Dispersion compensation unit and dispersion compensation method, optical resonant cavity

Abstract

This application provides a dispersion compensation unit, a dispersion compensation method, and an optical resonant cavity. The method includes: determining the required dispersion compensation amount based on the laser beam to be compensated; selecting at least one pair of chirped mirrors based on the dispersion compensation amount, and determining the number of reflections of the laser beam to be compensated between the at least one pair of chirped mirrors; wherein each pair of chirped mirrors includes two symmetrically arranged chirped mirrors; incident the laser beam to be compensated onto one of the at least one pair of chirped mirrors; adjusting the reflection angles of the other chirped mirrors in the at least one pair of chirped mirrors and the reflection angle of the zero-degree total internal reflection mirror located on the light-emitting side of the at least one pair of chirped mirrors, such that the number of reflections of the laser beam to be compensated between the at least one pair of chirped mirrors reaches the determined number of reflections, and returns along the original path after reflection by the zero-degree total internal reflection mirror. The method provided in this application allows for step-by-step adjustment of the dispersion amount, which is easy to adjust, thereby obtaining a laser beam with higher accuracy.

Description

Technical Field

[0001] This invention belongs to the field of ultrafast laser technology, and in particular, relates to a dispersion compensation unit, an optical resonant cavity, and a method for dispersion compensation of a laser beam. Background Technology

[0002] In the field of ultrafast lasers, a pair or multiple pairs of chirped mirrors with fixed dispersion are typically inserted into the optical resonant cavity (each reflection of light by a chirped mirror produces a specific amount of dispersion) to compensate for the dispersion within the optical resonant cavity. Grating pairs or prism pairs can also be used to achieve the same dispersion control and pulse shaping effects.

[0003] However, in existing technologies, there may be discrepancies between the calculated dispersion and the actual dispersion in practical applications, but the compensation dispersion is fixed, which brings great inconvenience to production and experimentation.

[0004] The content of the background section is merely the technology known to the inventor and does not necessarily represent the prior art in this field. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides an automatic dispersion compensation unit with adjustable dispersion, comprising:

[0006] There is at least one pair of first rotating stages, and the two first rotating stages of each pair are symmetrically arranged.

[0007] A pair of second rotary stages, the two second rotary stages are arranged symmetrically;

[0008] At least one pair of first optical adjustment frames, with the two first optical adjustment frames of each pair respectively mounted on the two first rotating platforms;

[0009] A pair of second optical adjustment frames, each of which is mounted on the pair of second rotary tables;

[0010] At least one pair of chirped mirrors, wherein the two chirped mirrors in each pair have the same dispersion, and are respectively mounted on the two first optical adjustment frames; and

[0011] A pair of zero-degree total reflection mirrors, each of which is mounted on the pair of second optical adjustment frames;

[0012] The rotation angles of the at least one pair of first rotating stages, the rotation angles of the pair of second rotating stages, and the angles of the pair of second optical adjustment frames can be adjusted respectively, so that the number of reflections of a laser beam incident on one of the at least one pair of chirped mirrors can be adjusted between the at least one pair of chirped mirrors, and the laser beam can return along its original path after being reflected by the at least one pair of chirped mirrors and the pair of zero-degree total reflection mirrors.

[0013] In some embodiments of this application, the dispersion compensation unit further includes a control element for controlling the rotation angle of the at least one pair of first rotary stages, the rotation angle of the pair of second rotary stages, and the angle of the pair of second optical adjustment frames.

[0014] In some embodiments of this application, the dispersion compensation unit further includes a display for displaying the optical path length and / or dispersion of the laser beam.

[0015] In some embodiments of this application, the dispersion compensation unit further includes a display for displaying the rotation angle of the at least one pair of first rotary stages, the rotation angle of the pair of second rotary stages, and the angle of the pair of second optical adjustment frames.

[0016] In some embodiments of this application, the dispersion of each of the at least one pair of chirped mirrors is -35 fs. 2 or -50fs 2 .

[0017] In some embodiments of this application, the at least one pair of chirped mirrors is any one of a concave chirped mirror, a convex chirped mirror, and a planar chirped mirror.

