Dye cell for dye laser, dye laser and dye circulation control method thereof

Abstract

The application discloses a dye cell for a dye laser, the dye laser and a dye circulation control method thereof, and belongs to the technical field of pulsed lasers. The dye cell for the dye laser is matched with an energy accumulator and an ultra-high-speed electromagnetic drive valve to realize high-speed release of dye with large flow, and can promote timely updating of the dye in the dye cell. The reduced diameter position in the dye cell can extrude air bubbles and further accelerate the flow of the dye, thereby avoiding the problem that air bubbles generated by high-speed flow of the dye can affect the pumping effect. The application is based on coupling of a string pulse solid laser and a dye laser, starts the string pulse solid laser output as a pumping source to output 10 kHz repetition frequency and 10 ms macro pulse width of pumping laser, simultaneously triggers the energy accumulator and the ultra-high-speed electromagnetic drive valve, pumps the dye into the dye cell at a flow of 10-15 L / s, can realize complete replacement of the dye in the dye cell within 10 ms, and completes local dye updating in each 100 microsecond pulse interval, thereby completely avoiding laser bleaching.

Description

Technical Field

[0001] This invention relates to the field of pulsed laser technology, and in particular to a dye pool for a dye laser, a dye laser, and a dye circulation control method thereof. Background Technology

[0002] (I) Terminology Explanation A burst-mode laser is a laser that outputs a series of high-repetition-frequency pulse sequences within a short period of time (e.g., milliseconds), with pulse repetition frequencies reaching the kHz level.

[0003] Dye laser: A laser that uses dye molecules as the gain medium and is excited by a pump source to produce stimulated emission, enabling wide-range wavelength tuning.

[0004] Pumping is the process of using external energy (such as lasers or electrical excitation) to excite particles in a gain medium (such as dye molecules) from their ground state to a higher energy level, thus providing the energy basis for laser generation.

[0005] Laser bleaching is a phenomenon in which dye molecules, under the action of a high-repetition-frequency pump laser, rapidly absorb energy to reach saturation, resulting in damage to their molecular structure or temporary / permanent loss of their luminescence ability.

[0006] (ii) Relevant existing technologies and their technical problems Traditional wavelength tuning techniques convert high-energy 1-micron wavelength laser light into other wavelengths to obtain continuously variable tunable laser light. Commonly used techniques include dye lasers or optical parametric oscillators (OPOs). Dye laser technology is mature and reliable. It uses the output energy of a solid-state laser to pump dye molecules such as Rhodamine 6G. After the dye molecules are excited, they emit light with a longer wavelength. Using this as a light source, the desired wavelength is selected through an optical cavity and grating to generate tunable laser output.

[0007] The core component of existing dye lasers is the dye cell. The dye cell is made of quartz glass, with a cross-sectional dimension of approximately 5 mm to match the solid-state laser output, and a length of approximately 10-20 mm to match the laser energy. Its hydrodynamic system mainly uses a liquid pump to circulate the dye within the dye cell.

[0008] However, the hydrodynamic system design of this traditional dye laser is limited to relatively low laser frequencies and energies, only compatible with low-frequency 10Hz lasers, and incompatible with high-repetition-rate pump lasers. When using high-repetition-rate pump lasers, laser bleaching occurs. For example, when the pump laser repetition frequency is 10kHz and the laser pulse interval is 100 microseconds, the hydrodynamic system of the traditional dye laser cannot keep up with the time required to refresh the dye in the dye bath. The unrefreshed dye absorbs energy to saturation and easily boils, resulting in a significant reduction in output spot uniformity, energy, and stability, and a drastically shortened dye lifetime. This necessitates more frequent dye replacements, leading to dye waste and increased dye costs.

