CN114216864A - Confocal microscopic method and device based on laser feedback - Google Patents

Confocal microscopic method and device based on laser feedback Download PDF

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CN114216864A
CN114216864A CN202111508906.0A CN202111508906A CN114216864A CN 114216864 A CN114216864 A CN 114216864A CN 202111508906 A CN202111508906 A CN 202111508906A CN 114216864 A CN114216864 A CN 114216864A
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谈宜东
邓世炜
花子誉
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Tsinghua University
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Abstract

The invention relates to a confocal microscopy method and a confocal microscopy device based on laser feedback, wherein the confocal microscopy method based on the laser feedback comprises the following steps: emitting laser by a linear polarization laser; the laser irradiates the microscopic sample through a collimating lens, an 1/2 wave plate, a 1/4 wave plate, a beam expander and an objective lens in sequence; driving a microscopic sample to perform same-view field scanning imaging to obtain a polarization-maintaining related component image by enabling an included angle between the main axis direction of the 1/4 wave plate and the polarization direction of laser to be 0 degrees; making the included angle between the main axis direction of the 1/4 wave plate and the polarization direction of the laser be 45 degrees; and driving the microscopic sample to perform scanning imaging in a same field of view to obtain an depolarization related component image. The confocal microscopy method based on laser feedback integrates the advantages of auto-collimation and high sensitivity of the laser feedback technology based on the laser feedback technology, obtains polarization-maintaining related component images and polarization-removing related component images of the microscopic sample, provides more image information data, improves the information acquisition capacity of a scattering medium of the microscopic sample, and expands the information quantity.

Description

Confocal microscopic method and device based on laser feedback
Technical Field
The invention relates to the technical field of laser measurement, in particular to a confocal microscopy method and device based on laser feedback.
Background
The laser feedback phenomenon refers to a phenomenon that after output light of the linear polarization laser is reflected or scattered by an external object, part of the light is fed back to the linear polarization laser and mixed with light in a cavity to cause output change of the linear polarization laser. The laser confocal feedback imaging technology is a novel imaging technology integrating a laser feedback technology and a confocal technology.
However, in the current research, since the information obtained by the laser confocal feedback imaging technology is single, the backscattering rate of the object is only used for imaging, so that scattering samples with similar backscattering rates cannot be distinguished, and the application prospect of the laser confocal feedback imaging technology is greatly limited.
Disclosure of Invention
In view of the above, there is a need to provide a confocal microscopy method based on laser feedback, which is directed to the problem that the conventional imaging technology cannot distinguish scattering samples with similar backscattering rate.
A confocal microscopy method based on laser feedback comprises the following steps:
emitting laser by a linear polarization laser;
the laser irradiates the microscopic sample through a collimating lens, an 1/2 wave plate, a 1/4 wave plate, a beam expander and an objective lens in sequence;
making the included angle between the main axis direction of the 1/4 wave plate and the polarization direction of the laser be 0 degree;
driving the microscopic sample to perform scanning imaging in a same-view field to obtain a polarization-preserving related component image;
making the included angle between the main axis direction of the 1/4 wave plate and the polarization direction of the laser be 45 degrees;
and driving the microscopic sample to perform scanning imaging in a same field of view to obtain a depolarization related component image.
The confocal microscopic method based on laser feedback is based on the laser feedback technology and integrates the advantages of simple structure, auto-collimation and high sensitivity of the laser feedback technology. An included angle between the main axis direction of the 1/4 wave plate and the polarization direction of laser emitted by a linear polarization laser is 0 degree, and a microscopic sample is driven to carry out same-view field scanning imaging to obtain a polarization-preserving related component image; and (3) setting an included angle of the main axis direction of the 1/4 wave plate and the polarization direction of laser emitted by the linear polarization laser to be 45 degrees, and driving the microscopic sample to perform scanning imaging in a same field of view to obtain an depolarization related component image. The method has the advantages that the polarization-preserving related component images and the polarization-degrading related component images of the microscopic samples are obtained, more image information data are provided, higher imaging identification and contrast are provided for the scattering samples with similar backscattering rates, the method is beneficial to obtaining clearer microscopic sample images, the information obtaining capability of scattering media of the microscopic samples is improved, and the information quantity is expanded.
