CN118303822A - Bimodal optical transmission unit and bimodal inner snoop head based on two-photon polymerization - Google Patents

Abstract

The embodiment of the present invention discloses a dual-mode optical transmission unit based on two-photon polymerization and a dual-mode endoscope probe, including: a single-mode optical fiber, used to transmit optical coherence tomography scanning excitation light and fluorescence excitation light; also used to transmit optical coherence tomography scanning collection light formed after the optical coherence tomography scanning excitation light is reflected by the object to be tested; a multi-mode optical fiber, used to transmit fluorescence collection light formed after the fluorescence excitation light is excited by the object to be tested; a first lens group is arranged at the front end of the single-mode optical fiber, used to redirect and focus the optical coherence tomography scanning excitation light and fluorescence excitation light transmitted by the single-mode optical fiber to the object to be tested; also used to collect the optical coherence tomography scanning collection light, and focus the optical coherence tomography scanning collection light to the single-mode optical fiber; at least one second lens group is arranged and located at the front end of the multi-mode optical fiber, used to collect the fluorescence collection light. The integration of the two modes of optical coherence tomography scanning and fluorescence imaging is realized.

Description

Dual-mode optical transmission unit and dual-mode endoscopy probe based on two-photon polymerization

Technical Field

The present invention relates to the technical field of endoscopic imaging, and in particular to a dual-mode optical transmission unit and a dual-mode endoscopic probe based on two-photon polymerization.

Background technique

Atherosclerotic plaques gradually narrow and block the arterial lumen, leading to the occurrence of dangerous diseases such as coronary heart disease, myocardial infarction, and cerebral infarction. The ability to detect and classify vulnerable plaques early is crucial for the understanding, diagnosis, and management of vascular diseases.

Currently, high-resolution intravascular three-dimensional imaging such as intravascular ultrasound and intravascular optical coherence tomography, as well as intravascular molecular imaging technologies, including intravascular near-infrared fluorescence imaging, intravascular near-infrared spectral imaging, and intravascular photoacoustic tomography, are used in clinical practice. They provide more options and data support for detecting plaque vulnerability. Although each detection technology can provide specific diagnostic parameters, a single imaging technology cannot comprehensively evaluate plaques. In addition, ultra-micro fiber endoscopes are currently used in clinical practice to greatly reduce damage to tiny organs (e.g., bronchioles in the lungs and coronary arteries in the heart). For ultra-micro fiber endoscopes, due to manufacturing limitations, they are no longer suitable for traditional grinding and polishing processes. Generally, arc melting is used to manufacture spherical lenses at the end of the optical fiber or self-focusing lenses are used. However, this method is restricted by size and shape and cannot solve the aberration problem, which limits the high-resolution imaging of optical coherence tomography. On the other hand, due to the limitation of the size of the endoscope probe, it is difficult to increase the fluorescence collection aperture, which limits the efficiency of fluorescence imaging.

Summary of the invention

Based on this, it is necessary to propose a dual-modal optical transmission unit and a dual-modal endoscope probe based on two-photon polymerization to address the above problems.

A dual-mode optical transmission unit based on two-photon polymerization, the unit comprising:

Single-mode optical fiber, used for transmitting optical coherence tomography scanning excitation light and fluorescence excitation light; and also used for transmitting the optical coherence tomography scanning collection light formed after the optical coherence tomography scanning excitation light is reflected by the object to be tested;

A multimode optical fiber, used for transmitting the fluorescence collection light formed after the fluorescence excitation light is excited by the object to be tested;

The first lens group is arranged at the front end of the single-mode optical fiber, and is used to redirect and focus the optical coherence tomography scanning excitation light and the fluorescence excitation light transmitted by the single-mode optical fiber to the object to be tested; and is also used to collect the optical coherence tomography scanning collection light formed after the optical coherence tomography scanning excitation light is reflected by the object to be tested, and focus and correct the optical coherence tomography scanning collection light to the single-mode optical fiber;

At least one second lens group is provided and is located at the front end of the multimode optical fiber, and is used to collect fluorescence collection light formed after the fluorescence excitation light is excited by the object to be tested.

Wherein, the first lens group includes a first beam directing element and a first focusing element;

The first beam directing element is used to redirect the optical coherence tomography scanning excitation light and the fluorescence excitation light; and is also used to correct the aberration of the optical coherence tomography scanning collection light and transmit it to the single-mode optical fiber;

The first focusing element is used to focus the redirected optical coherence tomography scanning excitation light and fluorescence excitation light onto the object to be tested; and is also used to collect and focus the optical coherence tomography scanning collection light.