[0009] Therefore, this invention proposes a novel dye cell and dye laser for dye lasers, enabling dye sensors to be matched with high repetition frequency pump lasers and to perform high flow rate dye circulation, thereby solving the problems of laser bleaching, drastic shortening of dye lifetime, and significant reduction in output spot uniformity, energy and stability of traditional dye lasers. Summary of the Invention

[0010] The purpose of this invention is to provide a novel dye pool for dye lasers, a dye laser, and a dye circulation control method thereof, which can achieve high-flow dye circulation, completely avoid laser bleaching, and maintain stable output even under 10kHz high repetition frequency pump laser, thereby solving the problems existing in the prior art.

[0011] To achieve the above objectives, the present invention provides the following solution: On one hand, the present invention provides a dye pool for a dye laser, including a dye pool body and a dye channel formed inside the dye pool body, wherein the two ends of the dye channel respectively penetrate the two ends of the dye pool body, and the cross-sectional area of ​​the dye channel gradually decreases from the two ends of the channel to the middle of the channel.

[0012] In some embodiments, the point where the cross-sectional area of ​​the dye channel is minimized is located at the 1 / 2 mark along the length of the dye channel, and the dye channel expands uniformly and symmetrically from the point where the cross-sectional area is minimized towards both ends of the dye channel.

[0013] In some embodiments, the cross-sectional shape of any part of the dye channel is circular, elliptical, or polygonal.

[0014] In some embodiments, the dye pool body is transparent from all four sides, and an observation window is also provided on the dye pool body.

[0015] In some embodiments, the dye bath body is provided with an input high-pressure sealing connector and an output high-pressure sealing connector at both ends.

[0016] On the other hand, the present invention proposes a dye laser, comprising a high repetition rate pump source, an accumulator, and a dye cell for a dye laser as described in any one of the above. The high repetition rate pump source is used to provide high repetition rate pump energy to the dye. The accumulator is sealed to the input end of the dye cell, and the output end of the dye cell is sealed to a dye container. The dye container is connected to the accumulator. An ultra-high speed electromagnetic drive valve is provided on the connection path between the dye cell and the dye container.

[0017] In some embodiments, the high repetition rate pump source is a pulsed solid-state laser configured with a repetition rate of 10 kHz, a macropulse width of 10 ms, and a pulse interval of 100 microseconds.

[0018] In some embodiments, the dye laser further includes a gas drive system for driving the accumulator, the gas drive system being capable of driving the accumulator to output dye at an instantaneous flow rate of 10 L / s-15 L / s; The response time of the ultra-high-speed electromagnetically driven valve is ≤50 microseconds.

[0019] In some embodiments, the dye laser further includes an optical cavity and grating frequency selection component, which is capable of selecting the desired wavelength from the broadband light of the pump excitation and generating tunable laser output.

[0020] This invention also proposes a dye circulation control method based on the above-mentioned dye laser, comprising: The high repetition rate pump source outputs a pump laser with a repetition rate of 10 kHz and a macro pulse width of 10 ms. Simultaneously, the accumulator and the ultra-high-speed electromagnetic drive valve are triggered, and the accumulator pumps the dye into the dye pool at an instantaneous flow rate of 10L / s-15L / s, achieving complete replacement of the dye in the dye pool within 10ms, and completing local dye renewal within each 100-microsecond pulse interval.

[0021] The present invention achieves the following technical effects compared to the prior art: The dye pool for dye lasers proposed in this invention features a streamlined, tapered dye channel design. This design eliminates dye bubbles at the narrowed section in the middle of the channel, accelerates the dye fluid flow rate, and promotes dye circulation within the dye pool. This dye pool not only possesses pressure resistance and high flow rate tolerance but also exhibits high sealing performance and high flow rate capability, making it suitable for high-flow-rate dye circulation and high-pressure operating conditions.

[0022] The dye laser proposed in this invention includes a high-repetition-rate pump source, a high-pressure gas-driven accumulator, an ultra-high-speed electromagnetically driven valve, and the aforementioned dye pool. The cooperation between the accumulator and the ultra-high-speed electromagnetically driven valve enables high-flow-rate, high-speed dye release, promoting timely dye renewal within the dye pool. The narrowing section within the dye pool effectively expels air bubbles and further accelerates dye flow, contributing to shorter dye renewal times and preventing the high-speed flow of dye from generating air bubbles, which could negatively impact the pumping effect. After releasing dye, the accumulator needs to be refilled; the back-and-forth release of the medium by the accumulator achieves dye circulation and replacement within the dye pool.

