WO2022252300A1

WO2022252300A1 - Femtosecond-laser-based optical fiber probe preparation device and method combined with super-resolution lens

Info

Publication number: WO2022252300A1
Application number: PCT/CN2021/100994
Authority: WO
Inventors: 杨树明; 李少博; 王飞; 程碧瑶; 张国锋
Original assignee: 西安交通大学
Priority date: 2021-06-04
Filing date: 2021-06-18
Publication date: 2022-12-08
Also published as: CN113352000B; CN113352000A

Abstract

A femtosecond-laser-based optical fiber probe preparation device and method combined with a super-resolution lens. A collimator (2) is provided in an emergent light path of a femtosecond laser light source (1), a semi-transmissive and semi-reflective mirror (6) is provided in an emergent light path of the collimator (2), a super-resolution lens (7) is provided in a transmission light path of the semi-transmissive and semi-reflective mirror (6), a lens (4) is provided in a reflection light path of the semi-transmissive and semi-reflective mirror (6), and an imaging device (5) is provided at a focal point of the lens (4); a three-dimensional displacement platform (10) is provided below the super-resolution lens (7), and the three-dimensional displacement platform (10) is provided with an optical fiber clamping device (9); and the super-resolution lens (7) is provided with a plurality of concentric light-transmitting strips (7-3) and a light-blocking strip (7-2) disposed between the light-transmitting strips (7-3), the light-transmitting strips (7-3) has a circular ring shape, and diffracted light from all the light-transmitting strips (7-3) meet a phase interference condition. The super-resolution lens (7) can form an elongated optical needle, which can ensure the imaging resolution and improve the processing accuracy, and can also satisfy micro-nano processing on a surface of a planar structure or complex three-dimensional structure having a structural mutation in combination with the three-dimensional displacement platform (10).

Description

Optical fiber probe preparation device and method based on femtosecond laser combined with super-resolution lens

technical field

The invention relates to the technical field of laser processing, in particular to an optical fiber probe preparation device and method based on a femtosecond laser combined with a super-resolution lens.

Background technique

Optical fiber waveguides can simplify the optical path and reduce the space occupied by instruments, and have great application potential for the construction of spatial optical paths and instrument integration. The scanning near-field optical microscope based on the development of fiber optic probes is widely used in near-field Raman detection, near-field super-resolution imaging and Near-field optical processing and other fields. In order to achieve better focusing performance and meet the focusing requirements of incident light sources with different polarizations, it is necessary to etch the structure on the fiber probe to meet the excitation conditions of surface plasmons. At present, the commonly used micro-nano processing of fiber optic probes mostly relies on focused ion beam technology, which can realize nanoscale processing, but this technology requires high vacuum conditions, and can only process simple structures such as strips and rings. For more complex, However, the ability to process three-dimensional structures that can achieve higher and better performance is very limited, such as the helical structure-this structure can not only achieve the focusing function under the incidence of linearly polarized incident light sources, but also has the chiral selection function of circularly polarized light sources. The existing electron beam lithography or ultraviolet lithography technology can only realize complex structure processing on the plane, and requires multiple processes, which cannot meet the micro-nano processing requirements of three-dimensional complex structures on fiber optic probes. Femtosecond laser technology can achieve flexible processing of complex three-dimensional structures by using non-thermal effects, and has great advantages in micro-nano processing of complex three-dimensional structures. However, limited by the focusing and imaging resolution of traditional optical components, the processing process cannot be monitored in real time when processing a size of 100nm or below, and it is difficult to determine the starting point of the focal spot, resulting in large processing position errors and precision errors. The biggest disadvantage of second processing technology compared to focused ion beam and lithography technology. In addition, the focusing element used in the prior art, that is, the super-resolution lens, is a single focal point. The lateral and longitudinal dimensions of the focal point are fixed. It is only suitable for the processing or focusing imaging of planar structures, and cannot be used for planar structures with sudden changes in structure or complex three-dimensional Micro-nanofabrication of structured surfaces.

Contents of the invention

In order to solve the problems existing in the prior art, the object of the present invention is to provide a fiber probe preparation device and method based on a femtosecond laser combined with a super-resolution lens. The super-resolution lens in the present invention can form a slender optical needle, which can not only Guaranteed imaging resolution and improved processing accuracy, combined with a three-dimensional displacement platform can also meet the micro-nano processing on the surface of a planar structure with a structural mutation or a complex three-dimensional structure.