Wherein, the first light beam directing element is printed on the end face of the single-mode optical fiber by two-photon polymerization, so as to shift the optical axes of the offset light and the collected light to 40° to 140°.

Wherein, the diameter of the first focusing element is less than 500 micrometers, and the working distance between the first focusing element and the object to be measured is 0 to 6 millimeters.

Wherein, each group of the second lens group comprises a second beam directing element and a focusing element;

The second focusing element is used to collect and focus the fluorescence collection light;

The second beam directing element is used to correct the fluorescent light collected by the focusing element and transmit it to the multimode optical fiber.

Wherein, the numerical aperture of the second focusing element is greater than 0.4, and the working distance between the second focusing element and the object to be measured is within a range of 0 to 6 mm.

The second beam directing element is designed as a hollow structure to make the optical paths of the optical coherence tomography scanning collection light and the fluorescence collection light coaxial, and the hollow structure is located at the light output end of the first focusing element, and is also used to accommodate a group of air lenses, and the air lenses are used to expand the collection aperture of the fluorescence collection light. The second beam directing element is printed on the end face of the multimode optical fiber through two-photon polymerization, and is coaxial with the optical coherence tomography scanning collection light after being reflected by the first beam directing element.

The unit further comprises a third lens group, which is located at the front end of the multimode optical fiber and is used to collect the fluorescence collection light formed by the fluorescence excitation light after the fluorescence excitation of the object to be tested. The third lens group is confocal with the second lens group, and the third lens group comprises a third focusing lens, a third light beam directing element, and an expansion air lens;

The third focusing lens is used to collect and focus the fluorescence light.

The third beam directing element is used to correct the fluorescent light collected by the third focusing lens and transmit it to the multimode optical fiber.

The expanded air lens is used to connect the second lens group and the third lens group to expand the collection aperture of the fluorescent light.

A dual-mode endoscopy probe based on two-photon polymerization, the probe comprising: a double-clad optical fiber, a double-clad optical fiber coupler, a metal sleeve, a torque coil, an optical fiber fixing bracket, a sheath, and the dual-mode optical transmission unit based on two-photon polymerization as described above;

The double-clad optical fiber is used to connect the single-mode optical fiber and the multi-mode optical fiber;

The double-clad fiber coupler is used to couple the core of the double-clad fiber with the core of the single-mode fiber, and the inner cladding of the double-clad fiber with the core of the multimode fiber, to transmit optical coherence tomography scanning excitation light and fluorescence excitation light, and also to transmit optical coherence tomography scanning collection light formed after the optical coherence tomography scanning excitation light is reflected by the object to be tested, and fluorescence collection light formed after the fluorescence excitation light is excited by the object to be tested;

The metal sleeve is used to encapsulate the double-clad optical fiber coupler and the dual-mode optical transmission unit based on two-photon polymerization;

The torque coil is used to accommodate the double-clad optical fiber and drive the metal sleeve to rotate;

The optical fiber fixing bracket is arranged inside the metal sleeve and is used to fix the double-clad optical fiber coupler and the dual-mode optical transmission unit based on two-photon polymerization;

The sheath is used to encapsulate the metal sleeve and the torque coil. The metal sleeve is driven by the torque coil to rotate in the sheath.

The embodiments of the present invention have the following beneficial effects:

It can be known from the above description that the present invention realizes optical coherence tomography scanning imaging by arranging a first lens group at the front end of a single-mode optical fiber to transmit optical coherence tomography scanning excitation light and fluorescence excitation light, as well as collecting and transmitting optical coherence tomography scanning collection light. At the same time, by arranging at least one second lens group at the front end of a multi-mode optical fiber to collect and transmit fluorescence collection light, the collection efficiency of fluorescence signals is improved, and fluorescence imaging with a high collection and long depth range is realized. The dual-mode optical transmission unit based on two-photon polymerization provided by the present invention realizes the integration of optical coherence tomography scanning and fluorescence imaging by cleverly combining a single-mode optical fiber, a multi-mode optical fiber, and a first lens group and a second lens group, thereby improving the receiving aperture of fluorescence imaging, and by expanding the collection lens group along the probe direction, it breaks through the technical difficulties of multi-modal fusion and improves the sensitivity and signal-to-noise ratio of fluorescence imaging.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

in:

FIG1 is a schematic structural diagram of an embodiment of a dual-mode optical transmission unit based on two-photon polymerization provided by the present invention;

FIG2 is a schematic structural diagram of another embodiment of a dual-mode optical transmission unit based on two-photon polymerization according to the present invention;

FIG. 3 is a schematic structural diagram of an embodiment of a first lens group and a second lens group provided by the present invention.