In one embodiment, the laser feedback-based confocal microscopy method further includes the following steps:
carrying out square calculation on the polarization-preserving related component image to obtain a polarization-preserving component image; performing square calculation on the depolarization related component image to obtain a depolarization component image; and adding the depolarization component image and the polarization-preserving component image to obtain a reflectivity image.
In one embodiment, the laser feedback-based confocal microscopy method further includes the following steps:
carrying out square calculation on the polarization-preserving related component image to obtain a polarization-preserving component image; performing square calculation on the depolarization related component image to obtain a depolarization component image; and the depolarization component image is divided by the polarization maintaining component image to obtain a depolarization image.
A laser feedback based confocal microscopy apparatus comprising:
the linear polarization laser is used for outputting laser, and the laser is linear polarization laser;
a scanning device for carrying a microscopic sample;
optical assembly, optical assembly locates linear polarization laser instrument with between the scanning device, optical assembly includes the edge collimator, 1/2 wave plate, 1/4 wave plate, beam expander and objective that the transmission direction of laser beam coaxial axis set gradually, 1/4 wave plate can be relative the laser coaxial axis is rotatory, the laser warp shine after the optical assembly transmits in microscopic sample.
According to the confocal microscope device based on laser feedback, based on a laser feedback technology, part of laser emitted by a linear polarization laser after being backscattered by a scattering medium of a microscopic sample is reflected back to the linear polarization laser and is mixed with laser in a linear polarization laser cavity to cause output change of the linear polarization laser, and the advantages of simple structure, auto-collimation and high sensitivity of the laser feedback technology are integrated; the beam waist radius in the linear polarization laser can be used as the needle diameter, so that the beam diameter of laser emitted by the linear polarization laser is reduced, the system installation and adjustment difficulty is greatly reduced due to the self-alignment characteristic of laser feedback, and the structure is more stable and simple; by combining the collimating lens and the beam expanding lens in the optical assembly, the confocal imaging principle is used, and the advantage of high confocal imaging resolution is obtained; the laser emitted by the linear polarization laser passes through the 1/2 wave plate and the 1/4 wave plate, so that the polarization information of the scattering medium of the microscopic sample is obtained, the polarization channel is expanded by utilizing the advantage of high information content of polarization imaging, and richer polarization information is obtained. This application utilizes the characteristics of laser feedback technique auto-collimation, combine confocal formation of image high resolution and polarization imaging high information volume's advantage, combine the comparatively simple optical component of light path structure, make the confocal polarization micro-device of timesharing of this application have the information volume abundant, can obtain the polarization information of micro-sample, the formation of image identification ability has been improved, scattering sample similar to backscattering rate provides higher formation of image identification degree and contrast, help obtaining more clear micro-sample image, the information acquisition ability to the scattering medium of micro-sample has been improved, the information volume has been expanded.
In one embodiment, the rotation angle of the main axis direction of the 1/4 wave plate and the polarization direction of the laser is in the range of 0-90 degrees.
In one embodiment, the optical assembly further comprises a beam splitter and an attenuation plate, the beam splitter is coaxially arranged between the collimating mirror and the 1/2 wave plate, and the attenuation plate is coaxially arranged between the 1/2 wave plate and the 1/4 wave plate; and/or the spectroscope and the attenuation sheet are coaxially and sequentially arranged between the collimating mirror and the 1/2 wave plate; and/or the spectroscope and the attenuation plate are coaxially and sequentially arranged between the 1/2 wave plate and the 1/4 wave plate.
In one embodiment, the laser feedback-based confocal microscopy apparatus further includes a photodetector, the photodetector is configured to measure an output of the linearly polarized laser after laser feedback, the beam splitter splits the laser into probe light and signal light, and the photodetector receives the signal light; and/or the photoelectric detector receives laser emitted by the linear polarization laser after the laser feedback effect.
In one embodiment, the laser feedback-based confocal microscopy apparatus further includes a signal processing module electrically connected to the photodetector, and the signal processing module is configured to demodulate an output of the photodetector.
In one embodiment, the optical assembly further includes an acousto-optic frequency shift module coaxially disposed between the 1/2 wave plate and the 1/4 wave plate, the acousto-optic frequency shift module includes a first frequency shifter and a second frequency shifter, and the laser light is differentially shifted by the acousto-optic frequency shift module.
In one embodiment, the optical assembly further comprises a mirror disposed between the beam expander and the objective lens.