[0018] In some embodiments of this application, the pair of zero-degree total reflection mirrors is any one of a concave zero-degree total reflection mirror, a convex zero-degree total reflection mirror, and a planar zero-degree total reflection mirror.

[0019] This application further provides an optical resonant cavity, including any of the dispersion compensation units described above.

[0020] This application also provides a method for dispersion compensation of a laser beam, including:

[0021] Determine the required dispersion compensation amount based on the laser beam to be compensated;

[0022] Based on the dispersion compensation amount, at least one pair of chirped mirrors is selected, and the number of reflections of the laser beam to be compensated between the at least one pair of chirped mirrors is determined; wherein each pair of chirped mirrors in the at least one pair of chirped mirrors includes two chirped mirrors arranged symmetrically.

[0023] The laser beam to be compensated is incident onto one of the at least one pair of chirped mirrors; and

[0024] The reflection angles of the other chirped mirrors in the at least one pair of chirped mirrors and the reflection angle of the zero-degree total internal reflection mirror located on the light-emitting side of the at least one pair of chirped mirrors are adjusted so that the number of reflections of the laser beam to be compensated between the at least one pair of chirped mirrors reaches the determined number of reflections, and returns along the original path after being reflected by the zero-degree total internal reflection mirror.

[0025] In some embodiments of this application, the method further includes:

[0026] The optical path length of the compensated laser beam is determined based on the reflection angle of the at least one pair of chirped mirrors; and

[0027] The vibration frequency of the compensated laser beam is confirmed based on the optical path.

[0028] This application fixes a pair of chirped mirrors with fixed dispersion on a rotating stage. By rotating the stage, the reflection angle of the chirped mirrors is adjusted, thereby adjusting the reflection angle of the laser beam between the chirped mirrors and achieving dispersion adjustment steps in integer multiples of a single chirped mirror. Simultaneously, a zero-degree total internal reflection mirror is provided at the light outlet. By adjusting the angle of the corresponding rotating stage and / or adjustment frame, the laser beam returns along its original path. This achieves step-by-step adjustment of the dispersion, which is also easily adjustable.

[0029] The method provided in this application enables stepwise adjustment of the dispersion amount, which is easy to adjust, thereby obtaining a laser beam with higher accuracy.

[0030] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0031] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure.

[0032] Figure 1 The optical path of a laser beam provided in one embodiment of this application between a chirped mirror and a zero-degree total reflection mirror is shown.

[0033] Figure 2 The optical path of a laser beam between a chirped mirror and a zero-degree total reflection mirror, according to another embodiment of this application, is shown.

[0034] Figure 3 This document illustrates a process flow diagram for dispersive compensation of a laser beam according to an embodiment of this application. Detailed Implementation

[0035] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0036] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and installations are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or installations discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0037] In this invention, the terms "first," "second," and other ordinal numbers are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] It should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances. Furthermore, in the accompanying drawings, the thickness, proportions, and dimensions of the components have been exaggerated or reduced for the purpose of effectively describing the technical content.

[0039] Furthermore, unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will also be understood that terms, such as those defined in common dictionaries, shall be interpreted as having the same meaning as they have in the context of the relevant technology and the invention, and shall not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0040] Taking into account the measurements discussed and the errors associated with the measurement of a particular quantity (i.e., limitations of the measurement system), as used herein, “about” or “approximately” includes the stated value and means within an acceptable range of deviation from the particular value as determined by a person skilled in the art. For example, “about” may mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0041] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and examples, so as to better understand the solution of the present invention and its advantages in various aspects. However, the specific embodiments and examples described below are for illustrative purposes only and are not intended to limit the present invention.

[0042] This application provides a dispersion compensation unit, which includes at least a pair of first rotating stages, a pair of second rotating stages, at least a pair of first optical adjustment frames, a pair of second optical adjustment frames, at least a pair of chirped mirrors, and a pair of zero-degree total reflection mirrors.

