Femtosecond pulse laser filament control system

Abstract

The utility model discloses a femtosecond pulse laser filament control system, which comprises a laser transmitter, a power meter, a target chamber, a beam collector, a vacuum pump, an optical fiber probe and an optical fiber spectrometer, a reflecting mirror I and a diaphragm are arranged between the laser transmitter and the power meter; a convex lens I is arranged between the reflecting mirror II and the target chamber; one side of the target chamber is provided with a light hole, the light hole is opposite to the optical fiber probe, a convex lens II is arranged between the light hole and the optical fiber probe, the optical fiber probe is connected with an optical fiber spectrometer through an optical fiber, and the optical fiber spectrometer is used for being connected with an upper computer; wherein the vacuum pump is communicated with the interior of the target chamber. According to the utility model, the size of the laser beam can be adjusted, the length of the laser filament can be controllably adjusted, and the influence of different environments on the spectral signal-to-noise ratio can be obtained, so that a stable and reliable basis is provided for a subsequent controllable LIBS (Laser-induced Breakdown Spectroscopy) experiment.

Description

Technical Field

[0001] This utility model relates to the field of optical detection technology, and in particular to a femtosecond pulsed laser filament control system. Background Technology

[0002] Laser-induced breakdown spectroscopy (LIBS) technology has become one of the current detection methods for measuring trace elements and non-destructive testing. By focusing a femtosecond pulsed laser to achieve extremely high power density, it further bombards the target material (gas, liquid, solid) to reach the detection limit and perform qualitative and quantitative analysis of the target material.

[0003] Current LIBS technology measures the atomic and molecular breakdown spectra of target materials. The dynamic equilibrium between the Kerr self-focusing effect of ultra-intense, ultra-short pulsed lasers and the plasma defocusing effect generated by multiphoton ionization of molecules and atoms produces a laser filament. Ultra-intense, ultra-short femtosecond laser filaments offer advantages such as high power density, long detection distance, real-time operation, and high speed. However, in actual experimental operations, factors such as laser beam edge jitter can affect the boundary effects of the laser filament. Furthermore, the instability of the focused filament and the jitter at the beam edge also influence the spectrum. Currently, the filament length cannot be reliably and stably adjusted as needed, nor can experiments on the effects of different environments on the spectrum be performed, which also impacts subsequent LIBS experiments. Utility Model Content

[0004] In view of the above-mentioned shortcomings of the existing technology, the purpose of this utility model is to solve the technical problems existing in the prior art and provide a femtosecond pulsed laser filament control system that can adjust the size of the laser beam, controllably adjust the length of the laser filament, and obtain the influence of different environments on the spectral signal-to-noise ratio, thereby providing a stable and reliable foundation for subsequent controllable LIBS experiments.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a femtosecond pulsed laser filament control system, characterized in that it includes a laser emitter, a power meter, a target chamber, a beam collector, a vacuum pump, and an optical fiber probe and an optical fiber spectrometer;

[0006] The laser emitter's output port faces the power meter. A reflector I is placed between the laser emitter and the power meter to reflect the laser beam. An aperture is placed between the laser emitter and reflector I to adjust the size of the laser beam. The laser emitter also includes a reflector II, which reflects the laser beam onto the laser beam and directs it toward the target chamber. A convex lens I is placed between the reflector II and the target chamber, focusing the laser beam so that it enters the target chamber through the entrance port and exits through the exit port, where it is collected by a beam collector.

[0007] A light-transmitting hole is provided on one side of the target chamber, which is directly opposite the fiber optic probe. A convex lens II is provided between the light-transmitting hole and the fiber optic probe. The light beam emitted from the light-transmitting hole can be projected onto the fiber optic probe after passing through the convex lens II. The fiber optic probe is connected to a fiber optic spectrometer via an optical fiber. The fiber optic spectrometer is used to connect to a host computer to transmit the collected data to the host computer. The light-transmitting hole is sealed with a transparent material. The vacuum pump is connected to the inside of the target chamber and is used to regulate the air pressure inside the target chamber.

[0008] Furthermore, nitrogen gas is filled inside the target chamber.

[0009] Furthermore, both mirror I and mirror II are high-reflectivity mirrors or total-reflectivity mirrors.

[0010] Furthermore, the laser beam emitted by the laser emitter forms an angle with the plane of reflector I; the laser beam reflected by reflector I also forms an angle with the plane of reflector II.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] 1. By adjusting the beam diameter through the aperture, the jitter at the edge of the beam (spot) can be reduced, thereby improving the stability of the pulsed laser focusing filament and enabling the creation of spots of different sizes. This allows for control over the excitation of ionized molecules and the spectral intensity information, making LIBS spectral analysis experiments more stable and reliable.

[0013] 2. By controlling the gas pressure in the chamber, the LIBS breakdown spectroscopy experiment can be improved and adjusted, thereby effectively increasing the LIBS spectral resolution. Furthermore, experiments can be conducted to investigate the effect of different gas pressure densities on the spectral signal-to-noise ratio, providing a foundation for subsequent spectral analysis experiments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structural principle of this utility model.

