A confocal cavity with symmetrical optical path and a laser processing method

Abstract

The present invention provides a multi-frequency confocal cavity, comprising: a laser inlet, through which laser light enters an optically symmetrical confocal cavity, and after being reflected several times within the optically symmetrical confocal cavity, is emitted from the laser inlet; a symmetrical lens, for reflecting the laser light; and a nonlinear optical crystal, for causing the laser light passing through the nonlinear optical crystal to undergo nonlinear frequency conversion; wherein the nonlinear optical crystal is located at the focal point of the symmetrical lens, and each reflection of the laser light passes through the nonlinear optical crystal, and the laser light does not oscillate in the optically symmetrical confocal cavity. The present invention also includes another optically symmetrical confocal cavity and a laser processing method corresponding to the optically symmetrical confocal cavity. The present invention provides an optically symmetrical confocal cavity and a laser processing method with greater applicability.

Description

Technical Field

[0001] The present invention belongs to the field of optical signal processing, and in particular relates to an optical path symmetrical confocal cavity and a laser processing method. Background Art

[0002] In optical processing, nonlinear optical crystals are often used to convert the frequency of optical signals. These crystals have different refractive indices for light of different frequencies, so when the original light beam passes through these materials, the frequency shifts. Using nonlinear optical crystals, infrared lasers can be converted into visible lasers, or visible lasers can be converted into shorter wavelengths. Multiple frequency doubling can be used to achieve even shorter wavelengths, thereby expanding the range of laser spectrum coverage and producing more granular, more penetrating lasers.

[0003] Prior art typically places a frequency-doubling crystal within a resonant cavity, causing the electromagnetic waves within the cavity to resonate with the frequency-doubling crystal, thereby increasing the efficiency of the nonlinear optical crystal. However, this laser processing method requires adjusting environmental factors such as the temperature and pressure within the cavity. Furthermore, the efficiency of frequency-doubling the nonlinear optical crystal within the cavity remains low, and the number of times the laser can pass through the nonlinear optical crystal is limited, limiting its widespread industrial application.

[0004] Based on the above, this application provides a technical solution to solve the above technical problems. Summary of the Invention

[0005] In view of the low efficiency of laser frequency doubling in the prior art, the present invention provides a confocal cavity with symmetrical optical paths, comprising:

[0006] A laser incident port, through which the laser enters the optically symmetrical confocal cavity, and after the laser is reflected several times in the optically symmetrical confocal cavity, it is emitted from the laser incident port;

[0007] a symmetrical lens, configured to reflect the laser light;

[0008] A nonlinear optical crystal is used to cause nonlinear frequency conversion of laser light passing through the nonlinear optical crystal; wherein the nonlinear optical crystal is located at the focus of the symmetrical lens, the laser light passes through the nonlinear optical crystal each time it is reflected, and the laser light does not oscillate in the optical path symmetrical confocal cavity.

[0009] In a specific embodiment of the present invention, the symmetrical lens is a high reflective mirror, and L=R, the radius of the symmetrical lens is R, and the cavity length of the optical path symmetrical confocal cavity is L.

[0010] In one embodiment of the present invention, the nonlinear frequency conversion is one of frequency doubling, sum frequency conversion, and difference frequency conversion. Laser light is incident parallel to the optically symmetrical confocal cavity through a laser input port, and a total of four nonlinear frequency conversions occur within the optically symmetrical confocal cavity. In one embodiment of the present invention, the laser input port is a notch hollowed out in a symmetrical lens.

[0011] In a specific embodiment of the present invention, the length of the gap is one quarter of the length of the lens.

[0012] In a specific embodiment of the present invention, the gap is a hole on a symmetrical lens.

[0013] In a specific embodiment of the present invention, the laser incident port is a coating portion on a symmetrical lens, and the coating is a lens anti-reflection coating.

[0014] In one embodiment of the present invention, ,in, represents the waist spot radius, L is the cavity length of the optical path symmetrical confocal cavity, represents the wavelength of the incident laser, and the radius of the symmetrical lens is R.

[0015] The present invention also provides an optically symmetrical confocal cavity, comprising: a nonlinear optical crystal, used to cause laser light passing through the nonlinear optical crystal to produce nonlinear frequency conversion, the nonlinear optical crystal being made into a symmetrical circular concave lens shape or a convex spherical mirror shape; a laser incident port, through which laser light is incident in parallel into the nonlinear optical crystal, and after the laser light passes through the nonlinear optical crystal several times, it is emitted from the laser incident port; wherein the laser light does not oscillate in the optically symmetrical confocal cavity.