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FIG. 1 is a schematic flow chart of a laser feedback-based confocal microscopy method according to an embodiment;
fig. 2 is a schematic structural diagram of a laser feedback-based confocal microscope apparatus according to an embodiment.
In the figure:
1. a linearly polarized laser; 2. a collimating mirror; 3. a beam splitter; 4. a photodetector; 5. 1/2 a wave plate; 6. an attenuation sheet; 7. a first frequency shifter; 8. a second frequency shifter; 9. 1/4 a wave plate; 10. a beam expander; 11. a mirror; 12. an objective lens; 13. a scanning device.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
Referring to fig. 1, the present application provides a confocal microscopy method based on laser feedback, including the following steps:
emitting laser by a linear polarization laser;
the laser irradiates the microscopic sample through a collimating lens, an 1/2 wave plate, a 1/4 wave plate, a beam expander and an objective lens in sequence;
making the included angle between the main axis direction of the 1/4 wave plate and the polarization direction of the laser be 0 degree;
driving the microscopic sample to perform scanning imaging in a same-view field to obtain a polarization-preserving related component image;
making the included angle between the main axis direction of the 1/4 wave plate and the polarization direction of the laser be 45 degrees;
and driving the microscopic sample to perform scanning imaging in a same field of view to obtain an depolarization related component image.
In the confocal technology, the conjugate relation of the point light source and the point detector effectively reduces the noise of a non-focal plane, so that the confocal technology has the advantages of three-dimensional chromatographic capacity and transverse resolution 1.4 times that of a common microscope. These advantages have led to the widespread use of laser imaging using confocal technology in the fields of biology, biomedicine, industrial detection, metrology, and the like.
Laser feedback has a high sensitivity, which benefits from resonant amplification of the feedback optical field in the resonator cavity. Especially the microchip laser frequency shift feedback technology, the gain coefficient can reach as high as 106This makes laser feedback technology a great advantage in weak signal detection. In addition, the combination of laser feedback technology and confocal technology has other advantages, such as: the beam waist radius of the laser can be used as a pinhole, the system installation and debugging difficulty is greatly reduced due to the self-alignment characteristic of laser feedback, and the structure is more stable and simple;not only amplitude information measurement but also phase information measurement can be utilized; the heterodyne principle of laser frequency shift feedback is utilized to modulate signals to high frequency, so that the imaging and measurement signal-to-noise ratio are improved, and the laser confocal feedback imaging technology has greater advantages.
The confocal microscopic method based on laser feedback is based on the laser feedback technology and integrates the advantages of simple structure, auto-collimation and high sensitivity of the laser feedback technology. An included angle between the main axis direction of the 1/4 wave plate and the polarization direction of laser emitted by a linear polarization laser is 0 degree, and a microscopic sample is driven to carry out same-view field scanning imaging to obtain a polarization-preserving related component image; and (3) setting an included angle of the main axis direction of the 1/4 wave plate and the polarization direction of laser emitted by the linear polarization laser to be 45 degrees, and driving the microscopic sample to perform scanning imaging in a same field of view to obtain an depolarization related component image. The method has the advantages that the polarization-preserving related component images and the polarization-degrading related component images of the microscopic samples are obtained, more image information data are provided, higher imaging identification and contrast are provided for the scattering samples with similar backscattering rates, the method is beneficial to obtaining clearer microscopic sample images, the information obtaining capability of scattering media of the microscopic samples is improved, and the information quantity is expanded.
In one embodiment, the laser feedback-based confocal microscopy method further comprises the following steps:
carrying out square calculation on the polarization-preserving related component image to obtain a polarization-preserving component image; performing square calculation on the depolarization related component image to obtain a depolarization component image; and adding the depolarization component image and the polarization-preserving component image to obtain a reflectivity image.
The polarization-preserving component image and the polarization-removing component image are obtained by respectively carrying out square calculation on the polarization-preserving related component image and the polarization-removing related component image, so that the polarization channel of the microscopic sample is widened, and richer polarization component information is obtained. More relevant images are provided for microscopic samples with similar backscattering rates, which helps to more finely restore the true image information of the microscopic samples. And the reflectance image is obtained by adding the depolarization component image and the polarization-maintaining component image, so that the image of the microscopic sample has higher contrast and definition.
In one embodiment, the laser feedback-based confocal microscopy method further comprises the following steps:
carrying out square calculation on the polarization-preserving related component image to obtain a polarization-preserving component image; performing square calculation on the depolarization related component image to obtain a depolarization component image; and the depolarization component image is divided by the polarization maintaining component image to obtain a depolarization image.