[0043] In this configuration, the two first rotating stages in each pair are symmetrically arranged. Each first rotating stage supports a first optical adjustment frame. The two first optical adjustment frames in each pair are respectively mounted on the two first rotating stages, thereby adjusting the reflection angle of the chirped mirrors to the laser beam, and thus regulating the number of reflections of the laser beam between the chirped mirrors. The two chirped mirrors in each pair have the same dispersion and are respectively mounted on the two first optical adjustment frames. That is, the two chirped mirrors in each pair are also opposite each other. The number of first rotating stages is the same as the number of first optical adjustment frames and chirped mirrors. In this application, the number of first rotating stages, the number of first optical adjustment frames, and the number of chirped mirrors can all be two.

[0044] In this application, in addition to adjusting the rotation angle of the first rotary stage, the reflection angle of the chirped mirror to the laser beam can also be adjusted by adjusting the angle of the first optical adjustment frame. However, the aforementioned method of adjusting the reflection angle of the chirped mirror to the laser beam by simply adjusting the angle of the first rotary stage is simpler and therefore preferred.

[0045] Two second rotating stages are symmetrically arranged. The second rotating stages support the second optical adjustment frames, which are respectively mounted on the two second rotating stages to adjust the reflection angle of the zero-degree total internal reflection mirror. The two zero-degree total internal reflection mirrors are respectively mounted on the two second optical adjustment frames. That is, the two mounted zero-degree total internal reflection mirrors are also opposite each other. In this application, the number of second rotating stages, the number of second optical adjustment frames, and the number of zero-degree total internal reflection mirrors are all two.

[0046] In this application, the rotation angle of the first rotary stage, the rotation angle of the second rotary stage, and the angle of the second optical adjustment frame can be adjusted respectively, so that the number of reflections of a laser beam incident on a chirped mirror between the chirped mirrors can be adjusted, and the laser beam can return along the original path after being reflected by the chirped mirror and the zero-degree total reflection mirror.

[0047] Figure 1 The optical path of a pair of chirped mirrors and a pair of zero-degree total reflection mirrors is shown. Figure 1 In the process, the laser beam first enters the second chirped mirror M2, then is reflected to the first chirped mirror M1, and then reflected again to the first zero-degree total internal reflection mirror RM1. After being reflected by the first zero-degree total internal reflection mirror RM1, the laser beam returns along the original path, that is, it is reflected again to the first chirped mirror M1, then to the second chirped mirror M2, and then leaves the dispersion compensation unit from the second chirped mirror M2.

[0048] Figure 2 This illustrates an alternative optical approach using a pair of chirped mirrors and a pair of zero-degree total reflection mirrors. Figure 2 In this process, the laser beam first enters the second chirped mirror M2, then is reflected to the first chirped mirror M1, then reflected again to the second chirped mirror M2, and then reflected to the second zero-degree total internal reflection mirror RM2. After being reflected by the second zero-degree total internal reflection mirror RM2, the laser beam returns along the same path, that is, it is reflected again to the second chirped mirror M2, then reflected to the first chirped mirror M1, then reflected to the second chirped mirror M2, and then leaves the dispersion compensation unit from the second chirped mirror M2.

[0049] Figure 1 In the embodiment shown, the laser beam is reflected once between the first chirped mirror M1 and the second chirped mirror M2 before it is incident on the first zero-degree total reflection mirror RM1. Figure 2 In the illustrated embodiment, the laser beam undergoes two reflections between the first chirped mirror M1 and the second chirped mirror M2 before being incident on the second zero-degree total internal reflection mirror RM2. In this application, the number of reflections between the first and second chirped mirrors can be adjusted by changing the rotation angle of the first rotary table, thereby obtaining... Figure 1 The illustrated embodiments or Figure 2 The example shown.

[0050] This application fixes a pair of chirped mirrors with fixed dispersion on a rotating stage. By rotating the stage, the reflection angle of the chirped mirrors is adjusted, thereby adjusting the reflection angle of the laser beam between the chirped mirrors and achieving dispersion adjustment steps in integer multiples of a single chirped mirror. Simultaneously, a zero-degree total internal reflection mirror is provided at the light outlet. By adjusting the angle of the corresponding rotating stage and / or adjustment frame, the laser beam returns along its original path. This achieves step-by-step adjustment of the dispersion, which is also easily adjustable.