FIG4 is a schematic structural diagram of another embodiment of a dual-mode optical transmission unit based on two-photon polymerization provided by the present invention;

FIG5 is a schematic structural diagram of an embodiment of a dual-modality endoscope probe provided by the present invention;

FIG6 is a schematic structural diagram of an embodiment of a double-clad optical fiber coupler provided by the present invention;

FIG. 7 is a schematic structural diagram of another embodiment of a dual-modality endoscopic probe proposed by the present invention.

In the figure: 10, dual-mode optical transmission unit; 1, single-mode optical fiber; 2, multi-mode optical fiber; 3, first lens group; 4, second lens group; 31, first beam directing element; 32, first focusing element; 33, coreless optical fiber; 41, second focusing element; 42, second beam directing element; 5, air lens; 6, third lens group; 61, third focusing element; 62, third beam directing element; 63, extended air lens; 7, double-clad optical fiber; 8, double-clad optical fiber coupler; 9, metal sleeve; 11, torque coil; 12, optical fiber fixing bracket; 13, sheath; 14, object to be measured.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

As shown in FIG1 , FIG1 is a schematic diagram of a structure of an embodiment of a dual-mode optical transmission unit based on two-photon polymerization provided by the present invention. A dual-mode optical transmission unit based on two-photon polymerization, the unit comprising:

The single-mode optical fiber 1 is used for transmitting optical coherence tomography scanning excitation light and fluorescence excitation light; and is also used for transmitting optical coherence tomography scanning collection light formed after the optical coherence tomography scanning excitation light is reflected by the object to be tested.

Exemplarily, as shown in FIG2 , FIG2 is a schematic diagram of the structure of another embodiment of a dual-mode optical transmission unit based on two-photon polymerization of the present invention. The dual-mode optical transmission unit 10 includes a single-mode optical fiber 1, which is arranged at the light input end of the dual-mode optical transmission unit, and its main function is to transmit two types of light, optical coherence tomography scanning excitation light and fluorescence excitation light. In addition, the single-mode optical fiber 1 is also responsible for transmitting the optical coherence tomography scanning collection light formed after the optical coherence tomography scanning excitation light is backscattered inside the object to be tested. The wavelength of the optical coherence tomography scanning excitation light is generally 1310 nm, and the spectral width is 100 nm.

The multimode optical fiber 2 is used to transmit the fluorescence collection light formed after the fluorescence excitation light is excited by the object to be tested.

Exemplarily, as shown in FIG2 , the dual-mode optical transmission unit based on two-photon polymerization includes a multimode optical fiber 2, which is located below the single-mode optical fiber 1 and is arranged at the light output end of the dual-mode optical transmission unit 10, and is used to transmit the fluorescence collection light formed by the fluorescence excitation light after the fluorescence excitation of the object to be tested. Since the fluorescence collection light often contains multiple modes of light, the use of multimode optical fiber 2 can more effectively collect and transmit such complex optical signals. For example, when the fluorescent dye uses indocyanine green, the wavelength of the fluorescence excitation light is 780nm, and the wavelength of the fluorescence collection light is 800nm to 830nm.

The single-mode optical fiber 1 is first fused with the coreless optical fiber 33, and then the coreless optical fiber is cut. The function of the coreless optical fiber is to obtain a precisely positioned expanded beam. The beam can also be expanded by manufacturing a filling material through two-photon polymerization.

The first lens group 3 is arranged at the front end of the coreless optical fiber, and is used to redirect and focus the optical coherence tomography scanning excitation light and the fluorescence excitation light transmitted by the single-mode optical fiber 1 onto the object to be tested; it is also used to collect the optical coherence tomography scanning collection light formed after the optical coherence tomography scanning excitation light is reflected by the object to be tested, and focus the optical coherence tomography scanning collection light onto the single-mode optical fiber 1.