The polarization-preserving component image and the polarization-canceling component image are obtained by respectively carrying out square calculation on the polarization-preserving related component image and the polarization-canceling related component image, and the polarization-canceling degree image is obtained by dividing the polarization-canceling component image and the polarization-preserving component image, so that the image data information of the microscopic sample is further enriched, and the image of the microscopic sample has higher definition and contrast.
Specifically, the working principle of the confocal microscopy method based on laser feedback is as follows:
fully polarized light is backscattered by the object, often as partially polarized light. Separating the backscattered light I into components I having the same polarization state as the incident laser light||And a component I orthogonal to the polarization state of the incident laser light⊥Wherein I ═ I⊥+||。
Defining the depolarization ratio rho and the polarization retention ratio beta of a scattering medium of a microscopic sample as follows:
Figure BDA0003404494160000071
β + ρ ═ 1 is present. Definition of degree of depolarization
Figure BDA0003404494160000072
The finite reflectivity is κ. The reflection coefficient for the polarization maintaining component is κ β and the reflection coefficient for the polarization maintaining component is κ ρ.
Considering only the depolarization of the scattering medium of the microscopic sample and neglecting the anisotropy of the depolarization, only the elements of the diagonal of the mueller matrix of the scattering medium of the microscopic sample are non-zero. The mueller matrix of the scattering medium of the microscopic sample was recorded as:
Figure BDA0003404494160000073
when the included angle between the principal axis of the 1/4 wave plate and the polarization direction of the laser emitted by the linear polarization laser is 0 degree, the optical field is effectively fed back according to the Mueller matrix derivation
Figure BDA0003404494160000074
When the included angle between the principal axis of the 1/4 wave plate and the polarization direction of the laser emitted by the linear polarization laser is 45 degrees, the effective feedback light field is derived according to the Mueller matrix
Figure BDA0003404494160000081
Under the weak feedback condition, the amplitude of the feedback light field of the laser feedback system is in direct proportion to the amplitude of the frequency shift signal. Therefore, when the 1/4 wave plate forms an angle of 0 ° with the polarization direction of the laser light emitted by the linear polarization laser, the scanned image is actually an image related to the polarization-maintaining component. When the principal axis of the 1/4 wave plate forms an angle of 45 degrees with the polarization direction of the laser emitted by the linear polarization laser, the scanned image is actually an image related to the depolarization component.
By further calculation:
Figure BDA0003404494160000082
Figure BDA0003404494160000083
thereby obtaining a polarization-maintaining component IMDepolarization component IDReflectivity of IRAnd degree of depolarization IDOP. And scanning and imaging the scattering medium of the microscopic sample to obtain a polarization maintaining component related image, a polarization removing component related image, a reflectivity related image and a polarization removing degree related image.
Referring to fig. 2, the present invention further provides a laser feedback-based confocal microscopy apparatus, which can be used to implement the laser feedback-based confocal microscopy method in any of the above embodiments. The confocal microscopy device based on laser feedback comprises: a linearly polarized laser 1, a scanning device 13 and an optical assembly. The linear polarization laser 1 is configured to output laser light, and the laser light is linearly polarized laser light. Further, the laser light output from the linearly polarized laser 1 is generally divided into a single longitudinal mode and a fundamental transverse mode. Alternatively, the linearly polarized laser 1 may be a solid laser, one of a fiber laser and a semiconductor laser, or another laser capable of emitting linearly polarized laser.
The scanning device 13 is used to carry microscopic samples. Further, the scanning device 13 may be a three-dimensional motion platform or a galvanometer, and may move the position of the microscopic sample according to actual measurement needs to obtain more scanning imaging areas.
