution photoacoustic three-dimensional imaging for both small samples (de-melanized zebrafish larvae) and large samples (wild adult zebrafish), and the two-dimensional images also have a high resolution.

[0055] An embodiment of the present invention provides a photoacoustic detection imaging system and method based on optical waveguide resonance sensing. The imaging system includes a detection light source, a polarization component, a first focusing lens, a prism, an objective lens, a sensor, a spectroscope, a first polarization analyzer component, a second polarization analyzer component, a photodetector, an excitation light source, a lens component, a first reflector, a second focusing lens, a second reflector, a two-dimensional mobile platform, and an imaging processing terminal. The sensor is an optical waveguide resonance sensor. The imaging system comprises a sensor with a tightly confined detection electric field having extremely strong optical resonance and a coupling medium, and has ultra-high sensitivity and wide bandwidth photoacoustic detection capabilities. The excitation light irradiates the sample to generate a photoacoustic signal, which interacts with the coupling medium to produce a change in the incident light beam to generate a detection beam. This enables reflection-mode photoacoustic microscopy imaging, enabling micrometer-scale three-dimensional microscopy regardless of the sample thickness, significantly improving depth resolution and image quality. Furthermore, the system can achieve a balance between photoacoustic signal detection sensitivity and bandwidth, achieving high sensitivity detection while also maintaining a bandwidth response of hundreds of megahertz.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A photoacoustic detection and imaging system based on optical waveguide resonance sensing, characterized in that: The photoacoustic detection imaging system includes a detection light source, a polarization component, a first focusing lens, a prism, an objective lens, a sensor, a spectroscope, a first polarization analyzer component, a second polarization analyzer component, a photodetector, an excitation light source, a lens component, a first reflector, a second focusing lens, a second reflector, a two-dimensional mobile platform and an imaging processing terminal; the sensor is an optical waveguide resonance sensor; The polarization component is arranged between the first focusing lens and the detection light source, the first focusing lens and the beam splitter are respectively arranged on both sides of the prism, the objective lens and the second reflector are respectively arranged at opposite ends of the prism, and the sensor is arranged on the side of the objective lens away from the prism; the sensor and the two-dimensional moving platform are respectively arranged on both sides of the sample, and the two-dimensional moving platform drives the sample to move horizontally; a coupling medium is provided between the sensor and the sample; The detection light source emits a light beam which passes through the polarization component and the first focusing lens and then enters the prism. The light beam is refracted by the prism and then enters the objective lens and illuminates the sensor. The sensor excites and generates a detection light beam which passes through the objective lens and then enters the prism. The incident detection light beam is refracted again and then enters the beam splitter. The first polarization analyzer is arranged between the photodetector and the beam splitter, the first reflector is arranged on the side of the beam splitter, and the second polarization analyzer is arranged between the photodetector and the first reflector; the beam splitter splits the incident light beam into a first light beam and a second light beam, the first light beam passes through the first polarization analyzer and enters the first probe of the photodetector, and the second light beam is reflected by the first reflector and passes through the second polarization analyzer and enters the second probe of the photodetector; The two-dimensional mobile platform, the photodetector, the detection light source and the excitation light source are respectively connected to the imaging processing terminal for communication, the lens assembly is arranged in front of the light beam exit port of the excitation light source, and the second focusing lens is arranged between the second reflector and the lens assembly; The cross-section of the prism is an isosceles trapezoid; the first focusing lens and the beam splitter are respectively arranged relative to the inclined side surfaces of the trapezoid; the objective lens is arranged at the end of the prism corresponding to the upper base of the isosceles trapezoid; and the second reflector is placed at the end of the prism corresponding to the lower base of the isosceles trapezoid; The sensor is composed of a polydimethylsiloxane film and a glass slide, wherein the polydimethylsiloxane film is deposited on the side of the glass slide facing the sample; The imaging processing terminal performs three-dimensional reconstruction on the stored electrical signal to obtain high spatial resolution photoacoustic three-dimensional microscopic image information; the stored electrical signal is an electrical signal of the detected light change obtained by the photodetector performing differential optical detection on the light beams detected by the first probe and the second probe; The preparation of the optical waveguide resonance sensor does not require photolithography or nanoimprinting, and the device preparation is achieved through a spin coater and a thermal fixation table.

2. The photoacoustic detection and imaging system based on optical waveguide resonance sensing according to claim 1, characterized in that: The detection light source is a continuous pulse helium-neon laser, and the laser wavelength generated by the detection light source is 615-650nm.

3. The photoacoustic detection and imaging system based on optical waveguide resonance sensing according to claim 1 or 2, characterized in that: The polarization component includes a polarizer, a half-wave plate and a quarter-wave plate; the polarizer is arranged on a side close to the detection light source.

4. The photoacoustic detection and imaging system based on optical waveguide resonance sensing according to claim 3, characterized in that: The excitation light source is a neodymium-doped yttrium aluminum garnet laser, and the excitation light generated by the excitation light source has a wavelength of 510-555nm and a pulse time of 0.8-5ns.

5. The photoacoustic detection and imaging system based on optical waveguide resonance sensing according to claim 4, characterized in that: The first polarization analyzing assembly includes a first polarizer and a first lens; the second polarization analyzing assembly includes a second polarizer and a second lens; the first lens and the second lens are both arranged on a side close to the photodetector.

6. The photoacoustic detection and imaging system based on optical waveguide resonance sensing according to claim 1, characterized in that: The lens assembly includes a third lens and a fourth lens that are oppositely arranged. The third lens and the fourth lens are combined to form a 4F lens assembly.

7. The photoacoustic detection and imaging system based on optical waveguide resonance sensing according to claim 6, characterized in that: The photoacoustic detection imaging system further includes a signal amplifier, one end of which is connected to the imaging processing terminal, and the other end of which is connected to the photodetector.

8. A photoacoustic detection imaging method based on optical waveguide resonance sensing, characterized in that: The photoacoustic detection and imaging method based on optical waveguide resonance sensing is applied to the photoacoustic detection and imaging system based on optical waveguide resonance sensing according to any one of claims 1 to 7; the photoacoustic detection and imaging method comprises: The detection laser light emitted by the detection light source passes through the polarization component and the first focusing lens and then enters the prism. The light beam is refracted by the prism and enters the objective lens and illuminates the sensor. The excitation light source emits excitation light that passes through the lens assembly and the second focusing lens, and the light beam is reflected by the second reflector and sequentially passes through the prism and the objective lens before irradiating the sensor; The excitation light passes through the sensor and is focused onto the sample surface to generate a photoacoustic signal, and the photoacoustic signal passes through the coupling medium to cause the light beam to change and obtain a detection light beam; The detection beam passes through the objective lens and enters the prism, and the incident detection beam is refracted again and then enters the beam splitter; The beam splitter splits the incident light beam into a first light beam and a second light beam. The first light beam passes through the first polarization analyzer assembly and then enters the first probe of the photodetector. The second light beam is reflected by the first reflector and passes through the second polarization analyzer assembly and then enters the second probe of the photodetector. The photoelectric detector performs differential light detection on the light beams detected by the first probe and the second probe to obtain an electrical signal of the detected light change and outputs the electrical signal to the imaging processing terminal; The imaging processing terminal controls the two-dimensional mobile platform to drive the sample to move horizontally, so as to scan and obtain electrical signals for detecting various positions in the sample and store the signals; The imaging processing terminal performs three-dimensional reconstruction on the stored electrical signals to obtain photoacoustic three-dimensional microscopic image information with high spatial resolution.

Images