Compact annular multi-pass laser amplification system

Abstract

The invention belongs to the technical field of lasers, and relates to a compact annular multi-pass laser amplification system which comprises a first polarizing film, a first amplifier, a 90-degree rotor, a second polarizing film, a first reflecting mirror, a second amplifier and a second reflecting mirror. The first amplifier amplifies the laser in the horizontal polarization state, the 90-degree rotor adjusts the laser in the horizontal polarization state into the laser in the vertical polarization state, the second polaroid reflects the laser in the vertical polarization state, the first reflector reflects the laser in the vertical polarization state reflected by the second polaroid again, and the second reflector reflects the laser in the vertical polarization state. The second amplifier amplifies the laser in the vertical polarization state reflected by the first reflector, and the second reflector reflects the amplified laser in the vertical polarization state to the first polaroid. And the amplification factor and the amplification efficiency of the whole system are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of lasers, and in particular relates to a compact annular multi-pass laser amplification system. Background Art

[0002] At present, when performing small signal traveling wave amplification on low energy laser, in order to improve the amplification factor of the laser, it is necessary to increase the number of laser amplifiers or increase the number of times the laser passes through the amplifier. In the prior art, when using two amplifiers for traveling wave amplification, the following two types of amplification systems are generally used: One amplification system is that the laser passes through the first laser amplifier, then passes through two 45° reflectors and then passes through the second laser amplifier. This type of amplification system is often limited by the laser small signal gain factor because the small energy laser passes through the two laser amplifiers at a time, resulting in the first laser amplifier still having a high residual energy storage. Obviously, the disadvantage of the above amplification system is that the overall amplification factor of the two laser amplifiers is low, and the energy storage is seriously wasted.

[0003] Another amplification system is to place a polarizer in front of the first laser amplifier, and at the same time place a quarter-wave plate and a 0° total reflection mirror behind the first laser amplifier, so that the low-energy laser passes through the first laser amplifier twice and then passes through the second laser amplifier once. That is, the laser first passes through the first laser amplifier after being polarized by the polarizer, and then passes through the quarter-wave plate and the 0° total reflection mirror. The polarization state is rotated 90 degrees and then reflected along the original path. The reflected laser beam passes through the first laser amplifier for a second time for secondary amplification. The secondary amplified laser is reflected by the polarizer and enters the second laser amplifier for a third amplification. This type of amplification system enables the low-energy laser to pass through the laser amplifier three times, and the amplification efficiency is higher than that of the first system. However, the problem with the above-mentioned amplification system is that when the injection energy of the laser amplifier is too high or the repetition rate is too high, the laser crystal is severely thermally depolarized, and the 0° total reflection mirror is easy to form a resonant cavity with other optical devices in the optical path, thereby generating parasitic oscillations, and the depolarized laser is easy to cause damage to other optical devices.

[0004] Therefore, there is an urgent need to propose a compact annular multi-pass laser amplification system to solve the technical problems of the existing laser amplification system or the two laser amplifiers included in the existing amplification system having a low overall amplification ratio and serious energy storage waste; or the amplification system having an injection energy or a repetition rate of the laser amplifier having a serious thermal depolarization of the laser crystal, the 0° total reflection mirror easily forming a resonant cavity with other optical devices in the optical path, thereby generating parasitic oscillations, and the depolarized laser easily causing damage to other optical devices. Summary of the invention

[0005] In view of the technical problems that the laser amplification system in the prior art has two laser amplifiers included in the amplification system with low overall amplification ratio and serious energy storage waste; or when the injection energy of the laser amplifier is too high or the repetition rate is too high, the laser crystal is seriously thermally depolarized, the 0° total reflection mirror easily forms a resonant cavity with other optical devices in the optical path, thereby generating parasitic oscillation, and the depolarized laser easily causes damage to other optical devices. Based on this, the present invention proposes a compact annular multi-pass laser amplification system to solve at least one of the above technical problems.