The optical assembly is arranged between the linear polarization laser 1 and the scanning device 13, the optical assembly comprises a collimating lens 2, an 1/2 wave plate 5, a 1/4 wave plate 9, a beam expander 10 and an objective lens 12 which are sequentially arranged along the transmission direction common optical axis of laser, the 1/4 wave plate 9 can rotate relative to the laser common optical axis, and the laser irradiates on a microscopic sample after being transmitted by the optical assembly. The collimating mirror 2 is used for collimating the laser beam emitted from the linearly polarized laser 1. Alternatively, the collimating mirror 2 may be a binary optical element, a wedge array focusing optical system, a liquid crystal spatial light modulator, a birefringent lens group, or the like, which can collimate the laser light. 1/2 wave plate 5 is used for adjusting the polarization direction of the laser output by the linear polarization laser 1, and through combining 1/2 wave plate 5 and 1/4 wave plate 9, the ellipticity and the rotation direction of the laser can be adjusted by rotating 1/4 wave plate 9, thereby realizing the output of any polarization state. The beam expander 10 functions to expand the laser light to match the clear aperture of the objective lens 12, thereby enabling more efficient coupling of the laser light into the objective lens 12. The laser forms a focused light after passing through the objective lens 12 and irradiates on the microscopic sample, the scattering medium of the microscopic sample forms the feedback light after passing through the optical component to emit back to the linear polarization laser 1, and the output change generated after the feedback light is mixed with the laser emitted by the linear polarization laser 1 obtains the image information of the microscopic sample.
In one embodiment, 1/4 wave plate 9 has a rotation angle of 0-90 ° between the principal axis and the polarization direction of the laser. Further, when the angle between the principal axis direction of the 1/4 wave plate 9 and the polarization direction of the laser light is 0 °, the laser light is still linearly polarized after passing through the 1/4 wave plate 9. When the angle between the principal axis direction of the 1/4 wave plate 9 and the polarization direction of the laser light is 45 °, the laser light becomes circularly polarized light after passing through the 1/4 wave plate 9. When the angle between the principal axis direction of the 1/4 wave plate 9 and the polarization direction of the laser light is other angles, the laser light becomes elliptically polarized light after passing through the 1/4 wave plate 9. Specifically, when the 1/4 wave plate 9 forms an angle of 0 ° with the polarization direction of the laser light emitted by the linear polarization laser 1, the scanning imaging obtains an image related to the polarization maintaining component. When the angle between the principal axis of the 1/4 wave plate 9 and the polarization direction of the laser emitted by the linear polarization laser 1 is 45 degrees, scanning imaging obtains an image related to the depolarization component.
In an embodiment, the optical assembly further includes a beam splitter 3 and an attenuation plate 6, the beam splitter 3 is disposed between the collimating mirror 2 and the 1/2 wave plate 5, and the attenuation plate 6 is disposed between the 1/2 wave plate 5 and the 1/4 wave plate 9; and/or the spectroscope 3 and the attenuation sheet 6 are coaxially and sequentially arranged between the collimating mirror 2 and the 1/2 wave plate 5; and/or the spectroscope 3 and the attenuation plate 6 are coaxially and sequentially arranged between the 1/2 wave plate 5 and the 1/4 wave plate 9. Further, the spectroscope 3 is arranged at an included angle of 45 degrees with the laser transmission direction. The attenuation sheet 6 is used for attenuating the energy of the laser, so that the confocal microscopic device based on laser feedback is at a weak feedback level, the detection sensitivity and accuracy are improved, and when the confocal microscopic device based on laser feedback is at other feedback levels, the measurement error caused by the nonlinear effect can be brought.
In an embodiment, the confocal microscopy apparatus based on laser feedback further includes a photodetector 4, the photodetector 4 is used for measuring the output of the linearly polarized laser 1 after the laser feedback effect, the spectroscope 3 splits the laser into detection light and signal light, and the photodetector 4 receives the signal light; and/or the photoelectric detector 4 receives the laser emitted by the linear polarization laser 1 after the laser feedback effect. The photodetector 4 is used for detecting the output of the laser to detect the light intensity signal and converting the light intensity signal into an electrical signal for output.
In an embodiment, the laser feedback-based confocal microscopy apparatus further includes a signal processing module, the signal processing module is electrically connected to the photodetector 4, and the signal processing module is configured to demodulate the output of the photodetector 4. Further, the signal processing module is connected to the output of the photodetector 4 through a lock-in amplifier, and the output of the photodetector 4 is demodulated.