Exemplarily, as shown in FIG2 , the first lens group 3 is disposed at the front end of the single-mode optical fiber 1 as a key component of the dual-mode optical transmission unit, and its main function is to redirect the optical coherence tomography scanning excitation light and the fluorescence excitation light transmitted by the single-mode optical fiber 1, and focus it on a specific area of the object to be tested. In addition, the first lens group 3 is also used to collect the optical coherence tomography scanning collection light formed after the optical coherence tomography scanning excitation light is reflected by the object to be tested, and refocus the optical coherence tomography scanning collection light onto the single-mode optical fiber 1 for subsequent analysis and processing. In a specific implementation scenario, the first lens group 3 includes a first beam directing element 31 and a first focusing element 32, and the optical coherence tomography scanning excitation light and the fluorescence excitation light are redirected by the first beam directing element 31 and transmitted to the first focusing element 32, so that the redirected optical coherence tomography scanning excitation light and the fluorescence excitation light are focused on a specific area of the object to be tested. At the same time, the first focusing element 32 collects the optical coherence tomography scanning collection light formed after the optical coherence tomography scanning excitation light is reflected by the object to be tested, and focuses the optical coherence tomography scanning collection light to the first beam directing element 31, and corrects the aberration of the optical coherence tomography scanning collection light through the beam directing element and transmits it to the single-mode optical fiber 1.

At least one second lens group 4 is provided and is located at the front end of the multimode optical fiber 2, and is used to collect the fluorescence collection light formed after the fluorescence excitation light is excited by the object to be tested.

Exemplarily, as shown in FIG2 , as another key component of the dual-mode optical transmission unit, two groups of second lens groups 4 are arranged at the front end of the multimode optical fiber 2, located below the first lens group 3, and their main function is to collect the fluorescence collection light formed by the fluorescence excitation light after the fluorescence excitation of the object to be tested. The two groups of second lens groups 4 are designed to be a hollow structure to facilitate the transmission of the fluorescence collection light. In a specific implementation scenario, each group of second lens groups 4 includes a second focusing element 41 and a second beam directing element 42. The second focusing element 41 is responsible for collecting the fluorescence collection light formed by the fluorescence excitation light after the fluorescence excitation of the object to be tested, and the second beam directing element 42 transmits the collected fluorescence collection light to the multimode optical fiber 2. Among them, the first lens group 3 and the second lens group 4 are directly printed on the front end of the single-mode optical fiber 1 and the multimode optical fiber 2 using photoresist through two-photon polymerization.

The beam directing element (the first beam directing element 31 and the second beam directing element 42) directs the beam by reflection. When the angle at which the beam enters the surface of the element is greater than the total reflection angle obtained according to the law of refraction, the beam will be deflected. When the beam is less than the total reflection angle, the reflective directing function can be achieved by coating a reflective film on the surface.

Among them, the beam directing element (first beam directing element 31, second beam directing element 42) can be composed of a reflective plane, an ellipsoidal surface, or a free-form surface, and the focusing element (first focusing element 32, second focusing element 41) can be composed of a spherical surface, an aspherical surface, or a free-form surface. A free-form surface generally refers to a complex, unconventional, continuous surface without a rotational symmetry axis, or in other words, it can be a surface of any shape, which has a strong aberration correction ability and can achieve a better focusing effect. The free-form surface has the best focusing effect, and its surface can be described by an extended polynomial:

Among them, z is the surface height, c is the radius of curvature, x and y are unit coordinates, _Ai is the coefficient of the expansion polynomial, and _Ei is the power series in the x and y directions.

It should be noted that the first lens group 3 and the second lens group 4 can be customized and optimized according to the characteristics of the object to be tested and the required diagnostic accuracy. For example, the best excitation light focusing and collection light collection effects can be achieved by adjusting the lens parameters such as focal length, aperture and material.

It can be seen from the above description that the present invention realizes optical coherence tomography scanning imaging by arranging a first lens group 3 at the front end of a single-mode optical fiber 1 to transmit optical coherence tomography scanning excitation light and fluorescence excitation light, as well as collecting and transmitting optical coherence tomography scanning collection light. At the same time, by arranging at least one second lens group 4 at the front end of a multi-mode optical fiber 2 to collect and transmit fluorescence collection light, the collection efficiency of fluorescence signals is improved, and fluorescence imaging with a high collection and long depth range is realized. The collection efficiency of fluorescence imaging is related to the numerical aperture of optical collection, and traditional fluorescence collection is limited by the size of the probe. The dual-mode optical transmission unit based on two-photon polymerization provided by the present invention integrates the two modes of optical coherence tomography scanning and fluorescence imaging by cleverly combining the single-mode optical fiber 1, the multi-mode optical fiber 2, the first lens group 3, and the second lens group 4, decoupling the optical coherence tomography scanning optical path from the fluorescence imaging optical path, improving the receiving aperture of fluorescence imaging, and by expanding the collection lens group along the probe direction, breaking through the technical difficulties of multi-modal fusion, and improving the sensitivity and signal-to-noise ratio of fluorescence imaging.