In order to achieve the above object, the scheme provided by the present invention is:

Fiber probe preparation device based on femtosecond laser combined with super-resolution lens, including femtosecond laser light source, collimator, half mirror, super-resolution lens, three-dimensional displacement platform, lens and imaging device;

The collimator is set on the outgoing light path of the femtosecond laser light source, the half-transparent mirror is set on the outgoing light path of the collimator, the super-resolution lens is set on the transmission light path of the half-mirror, and the lens is set on the semi-transparent On the reflection light path of the mirror, the imaging device is arranged at the focal point of the lens;

The three-dimensional displacement platform is set under the super-resolution lens, and the three-dimensional displacement platform is equipped with an optical fiber clamping device;

The super-resolution lens has several concentric light-transmitting zones and light-shielding zones arranged between the light-transmitting zones. The shape of the light-transmitting zones is circular, and the diffracted light of all the light-transmitting zones satisfies the condition of phase interference.

Preferably, the super-resolution lens includes a circular light-transmitting plate and an opaque metal film layer arranged on the light-transmitting plate, the opaque metal film layer is used as the light-shielding belt, and the light-transmitting metal film layer The outside area acts as a light-transmitting zone.

Preferably, the focused spot of the super-resolution lens has a lateral diameter of ≤200 nm and a longitudinal size of 500 nm to 10 μm.

The present invention also provides a method for preparing an optical fiber probe based on a femtosecond laser combined with a super-resolution lens. The preparation method is carried out by using the fiber probe preparation device based on a femtosecond laser combined with a super-resolution lens of the present invention, including the following process:

Clamp the tapered optical fiber coated with a metal film layer on the optical fiber clamping device, so that the axis of the tapered optical fiber is parallel to the incident direction of the femtosecond laser;

The femtosecond laser light source emits femtosecond laser, and after the femtosecond laser passes through the collimator, half-transparent mirror and super-resolution lens in sequence, it forms a light needle on the side of the super-resolution lens; at the same time, the femtosecond laser reflected by the tapered optical fiber The second laser beam is focused into the imaging device and imaged through the super-resolution lens, half-mirror and lens in turn;

Determine the starting position of the light needle formed by the super-resolution lens on the tapered optical fiber by an imaging device;

The three-dimensional displacement platform controls the movement of the tapered optical fiber, and uses the light to ablate the metal film layer of the tapered optical fiber to form a preset pattern on the metal film layer to obtain an optical fiber probe.

Preferably, the femtosecond laser has a pulse width of 10 fs-1000 fs, a wavelength of 500 nm-1200 nm, and a repetition frequency of 1 Hz-100 MHz.

Preferably, when the femtosecond laser is focused and processed by a super-resolution lens, the pulse width of the femtosecond laser is not greater than 500 fs; when the femtosecond laser is imaged by the super-resolution lens and the lens, the pulse width is not less than 500 fs, and the repetition frequency is not less than 40 MHz.

The present invention also provides an optical fiber probe, which is prepared by the method for preparing an optical fiber probe based on a femtosecond laser combined with a super-resolution lens as described above.

Preferably, the shape of the tapered fiber portion of the fiber probe is conical or truncated-conical.

Preferably: when the shape of the tapered fiber part of the fiber probe is conical, the cone angle of the tapered fiber is 20° to 90°, and the diameter of the cone tip is 10 nm to 200 nm;

When the shape of the tapered optical fiber portion of the optical fiber probe is a truncated cone, the tapered optical fiber has a taper angle of 20°-90° and a diameter of the small end surface of 1 μm-100 μm.

Preferably, the material of the metal film layer is gold, silver or aluminum, and the thickness is 10nm-200nm.

In the optical fiber probe preparation device based on the femtosecond laser combined with the super-resolution lens of the present invention, the super-resolution lens has several concentric light-transmitting zones and light-shielding zones arranged between the light-transmitting zones, and the shape of the light-transmitting zones is circular , the phase interference condition is satisfied between the diffracted lights of all the light transmission bands. In the super-resolution lens of this structure, several concentric light transmission bands have different diameters, so the diffraction focus positions of the light transmission bands with different diameters are different, so the multiple light transmission bands The superposition of the diffraction focus of the band can form a slender optical needle with a limited lateral size and a certain longitudinal scale. When performing micro-nano processing, within the length range of the light needle, there is always a focal point acting on the surface to be processed. Therefore, the present invention can realize the plane structure or complex Micro-nanofabrication of three-dimensional structured surfaces. In addition, the super-resolution lens can form a slender light needle, so it can ensure the imaging resolution and improve the processing accuracy. Combined with the imaging device, it can also realize the visual control in the process of micro-nano processing, and further improve the processing accuracy.