[0051] Optionally, in this application, the dispersion compensation unit further includes a control element. This element controls the rotation angle of the first rotary table, the rotation angle of the second rotary table, and the angle of the second optical adjustment frame.

[0052] Optionally, in this application, the dispersion compensation unit further includes a display. It is used to display the optical path length and / or dispersion of the laser beam, that is, the optical path length of the laser beam and the amount of dispersion being compensated throughout the dispersion compensation process.

[0053] Optionally, in this application, the display can be used to show the rotation angle of the first rotary stage, the rotation angle of the second rotary stage, and the angle of the second optical adjustment frame. The optical path of the laser beam can be calculated by the reflection angle of the chirped mirror used, or the optical path corresponding to different reflections can be directly looked up in a lookup table.

[0054] Of course, the monitor can display all of the above parameters at the same time, and you can set them as needed.

[0055] Each time the laser beam is reflected by the chirped mirror, a fixed amount of dispersion is generated. The specific amount of dispersion is determined by the different coatings, i.e., the different models of the chirped mirrors. Optionally, in this application, the dispersion of each chirped mirror is -35 fs. 2 or -50fs 2 Of course, the dispersion amount can also be other values; simply set it as needed.

[0056] Optionally, the chirped mirror is any one of a concave chirped mirror, a convex chirped mirror, and a planar chirped mirror. More preferably, it is a planar chirped mirror. Optionally, the zero-degree total internal reflection mirror is any one of a concave zero-degree total internal reflection mirror, a convex zero-degree total internal reflection mirror, and a planar zero-degree total internal reflection mirror. More preferably, it is a planar zero-degree total internal reflection mirror.

[0057] This application further provides an optical resonant cavity, including any of the dispersion compensation units described above. Due to the presence of the dispersion compensation unit, the dispersion within the optical resonant cavity can be adjusted stepwise and easily, thereby obtaining a laser beam with higher precision.

[0058] Figure 3 This application illustrates a method for dispersive compensation of a laser beam according to an embodiment of the present application, which includes the following steps S1 to S4.

[0059] S1: Determine the required dispersion compensation amount based on the laser beam to be compensated.

[0060] Here, the dispersion compensation amount is determined based on the laser beam to be compensated.

[0061] S2: Select at least one pair of chirped mirrors according to the dispersion compensation amount, and determine the number of reflections of the laser beam to be compensated between at least one pair of chirped mirrors.

[0062] For example, you can first select the number of chirped mirrors, such as two, and then select the dispersion of the chirped mirrors. Next, you can calculate the number of times the laser beam reflects between the chirped mirrors to achieve the required dispersion compensation. Then, you can adjust the reflection angle of the chirped mirrors to achieve the corresponding number of reflections.

[0063] As described above, each pair of chirped mirrors in at least one pair comprises two chirped mirrors arranged symmetrically. The reflection angle of the chirped mirrors can be adjusted by adjusting the rotational teaching of the first rotary stage.

[0064] S3: The laser beam to be compensated is incident onto one of at least one pair of chirped mirrors.

[0065] For example Figure 1 and Figure 2 In this case, the laser beam is incident on the second chirped mirror M2. Of course, it can also be incident on the first chirped mirror M1.

[0066] S4: Adjust the reflection angles of the other chirped mirrors in at least one pair of chirped mirrors and the reflection angle of the zero-degree total reflection mirror located on the light-emitting side of at least one pair of chirped mirrors, so that the laser beam to be compensated reflects the determined number of times between at least one pair of chirped mirrors, and returns from the original path after being reflected by the zero-degree total reflection mirror.

[0067] For example, such as Figure 1 and Figure 2 As shown, the laser beam is incident on the second chirped mirror M2. By adjusting the reflection angle of the laser beam by the first chirped mirror M1, the laser beam can be made to appear as shown. Figure 1 or Figure 2 The optical path shown.

[0068] The method provided in this application enables stepwise adjustment of the dispersion amount, which is easy to adjust, thereby obtaining a laser beam with higher accuracy.