[0023] In addition, the accumulator, dye pool, and dye container are connected in sequence to form a dye circulation path. Based on the synergistic cooperation of the accumulator, ultra-high-speed electromagnetic drive valve, and dye pool diameter reduction design, high-flow dye circulation in the dye laser is achieved, and stable output can still be maintained under 10kHz high repetition frequency pump laser.

[0024] This invention is based on the coupling of a pulsed solid-state laser and a dye laser. The pulsed solid-state laser, acting as the pump source, outputs a pump laser with a repetition frequency of 10 kHz and a macro-pulse width of 10 ms. Simultaneously, it triggers an accumulator and an ultra-high-speed electromagnetically driven valve. The plunger of the accumulator moves under the action of high-pressure gas, pumping dye into the dye bath at a flow rate of 10 L / s-15 L / s. This achieves complete dye replacement within the dye bath within 10 ms (adapting to the macro-pulse width), and local dye renewal is completed within each 100 microsecond pulse interval, completely avoiding laser bleaching. This invention maintains stable output even at a high repetition frequency of 10 kHz, with a spot uniformity error ≤5% and energy fluctuation ≤3%.

[0025] This invention can directly replace existing OPO pulsed lasers and is suitable for high-end applications such as fluid imaging, engine combustion diagnostics, and high-precision industrial testing. The technology is mature, reliable, and highly applicable. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the overall structure of the dye pool disclosed in an embodiment of the present invention; Figure 2 This is a front view of the dye pool disclosed in an embodiment of the present invention; Figure 3This is a side view of the dye pool disclosed in an embodiment of the present invention; Figure 4 This is a top view of the dye pool disclosed in an embodiment of the present invention; Figure 5 This is a schematic diagram of a dye laser disclosed in an embodiment of the present invention; Figure 6 This is a schematic diagram of the optical path disclosed in an embodiment of the present invention.

[0028] In the figure, the attached reference numerals are: 1. Dye tank; 11. Dye tank body; 12. Dye channel; 13. Reduction point; 14. Inlet flange; 15. Outlet flange; 16. Observation window; 2. Accumulator; 3. Gas-driven system; 4. Dye container; 5. Ultra-high speed electromagnetic drive valve. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] One objective of this invention is to provide a novel dye cell for dye lasers, which not only eliminates air bubbles in the dye fluid and accelerates its circulation, but also enables high-flow-rate dye circulation in dye lasers, completely avoiding laser bleaching and maintaining stable output even under 10kHz high-repetition-rate pump lasers, thus solving the problems existing in the prior art. Another objective of this invention is to provide a novel dye laser that can achieve high-flow dye circulation, completely avoid laser bleaching, and maintain stable output even under 10kHz high-repetition-rate pump laser, thereby solving the problems existing in the prior art.

[0031] Another objective of this invention is to provide a dye circulation control method based on the above-mentioned dye laser, which can achieve high-flow dye circulation, completely avoid laser bleaching, and ensure that the dye laser can maintain stable output under a 10kHz high repetition frequency pump laser, thereby solving the problems existing in the prior art.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1 This embodiment proposes a novel dye cell 1 for dye lasers, specifically a highly sealed, high-flow-rate dye cell. For example... Figure 1 As shown, a dye channel 12 is formed inside the dye pool body 11, with both ends of the dye channel 12 penetrating both ends of the dye pool body 11. The cross-sectional area of ​​the dye channel 12 gradually decreases from both ends to the middle, forming a narrow-diameter channel design with a large cross-sectional area at both ends and a small cross-sectional area in the middle. This narrow-diameter channel can utilize the sudden decrease in cross-sectional area to compress the dye fluid, preventing the formation of bubbles in the dye fluid at high speeds, thus allowing the laser to effectively hit the dye fluid. At the same time, the local narrowing can pressurize the dye fluid, causing it to flow out at high speed, promoting timely and rapid renewal of the dye fluid in the dye pool. If the dye channel 12 adopts a constant cross-section design, bubbles will easily form when the dye fluid flow rate is small, affecting the laser operation.