[0006] In a preferred embodiment of the present invention, a compact annular multi-pass laser amplification system is provided, the compact annular multi-pass laser amplification system comprising: A first polarizer, wherein the first polarizer adjusts the polarization direction of the incident laser to a horizontal polarization state; A first amplifier, which is disposed downstream of the first polarizer and amplifies the laser light in a horizontal polarization state; A 90° rotor, the 90° rotor being disposed downstream of the first amplifier, and the 90° rotor adjusting the laser light in a horizontal polarization state to the laser light in a vertical polarization state; A second polarizer, which is disposed downstream of the 90° rotor and reflects the vertically polarized laser light; A first reflector, wherein the first reflector is disposed downstream of the second polarizer, and the first reflector reflects the vertically polarized laser reflected by the second polarizer again; a second amplifier, the second amplifier being disposed downstream of the first reflector, and amplifying the vertically polarized laser reflected by the first reflector; a second reflector, the second reflector being arranged downstream of the second amplifier, the second reflector reflecting the amplified vertically polarized laser to the first polarizer, and the first polarizer reflecting the vertically polarized laser to the first amplifier for amplification; wherein, The vertically polarized laser light reflected by the first polarizer to the first amplifier for amplification is converted into a horizontally polarized laser light by the 90° rotor and outputted through the second polarizer.

[0007] Preferably, the laser is a low-energy laser.

[0008] Preferably, the first polarizer, the first amplifier, the 90° rotor, the second polarizer, the first reflector, the second amplifier, and the second reflector are arranged on an annular optical path.

[0009] Compared with the prior art, the present invention can bring at least one of the following beneficial effects: 1) A compact annular multi-pass laser amplification system of the present application achieves the technical effect of three-pass amplification by using two laser amplifiers, thereby improving the overall amplification ratio and amplification efficiency of the system; 2) The structural arrangement of the first amplifier, the 90° rotor, and the second amplifier in a compact annular multi-pass laser amplification system of the present application forms a multi-pass laser amplification system with a small volume and a compact structure; 3) In the compact annular multi-pass laser amplification system of the present application, a quarter-wave plate and a 0° total reflection mirror are not added, thereby avoiding damage to optical devices caused by depolarized lasers and weakening parasitic oscillations of the laser amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] 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-mentioned characteristics, technical features, advantages and their implementation methods.

[0011] Figure 1 It is a schematic diagram of a compact annular multi-pass laser amplification system according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0012] Various aspects of the present invention are described in further detail below.

[0013] Unless otherwise defined or indicated, all professional 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 method of the present invention.

[0014] Unless otherwise clearly specified and limited, the "or" mentioned in the present invention includes the relationship of "and". The "and" is equivalent to the Boolean logic operator "AND", the "or" is equivalent to the Boolean logic operator "OR", and "AND" is a subset of "OR".

[0015] It is to be understood that although the terms "first", "second", etc. may be used herein to describe different elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, the first element may be referred to as the second element without departing from the teachings of the present invention.

[0016] In the present invention, the terms "consisting mainly of" and "consisting of" are included in the terms "containing", "including" or "comprising".

[0017] Unless otherwise clearly specified and limited, the terms "connected", "connected" and "connection" in the present invention should be understood in a broad sense, for example, it can be a fixed connection, or it can be connected through an intermediary medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0018] 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 formed on, coupled to, or connected to the other element, or there may be one or more intervening elements between them. In contrast, if the expressions "directly on," "directly coupled to," and "directly connected to" are used herein, then no intervening elements are indicated. Other words used to describe the relationship between elements should be similarly interpreted, such as "between" and "directly between," "attached" and "directly attached," "adjacent" and "directly adjacent," etc.

[0019] It should also be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the drawings. The words "inner" and "outer" used refer to directions toward or away from the geometric center of a particular component, respectively. It can be understood that these terms are used here to describe the relationship of one element, layer or region relative to another element, layer or region as shown in the drawings. In addition to the orientations described in the drawings, these terms should also include other orientations of the device.

[0020] Other aspects of the present invention will be apparent to those skilled in the art in view of the disclosure herein.

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0022] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show the components related to the present application and are not drawn according to the number, shape and size of the components in actual implementation. The type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the component layout may also be more complicated. For example, the thickness of the components in the drawings may be exaggerated for the sake of clarity.

[0023] See attached Figure 1 In a preferred embodiment of the present invention, a compact annular multi-pass laser amplification system is provided, and the compact annular multi-pass laser amplification system comprises: A first polarizer 1, wherein the first polarizer 1 adjusts the polarization direction of the incident laser to a horizontal polarization state; A first amplifier 2, which is disposed downstream of the first polarizer and amplifies the laser light in a horizontal polarization state; A 90° rotor 3, wherein the 90° rotor 3 is disposed downstream of the first amplifier, and the 90° rotor adjusts the laser light in a horizontal polarization state to the laser light in a vertical polarization state; A second polarizer 4, which is disposed downstream of the 90° rotor and reflects the vertically polarized laser light; A first reflector 5, wherein the first reflector 5 is disposed downstream of the second polarizer, and the first reflector re-reflects the vertically polarized laser reflected by the second polarizer; A second amplifier 6, which is disposed downstream of the first reflector and amplifies the vertically polarized laser light reflected by the first reflector; A second reflector 7, wherein the second reflector 7 is disposed downstream of the second amplifier, and the second reflector 7 reflects the amplified vertically polarized laser light to the first polarizer, and the first polarizer reflects the vertically polarized laser light to the first amplifier for amplification; wherein, The vertically polarized laser light reflected by the first polarizer to the first amplifier for amplification is converted into a horizontally polarized laser light by the 90° rotor and outputted through the second polarizer.