Furthermore, the super-resolution lens of the present invention has a focused spot with a transverse diameter of ≤200 nm and a longitudinal dimension of 500 nm to 10 μm, so it has high resolution and high processing accuracy.

Description of drawings

Fig. 1 is the schematic diagram of the structure of the optical fiber probe preparation device based on the femtosecond laser combined with the super-resolution lens of the present invention;

Fig. 2 is the super-resolution lens structure and its focusing principle of the present invention;

Fig. 3 is a schematic diagram of an optical fiber probe with a three-dimensional helical structure processed by a femtosecond laser when the shape of the optical fiber probe is a cone in an embodiment of the present invention;

Fig. 4 is a schematic diagram of an optical fiber probe with a helical structure processed by a femtosecond laser on the end face when the shape of the optical fiber probe is a truncated cone in an embodiment of the present invention;

In the figure: 1 is a femtosecond laser light source, 2 is a collimator, 3 is a femtosecond laser beam, 4 is a lens, 5 is an imaging device; 6 is a half-transparent mirror; 7 is a super-resolution lens; 7-1 is 7-2 is a light-shielding belt; 7-3 is a light-transmitting belt; 8 is a tapered optical fiber probe; 9 is an optical fiber clamping device; 10 is a three-dimensional displacement platform.

Detailed ways

The present invention will be clearly and specifically described below in conjunction with the accompanying drawings and specific implementation methods.

Referring to Figures 1 and 2, the present invention is based on a femtosecond laser combined with a super-resolution lens fiber probe preparation device, including a femtosecond laser light source 1, a collimator 2, a half mirror 6, a super-resolution lens 7, and a three-dimensional displacement Platform 10, lens 4 and imaging device 5; collimator 2 is arranged on the outgoing light path of femtosecond laser light source 1, half mirror 6 is arranged on the outgoing light path of collimator 2, super-resolution lens 7 is arranged on half On the transmitted light path of the half mirror 6, the lens 4 is arranged on the reflected light path of the half mirror 6, and the imaging device 5 is arranged at the focal point of the lens 4; the three-dimensional displacement platform 10 is arranged under the super-resolution lens 7, and the three-dimensional displacement The platform 10 is provided with an optical fiber clamping device 9; the super-resolution lens 7 has several concentric light-transmitting strips 2 and light-shielding strips 7-2 arranged between the light-transmitting strips 2, and the light-transmitting strips 2 are in the shape of a ring , the phase interference condition is satisfied between all the diffracted lights in the transparent band 2. When the diffracted light of all the light-transmitting bands 2 satisfies the phase interference condition, all the light-transmitting bands 2 satisfy the phase-constructive interference condition, and a focused bright spot is formed at the center of the ring. The super-resolution lens designed in the present invention can realize the needle-shaped focusing spot whose lateral size exceeds the diffraction limit and whose longitudinal size range is adjustable. It has the advantage of adjusting the longitudinal range for the processing or measurement imaging of abrupt structures or complex three-dimensional structures. The slender focusing The light spot can always ensure that the focus falls on the surface of the sample, which is more suitable for complex three-dimensional structures.

As a preferred embodiment of the present invention, with reference to Fig. 2, the super-resolution lens 7 comprises a circular light-transmitting plate arranged on a light-transmitting metal film layer on the light-transmitting plate, and the light-proof metal film layer is used as the light-shielding band 7-2 , the area outside the opaque metal film layer on the light-transmitting plate is used as the light-transmitting belt 2 .

As a preferred embodiment of the present invention, the super-resolution lens 7 has a focused spot with a transverse diameter of ≤200 nm and a longitudinal dimension of 500 nm˜10 μm.