[0034] It should be noted that the aforementioned "middle of the channel" does not refer only to the midpoint of the entire length direction of the dye channel 12 (i.e., the flow direction of the fluid in the channel), but can cover multiple positions located between the two ends of the dye channel 12. For example, the "middle of the channel" can be defined at the 1 / 2, 1 / 3, or 1 / 4 dividing point of the entire length direction of the dye channel 12.

[0035] In some feasible implementations, in order to ensure the narrowing effect of the dye channel 12 and the flow stability of the dye fluid after passing through the narrowing position 13, it is preferable that the "middle of the channel" is the midpoint of the length direction of the dye channel 12. That is, the narrowing position 13 with the smallest cross-sectional area in the entire dye channel 12 is located at the 1 / 2 dividing point of the length direction of the dye channel 12. Then, the narrowing position 13 expands the diameter uniformly and symmetrically to both ends of the dye channel 12, so that the cross-sectional area of ​​the channel gradually increases from the middle to both ends, and the two ends of the entire dye channel 12 form a symmetrical funnel shape.

[0036] The shape of any cross-section of the dye channel 12 is identical, and the outlines of cross-sections at different locations are similar to each other. In practical applications, the cross-sectional shape of the dye channel 12 includes, but is not limited to, circles, ellipses, or regular polygons. Regular polygons include, but are not limited to, triangles, rectangles, and pentagons. In this embodiment, the cross-sectional shape of the dye channel 12 is preferably rectangular, and the aforementioned definition of "diameter reduction" still applies to rectangular cross-sections. The entire wall of the dye channel 12 adopts a streamlined curved surface with a smooth transition to ensure smooth connection between different cross-sections and avoid uneven wall surfaces that could affect fluid performance.

[0037] In some feasible implementations, the shape of the dye pool body 11 may be the same as or different from the cross-sectional shape of the dye channel 12. For example... Figure 1As shown, the dye pool body 11 in this embodiment is a cuboid, and the dye channel 12 is opened at the center of its length direction.

[0038] In some feasible implementations, the dye bath body 11 is also equipped with an observation window 16. One end of the observation window 16 is inserted into the side wall of the dye bath body 11, and the other end is located on the outside of the dye bath body 11. The design of the observation window 16 is mainly to facilitate the connection between the dye bath and the output end of the optical cavity and the grating frequency selection component, so that the pulsed solid-state laser (1064nm) of the pump source enters the dye bath through the optical cavity, the grating frequency selection component, and the observation window 16, and fully strikes the fluid in the dye bath. The observation window 16 is preferably located at the minimum cross-section of the dye channel 12 to achieve optimal coupling between the fluid and the pump source, further improving the pumping effect. The dye bath body 11 can be configured as follows: Figure 1 As shown, an observation window 16 is set on only one side. In practical applications, observation windows 16 can also be set on multiple sides of the dye bath body 11 as needed.

[0039] In some feasible implementations, the dye bath body 11 is made entirely of a light-transmitting material, allowing light to pass through from all four sides. This ensures that the pump light and output light are unobstructed, while also facilitating observation of the fluid state within the dye bath. Suitable light-transmitting materials include, but are not limited to, quartz glass.

[0040] In some feasible implementations, the minimum cross-sectional (rectangular) size of the dye channel 12 is 20mm × 5mm, the maximum cross-sectional (rectangular) size is 50mm × 30mm, and the channel length is 150mm. The above cross-sectional size design can ensure the high flow rate characteristics of the dye channel 12 and adapt to high flow rate dye circulation conditions.