[0024] It should be noted that the present application arranges a first amplifier 2 in the optical path of the compact annular multi-pass laser amplification system, wherein the first amplifier 2 is arranged downstream of the first polarizer and amplifies the horizontally polarized laser; and a second amplifier 6, wherein the second amplifier 6 is arranged downstream of the first reflector and amplifies the vertically polarized laser reflected by the first reflector. By using the first amplifier 2 and the second amplifier 6 as two laser amplifiers and cooperating with the annular optical path design, the technical effect of three-pass amplification of the laser amplification system is achieved, and the overall amplification factor and amplification efficiency of the system are greatly improved while simplifying the overall structure of the amplification system.

[0025] It should be noted that the upstream and downstream structural arrangement of the first amplifier 2, the 90° rotor 3, and the second amplifier 6 in a compact annular multi-pass laser amplification system of the present application forms a multi-pass laser amplification system with a small volume and compact structure. The 90° rotor 3 of the present application is a 90° polarization rotator, which can realize the rotation of the linear polarization direction. In this embodiment, the 90° polarization rotator is used to rotate the polarization direction of polarized light by 90° to realize the mutual switching of vertical polarization and horizontal polarization.

[0026] Preferably, the 90° rotor may be configured as a 90° quartz polarization rotator.

[0027] Alternatively, the 90° rotor may be replaced by a half wave plate.

[0028] As a preferred embodiment, the laser is a low-energy laser.

[0029] As a preferred embodiment, the first polarizer 1, the first amplifier 2, the 90° rotor 3, the second polarizer 4, the first reflector 5, the second amplifier 6, and the second reflector 7 are arranged on an annular optical path.

[0030] It should be noted that the compact annular multi-pass laser amplification system does not include the quarter-wave plate and the 0° total reflection mirror that are usually provided in the prior art, thereby avoiding damage to optical devices caused by depolarized lasers and weakening parasitic oscillations of the laser amplifier.

[0031] Based on this application, it should be understood by those skilled in the art that one 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, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0032] It should be noted that the above embodiments can be freely combined as needed. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention.

[0033] All documents mentioned in the present invention are cited as references in this application, just as each document is cited as reference separately. In addition, it should be understood that after reading the above content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A compact annular multi-pass laser amplification system, characterized in that: The laser amplification system comprises: A first polarizer, wherein the first polarizer adjusts the polarization direction of the incident laser to a horizontal polarization state; A first amplifier, which is disposed downstream of the first polarizer and amplifies the laser light in a horizontal polarization state; A 90° rotor, the 90° rotor being disposed downstream of the first amplifier, and the 90° rotor adjusting the laser light in a horizontal polarization state to the laser light in a vertical polarization state; A second polarizer, which is disposed downstream of the 90° rotor and reflects the vertically polarized laser light; A first reflector, wherein the first reflector is disposed downstream of the second polarizer, and the first reflector reflects the vertically polarized laser reflected by the second polarizer again; a second amplifier, the second amplifier being disposed downstream of the first reflector, and amplifying the vertically polarized laser reflected by the first reflector; a second reflector, the second reflector being arranged downstream of the second amplifier, the second reflector reflecting the amplified vertically polarized laser to the first polarizer, and the first polarizer reflecting the vertically polarized laser to the first amplifier for amplification; wherein, The vertically polarized laser light reflected by the first polarizer to the first amplifier for amplification is converted into a horizontally polarized laser light by the 90° rotor and outputted through the second polarizer.

2. A compact annular multi-pass laser amplification system according to claim 1, characterized in that: The laser is a low-energy laser.

3. A compact annular multi-pass laser amplification system according to claim 1, characterized in that: The first polarizer, the first amplifier, the 90° rotor, the second polarizer, the first reflector, the second amplifier, and the second reflector are arranged on an annular optical path.

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