Clamp the tapered optical fiber whose tapered surface is coated with a metal film layer on the optical fiber clamping device 9, so that the axis of the tapered optical fiber is parallel to the incident direction of the femtosecond laser;

The femtosecond laser light source 1 emits femtosecond laser, and the femtosecond laser passes through the collimator 2, half-mirror 6 and super-resolution lens 7 successively, and forms a light needle on one side of the super-resolution lens 7; The femtosecond laser beam reflected back by the optical fiber is focused into the imaging device 5 through the super-resolution lens 7, the half-mirror 6 and the lens 4 in sequence and forms an image;

Determine the starting position of the light needle formed by the super-resolution lens 7 on the tapered optical fiber by the imaging device 5;

The three-dimensional displacement platform 10 controls the movement of the tapered optical fiber, and uses the light to ablate the metal film layer of the tapered optical fiber to form a preset pattern on the metal film layer to obtain an optical fiber probe.

As a preferred embodiment of the present invention, the pulse width of the femtosecond laser is 10 fs-1000 fs, the wavelength is 500 nm-1200 nm, and the repetition frequency is 1 Hz-100 MHz.

As a preferred embodiment of the present invention, when the femtosecond laser is focused and processed by the super-resolution lens 6, the pulse width of the femtosecond laser is not greater than 500 fs; when the femtosecond laser is imaged by the super-resolution lens 7 and lens 4, the pulse width is not less than 500 fs , The repetition frequency is not less than 40MHz.

As a preferred embodiment of the present invention, the shape of the tapered fiber portion of the fiber probe is conical or frustoconical.

As a preferred embodiment of the present invention:

When the shape of the tapered fiber part of the fiber probe is conical, the cone angle of the tapered fiber is 20°-90°, and the diameter of the cone tip is 10nm-200nm;

As a preferred embodiment of the present invention, the material of the metal film layer is gold, silver or aluminum, and the thickness is 10nm-200nm.

For the flexible processing of complex three-dimensional micro-nano structures, in order to break through the traditional femtosecond laser processing process, the processing process of smaller sizes (such as less than 100 nanometers) cannot be monitored in real time, and there are large processing position errors and precision errors. The present invention combines the flexible three-dimensional processing capability of the femtosecond laser and the ability to break through the optical diffraction limit of the super-resolution lens provided by the present invention, and realizes the realization of any Micro-nano processing of complex three-dimensional structures, and real-time monitoring of the processing process under the condition of femtosecond laser wide pulse width and low energy, improves the excellent performance of fiber optic probes, and meets different needs in the field of micro-nano optics. At the same time, the invention is simple and easy to implement.

Example 1

In this embodiment, a method for preparing a fiber probe based on a femtosecond laser combined with a super-resolution lens includes the following steps:

The first step is to corrode the bare fiber into a tapered shape and add a tapered fiber;

In the second step, a layer of metal film is coated on the tapered end face of the tapered optical fiber;

The third step is to clamp the tapered optical fiber coated with the metal film layer on the high-precision three-dimensional displacement platform 10; the axis of the tapered optical fiber is parallel to the incident direction of the femtosecond laser;

In the fourth step, the outgoing beam of the femtosecond laser light source 1 passes through the collimator 2, the half-mirror 6, and the super-resolution lens 7 to focus on the metal film layer of the tapered optical fiber; After the super-resolution lens 7, the half-mirror 6, and the lens 4 are focused into the high-precision imaging device 5 and imaged;

The fifth step is to use the computer to control the femtosecond laser program, scan the tapered optical fiber metal film layer according to the preset parameters, ablate the scanned area, and use the imaging device 5 to monitor the position of the focused spot in real time, and move the three-dimensional displacement platform to complete the optical fiber detection. Complex three-dimensional structure processing on the needle.

The above solution of this embodiment can process a tapered optical fiber whose shape is a cone or a truncated cone (ie, a truncated cone). When the tapered optical fiber is a cone, the apex angle of the cone is 20°-90°, and the diameter of the tip of the cone is 10nm-200nm. When the tapered optical fiber is a truncated cone, the apex angle of the cone is 20°-90°, and the diameter of the truncated end surface of the cone is 1 μm-100 μm. The material of the metal film layer is gold, silver or aluminum, and the thickness is 10nm-200nm. The parameters of the femtosecond laser used are: pulse width 10fs-1000fs, wavelength 500nm-1200nm, repetition frequency 1Hz-100MHz. When the femtosecond laser is focused and processed by a super-resolution lens, the pulse width of the femtosecond laser is not greater than 500fs; when the femtosecond laser is imaged by a super-resolution lens and lens, the pulse width is not less than 500fs, and the repetition frequency is >40MHz. As shown in Figure 2, the super-resolution lens 7 is composed of ring structures with unequal spacing, and the phase interference conditions are satisfied between the diffracted lights passing through each ring, the diffraction focus positions of different rings are different, and the diffraction focus of multiple rings Superimposed to form a slender light needle with limited lateral size and adjustable vertical size. The focal spot of the super-resolution lens has a transverse diameter of ≤200nm and a longitudinal dimension of 500nm-10μm.

