A high power liquid quantum dot laser amplifier

Abstract

This invention discloses a high-power liquid quantum dot laser amplifier. After the pump beam enters the amplifier, it is split into optical path I and optical path II. Optical path I and optical path II then simultaneously reach a second liquid quantum dot laser medium. Optical path I, along the incident direction of the pump beam, sequentially comprises: a beam splitter, a cylindrical mirror, a first liquid quantum dot laser medium, a reflective blazed grating, a tunable total reflection mirror, an output coupling mirror, a total reflection mirror, an aperture, a collimating lens, and a second liquid quantum dot laser medium. Optical path II, along the incident direction of the pump beam, sequentially comprises: a beam splitter, two mirror-mounted right-angle prisms, a collimating lens, a focusing lens, and a second liquid quantum dot laser medium. The method provided by this invention is stable and universal, achieving stable high-power tunable liquid quantum dot laser output, effectively overcoming the shortcomings of existing organic dye molecular lasers, such as easy deactivation of the gain medium and low operational stability at high power.

Description

Technical Field

[0001] This invention belongs to the field of liquid laser equipment technology, specifically relating to a high-power liquid quantum dot laser amplifier. Background Technology

[0002] Solution-based optical amplification effectively avoids a series of problems encountered when exciting solid-state thin-film gain media, such as heat accumulation under high-power operation, scattering caused by particle agglomeration, non-radiative losses due to Foster resonance energy transfer, environmental influences on the performance of solid-state gain media, and the impact of film morphology on laser performance. Since the 1960s, research on solution lasers has primarily used organic dye molecules as gain media, employing simple two-mirror systems or ring fibers as resonant cavities. It is important to note that irreversible photobleaching occurs when the organic dye molecule solution is static, requiring a complex pumping system to maintain constant flow of the dye solution. Furthermore, under continuous photoexcitation, organic dye molecules gradually undergo photodecomposition, which is detrimental to stable high-power laser output. Colloidal semiconductor quantum dots possess high light absorption coefficients, photoluminescence quantum yields, and tunable band gaps, theoretically making them well-suited to replace organic dye molecules as the next generation of liquid quantum dot laser media. However, current research on colloidal quantum dot lasers is mostly limited to solid-state lasers, with only a few reports on liquid quantum dot lasers, and even these have only achieved preliminary laser emission, with output power and system stability far from meeting the requirements of practical applications. Therefore, developing a liquid quantum dot laser amplifier with high average power and high beam quality is of great significance to the application and development of liquid lasers. Summary of the Invention

[0003] The purpose of this invention is to provide a high-power liquid quantum dot laser amplifier that can effectively solve the problems existing in the background art.

[0004] To address the shortcomings of existing technologies, this invention provides a high-power liquid quantum dot laser amplifier that employs a grazing incidence grating operation mode to tune the output wavelength of the liquid quantum dot laser and a dual-sided transverse pumping method to amplify the injected laser. After entering the laser amplifier, the pump beam is split into optical path I and optical path II. Optical path I and optical path II, after separating, simultaneously reach the second liquid quantum dot laser medium 10. Optical path I, along the pump beam incident direction, sequentially comprises: a beam splitter 1, a cylindrical mirror 2, a first liquid quantum dot laser medium 3, a reflective blazed grating 4, a tunable total reflection mirror 5, an output coupling mirror 6, a total reflection mirror 11, an aperture 7, a collimating lens 8, and the second liquid quantum dot laser medium 10. Optical path II, along the pump beam incident direction, sequentially comprises: a beam splitter 1, two mirror-mounted right-angle prisms 9, a collimating lens 12, a focusing lens 13, and the second liquid quantum dot laser medium 10.

[0005] The pump beam is maintained at a fixed horizontal height and propagates within the laser. The injected laser is spatially shaped by the focusing lens 13 and focused into a thin line in the lateral direction of the laser amplifier to provide high-energy excitation light. The first liquid quantum dot laser medium 3 is made of quartz material (pulsed laser damage threshold is 20 MW / cm²). 2 (Approximately), controlling the peak intensity of the pump light pulse at 20 MW / cm². 2 under.