[0041] In some feasible implementations, an input end connecting flange 14 and an output end connecting flange 15 are respectively configured at both ends of the dye bath body 11 along its length. Input end high-pressure sealing joints and output end high-pressure sealing joints are respectively connected to the input end connecting flange 14 and the output end connecting flange 15 to facilitate sealed installation of the dye bath with other components, ensuring fluid tightness during dye bath use. Both the input end high-pressure sealing joint and the output end high-pressure sealing joint can be sealing joints with a pressure resistance of ≥2MPa, suitable for high-pressure operating conditions.

[0042] In this embodiment, the dye tank features a streamlined constriction section design for the dye channel 12. This constriction point 13 eliminates dye bubbles, accelerates the dye flow rate, and promotes dye circulation within the tank. This dye tank not only possesses pressure resistance and high flow rate tolerance but also high sealing performance and high flow rate capability, making it suitable for high-flow-rate dye circulation and high-pressure operating conditions.

[0043] Example 2 This embodiment provides a novel dye laser, comprising a high repetition rate pump source, a dye cell 1 as described in Embodiment 1, an energy storage device 2, a gas driving system 3, and an optical cavity and grating frequency selection assembly; each assembly is connected to the circuit via pipelines (withstanding pressure ≥2MPa). Specifically: the high repetition rate pump source provides high repetition rate pump energy to the dye; the energy storage device 2 is sealed to the input end of the dye cell 1 via a high-pressure sealing connector; the output end of the dye cell 1 is connected to the dye container 4 via a high-pressure sealing connector; the dye container 4 and the energy storage device 2 form a closed loop to create a circulation path for the dye within the dye cell 1. The optical cavity and grating frequency selection assembly is part of the optical path of the laser, and its main function is to generate light that strikes the observation window 16 of the dye cell 1; the high repetition rate pump source is generally located on the side of the dye laser resonator in the optical cavity and grating frequency selection assembly, and the pump light is incident on the dye medium within the dye cell 1 perpendicular to the optical axis of the dye laser resonator.

[0044] In some feasible implementations, the high repetition rate pump source is preferably a pulsed solid-state laser configured with a repetition rate of 10 kHz and a macro pulse width of 10 ms.

[0045] In some feasible implementations, the dye pool 1 is a highly sealed, high-flow-rate dye pool, and it also possesses four-sided light transmission and pressure and high-flow-rate resistance characteristics. The dye channel 12 adopts a streamlined constriction section design, which accelerates the dye flow and facilitates the discharge of dye bubbles, ensuring that the laser effectively hits the dye fluid.

[0046] In the dye laser of this embodiment, one dye pool 1 can be provided, or two or more can be provided in parallel. For example... Figure 5 As shown, three dye pools 1 are connected in parallel, and the high-pressure sealing connectors at the input ends of the three dye pools 1 are all connected in series with the accumulator 2, and the high-pressure sealing connectors at the output ends of the three dye pools 1 are all connected in series with the dye container 4.

[0047] Some feasible implementation methods, such as Figure 5 As shown, a high-frequency pressure sensor and an ultra-high-speed electromagnetically driven valve 5 are sequentially installed along the dye flow direction on the series pipeline between dye tank 1 and dye container 4. This valve is preferably a pneumatic solenoid valve with a response time ≤ 50 microseconds. The high-frequency pressure sensor is installed to monitor the pressure in the dye discharge path (discharge from dye tank 1) in real time. A safety valve is generally installed on dye container 4.