In one embodiment, the optical assembly further includes an acousto-optic frequency shift module, the acousto-optic frequency shift module is coaxially disposed between the 1/2 wave plate 5 and the 1/4 wave plate 9, the acousto-optic frequency shift module includes a first frequency shifter 7 and a second frequency shifter 8, and the laser is differentially shifted by the acousto-optic frequency shift module. Further, the principal axis direction of the first frequency shifter 7 is parallel to the principal axis direction of the 1/2 wave plate 5, or the principal axis direction of the second frequency shifter 8 is parallel to the principal axis direction of the 1/2 wave plate 5. The laser passing through 1/2 wave plate 5 passes through the acousto-optic frequency shift module to realize differential frequency shift. Wherein, the 1/2 wave plate 5 is used for making the polarization direction of the laser parallel to the main axis direction of the first frequency shifter 7 or the second frequency shifter 8 in the acousto-optic frequency shift module. In other embodiments, the 1/2 wave plate 5 can be removed when the principal axis direction of the first frequency shifter 7 or the second frequency shifter 8 in the acousto-optic frequency shift module is the same as the polarization direction of the laser light output by the linearly polarized laser 1.
In an embodiment, the optical assembly further comprises a mirror 11, the mirror 11 being arranged between the beam expander 10 and the objective lens 12. Further, speculum 11 is 45 contained angles with the laser that expands behind beam expander 10 and sets up, carries out 90 rotations with the transmission light path of laser, and the laser of being convenient for gets into the buildding of objective 12 and laboratory light path, if when the axis perpendicular to ground of objective 12 sets up, has prevented the axial distance overlength of whole light path. In other embodiments, the angle between the reflecting mirror 11 and the laser beam expanded by the beam expander 10 may be set according to the actual positional relationship between the beam expander 10 and the objective lens 12.
Specifically, referring to fig. 2, an embodiment of a confocal microscope device based on laser feedback includes a linearly polarized laser 1, a collimating mirror 2, a beam splitter 3, a photodetector 4, an 1/2 wave plate 5, an attenuator 6, an acousto-optic frequency shift module, a 1/4 wave plate 9, a beam expander 10, a reflector 11, an objective lens 12, a scanning device 13, and a signal processing module. The linear polarization laser 1 emits laser light, then the laser light enters the collimating mirror 2 to be subjected to light path collimation, then the laser light is divided into detection light and signal light through the spectroscope 3, the detection light irradiates the 1/2 wave plate 5 and is attenuated through the attenuation sheet 6 to enable the confocal microscopy device based on laser feedback to be in a weak feedback state, then the laser light is subjected to differential frequency shift through the first frequency shifter 7 and the second frequency shifter 8 in the acousto-optic frequency shift module and is irradiated into the 1/4 wave plate 9, then the laser light is subjected to beam diameter adjustment through the beam expander 10, the laser light transmission direction adjustment through the reflector 11 is then introduced into the objective 12, the laser light is formed into focusing light through the objective 12 and is irradiated on a microscopic sample placed on the scanning device 13, the scattering medium of the microscopic sample reflects part of the light and causes output change of the linear polarization laser 1, the output change of the linear polarization laser 1 is irradiated on the photoelectric detector 4 and is transmitted to the signal processing module, by rotating 1/4 the included angle between the principal axis direction of the wave plate 9 and the polarization direction of the laser, when the included angle is 0 °, the image related to polarization maintaining component is obtained, and when the included angle is 45 °, the image related to polarization removing component is obtained.
In summary, in the above confocal microscope apparatus based on laser feedback, based on the laser feedback technology, part of laser light emitted from the linear polarization laser 1 after being backscattered by the microscopic sample is reflected back to the linear polarization laser 1 again, and is mixed with the laser light in the cavity of the linear polarization laser 1 to cause the output change of the linear polarization laser 1, thereby integrating the advantages of simple structure, auto-collimation and high sensitivity of the laser feedback technology; the beam waist radius in the linear polarization laser 1 can be used as the needle diameter, so that the beam diameter of laser emitted by the linear polarization laser 1 is reduced, the difficulty of system installation and adjustment is greatly reduced due to the self-alignment characteristic of laser feedback, and the structure is more stable and simple; by combining the collimating lens 2 and the beam expanding lens 10 in the optical assembly, the confocal imaging principle is used, and the advantage of high confocal imaging resolution is obtained; the laser emitted by the linear polarization laser 1 passes through the 1/2 wave plate 5 and the 1/4 wave plate 9, so that the polarization information of the scattering medium of the microscopic sample is obtained, the polarization channel is expanded by utilizing the advantage of high information content of polarization imaging, and richer polarization information is obtained. This application utilizes the characteristics of laser feedback technique auto-collimation, combine confocal formation of image high resolution and polarization imaging high information volume's advantage, combine the comparatively simple optical component of light path structure, make the confocal polarization micro-device of timesharing of this application have the information volume abundant, can obtain the polarization information of micro-sample, the formation of image identification ability has been improved, scattering sample similar to backscattering rate provides higher formation of image identification degree and contrast, help obtaining more clear micro-sample image, the information acquisition ability to the scattering medium of micro-sample has been improved, the information volume has been expanded.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A confocal microscopy method based on laser feedback is characterized by comprising the following steps:
emitting laser by a linear polarization laser;
the laser irradiates the microscopic sample through a collimating lens, an 1/2 wave plate, a 1/4 wave plate, a beam expander and an objective lens in sequence;
making the included angle between the main axis direction of the 1/4 wave plate and the polarization direction of the laser be 0 degree;
driving the microscopic sample to perform scanning imaging in a same-view field to obtain a polarization-preserving related component image;
making the included angle between the main axis direction of the 1/4 wave plate and the polarization direction of the laser be 45 degrees;
and driving the microscopic sample to perform scanning imaging in a same field of view to obtain a depolarization related component image.