As shown in FIG3 , FIG3 is a schematic diagram of the structure of an embodiment of the first lens group and the second lens group provided by the present invention. The first lens group 3 includes a first beam directing element 31 and a first focusing element 32. The first beam directing element 31 is used to redirect the optical coherence tomography scanning excitation light and the fluorescence excitation light; it is also used to correct the aberration of the optical coherence tomography scanning collection light and transmit it to the single-mode optical fiber 1. The first focusing element 32 is used to focus the redirected optical coherence tomography scanning excitation light and the fluorescence excitation light onto the object to be measured; it is also used to focus and focus the optical coherence tomography scanning collection light.

In a specific implementation scenario, the first lens group 3 includes a first beam directing element 31 and a first focusing element 32. The first beam directing element 31 is arranged at the front end of the single-mode optical fiber 1, receives the optical coherence tomography scanning excitation light and the fluorescence excitation light transmitted by the single-mode optical fiber 1, and redirects the optical coherence tomography scanning excitation light and the fluorescence excitation light and transmits them to the first focusing element 32. The first focusing element 32 is responsible for focusing the redirected excitation light to a specific area of the object to be measured, and collecting the optical coherence tomography scanning collection light formed by the optical coherence tomography scanning excitation light after being reflected by the object to be measured, and refocusing the optical coherence tomography scanning collection light and transmitting it to the first beam directing element 31. The optical coherence tomography scanning collection light is corrected by the first beam directing element 31 and transmitted to the single-mode optical fiber 1 for subsequent analysis and processing to form an optical coherence tomography scanning image.

It should be noted that the first beam directing element 31 is printed on the end face of the single-mode optical fiber 1 by two-photon polymerization, and is used to shift the optical axis of the offset light and the collection light to 40° to 140°. The diameter of the first focusing element is less than 500 microns, and the working distance between the first focusing element and the object to be measured includes 0 to 6 mm.

For example, the focal length of the first focusing element is f=1200 microns, and the beam diameter is d=100 microns. According to the Gaussian beam focusing formula,

Where λ is the wavelength, f is the focal length, d is the beam diameter, _w0 is the beam waist radius, and the beam waist radius _w0 is 10 microns.

Wherein, DOF is the depth of field, Z _R is the Rayleigh range, the focal depth is 480 microns, and the first lens group 3 can maintain high lateral resolution imaging in the range of 960 microns to 1440 microns.

As shown in FIG3 , each second lens group 4 includes a second focusing element 41 and a second beam directing element 42 ; the second focusing element 41 is used to collect and focus the fluorescent light; the second beam directing element 42 is used to correct the fluorescent light collected by the second focusing element 41 and transmit it to the multimode optical fiber 2 .

In a specific implementation scenario, referring to FIG. 2 and FIG. 3 , the dual-mode optical transmission unit 10 includes two groups of second lens groups 4, and the two groups of second lens groups 4 are designed as a hollow structure, and the transmission of the fluorescence collection light between the two groups of second lens groups 4 is realized through the hollow structure. Each group of second lens groups 4 includes a second focusing element 41 and a second beam directing element 42. The second beam directing element 42 is printed on the end face of the multimode optical fiber 2 by two-photon polymerization, and shares the same optical axis with the optical coherence tomography scanning collection light reflected by the first beam directing element 31. The second focusing element 41 is used to collect the fluorescence collection light formed by the fluorescence excitation light after the fluorescence excitation of the object to be tested, focus the fluorescence collection light, and transmit it to the second beam directing element 42. The fluorescence collection light is transmitted to the multimode optical fiber 2 after being corrected by the second beam directing element 42.

It should be noted that the numerical aperture of the second focusing element is greater than 0.4, and the working distance between the second focusing element and the object to be measured includes 0 to 6 mm.

Exemplarily, the focal length of the second focusing element f=1000 microns, and the diameter of the second focusing element d=500 microns. As shown in FIG3 , the second light beam directing element 42 is designed as a hollow structure to make the optical paths of the optical coherence tomography collection light and the fluorescence collection light coaxial, and the hollow structure is located at the light output end of the first focusing element 32, and is also used to accommodate a group of air lenses 5, which are formed by setting two curved surfaces for imaging on the inner wall of the hollow, and their function is to connect the two second lens groups 4 to expand the collection aperture of the fluorescence collection light.

It should be noted that the spacing of the air lenses is related to the focal length, and no specific limitation is made here.