[0048] Accumulator 2 refers to a pump structure that uses a plunger to reciprocate within a cylinder to achieve fluid intake and exhaust, generating high-pressure, high-flow-rate fluid output. In this embodiment, accumulator 2 is connected to a gas drive system 3, and is driven by high-pressure gas with a driving pressure ≥2MPa from the gas drive system 3. By controlling the high-speed reciprocating motion of the plunger in the accumulator 2 through the gas pressure control of the gas drive system 3, an instantaneous high flow rate of 10L / s-15L / s can be achieved. Because the capacity of the accumulator 2 itself is large enough, the introduction of the ultra-high-speed electromagnetic drive valve 5 with rapid response can enable the dye in the accumulator 2 to be released quickly under high pressure, generating a large flow rate within 10ms, displacing the original dye in the dye pool 1, and prompting the dye in the dye pool 1 to be renewed in a timely manner. The cooperation between the accumulator 2 and the ultra-high-speed electromagnetic drive valve 5 ensures the dye renewal flow rate and speed in the dye pool. It is precisely matched with the 100 microsecond pulse interval and 10ms macro pulse width of the 10kHz serial pulse laser of the pump source, which can ensure that the pump laser hits the renewed dye every time. This solves the problem that the dye cannot be discharged quickly due to the valve opening and closing delay, which makes it impossible for the laser to hit the dye in a timely and accurate manner.

[0049] In some feasible implementations, the gas-driven system 3 may employ Figure 5 The illustrated pneumatic path structure includes, in sequence, a high-pressure gas source, a pressure reducing valve, a high-pressure ball valve, a pressure control needle valve, and a pressure sensor, which is connected to the accumulator 2. The pressure sensor in the gas drive system 3 is used to monitor the pressure in the high-pressure pneumatic path in real time, facilitating risk assessment.

[0050] Some feasible implementation methods, such as Figure 5 As shown, along the series pipeline connecting the accumulator 2 and the dye container 4, a ball valve, a needle valve, a check valve, a gear pump, a pressure sensor, and another ball valve are sequentially installed in the dye flow direction. The pressure sensor is installed along this path to monitor the pressure in the dye circulation path in real time.

[0051] The combination of accumulator 2 and ultra-high-speed electromagnetic drive valve 5 enables high-flow-rate, high-speed dye release, promoting timely dye renewal in dye tank 1. The constriction point 13 within dye tank 1 promptly expels air bubbles and further accelerates dye flow, aiding in shortening dye renewal time and preventing the generation of air bubbles during high-speed dye flow, which could negatively impact pumping efficiency if the laser strikes the bubbles. After releasing dye, accumulator 2 needs to be refilled; the back-and-forth release of the medium by accumulator 2 achieves dye circulation and replacement within dye tank 1.

[0052] In practical applications, the dye used can be Rhodamine 6G dye molecules. The pulsed solid-state laser (1064nm) used as the pump source is reflected by the mirror of the optical cavity and grating frequency selection component, and then introduced into the dye cell 1 through the observation window 16. The broadband light after excitation enters the dye laser resonant cavity of the optical cavity and grating frequency selection component for resonance amplification. After frequency selection by the grating (resolution ≥1nm) of the optical cavity and grating frequency selection component, a pulsed laser with a tunable wavelength of 350-700nm is output, with a single pulse energy ≥500mJ and a pulse repetition frequency of 10kHz within the macropulse.

[0053] This invention achieves precise matching between dye renewal and a 10kHz high repetition rate and a 10ms macropulse width by coupling a pulsed solid-state laser with a dye laser. The specific working principle and usage process are as follows: Preparation phase: High-pressure gas (2MPa) is injected into accumulator 2 through gas drive system 3, and dye is injected into dye pool 1 through pipeline to expel air from inside dye pool 1 and ensure system sealing.

[0054] Start-up phase: The pulsed solid-state laser, which serves as the pump source, is activated, outputting a pump laser with a repetition frequency of 10kHz and a macro pulse width of 10ms. Simultaneously, the accumulator 2 and the ultra-high-speed electromagnetic drive valve 5 are triggered. The plunger of the accumulator 2 moves under the action of high-pressure gas, pumping the dye into the dye pool 1 at a flow rate of 10L / s-15L / s, achieving complete replacement of the dye in the dye pool 1 within 10ms (adapting to the macro pulse width). Furthermore, local dye renewal is completed within each 100-microsecond pulse interval, which can completely avoid laser bleaching.