[0006] The resonant cavity, composed of a first liquid quantum dot laser medium 3, a reflective blazed grating 4, a tunable total reflection mirror 5, and an output coupling mirror 6, has a cavity length of 15 cm. The reflective blazed grating 4 has a specification of 1200 lines / mm, a blaze wavelength of 500 nm, and a width of 50 mm. The tunable total reflection mirror 5 is a gold-coated broadband reflector. The output coupling mirror 6 has high reflectivity (reflectivity R > 95%) for the output wavelength of the liquid quantum dot laser and enhances the transmission of the pump beam (transmittance T > 95%).

[0007] The output wavelength range of the liquid quantum dot laser is tuned by using a grazing incidence reflective blazed grating 4. The laser diffracts twice in the grazing incidence grating to improve resolution. The wavelength is tuned by fixing the grazing incidence angle and rotating the total reflection mirror 5.

[0008] A high-power liquid quantum dot laser amplifier is realized using a master resonance-power amplification method. It mainly consists of a resonant cavity and an amplifier. Considering the trigger delay and pulse width variation of the output laser pulse, the time matching between the liquid quantum dot laser pulse and the pump laser pulse is achieved by adjusting the optical path. The laser pulse waveform is numerically quantized by acquiring signals, and the peak point of the laser pulse is used as the measurement point for delay measurement. Only wave packets near the peak are selected for binomial fitting to estimate the delay time. The strong first-order diffracted light returns to the resonant cavity after feedback through a total reflection mirror and continues to oscillate. The quantum dot laser propagating along the axial direction is finally output along the 0th-order direction of the grating diffraction. A second liquid quantum dot laser medium 10 is injected and propagates in a direction perpendicular to the pump beam. The pump beam provides the energy for the quantum dot to transition from the ground state to the excited state. The first excited state undergoes stimulated emission transition under the excitation of the injected laser, realizing the amplification effect of the injected laser.

[0009] As a further optimization: the first liquid quantum dot laser medium 3 and the second liquid quantum dot laser medium 10 are colloidal quantum dot suspensions with high dispersibility and high stability, and the quantum dot concentration is not less than 100 μmol / L.

[0010] As a further optimization scheme: taking a pump laser pulse energy of 25 mJ as an example, the width of the liquid quantum dot gain medium cell is set at about 3.6 mm.

[0011] As a further optimization, the liquid quantum dot gain medium cells are placed non-horizontally at positions 3 and 10.

[0012] As a further optimization: the distance between the liquid quantum dot laser medium and the center of the grating. d ≈ (say 2 ) / min ,in oh denoted as the beam waist radius of the pump light in the liquid quantum dot laser medium.

[0013] Beneficial effects: The method provided by this invention is stable and universal, and realizes stable high-power tunable liquid quantum dot laser output, effectively making up for the shortcomings of the gain medium of organic dye molecular lasers being prone to deactivation and having low working stability at high power. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0015] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0016] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0017] See Figure 1 This specific embodiment is implemented using the following technical solution: after the pump beam enters the laser, it is split into two optical paths and simultaneously arrives at the second liquid quantum dot laser medium 10; for optical path I, the following are arranged sequentially along the incident direction of the pump beam: beam splitter 1, cylindrical mirror 2, first liquid quantum dot laser medium 3, reflective blazed grating 4, tunable total reflection mirror 5, output coupling mirror 6, total reflection mirror, aperture 7, collimating lens 8, and second liquid quantum dot laser medium 10; for optical path II, the following are arranged sequentially along the incident direction of the pump beam: beam splitter 1, two mirror-set right-angle prisms 9, collimating lens 12, focusing lens 13, and second liquid quantum dot laser medium 10.

