Broadband laser polarization state regulation and control device based on Fresnel prism
By setting a half and quarter Fresnel rhombus prism in the laser optical path, and using its rotation to adjust the linear polarization direction and provide phase delay, the problem of height difference between the emitted light and incident light of the quarter Fresnel prism is solved, and the accurate regulation of the laser polarization state and the precise control of the laser position are achieved.
Patent Information
- Application Number
- CN202421519758.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-28
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-06-28
AI Technical Summary
There is a height difference between the emitted light and the incident light of the quarter Fresnel prism, which limits the precise regulation of the polarization state of the laser, especially in scenarios where precise control of the laser excitation position is required.
By introducing a half Fresnel rhombus prism and combining its rotation operation, the linear polarization direction of the incident laser light is adjusted, and then using a quarter Fresnel rhombus prism to provide phase delay, the regulation of the laser polarization state is achieved.
The problem of height difference between the emitted light and incident light of the one-quarter Fresnel prism is solved, and the laser polarization state is more convenient and accurate regulation is achieved, ensuring that the laser excites the sample at the same position, improving the reliability and accuracy of the experiment.
Smart Images
Figure CN222653189U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of laser polarization state regulation, in particular to a broadband laser polarization state regulation device based on a Fresnel prism. Background Art
[0002] Wave plates are optical elements used in the field of laser technology and applications to change the polarization state of lasers. The principle is that when light passes through a birefringent crystal, an additional phase difference is generated between ordinary light (o light) and extraordinary light (e light), thereby changing the polarization state of the light. However, since the phase difference between o light and e light is related to the wavelength of the incident laser, wave plates are usually divided into narrowband and broadband. Different wave plates are required to change the polarization state of lasers of different wavelengths.
[0003] Fresnel is a polarization element that can achieve wide-band polarization state regulation. It works like a broadband wave plate and can provide uniform λ / 4 or λ / 2 phase delay in a wide wavelength range, and the wavelength range is wider than that of a birefringent wave plate. It can replace the delay wave plate used in broadband or tunable laser light sources. The principle is to use the laser to cause a 45-degree reflection phase difference on the surface of the medium each time, thereby providing a λ / 4 phase delay. Since the phase difference is related to the slowly changing diamond prism dispersion, the delay change caused by wavelength is much smaller than that of other types of retarders. Therefore, the application range is wide and the price is relatively cheap. Common ones are quarter and half Fresnel prisms.
[0004] However, there is a certain height difference between the outgoing light and the incident light of the quarter Fresnel prism, which will limit practical applications. For example, in experiments, it is often necessary to obtain various polarization states such as linear polarization, left-handed elliptical polarization, left-handed circular polarization, right-handed elliptical polarization and right-handed circular polarization by rotating the quarter wave plate, and then study the influence of lasers with different polarization states on the photoelectric response of the material at the same sample excitation position. If the heights of the outgoing light and the incident light are inconsistent, when the quarter Fresnel wave plate is rotated around the incident light as the axis, the outgoing light will form a circle in space, and it cannot be guaranteed that the outgoing light excites the sample at the same position. Therefore, the height difference problem brings many inconveniences in practical applications, especially in scenarios where the laser excitation position needs to be precisely controlled.
[0005] In view of the above reasons, the utility model provides a broadband laser polarization state control device based on Fresnel prism, which is used to solve the problem of how to overcome the height difference between the output light and the incident light of a quarter Fresnel prism, so that in practical applications the polarization state of the laser can be controlled more conveniently and accurately, and the laser can be ensured to excite the sample at the same position. Utility Model Content
[0006] The purpose of the utility model is to provide a broadband laser polarization state control device based on a Fresnel prism, which solves the problem of height difference between the output light and the incident light of a quarter Fresnel prism, and can more conveniently and accurately control the polarization state of the laser in practical applications, and ensure that the laser excites the sample at the same position.
[0007] The utility model provides a broadband laser polarization state control device based on Fresnel prism, comprising: a half Fresnel rhombus prism and a quarter Fresnel rhombus prism which are sequentially arranged in an optical path, wherein the half Fresnel rhombus prism is rotatable, the half Fresnel rhombus prism is used to adjust the linear polarization direction of the incident laser, and the quarter Fresnel rhombus prism is used to provide phase delay, and the two cooperate to realize laser polarization state control.
[0008] Preferably, the quarter Fresnel rhombus prism has a rhombus shape, and the half Fresnel rhombus prism is formed by symmetrically connecting two quarter Fresnel rhombus prisms.
[0009] Preferably, the quarter Fresnel rhombus prism is arranged to be inclined relative to the vertical direction, and the half Fresnel rhombus prism is formed by connecting two quarter Fresnel rhombus prisms symmetrically about the vertical direction.
[0010] Preferably, the half Fresnel rhombus prism and the quarter Fresnel rhombus prism are respectively arranged on a first mounting base and a second mounting base.
[0011] Preferably, the first mounting base and the second mounting base are both glass clamps, and a receiving groove is provided inside the glass clamp.