It should also be noted that the first beam directing element, the second beam directing element, the first focusing element, the second focusing element, and the air lens all adopt a free-form surface optical design.

The present invention uses two-photon polymerization to print the first lens group and the second lens group. Two-photon polymerization is an additive manufacturing technology based on femtosecond lasers, also known as direct laser writing. The laser is focused in a transparent photosensitive material, and multi-photon absorption is generated only at the focus to cause local solidification, with an accuracy of tens of nanometers. At present, photosensitive materials use sol-gel technology, so that the laser is focused in the gel and moves along a continuous trajectory to obtain a smooth 3D structure similar to glass, such as Nanoscribe's IP-S photoresist, which has the characteristics of high refractive index and low Abbe number (refractive index 1.5067, Abbe number 46.16) compared with other printing materials. Two-photon polymerization can freely construct optical devices at a sub-micron scale, and has excellent transparency, which is suitable for constructing complex optical systems at the end of optical fibers for endoscopic imaging. It can provide a better PSF (point spread function) without increasing the size of the lens. Another advantage is one-step molding without assembly.

As shown in Fig. 4, Fig. 4 is a schematic diagram of the structure of another embodiment of a dual-mode optical transmission unit based on two-photon polymerization provided by the present invention. A dual-mode optical transmission unit 10 based on two-photon polymerization, the unit includes a third lens group 6, located at the front end of the multimode optical fiber 2, for collecting the fluorescence collection light formed by the fluorescence excitation light after the fluorescence excitation of the object to be tested, and the third lens group 6 and the second lens group 4 are confocal.

Exemplarily, the third lens group 6 includes a third focusing lens 61, a third beam directing element 62 and an expanded air lens 63; the third focusing lens 61 is used to collect and focus the fluorescent collected light; the third beam directing element 62 is used to correct the fluorescent collected light collected by the third focusing lens 61 and transmit it to the multimode optical fiber 2.

In a specific implementation scenario, the third lens group 6 is arranged at the front end of the multimode optical fiber 2, and there is an expanded air lens 63 with a hollow structure between the third lens group 6 and the second lens group 4 to transmit the fluorescent collection light. The third lens group 6 includes a third focusing lens 61 and a third beam directing element 62. The third focusing lens 61 collects the fluorescent collection light formed after the fluorescent excitation light of the object to be tested is excited, and transmits the fluorescent collection light to the third beam directing element 62. The third beam directing element 62 transmits the collected fluorescent collection light to the multimode optical fiber 2 through the expanded air lens 63 and the air lens 5 to complete the collection of the fluorescent collection light. Through the third lens group 6, the collection range of the fluorescent collection light can be further expanded along the probe direction.

It should be noted that the third lens group 6 adopts a free-form surface optical design.

As shown in FIG5 , FIG5 is a schematic diagram of the structure of an embodiment of a dual-mode endoscope probe provided by the present invention. A dual-mode endoscope probe, the probe comprises: a double-clad optical fiber 7, a double-clad optical fiber coupler 8, a metal sleeve 9, a torque coil 11, an optical fiber fixing bracket 12, a sheath 13, and a dual-mode optical transmission unit 10 based on two-photon polymerization;

The double-clad optical fiber 7 is used to connect the single-mode optical fiber and the multi-mode optical fiber. The double-clad optical fiber coupler 8 is used to couple the core of the double-clad optical fiber 7 with the core of the single-mode optical fiber, and the core of the double-clad optical fiber 7 is coupled with the core of the single-mode optical fiber to transmit the optical coherence tomography scanning excitation light and the fluorescence excitation light to the micro-probe, and transmit the optical coherence tomography scanning collection light formed after the object to be tested is reflected to the collection system. The inner cladding of the double-clad optical fiber 7 is coupled with the core of the multi-mode optical fiber to transmit the fluorescence collection light formed after the fluorescence excitation of the object to be tested to the collection system.

For example, as shown in FIG6 , FIG6 is a schematic diagram of the structure of an embodiment of a double-clad fiber coupler provided by the present invention. The single-mode optical fiber 1 comprises a core with a diameter of 9 microns and a cladding with a diameter of 125 microns, the multi-mode optical fiber 2 comprises a core with a diameter of 105 microns and a cladding with a diameter of 125 microns, and a core with a diameter of 200 microns and a cladding with a diameter of 220 microns can also be selected to increase the fluorescence collection efficiency, and the double-clad optical fiber 7 comprises a core with a diameter of 9 microns, an inner cladding with a diameter of 105 microns, and a cladding with a diameter of 125 microns. Both the core and the inner cladding of the double-clad optical fiber 7 can be used as light transmission channels.