The preparation method of the optical fiber probe provided by the present invention overcomes the shortcomings of single processing structure in the preparation of the existing optical fiber probe, and the inability to monitor the processing process of hundreds of nanometers in real time in the traditional femtosecond laser processing process, and there are large processing position errors and precision errors. The complex three-dimensional structure can be etched on the tapered fiber optic probe, and the processing resolution is high, which can realize nanoscale processing and real-time monitoring; the processing procedure is simple, and the fiber probe can be completed in one process in the natural air environment Preparation of structures of arbitrary complexity.

Example 2:

This embodiment provides a method for preparing an optical fiber probe based on a femtosecond laser combined with a super-resolution lens, referring to Figures 1 and 3: including the following steps:

In the first step, the bare optical fiber is corroded to prepare a tapered optical fiber 8, wherein the tapered optical fiber has a taper angle of 30° and a tip diameter of 60 nm;

In the second step, a 100nm thick gold film is plated on the tapered optical fiber 8 tapered surface;

In the third step, the gold-plated tapered optical fiber 8 is clamped on the optical fiber clamping device 9 of the three-dimensional displacement platform 10;

The fourth step is to focus the output beam of the femtosecond laser source 1 with a wavelength of 800nm, a pulse width of 30fs, a repetition rate of 1kHz, a pulse width of 1000fs, and a repetition rate of 80MHz through the collimator 2, half-mirror 6, and super-resolution lens 7 in sequence to the metal film layer of the tapered optical fiber 8, wherein the super-resolution lens 7 adopts the above-mentioned structure as shown in Figure 2, and satisfies the phase interference condition between the diffracted light passing through each ring (that is, all light-transmitting bands 7-3), The focused light spot superimposed by the diffraction focal points of multiple rings has a lateral diameter of 200 nm and a longitudinal diameter of 1 μm, as shown in Figure 2; at the same time, the reflected light beam with a repetition frequency of 80 MHz passes through the super-resolution lens 7 and the half-mirror 6 in sequence , the lens 4 is focused into the high-precision imaging device 5 and imaged;

The fifth step is to use the computer to control the femtosecond laser program, scan the metal film layer of the tapered optical fiber 8 according to the preset parameters, ablate the scanned area, and use the high-precision imaging device 5 to monitor the position of the focused spot in real time, and move the three-dimensional displacement platform 10 Complete the processing of the three-dimensional helical structure 11 on the tapered surface of the optical fiber probe, and finally prepare the optical fiber probe, as shown in FIG. 3 .

Example 3:

The preparation method of this embodiment is basically the same as that of Example 2, except that the present embodiment is that the tapered optical fiber prepared in the first step is processed into a truncated tapered optical fiber (i.e. a truncated conical optical fiber) by using a focused ion beam, wherein , the truncated end face (i.e. the small end of the truncated cone) has a diameter of 5 μm; then plate an 80nm thick gold film on the end face of the tapered optical fiber 3; then repeat the fourth step and the fifth step in Example 2, and move the three-dimensional displacement platform to complete the optical fiber The processing of the helical structure 11 on the end surface of the probe finally produces the fiber probe, as shown in FIG. 4 .

In summary, the present invention has the following advantages: (1) It overcomes the disadvantage of single processing structure in the preparation of existing optical fiber probes, and can etch complex three-dimensional structures on tapered optical fiber probes, and the processing resolution is high, which can realize Nano-scale processing; (2) No need for a vacuum environment, the processing can be completed in a natural air environment, and at the same time, the processing procedure is simple, and the complex structure etching on the fiber probe can be completed in one process; (3) In the femtosecond laser Under the condition of narrow pulse width and high energy, the micro-nano processing of any complex three-dimensional structure on the fiber optic probe can be realized in the air environment, and the real-time monitoring of the processing process can be carried out under the condition of femtosecond laser wide pulse width and low energy, which can also be used for other micro-nano scales. The three micro-processing of the structure can meet different measurement and processing requirements.