[0012] Preferably, edges of the half Fresnel rhombus prism and the quarter Fresnel rhombus prism respectively abut against two sides of the accommodation grooves in the first mounting base and the second mounting base.
[0013] Preferably, the glass sandwich panel is formed by bonding at least four transparent glass plates.
[0014] Preferably, one side of the first mounting base and the second mounting base are fitted and embedded with the side surface of the threaded sleeve.
[0015] Preferably, one side of the first mounting base and the second mounting base are cooperatively connected with the side surface of the threaded sleeve via fasteners.
[0016] Preferably, the threaded sleeve is rotatable and drives the first mounting base or the second mounting base to rotate.
[0017] Compared with the prior art, the utility model has the following beneficial effects:
[0018] 1. The utility model can adjust the linear polarization of the incident laser by introducing a half Fresnel rhombus prism and combining its rotation operation, and then provide phase delay through a quarter Fresnel prism, successfully solving the height difference problem between the output light and the incident light of the quarter Fresnel prism, which makes the regulation of the laser polarization state more convenient and accurate, ensuring that the laser excites the sample at the same position, greatly improving the reliability and accuracy of the experiment;
[0019] 2. Since the Fresnel prism has a wide-band characteristic, the utility model is applicable to lasers of various wavelengths and has greater versatility and flexibility;
[0020] 3. The application of the utility model helps to improve production efficiency and quality. By accurately controlling the laser polarization state, the photoelectric response effect of the material can be optimized, thereby improving product quality and performance. In addition, since errors and repeated operations caused by height differences during the experiment are reduced, it also helps to reduce production costs and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0022] Figure 1 The optical principle diagram of the device of the utility model;
[0023] Figure 2 This is the principle diagram of the conversion relationship between the components of the electric vector in two coordinate expressions;
[0024] Figure 3 is a schematic diagram of the polarization state of linearly polarized light;
[0025] Figure 4 Schematic diagram of the change of polarization state when the Fresnel prism is rotated by half;
[0026] Figure 5 Schematic diagram of the change in polarization of the outgoing light from the quarter Fresnel prism after rotating the half Fresnel prism at different angles.
[0027] Description of reference numerals:
[0028] 1: half Fresnel rhombus prism; 2: quarter Fresnel rhombus prism; 3: first mounting base; 4: second mounting base; 5: threaded sleeve. DETAILED DESCRIPTION
[0029] The technical solution of the utility model will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.
[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0032] like Figure 1 As shown, the utility model provides a broadband laser polarization state control device based on Fresnel prism, comprising: a half Fresnel rhombus prism 1 and a quarter Fresnel rhombus prism 2 which are sequentially arranged in the optical path, wherein the half Fresnel rhombus prism 1 is rotatable, the half Fresnel rhombus prism 1 is used to adjust the linear polarization direction of the incident laser, and the quarter Fresnel rhombus prism 2 is used to provide phase delay, and the cooperation between the two can realize the laser polarization state control.
[0033] The outer contour of the quarter Fresnel rhombus 2 is rhombus-shaped, and the half Fresnel rhombus 1 is formed by symmetrically connecting two quarter Fresnel rhombus prisms 2. The quarter Fresnel rhombus 2 is arranged tilted relative to the vertical direction, and the half Fresnel rhombus 1 is formed by symmetrically connecting two quarter Fresnel rhombus prisms 2 about the vertical direction.
[0034] Specifically, the half Fresnel rhombus prism 1 and the quarter Fresnel rhombus prism 2 are respectively arranged on the first mounting base 3 and the second mounting base 4. In this embodiment, the first mounting base 3 and the second mounting base 4 are both glass sandwich panels, which are formed by bonding at least four transparent glass plates, and the glass sandwich panels are provided with a receiving groove inside. The edges of the half Fresnel rhombus prism 1 and the quarter Fresnel rhombus prism 2 are respectively in conflict with the two sides of the receiving groove in the first mounting base 3 and the second mounting base 4.
[0035] In this embodiment, one side of the first mounting base 3 and the second mounting base 4 are both embedded in the side of the threaded sleeve 5 or fixedly connected by fasteners such as screws. When the optical path is installed, the threaded sleeve 5 can rotate in cooperation with accessories such as studs, and drive the first mounting base 3 or the second mounting base 4 to rotate.
[0036] The utility model device is assembled and the laser polarization state is regulated according to the following steps:
[0037] Step 1: Arrange the quarter Fresnel rhombus 2 after the half Fresnel rhombus 1 in the optical path;
[0038] Step 2: The laser is incident on the half Fresnel rhombus prism 1;
[0039] Step 3: Change the linear polarization direction of the laser by rotating the half Fresnel rhombus prism 1;
[0040] Step 4: The laser passes through a quarter Fresnel rhombus prism 2 to produce the required phase delay, thereby achieving regulation of the laser polarization state; observe and adjust the laser polarization state to the required state to meet the needs of experiments or production.