[0055] Laser output stage: The pump laser excites the dye molecules to generate broadband light, which is amplified by the dye laser resonant cavity and then output as laser of the target wavelength through the grating frequency selection; after the macro pulse ends, the ultra-high speed electromagnetic drive valve 5 is closed, the dye stops high-speed circulation and enters low-speed heat preservation circulation state.

[0056] Optical cavity and grating frequency selection components are conventional structures in this field, and their optical path design is also existing technology, so details will not be elaborated further. The optical path principle involved in the above-described operation of the optical cavity and grating frequency selection components is as follows: like Figure 6 As shown, M1, M2, and M3 are all high-reflectivity mirrors. The combination of M1, M2, and M3 forms a "three-mirror folded cavity" to constrain the laser to oscillate back and forth within the cavity and amplify it.

[0057] BS1 is a beam splitter, a low-reflectivity beam splitting element whose function is to couple pump light into the resonant cavity (or split a portion of the laser light from the cavity for monitoring).

[0058] S1 and S2 are aperture stops (Slits) used to limit the modes of the laser within the cavity, filter out low-order modes, and improve the beam quality of the laser.

[0059] WO3 and WA3 are transparent optical windows, usually Brewster's angle windows (to reduce reflection loss), used to isolate the internal and external environments of the cavity. WO3 is the observation window 16 of dye cell 1.

[0060] FO3 / FA3 are focusing lenses used to focus pump light onto the dye medium (FO3) or to focus / collimate the laser beam (FA3).

[0061] Optical path principle: Figure 6 The image shows a folded cavity dye laser, the core of which is the "pump-oscillation-amplification" process: 1. Pump light injection: The “Lasergaizei” on the right is the pump source Nd:YAG frequency-doubled laser. The pump light generated is collimated by the FA3 lens, transmitted through the WA3 window, focused by the FO3 lens, and then coupled into the dye laser resonant cavity by the BS1 beam splitter. Finally, it acts on the dye medium in WO3 (i.e., in dye pool 1) to excite the dye molecules to achieve population inversion (providing gain for the laser).

[0062] 2. Resonant cavity oscillation: The spontaneous emission light generated by the dye is reflected back and forth in the folded cavity formed by M1, M2, and M3, and is amplified each time it passes through the dye medium; S1 and S2 filter out light of a specific mode, which eventually forms a stable laser oscillation.

[0063] 3. Laser output: One of the reflectors, M1, serves as the output coupling mirror (partially transparent), allowing the amplified laser to be extracted from the cavity; alternatively, a portion of the light may be split off through BS1 as the output.

[0064] The typical operating frequency of the pulsed laser is 10kHz, with a pulse interval of 100 microseconds and a total duration of 10 milliseconds. Verification has shown that the dye laser in this embodiment, using 2MPa high-pressure gas to drive the accumulator 2, pumps dye into the dye pool 1 at a flow rate of 10L / s-15L / s. Combined with the cross-sectional design of the dye pool 1, the dye fluid within the pool can be replaced within 10 milliseconds at 100-microsecond intervals. This achieves precise matching between the high-flow-rate dye pool and the frequency and macro-pulse width of the pulsed laser, solving the core problem of traditional dye lasers' difficulty in generating high-repetition-rate (10kHz and above), high-energy, and tunable-wavelength pulsed laser output. Simultaneously, it overcomes the problems of bleaching, poor output stability, and short dye lifetime that traditional dye lasers easily exhibit under high-repetition-rate pumping.

[0065] The dye channel 12 of the high-sealing dye pool adopts a streamlined contraction section structure design, which is transparent on all four sides and pressure resistant ≥2MPa, and is suitable for large flow of dye.