[0016] The present invention also provides a laser processing method, comprising: step S1, laser light is incident on a light-path symmetrical confocal cavity from a laser incident port; step S2, the laser light is reflected several times by a symmetrical lens in the light-path symmetrical confocal cavity, a nonlinear optical crystal is provided at the focus of the light-path symmetrical confocal cavity, and the laser light passes through the nonlinear optical crystal each time it is reflected; step S3, the laser light is emitted from the laser incident port; wherein the nonlinear optical crystal is used to cause the laser light passing through the nonlinear optical crystal to produce nonlinear frequency conversion, and the laser light does not oscillate in the light-path symmetrical confocal cavity.

[0017] The present invention can bring at least one of the following beneficial effects: the present invention places a nonlinear optical crystal at the focus of a symmetrical confocal cavity, and through the reflection effect of a lens, can enable the incident laser to stably achieve multiple nonlinear frequency conversions in the confocal cavity, without the need to use an optical resonant cavity, and without the need to strictly limit environmental factors such as temperature. It can be applied to a wider range of operating environments and has stronger industrial applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The preferred implementation scheme will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above characteristics, technical features, advantages and their implementation methods.

[0019] Figure 1 Schematic diagram of the structure of a confocal cavity with symmetrical optical paths in one embodiment of the present invention;

[0020] Figure 2 Schematic diagram of another optical path symmetrical confocal cavity according to an embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the structure of the optical path symmetrical confocal cavity in another embodiment of the present invention;

[0022] Figure 4 Schematic diagram of the structure of another optical path symmetrical confocal cavity in another embodiment of the present invention;

[0023] Figure 5 Schematic diagram of the structure of another optical path symmetrical confocal cavity in another embodiment of the present invention;

[0024] Figure 6 Schematic diagram of the steps of a laser processing method in another embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following further describes various aspects of the present invention. Unless otherwise defined or indicated, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the present invention.

[0026] The following describes the terms.

[0027] Unless otherwise specified or limited, the "or" mentioned in the present invention includes the "and" relationship. The "and" is equivalent to the Boolean logic operator "AND", and the "or" is equivalent to the Boolean logic operator "OR", and "AND" is a subset of "OR".

[0028] It will be understood that although the terms "first," "second," and the like may be used herein to describe different elements, these elements should not be limited by these terms. These terms are merely used to distinguish one element from another. Thus, a first element may be referred to as a second element without departing from the teachings of the present invention.

[0029] In the present invention, the terms "comprising", "including" or "comprising" indicate that various components can be used together in the mixture or composition of the present invention. Therefore, the term "consisting mainly of..." is included in the terms "comprising", "including" or "comprising".

[0030] Unless otherwise expressly specified or limited, the terms "connected," "connected," and "connected" in this application should be understood broadly. For example, they may refer to a fixed connection, a connection through an intermediary medium, internal communication between two components, or an interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0031] For example, if an element (or component) is referred to as being on, coupled to, or connected to another element, the element may be directly on, coupled to, or connected to the other element, or one or more intervening elements may be present. In contrast, if the expressions "directly on," "directly coupled to," and "directly connected to" are used herein, no intervening elements are present. Other words used to describe the relationship between elements should be interpreted similarly, such as "between" and "directly between," "attached" and "directly attached," "adjacent" and "directly adjacent," etc.

[0032] It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings. The terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component. It will be understood that these terms are used herein to describe the relationship of one element, layer, or region relative to another element, layer, or region as illustrated in the accompanying drawings. These terms are intended to encompass orientations of the device in addition to the orientation depicted in the accompanying drawings.

[0033] Other aspects of the present invention will be apparent to those skilled in the art in view of the disclosure herein.

[0034] To more clearly illustrate the embodiments of the present invention or technical solutions in the prior art, specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. Those skilled in the art can, without inventive effort, derive other drawings and other embodiments based on these drawings.

[0035] It should also be noted that the figures provided in the following embodiments are merely schematic illustrations of the basic concepts of the present application. The figures only show components relevant to the present application and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be varied arbitrarily, and the component layout may be more complex. For example, the thickness of components in the drawings may be exaggerated for clarity.

[0036] Example 1

[0037] In view of the low frequency doubling efficiency and limited operating environment in the existing technology, as shown in the attached Figure 1 As shown, the present invention proposes an optical path symmetrical confocal cavity, comprising: a laser incident port, through which the laser 3 enters the optical path symmetrical confocal cavity, and when the laser 3 is reflected several times in the optical path symmetrical confocal cavity, it is emitted from the laser incident port. A symmetrical lens, for reflecting the laser. A nonlinear optical crystal 4, for causing the laser 3 passing through the nonlinear optical crystal 4 to produce a nonlinear frequency conversion. The nonlinear optical crystal 4 is located at the focus of the symmetrical lens, and the laser 3 passes through the nonlinear optical crystal 4 each time it is reflected, and the laser 3 does not oscillate in the optical path symmetrical confocal cavity. In a preferred embodiment of the present invention, the symmetrical lens is a high reflective mirror, and L=R, the radius of the symmetrical lens is R, and the cavity length of the optical path symmetrical confocal cavity is L.