Claims

An optical fiber probe preparation device based on a femtosecond laser combined with a super-resolution lens, characterized in that it includes a femtosecond laser light source (1), a collimator (2), a half-transparent mirror (6), and a super-resolution lens (7) , a three-dimensional displacement platform (10), a lens (4) and an imaging device (5);

The collimator (2) is arranged on the outgoing light path of the femtosecond laser light source (1), the half mirror (6) is arranged on the outgoing light path of the collimator (2), and the super-resolution lens (7) is arranged on the half On the transmission light path of the half mirror (6), the lens (4) is arranged on the reflection light path of the half mirror (6), and the imaging device (5) is arranged at the focal point of the lens (4);

The three-dimensional displacement platform (10) is arranged below the super-resolution lens (7), and the three-dimensional displacement platform (10) is provided with an optical fiber clamping device (9);

The super-resolution lens (7) has several concentric light-transmitting bands (2) and light-shielding bands (7-2) arranged between the light-transmitting bands (2), and the light-transmitting bands (2) are circular in shape, The phase interference condition is satisfied between the diffracted lights of all the light transmission bands (2).
The optical fiber probe preparation device based on a femtosecond laser combined with a super-resolution lens according to claim 1, wherein the super-resolution lens (7) comprises a circular light-transmitting plate arranged on the light-transmitting plate. The metal film layer, the opaque metal film layer is used as the light-shielding belt (7-2), and the area outside the light-transmitting metal film layer on the light-transmitting plate is used as the light-transmitting belt (2).
The optical fiber probe preparation device based on a femtosecond laser combined with a super-resolution lens according to claim 1, characterized in that the super-resolution lens (7) has a focused spot with a lateral diameter of ≤200 nm and a longitudinal size of 500 nm to 10 μm.
A method for preparing an optical fiber probe based on a femtosecond laser in combination with a super-resolution lens, characterized in that it is performed using the fiber probe preparation device based on a femtosecond laser in combination with a super-resolution lens according to any one of claims 1-3, including the following process :

Clamp the tapered optical fiber with the tapered surface coated with a metal film layer on the optical fiber clamping device (9), so that the axis of the tapered optical fiber is parallel to the incident direction of the femtosecond laser;

The femtosecond laser light source (1) emits femtosecond laser, and after the femtosecond laser passes through the collimator (2), half-transparent mirror (6) and super-resolution lens (7) in sequence, it passes through the super-resolution lens (7) At the same time, the femtosecond laser beam reflected by the tapered optical fiber passes through the super-resolution lens (7), half-transparent mirror (6) and lens (4) in turn to focus into the imaging device (5) and form an image ;

Determine the initial position of the light needle formed by the super-resolution lens (7) on the tapered optical fiber by the imaging device (5);

The three-dimensional displacement platform (10) controls the movement of the tapered optical fiber, and uses the light to ablate the metal film layer of the tapered optical fiber to form a preset pattern on the metal film layer to obtain an optical fiber probe.
The method for preparing an optical fiber probe based on a femtosecond laser combined with a super-resolution lens according to claim 4, wherein the femtosecond laser has a pulse width of 10 fs to 1000 fs, a wavelength of 500 nm to 1200 nm, and a repetition frequency of 1 Hz to 1000 fs. 100MHz.
The fiber probe preparation method based on femtosecond laser combined with super-resolution lens according to claim 4, characterized in that, when the femtosecond laser is focused and processed by the super-resolution lens (6), the pulse width of the femtosecond laser is not greater than 500 fs; when the femtosecond laser is imaged by the super-resolution lens (7) and the lens (4), the pulse width is not less than 500 fs, and the repetition frequency is not less than 40 MHz.
An optical fiber probe, characterized in that the optical fiber probe is prepared by the method for preparing an optical fiber probe based on a femtosecond laser combined with a super-resolution lens according to any one of claims 4-6.
The optical fiber probe according to claim 7, characterized in that, the shape of the tapered optical fiber portion of the optical fiber probe is conical or truncated-conical.
A kind of fiber optic probe according to claim 8, characterized in that:

When the shape of the tapered fiber part of the fiber probe is conical, the cone angle of the tapered fiber is 20°-90°, and the diameter of the cone tip is 10nm-200nm;

When the shape of the tapered optical fiber portion of the optical fiber probe is a truncated cone, the tapered optical fiber has a cone apex angle of 20°-90° and a diameter of the small end surface of 1 μm-100 μm.
The optical fiber probe according to claim 7, characterized in that the material of the metal film layer is gold, silver or aluminum, and the thickness is 10nm-200nm.