The double-clad fiber coupler 8 couples the core of the C-port double-clad fiber 7 with the core of the single-mode fiber 1, and the core of the C-port double-clad fiber 7 is coupled with the core of the single-mode fiber 1 and connected to the A-port, for transmitting optical coherence tomography scanning excitation light and fluorescence excitation light, and also for transmitting optical coherence tomography scanning excitation light and fluorescence excitation light to the micro-probe, and transmitting optical coherence tomography scanning collection light formed after reflection of the object to be tested to the collection system. The inner cladding of the double-clad fiber 7 is coupled with the core of the B-port multimode fiber 2, and the fluorescence collection light formed after fluorescence excitation of the object to be tested is transmitted to the collection system.

Port D also has an empty port of multimode optical fiber 2. Port A can be single-mode optical fiber 1, or double-clad optical fiber 7, but only the core part of double-clad optical fiber 7 is used.

The metal sleeve 9 is used to encapsulate the double-clad optical fiber coupler 8 and the dual-mode optical transmission unit 10 based on two-photon polymerization.

For example, the metal sleeve 9 has a diameter of less than 800 microns and is located at the front end of the probe, which is a rigid part that helps the dual-modality endoscope probe to navigate stably in the blood vessel. It should be noted that the length of the rigid part of the dual-modality endoscope probe ranges from a few millimeters to one centimeter, and no specific limitation is made here.

The torque coil 11 is used to accommodate the double-clad optical fiber 7 and drive the metal sleeve 9 to rotate.

Exemplarily, the torsion coil is fixed to the metal sleeve, and the coil contains a double-clad optical fiber 7.

The optical fiber fixing bracket 12 is arranged inside the metal sleeve 9 and is used to fix the double-clad optical fiber coupler 8 and the dual-mode optical transmission unit 10 .

Exemplarily, the optical fiber fixing bracket 12 is formed by curing light-curing glue to fix the assembled optical fiber, the double-clad optical fiber 7 coupler and the metal sleeve 9.

The sheath 13 is used to encapsulate the metal sleeve 9 and the torque coil 11 . The metal sleeve 9 is driven by the torque coil 11 to rotate in the sheath 13 .

Exemplarily, as shown in FIG. 5 and FIG. 7 , FIG. 7 is a schematic diagram of the structure of another embodiment of a dual-mode endoscope probe proposed by the present invention. The dual-mode optical transmission unit 10 (first beam directing element 31, second beam directing element 42, first focusing element 32, second focusing element 41, single-mode optical fiber 1, multi-mode optical fiber 2), double-clad optical fiber 7, and double-clad optical fiber coupler 8 are all installed and fixed inside the metal sleeve 9. Through the conduction of the torque coil 11, the entire probe is freely rotated in the sheath 13, and the sheath 13 remains stationary. The metal sleeve 9 has a window at the microlens to allow the light beam to pass through and focus on the object to be measured 14. Among them, the diameter of the sheath 13 is less than 1 mm, which is a protective layer separating the endoscope from the vascular tissue to prevent damage to the vascular tissue. It not only protects the animal or patient from trauma when the probe rotates for scanning, but also can be replaced so that the probe part can be reused many times. The material of the sheath should be safe and non-toxic, and transparent to the excitation light and collection light of optical coherence tomography scanning and the excitation light and collection light of fluorescence. Selecting materials with low absorption and loss can improve the imaging quality. The torque coil 11 allows rotation and linear motion to be accurately transmitted from the proximal end to the distal end of the imaging probe, thereby realizing 3D scanning.

In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Finally, it should be noted that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Finally, it should be noted that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (10)

1. A bimodal optical transmission unit based on two-photon polymerization, characterized in that it comprises:

a single mode fiber for transmitting optical coherence tomography excitation light and fluorescence excitation light; the device is also used for transmitting the optical coherence tomography collecting light formed by the optical coherence tomography excitation light after the reflection of the object to be detected;

The multimode optical fiber is used for transmitting fluorescence excitation light to form fluorescence collection light after fluorescence excitation of the object to be detected;

The first lens group is arranged at the front end of a single-mode fiber and is used for redirecting and focusing optical coherence tomography excitation light and fluorescence excitation light transmitted by the single-mode fiber to an object to be detected; the optical coherence tomography collecting light is formed after the optical coherence tomography exciting light is reflected by the object to be measured, and the optical coherence tomography collecting light is focused and corrected to the single-mode optical fiber;

the second lens group is arranged at least one group and is positioned at the front end of the multimode optical fiber and used for collecting fluorescence collecting light formed by fluorescence excitation light after fluorescence excitation of the object to be detected.