[0015] In the diagram: 1—Laser emitter, 2—Power meter, 3—Target chamber, 4—Beam collector, 5—Vacuum pump, 6—Fiber optic probe, 7—Fiber optic spectrometer, 8—Mirror I, 9—Aperture, 10—Mirror II, 11—Convex lens I, 12—Convex lens II, 13—Host computer. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0018] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] Example: See Figure 1 A femtosecond pulsed laser filament control system includes a laser emitter 1, a power meter 2, a target chamber 3, a beam collector 4, a vacuum pump 5, an optical fiber probe 6, and an optical fiber spectrometer (ICCD) 7.

[0020] The laser emitter 1 has its output port directly opposite the power meter 2. A reflector I 8 is positioned between the laser emitter 1 and the power meter 2 to reflect the laser beam. The power meter 2 is used to measure the power of the beam passing through the reflector I 8. An aperture 9 is positioned between the laser emitter 1 and the reflector I 8 to adjust the size of the laser beam. A reflector II 10 is also included. After being reflected by the reflector I 8, the laser beam can be projected onto the reflector II 10, and the laser beam reflected by the reflector II 10 can be directed towards the target chamber 3. During implementation, both the reflector I 8 and the reflector II 10 are high-reflection or total-reflection mirrors, thereby increasing the reflection efficiency. Specifically, the laser beam emitted by the laser emitter 1 forms an angle with the plane of the reflector I 8; the laser beam reflected by the reflector I 8 also forms an angle with the plane of the reflector II 10, making the optical path more rational and facilitating the arrangement of various components.

[0021] A convex lens I11 is provided between the reflector II10 and the target chamber 3. After being focused by the convex lens I11, the laser beam can enter the target chamber 3 from the inlet and exit the target chamber 3 from the outlet, and be collected by the beam collector 4.

[0022] A light-transmitting hole is provided on one side of the target chamber 3, directly opposite the fiber optic probe 6. A convex lens II 12 is placed between the light-transmitting hole and the fiber optic probe 6. The light beam emitted from the light-transmitting hole passes through the convex lens II 12 and is then directed onto the fiber optic probe 6. The fiber optic probe 6 is connected to a fiber optic spectrometer 7 via an optical fiber. The fiber optic spectrometer 7 is used to connect to a host computer 13 to transmit the collected data. The host computer 13 is a computer, which makes operation more convenient. The light-transmitting hole is sealed with a transparent material. The vacuum pump 5 is connected to the inside of the target chamber 3 and is used to regulate the gas pressure inside the target chamber 3. The target chamber 3 is filled with nitrogen gas to focus the gaseous target material for high-power-density laser action, improving the stability of the laser focusing filament and allowing for control and adjustment as needed.

[0023] This scheme adjusts the beam diameter using aperture 9, reducing beam (spot) edge jitter and improving the stability of the pulsed laser focusing filament. It also allows for the creation of spots of varying sizes, enabling control over the excitation of ionized molecules and the spectral intensity information, thus making LIBS spectral analysis experiments more stable and reliable. By controlling the cavity gas pressure, the LIBS breakdown spectroscopy experiment can be further improved, effectively enhancing the LIBS spectral resolution. Furthermore, it allows for experiments on the effect of different gas pressure densities on the spectral signal-to-noise ratio, providing a foundation for subsequent spectral analysis experiments.

[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of this utility model that do not depart from the spirit and scope of this technical solution should be covered within the scope of the claims of this utility model.

Claims

1. A femtosecond pulsed laser filament control system, characterized in that: It includes a laser emitter, power meter, target chamber, beam collector, vacuum pump, fiber optic probe, and fiber optic spectrometer; The laser emitter's output port faces the power meter. A reflector I is placed between the laser emitter and the power meter to reflect the laser beam. An aperture is placed between the laser emitter and reflector I to adjust the size of the laser beam. The laser emitter also includes a reflector II, which reflects the laser beam onto the laser beam and directs it toward the target chamber. A convex lens I is placed between the reflector II and the target chamber, focusing the laser beam so that it enters the target chamber through the entrance port and exits through the exit port, where it is collected by a beam collector. A light-transmitting hole is provided on one side of the target chamber, which is directly opposite the fiber optic probe. A convex lens II is provided between the light-transmitting hole and the fiber optic probe. The light beam emitted from the light-transmitting hole can be projected onto the fiber optic probe after passing through the convex lens II. The fiber optic probe is connected to a fiber optic spectrometer via an optical fiber. The fiber optic spectrometer is used to connect to a host computer to transmit the collected data to the host computer. The light-transmitting hole is sealed with a transparent material. The vacuum pump is connected to the inside of the target chamber and is used to regulate the air pressure inside the target chamber.

2. The femtosecond pulsed laser filament control system according to claim 1, characterized in that: The target chamber is filled with nitrogen gas.

3. The femtosecond pulsed laser filament control system according to claim 1, characterized in that: Both mirror I and mirror II are high-reflectivity mirrors or total-reflectivity mirrors.

4. The femtosecond pulsed laser filament control system according to claim 1, characterized in that: The laser beam emitted by the laser emitter forms an angle with the plane of reflector I; the laser beam reflected by reflector I also forms an angle with the plane of reflector II.

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