[0018] The working process of the device of the present invention is as follows: The pump beam enters the system horizontally and is first split into two optical paths (optical path I and optical path II) by the beam splitter 1. For optical path I: the pump beam is transformed into transverse stripes by the cylindrical mirror 2 to excite the first liquid quantum dot laser medium 3. Due to the waveguide effect, the spontaneous emission light is amplified and emitted from one end of the liquid quantum dot pool and enters the reflective blazed grating 4 at a fixed angle. The first-order diffracted light oscillates after being oscillated by the tunable total reflection mirror 5 and returns to the resonant cavity to continue oscillating. Then, it is axially output to the output coupling mirror 6 along the 0th order diffraction direction of the grating. After being reflected by the total reflection mirror to the aperture 7, the spatially shaped injected liquid quantum dot laser is collimated by the collimating lens 8 to reach the second liquid quantum dot laser medium 10. For optical path II: the pump beam transmitted through two right-angle prisms is collimated by the collimating lens and then spatially shaped into stripes by the cylindrical mirror. It arrives at the second liquid quantum dot laser medium 10 at the same time as the injected liquid quantum dot laser. Here, the injected liquid quantum dot laser beam and the pump beam propagate in a direction that intersects perpendicularly. The pump light intensity provides the energy for the quantum dot to transition from the ground state to the excited state. The first excited state undergoes stimulated emission transition under the excitation of the injected liquid quantum dot laser, thus realizing the amplification effect of the injected laser.

[0019] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-power liquid quantum dot laser amplifier, characterized in that: After the pump beam enters the laser amplifier, it is split into optical path I and optical path II. After optical path I and optical path II separate, they simultaneously arrive at the second liquid quantum dot laser medium (10). Optical path I is provided with the following components in sequence along the incident direction of the pump beam: beam splitter (1), cylindrical mirror (2), first liquid quantum dot laser medium (3), reflective blazed grating (4), tunable total reflection mirror (5), output coupling mirror (6), total reflection mirror (11), aperture (7), collimating lens (8), and second liquid quantum dot laser medium (10). Optical path II is provided with the following components in sequence along the incident direction of the pump beam: beam splitter (1), two mirror-set right-angle prisms (9), collimating lens (12), focusing lens (13), and second liquid quantum dot laser medium (10). After the pump light enters the laser, it is split into two beams. By adjusting the optical path, the two beams arrive at the second liquid quantum dot laser medium (10) at the same time. Here, the injected laser beam is amplified and propagates in a direction perpendicular to the pump beam, thus realizing the amplification of the injected laser.

2. The high-power liquid quantum dot laser amplifier according to claim 1, characterized in that: The first liquid quantum dot laser medium (3) and the second liquid quantum dot laser medium (10) are colloidal quantum dot suspensions with high dispersibility and high stability.

3. A high-power liquid quantum dot laser amplifier according to claim 1 or 2, characterized in that: The first liquid quantum dot laser medium (3) and the second liquid quantum dot laser medium (10) are placed in a non-horizontal quartz cuvette.

4. A high-power liquid quantum dot laser amplifier according to claim 1, characterized in that: The resonant cavity is composed of a first liquid quantum dot laser medium (3), a reflective blazed grating (4), a tunable total reflection mirror (5), and an output coupling mirror (6), with a cavity length of 15 cm.

5. A high-power liquid quantum dot laser amplifier according to claim 1 or 4, characterized in that: The reflective blazed grating (4) has a specification of 1200 lines / mm, a blaze wavelength of 500 nm, and a width of 50 mm.

6. A high-power liquid quantum dot laser amplifier according to claim 4, characterized in that: The tunable total reflection mirror (5) is a gold-coated broadband reflector.

7. A high-power liquid quantum dot laser amplifier according to claim 4, characterized in that: The output coupling mirror (6) is highly reflective to the output wavelength of the liquid quantum dot laser with a reflectivity R > 95%, and enhances the transmission of the pump light with a transmittance T > 95%.

8. A high-power liquid quantum dot laser amplifier according to claim 4, characterized in that: The grating operates in a grazing incidence mode to tune the liquid quantum dot laser. The grazing incidence angle is fixed, and the angle of the tunable total reflection mirror (5) is adjusted to achieve tunable output of the liquid quantum dot laser.

9. A high-power liquid quantum dot laser amplifier according to claim 4, characterized in that: The distance of the first liquid quantum dot laser medium (3) from the center of the grating d ≈ (πω 2 ) / λ ,in ω denoted as the beam waist radius of the pump light in the liquid quantum dot laser medium.

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