2. The two-photon polymerization-based bimodal light transmission unit of claim 1 wherein the first lens group comprises a first beam directing element and a first focusing element;

The first beam orientation element is used for redirecting the optical coherence tomography excitation light and the fluorescence excitation light; and also for correcting aberrations of the optically coherent tomography collection light and transmitting to a single mode fiber;

The first focusing element is used for focusing the redirected optical coherence tomography excitation light and fluorescence excitation light to an object to be detected; and also for collecting and focusing the optically coherent tomography collection light.

3. The two-photon polymerization-based bimodal light transmission unit according to claim 2, wherein the first beam directing element is printed on the single mode fiber end face by two-photon polymerization for shifting the optical axes of the shift light and the collection light by 40 ° to 140 °.

4. A bimodal light transmission unit based on two-photon polymerization according to claim 3, wherein the diameter of the first focusing element is less than 500 μm and the working distance between the first focusing element and the object to be measured comprises 0-6 mm.

5. The two-photon polymerization-based bimodal light transmission unit as in any one of claims 1 to 4, wherein each said second lens group comprises a second beam directing element, a second focusing element;

the second focusing element is used for collecting and focusing fluorescence collection light;

The second beam orientation element is used for correcting the fluorescence collected light collected by the focusing element and transmitting the fluorescence collected light to the multimode optical fiber.

6. The two-photon polymerization-based bimodal light transmission unit according to claim 5, wherein the numerical aperture of the second focusing element is larger than 0.4, and the working distance between the second focusing element and the object to be measured is comprised between 0 and 6 mm.

7. The two-photon polymerization-based bimodal light transmission unit according to claim 6, wherein the second beam directing element is designed as a hollowed structure to make the optical paths of the optical coherence tomography collecting light and the fluorescence collecting light coaxial, the hollowed structure being located at the light output end of the first focusing element, and further configured to accommodate a set of air lenses for enlarging the collecting aperture of the fluorescence collecting light.

8. The two-photon polymerization-based bimodal light transmission unit as in claim 7, wherein the second beam directing element is printed on the multimode fiber end face by two-photon polymerization and is co-axial with the optical coherence tomography collection light reflected by the first beam directing element.

9. The two-photon polymerization-based bimodal light transmission unit according to claim 8, wherein the unit further comprises a third lens group located at the front end of the multimode optical fiber for collecting fluorescence collection light formed by fluorescence excitation light after fluorescence excitation of the object to be measured, the third lens group being in confocal point with the second lens group, the third lens group comprising a third focusing lens, a third beam directing element and an expanding air lens;

the third focusing lens is used for collecting and focusing fluorescence collection light;

The third beam orientation element is used for correcting fluorescence collected light collected by the plurality of extended fluorescence focusing lenses and transmitting the fluorescence collected light to the multimode optical fiber;

the expanding air lens is used for connecting the second lens group and the third lens group and expanding the collecting aperture of fluorescence collecting light.

10. A two-photon polymerization-based bimodal endoscopic probe, said probe comprising: a double-clad optical fiber, a double-clad optical fiber coupler, a metal sleeve, a torque coil, an optical fiber fixing bracket, a sheath, a bimodal optical transmission unit based on two-photon polymerization as claimed in any one of claims 1 to 9;

the double-clad optical fiber is used for connecting the single-mode optical fiber and the multimode optical fiber;

The double-clad fiber coupler is used for coupling the fiber core of the double-clad fiber with the fiber core of a single-mode fiber, coupling the inner cladding of the double-clad fiber with the fiber core of the multi-mode fiber, transmitting optical coherence tomography excitation light and fluorescence excitation light, and transmitting optical coherence tomography collection light formed after reflection of the optical coherence tomography excitation light by an object to be detected and fluorescence collection light formed after fluorescence excitation of the fluorescence excitation light by the object to be detected;

The metal sleeve is used for packaging the double-cladding optical fiber coupler and the bimodal optical transmission unit;

the torque coil is used for accommodating the double-clad optical fiber and driving the metal sleeve to rotate;

the optical fiber fixing bracket is arranged on the inner side of the metal sleeve and is used for fixing the double-cladding optical fiber coupler and the bimodal optical transmission unit;

The sheath is used for packaging the metal sleeve and the torque coil, and the metal sleeve rotates in the sheath through driving of the torque coil.