[0069] Optionally, the method provided in this application may also include:

[0070] The optical path length of the compensated laser beam is determined based on the reflection angles of at least one pair of chirped mirrors; and

[0071] The vibration frequency of the compensated laser beam is determined based on the optical path length.

[0072] Calculating the vibration frequency facilitates the application of the compensated laser beam.

[0073] Obviously, the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A dispersion compensation unit, characterized in that, include: There is at least one pair of first rotating stages, and the two first rotating stages of each pair are symmetrically arranged. A pair of second rotary stages, the two second rotary stages are arranged symmetrically; At least one pair of first optical adjustment frames, with the two first optical adjustment frames of each pair respectively mounted on the two first rotating platforms; A pair of second optical adjustment frames, each of which is mounted on the pair of second rotary tables; At least one pair of chirped mirrors, wherein the two chirped mirrors in each pair have the same dispersion, and are respectively mounted on the two first optical adjustment frames; and A pair of zero-degree total reflection mirrors, each of which is mounted on the pair of second optical adjustment frames; The rotation angles of the at least one pair of first rotating stages, the rotation angles of the pair of second rotating stages, and the angles of the pair of second optical adjustment frames can be adjusted respectively, so that the number of reflections of a laser beam incident on one of the at least one pair of chirped mirrors can be adjusted between the at least one pair of chirped mirrors, and the laser beam can return along its original path after being reflected by the at least one pair of chirped mirrors and the pair of zero-degree total reflection mirrors.

2. The dispersion compensation unit according to claim 1, characterized in that, Also includes: A control element for controlling the rotation angle of the at least one pair of first rotary tables, the rotation angle of the pair of second rotary tables, and the angle of the pair of second optical adjustment frames.

3. The dispersion compensation unit according to claim 1, characterized in that, Also includes: A display for showing the optical path length and / or dispersion of the laser beam.

4. The dispersion compensation unit according to claim 1, characterized in that, Also includes: A display for showing the rotation angle of the at least one pair of first rotary stages, the rotation angle of the pair of second rotary stages, and the angle of the pair of second optical adjustment frames.

5. The dispersion compensation unit according to claim 1, characterized in that, The dispersion of each of the at least one pair of chirped mirrors is -35 fs. 2 or -50fs 2 .

6. The dispersion compensation unit according to claim 1, characterized in that, The at least one pair of chirped mirrors is any one of a concave chirped mirror, a convex chirped mirror, and a planar chirped mirror.

7. The dispersion compensation unit according to claim 1, characterized in that, The pair of zero-degree total reflection mirrors can be any one of a concave zero-degree total reflection mirror, a convex zero-degree total reflection mirror, or a planar zero-degree total reflection mirror.

8. An optical resonant cavity, characterized in that, Includes the dispersion compensation unit as described in any one of claims 1 to 7.

9. A method for performing dispersion compensation on a laser beam using the dispersion compensation unit described in any one of claims 1 to 7, characterized in that, include: Determine the required dispersion compensation amount based on the laser beam to be compensated; Based on the dispersion compensation amount, at least one pair of chirped mirrors is selected, and the number of reflections of the laser beam to be compensated between the at least one pair of chirped mirrors is determined; wherein each pair of chirped mirrors in the at least one pair of chirped mirrors includes two chirped mirrors arranged symmetrically. The laser beam to be compensated is incident on one of the at least one pair of chirped mirrors; as well as The reflection angles of the other chirped mirrors in the at least one pair of chirped mirrors and the reflection angle of the zero-degree total internal reflection mirror located on the light-emitting side of the at least one pair of chirped mirrors are adjusted so that the number of reflections of the laser beam to be compensated between the at least one pair of chirped mirrors reaches the determined number of reflections, and returns along the original path after being reflected by the zero-degree total internal reflection mirror.

10. The method according to claim 9, characterized in that, Also includes: The optical path length of the compensated laser beam is determined based on the reflection angle of the at least one pair of chirped mirrors; as well as The vibration frequency of the compensated laser beam is confirmed based on the optical path.

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