[0038] In a preferred embodiment of the present invention, see the attached Figure 1 In the optical path shown, laser light 3 enters the optically symmetrical confocal cavity from the laser inlet in parallel. Because lenses 1 and 2 are symmetrical, laser light 3 is reflected by lens 2 at a position symmetrical to the laser inlet. After passing through the common focal point of lenses 1 and 2, the reflected laser light is reflected again by lens 1 into a parallel beam. This parallel beam is then reflected by lens 2, passes through the common focal point of lenses 1 and 2, and exits the optically symmetrical confocal cavity from the laser inlet. Each reflection of the laser light passes through the nonlinear optical crystal 4, and laser light 3 undergoes four nonlinear frequency conversions within the optically symmetrical confocal cavity.

[0039] In a preferred embodiment of the present invention, the nonlinear frequency conversion is frequency conversion, which can be specifically one of frequency multiplication, sum frequency, and difference frequency.

[0040] In a preferred embodiment of the present invention, as shown in the attached Figure 1As shown, the laser entrance port is a hollowed-out notch on lens 1, and the length of the notch is one-quarter the length of lens 1. It should be noted that in the present invention, the size of the laser entrance port includes but is not limited to one-quarter the length of lens 1, and any addition or deletion in any form shall be included in the spirit of the present invention as long as it does not limit the purpose of the invention.

[0041] In a preferred embodiment of the present invention, the laser incident port may also be a hole on a symmetrical lens, and the hole size is at least sufficient to allow the laser to pass through the hole and enter the optically symmetrical confocal cavity.

[0042] In a preferred embodiment of the present invention, see the attached Figure 2 The laser incident port is the coating portion on the symmetrical lens 1. The coating is a lens anti-reflection film that can reduce the reflected light on the optical surface of the lens. The laser 3 can directly pass through the lens anti-reflection film and enter the multiple frequency confocal cavity.

[0043] In a preferred embodiment of the present invention, ,in, represents the waist spot radius (the waist spot is not shown in the figure), L is the cavity length of the multi-frequency confocal cavity, represents the wavelength of the incident laser, and the radius of the symmetrical lens is R.

[0044] The waist radius determines the size of the light spot. The larger the light spot, the smaller the divergence angle.

[0045] In practical applications, the confocal cavity length is usually set between 1cm and 5cm. For example, the confocal cavity length L is 1cm and the waist spot radius is The confocal cavity length is 2 cm, and the waist radius is 56 μm. is 97μm; the confocal cavity length L is 5cm, the waist radius It is 126μm.

[0046] It should be noted that, in the present invention, the confocal cavity length L includes but is not limited to 1 cm, 2 cm or 5 cm, and any form of addition or deletion should be included in the gist of the present invention as long as it does not limit the purpose of the present invention.

[0047] The solution of the present invention does not involve a resonant cavity, and only requires that the nonlinear optical crystal laser oscillate in a confocal cavity, that is, there is no need to strictly limit environmental factors such as temperature, and the operating environment is wider and the industrial applicability is stronger.

[0048] Example 2

[0049] See also Figure 3 , which is another specific embodiment of the present invention, is an optical path symmetrical confocal cavity, comprising:

[0050] A nonlinear optical crystal 4, used to cause the laser light 3 passing through the nonlinear optical crystal 4 to generate nonlinear frequency conversion, wherein the nonlinear optical crystal 4 is made into a symmetrical circular concave lens shape;

[0051] A laser incident port, through which the laser 3 is incident in parallel on the nonlinear optical crystal 4. After the laser 3 passes through the nonlinear optical crystal 4 several times, it is emitted from the laser incident port;

[0052] The laser does not oscillate in the optically symmetrical confocal cavity.

[0053] Preferably, as attached Figure 4 As shown, the nonlinear optical crystal 4 can also be made into a convex spherical mirror shape.

[0054] Preferably, as attached Figure 5 As shown, the upper left side of the nonlinear optical crystal 4 can also be made into a straight line.

[0055] It should be noted that one or more technical features of Example 2 can be combined with one or more technical features of Example 1, such as the structure of the laser incident port, waist spot, confocal cavity length and other data, and these combinations all fall within the scope of protection of the present invention.

[0056] In this embodiment, the nonlinear optical crystal is directly manufactured into a circular concave lens shape or a convex spherical mirror shape without using a lens, thereby further improving the efficiency of laser frequency doubling and being applicable to various industrial environments.

[0057] Example 3

[0058] See also Figure 6 , which is another specific embodiment of the present invention, is a laser processing method, comprising:

[0059] Step S1, laser light enters the confocal cavity with a symmetrical optical path from the laser incident port;

[0060] Step S2: The laser light is reflected several times by a symmetrical lens in the optical path symmetrical confocal cavity. A nonlinear optical crystal is provided at the focus of the optical path symmetrical confocal cavity. The laser light passes through the nonlinear optical crystal each time it is reflected.