[0066] The design of the instantaneous high-pressure high-flow accumulator 2 (including the gas drive mode and the parameter setting of 10L / s-15L / s flow rate), the ultra-high-speed electromagnetic drive valve 5 (response time ≤50 microseconds), and the structure design of the dye pool 1 are based on the collaborative control logic to replace the dye in the dye pool 1, which can ensure that the dye is completely replaced within 10 millisecond macro pulses and that the dye is partially updated within 100 microsecond pulse intervals.

[0067] The dye laser of this invention completely avoids laser bleaching through high-flow dye circulation, and can still maintain stable output at a high repetition frequency of 10kHz, with a spot uniformity error of ≤5% and energy fluctuation of ≤3%.

[0068] Performance advantages: Wide wavelength adjustable range (350-700nm), single pulse energy ≥500mJ, strong robustness, adaptable to complex working conditions; dye lifespan is extended by more than 3 times, reducing replacement frequency and usage costs.

[0069] Application advantages: This invention can directly replace existing OPO pulsed lasers and is suitable for high-end scenarios such as fluid imaging, engine combustion diagnosis, and high-precision industrial testing. The technology is mature, reliable, and highly applicable.

[0070] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings of this specification are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the content disclosed herein. They are not intended to limit the conditions under which the invention can be implemented and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms used in this specification, such as "upper," "lower," "left," "right," "middle," and "one," are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0071] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A dye cell for a dye laser, characterized in that, It includes a dye pool body and a dye channel opened inside the dye pool body. The dye channel passes through both ends of the dye pool body, and the cross-sectional area of ​​the dye channel gradually decreases from both ends of the channel to the middle of the channel.

2. The dye cell for a dye laser according to claim 1, characterized in that, In the dye channel, the point where the channel cross-sectional area is smallest is located at the 1 / 2 dividing point along the length of the dye channel, and the dye channel expands uniformly and symmetrically from the point where the channel narrows towards both ends.

3. The dye cell for a dye laser according to claim 1 or 2, characterized in that, The cross-sectional shape of any part of the dye channel is circular, elliptical, or polygonal.

4. The dye cell for a dye laser according to claim 1 or 2, characterized in that, The dye pool body is transparent on all four sides, and an observation window is also provided on the dye pool body.

5. The dye cell for a dye laser according to claim 1 or 2, characterized in that, The dye bath body is equipped with an input high-pressure sealing connector and an output high-pressure sealing connector at both ends.

6. A dye laser, characterized in that, The device includes a high repetition rate pump source, an accumulator, and a dye cell for a dye laser as described in any one of claims 1-5. The high repetition rate pump source is used to provide high repetition rate pump energy to the dye. The accumulator is sealed to the input end of the dye cell, and the output end of the dye cell is sealed to the dye container. The dye container is connected to the accumulator. An ultra-high speed electromagnetic drive valve is provided on the connection path between the dye cell and the dye container.

7. The dye laser according to claim 6, characterized in that, The high repetition rate pump source is a pulsed solid-state laser, configured with a repetition rate of 10 kHz, a macro pulse width of 10 ms, and a pulse interval of 100 microseconds.

8. The dye laser according to claim 7, characterized in that, It also includes a gas drive system for driving the accumulator, the gas drive system being able to drive the accumulator to output dye at an instantaneous flow rate of 10L / s-15L / s; The response time of the ultra-high-speed electromagnetically driven valve is ≤50 microseconds.

9. The dye laser according to any one of claims 6-8, characterized in that, It also includes an optical cavity and grating frequency selection component, which can select the desired wavelength from the broadband light of the pump excitation and generate tunable laser output.

10. A dye circulation control method based on the dye laser according to any one of claims 6-9, characterized in that, include: The high repetition rate pump source outputs a pump laser with a repetition rate of 10 kHz and a macro pulse width of 10 ms. Simultaneously, the accumulator and the ultra-high-speed electromagnetic drive valve are triggered, and the accumulator pumps the dye into the dye pool at an instantaneous flow rate of 10L / s-15L / s, achieving complete replacement of the dye in the dye pool within 10ms, and completing local dye renewal within each 100-microsecond pulse interval.

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