[0041] The following is a detailed description of the principle of laser polarization state regulation by this device:
[0042] like Figure 2 As shown, for the polarization state of the outgoing light after a beam of polarized light passes through a Fresnel prism, first, it is necessary to identify the coordinate axis of the incident linear polarized light and the definition of the fast axis and slow axis of the Fresnel prism (whether it is a half Fresnel prism or a quarter Fresnel prism). The role of the wave plate is to introduce a phase difference between the fast axis and the slow axis. The polarization state of the outgoing light is determined by the vector synthesis of these two axes.
[0043] The components of the electric vector E1 on the original coordinate axis (xoy) and the new coordinate axis (x`0y`) can be expressed using the matrix and The transformation relationship between these two matrices can be expressed as Figure 2 The analysis shows that E1 can be expressed as:
[0044]
[0045]
[0046] Next consider the phase difference between the fast and slow axes:
[0047]
[0048] Finally, by calculating the projection of the fast and slow axis components on the original coordinate axis (xoy), the polarization state of the outgoing light can be obtained:
[0049]
[0050] In summary, for linearly polarized light after an arbitrary wave plate, its Jones matrix can be expressed in the form of continuous matrix multiplication:
[0051]
[0052] E in is the Jones matrix of the incident light, R(θ) is the projection matrix of the two-dimensional rectangular coordinate system or the rotation matrix of the rectangular coordinate system rotating around the origin by an angle θ, and the phase difference δ corresponding to the half and quarter Fresnel prisms 1 / 2 =Π、 Substitute into the matrix and calculate E out .
[0053] According to the structure designed in this patent, a beam of linearly polarized light first passes through a half Fresnel prism, and after rotating the half Fresnel prism, its outgoing light is then incident on a quarter Fresnel prism. The change in its polarization state can be expressed by the following formula:
[0054] The incident polarized light is expressed as:
[0055]
[0056] After passing through a half Fresnel prism, its polarization state is:
[0057]
[0058] It then enters a quarter Fresnel prism, which further changes its polarization state:
[0059]
[0060] To simulate the above theoretical process, we use MATLAB to perform simulation according to the following steps:
[0061] First, define a beam of linearly polarized light along the x-axis, whose Jones matrix can be expressed as Its polarization state in three-dimensional space is Figure 3 As shown;
[0062] Then, simulate the light beam passing through a half Fresnel prism rotated at different angles, and record the change in its polarization state after the light passes through the half Fresnel prism, such as Figure 4 As shown. The polarization state does not change after passing through the half Fresnel prism, and it is still linearly polarized light;
[0063] Next, the light emitted from the half Fresnel prism is used as the incident light to simulate its process of passing through the quarter Fresnel prism, and the polarization state of the light after passing through the quarter Fresnel prism is recorded, such as Figure 5 By rotating the half Fresnel prism, the polarization state of the light emitted from the quarter Fresnel prism can be controlled.
[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.
Claims
1. A broadband laser polarization state control device based on Fresnel prism, characterized in that: include: A half Fresnel rhombus prism and a quarter Fresnel rhombus prism are sequentially arranged in the optical path, wherein the half Fresnel rhombus prism is rotatable, the half Fresnel rhombus prism is used to adjust the linear polarization direction of the incident laser, and the quarter Fresnel rhombus prism is used to provide phase delay, and the cooperation of the two can realize the laser polarization state regulation.
2. The broadband laser polarization state control device based on Fresnel prism according to claim 1, characterized in that: The quarter Fresnel rhombus prism has a rhombus shape, and the half Fresnel rhombus prism is formed by symmetrically connecting two quarter Fresnel rhombus prisms.
3. The broadband laser polarization state control device based on Fresnel prism according to claim 1, characterized in that: The quarter Fresnel rhombus prism is arranged tilted relative to the vertical direction, and the half Fresnel rhombus prism is formed by connecting two quarter Fresnel rhombus prisms symmetrically about the vertical direction.
4. The broadband laser polarization state control device based on Fresnel prism according to claim 1, characterized in that: The half Fresnel rhombus prism and the quarter Fresnel rhombus prism are respectively arranged on the first mounting base and the second mounting base.
5. The broadband laser polarization state control device based on Fresnel prism according to claim 4, characterized in that: The first mounting base and the second mounting base are both glass clamps, and a receiving groove is arranged inside the glass clamp.
6. The broadband laser polarization state control device based on Fresnel prism according to claim 5, characterized in that: The edges of the half Fresnel rhombus prism and the quarter Fresnel rhombus prism respectively conflict with the two sides of the accommodation grooves in the first mounting base and the second mounting base.
7. The broadband laser polarization state control device based on Fresnel prism according to claim 5, characterized in that: The glass sandwich panel is formed by bonding at least four transparent glass plates.
8. The broadband laser polarization state control device based on Fresnel prism according to claim 4, characterized in that: One side of the first mounting base and the second mounting base is fitted and embedded with the side surface of the threaded sleeve.
9. The broadband laser polarization state control device based on Fresnel prism according to claim 4, characterized in that: One side of the first mounting base and the second mounting base is connected to the side surface of the threaded sleeve through a fastener.
10. The broadband laser polarization state control device based on Fresnel prism according to claim 8 or 9, characterized in that: The threaded sleeve is rotatable and drives the first mounting base or the second mounting base to rotate.