2. The laser feedback-based confocal microscopy method of claim 1, further comprising the steps of:
carrying out square calculation on the polarization-preserving related component image to obtain a polarization-preserving component image;
performing square calculation on the depolarization related component image to obtain a depolarization component image;
and adding the depolarization component image and the polarization-preserving component image to obtain a reflectivity image.
3. The confocal microscopy method based on laser feedback according to claim 1, characterized by further comprising the steps of:
carrying out square calculation on the polarization-preserving related component image to obtain a polarization-preserving component image;
performing square calculation on the depolarization related component image to obtain a depolarization component image;
and the depolarization component image is divided by the polarization maintaining component image to obtain a depolarization image.
4. A confocal microscopy device based on laser feedback is characterized by comprising:
the linear polarization laser is used for outputting laser, and the laser is linear polarization laser;
a scanning device for carrying a microscopic sample;
optical assembly, optical assembly locates linear polarization laser instrument with between the scanning device, optical assembly includes the edge collimator, 1/2 wave plate, 1/4 wave plate, beam expander and objective that the transmission direction of laser beam coaxial axis set gradually, 1/4 wave plate can be relative the laser coaxial axis is rotatory, the laser warp shine after the optical assembly transmits in microscopic sample.
5. The confocal microscopy apparatus according to claim 4, wherein the rotation angle between the principal axis of the 1/4 wave plate and the polarization direction of the laser is in the range of 0 ° -90 °.
6. The laser feedback-based confocal microscopy apparatus as claimed in claim 4, wherein the optical assembly further comprises a beam splitter and an attenuation plate, the beam splitter is coaxially disposed between the collimating mirror and the 1/2 wave plate, and the attenuation plate is coaxially disposed between the 1/2 wave plate and the 1/4 wave plate; and/or the presence of a gas in the gas,
the spectroscope and the attenuation sheet are coaxially and sequentially arranged between the collimating mirror and the 1/2 wave plate; and/or the presence of a gas in the gas,
the spectroscope and the attenuation plate are coaxially and sequentially arranged between the 1/2 wave plate and the 1/4 wave plate.
7. The confocal microscopy apparatus based on laser feedback as claimed in claim 6, further comprising a photodetector for measuring the output of the linearly polarized laser after laser feedback, wherein the beam splitter splits the laser light into the detection light and the signal light, and the photodetector receives the signal light; and/or the presence of a gas in the gas,
and the photoelectric detector receives the laser emitted by the linear polarization laser after the laser feedback effect.
8. The confocal microscopy apparatus based on laser feedback as claimed in claim 7, further comprising a signal processing module electrically connected to the photodetector, wherein the signal processing module is configured to demodulate the output of the photodetector.
9. The laser feedback-based confocal microscopy apparatus as claimed in claim 4, wherein the optical assembly further comprises an acousto-optic frequency shift module coaxially disposed between the 1/2 wave plate and the 1/4 wave plate, the acousto-optic frequency shift module comprises a first frequency shifter and a second frequency shifter, and the laser is differentially shifted by the acousto-optic frequency shift module.
10. The laser feedback-based confocal microscopy apparatus according to claim 4, wherein the optical assembly further comprises a mirror disposed between the beam expander and the objective lens.
CN202111508906.0A 2021-12-10 2021-12-10 Confocal microscopic method and device based on laser feedback Pending CN114216864A (en)

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