[0061] Step S3: The laser is emitted from the laser incident port;

[0062] The nonlinear optical crystal is used to cause the laser passing through the nonlinear optical crystal to generate nonlinear frequency conversion, and the laser does not oscillate in the optical path symmetrical confocal cavity.

[0063] It should be noted that one or more technical features of Example 3 can be combined with one or more technical features of Example 1, such as the structure of the laser incident port, waist spot, confocal cavity length and other data and calculation methods. These combinations all fall within the scope of protection of the present invention.

[0064] In summary, the present invention has achieved the following effects:

[0065] The present invention places a nonlinear optical crystal at the focus of a symmetrical confocal cavity. Through the reflection effect of the lens, the incident laser can stably achieve multiple frequency changes in the confocal cavity. There is no need to use an optical resonant cavity, and there is no need to strictly limit environmental factors such as temperature. The invention can be applied to a wider range of operating environments and has stronger industrial applicability.

[0066] Based on this application, those skilled in the art will appreciate that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, an apparatus and / or method can be implemented using any number and aspects described herein. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement the apparatus and / or method.

[0067] Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, and units provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same functions of the system and its various devices, modules, and units provided by the present invention in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; the devices, modules, and units for implementing various functions can also be considered as both software modules implementing the method and structures within the hardware component.

[0068] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

[0069] All documents mentioned in this application are incorporated herein by reference, just as if each document were incorporated herein by reference individually. It should also be understood that after reading the above disclosure, those skilled in the art may make various changes or modifications to the present invention, and that such equivalents also fall within the scope of the claims appended hereto.

Claims

1. A confocal cavity with symmetrical optical path, characterized in that: include: A laser incident port, through which the laser is incident in parallel with the multi-frequency confocal cavity, the laser is frequency-doubled four times in the multi-frequency confocal cavity, and then emitted from the laser incident port; A symmetrical lens, which is a high-reflection mirror and is used to reflect the laser; A nonlinear optical crystal, used to generate a frequency doubling effect on the laser light passing through the nonlinear optical crystal; The nonlinear optical crystal is located at the confocal point of the symmetrical lens, and the laser passes through the nonlinear optical crystal each time it is reflected, and the laser does not oscillate in the multi-frequency confocal cavity; the multi-frequency confocal cavity is a spherical cavity, L=R, the radius of the symmetrical lens is R, and the cavity length of the multi-frequency confocal cavity is L.

2. The optical path symmetrical confocal cavity according to claim 1, characterized in that: The laser incident port is a hollowed-out gap on the symmetrical lens.

3. The optical path symmetrical confocal cavity according to claim 2, characterized in that: The length of the notch is one quarter of the length of the lens.

4. The optical path symmetrical confocal cavity according to claim 1, characterized in that: The laser incident port is a coating portion on the symmetrical lens, and the coating is a lens anti-reflection coating.

5. The optical path symmetrical confocal cavity according to claim 1, characterized in that: ,in, represents the waist spot radius, L is the cavity length of the multi-frequency confocal cavity, represents the wavelength of the incident laser, and the radius of the symmetrical lens is R.

6. A confocal cavity with symmetrical optical path, characterized in that: include: A nonlinear optical crystal, used to generate a frequency doubling effect on the laser passing through the nonlinear optical crystal, wherein the nonlinear optical crystal is made into a symmetrical circular concave lens shape to form a multi-frequency symmetrical confocal cavity; a laser incident port, through which laser light enters the nonlinear optical crystal in parallel and is reflected on the inner wall of the nonlinear optical crystal, L=R, the radius of the circular concave lens is R, the cavity length of the multi-frequency confocal cavity is L, and after the laser light is frequency-doubled four times in the nonlinear optical crystal, it is emitted from the laser incident port; The laser does not oscillate in the multi-frequency confocal cavity.

7. A laser processing method, characterized in that: include: Step S1, laser is incident on the multi-frequency confocal cavity in parallel from the laser incident port; Step S2: The laser is frequency-doubled four times in the multi-frequency confocal cavity, wherein the multi-frequency confocal cavity includes a symmetrical lens, which is a high-reflectivity mirror for reflecting the laser. A nonlinear optical crystal is provided at the confocal point of the multi-frequency confocal cavity, and each reflection of the laser passes through the nonlinear optical crystal. Step S3: The laser is emitted from the laser incident port; In which, the nonlinear optical crystal is used to make the laser passing through the nonlinear optical crystal produce a frequency doubling effect, and the laser does not oscillate in the multi-frequency confocal cavity. The multi-frequency confocal cavity is a spherical cavity, L=R, the radius of the symmetrical lens is R, and the cavity length of the multi-frequency confocal cavity is L.

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