193nm wavelength vacuum ultraviolet all-solid-state pulsed laser

Abstract

The application discloses a 193nm wavelength vacuum ultraviolet all-solid-state pulse laser and belongs to the technical field of lasers. A 355nm laser pulse is obtained by tripling a 1064nm fundamental frequency pulse laser, the 355nm laser pulse is used as pumping light of an optical parametric oscillator, 472nm signal laser output is obtained, and 236nm deep ultraviolet laser pulses are obtained by frequency doubling. The 236nm deep ultraviolet pulses are combined with the 1064nm fundamental frequency laser pulses after time delay to generate frequency sum, and finally, 193nm vacuum ultraviolet laser pulse output is obtained. The application has the characteristics of compact structure, high peak power and scalable repetition frequency, and the obtained 193nm vacuum ultraviolet laser can be used as an important tool in the research fields of precision laser processing, fiber grating preparation, semiconductor integrated circuit manufacturing and the like.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, specifically relating to a 193nm wavelength vacuum ultraviolet all-solid-state pulsed laser. Background Technology

[0002] Short-wavelength ultraviolet light with wavelengths in the range of 100–200 nm is also known as vacuum ultraviolet light. The 193 nm vacuum ultraviolet laser is a significant laser source in this band, playing a crucial role in precision laser processing, high-resolution spectroscopy, fiber grating fabrication, and semiconductor integrated circuit manufacturing. The 193 nm vacuum ultraviolet laser can be generated through two methods: argon fluoride (ArF) excimer lasers and solid-state lasers. ArF excimer gas lasers are currently the most mature and the only source capable of directly generating 193 nm vacuum ultraviolet lasers. However, gas lasers suffer from drawbacks such as large size, high cost, limited output laser repetition frequency, poor beam quality, and the generation of gases harmful to humans and the environment during operation.

[0003] All-solid-state lasers have advantages such as compact structure, good beam quality, high peak power, tunable wavelength, and scalable repetition rate, and can become a new trend in the development of 193nm vacuum ultraviolet light sources. As a supplement and extension of excimer lasers, they can expand and enrich the applications of 193nm vacuum ultraviolet laser sources.

[0004] Patent CN 101202405A describes a method for obtaining 192nm ultraviolet laser by frequency-harmonic generation of a 1342nm Nd:YVO4 laser. However, the generation of 1342nm laser requires suppression of stimulated emission of the laser gain crystal in the 1064nm band. Nd:YVO4 has a large stimulated emission cross-section at 1064nm, easily generating stimulated spontaneous emission at 1064nm, making it difficult to obtain high-energy, high-peak-power 1342nm laser. Consequently, the 192nm ultraviolet laser generated by its 7th frequency harmonic generation also has very low power, failing to meet practical application requirements. Paper 103151694A describes a method for generating 193nm ultraviolet laser using a 579nm solid-state laser through frequency doubling and summing. The 579nm solid-state laser used in this method is a Raman-shifted yellow laser. Stimulated Raman scattering is inelastic scattering; during scattering, some energy is stored as heat in the Raman crystal, and the absorption of pump light by the Raman crystal also generates heat. This heat leads to self-focusing and thermally induced birefringence in the Raman crystal, causing instability in the output Raman laser's power and pointing. When generating 193nm laser using frequency doubling and summing, phase mismatch occurs, and efficiency is low. This invention uses a 1064nm pulsed laser as the fundamental frequency source. Compared to the above sources, the 1064nm laser and its third-harmonic generation technology are mature and offer higher conversion efficiency, better beam quality, and stability, which is beneficial for improving the efficiency of subsequent nonlinear conversion processes and enhances the overall practicality of the device. Summary of the Invention

[0005] To overcome the shortcomings of current vacuum ultraviolet excimer lasers and all-solid-state laser technologies, this invention provides a novel 193nm vacuum ultraviolet all-solid-state laser scheme, which has advantages such as compact structure, high peak power, and scalable repetition frequency.

[0006] The technical solution of the present invention is as follows:

[0007] A 193nm wavelength vacuum ultraviolet all-solid-state pulsed laser comprises three parts: a 1064nm fundamental frequency pulse and its third harmonic laser generation device, an optical parametric oscillator and its frequency doubling device, and a sum-frequency device.

[0008] The 1064nm fundamental frequency pulse and its third harmonic laser generating device includes a 1064nm fundamental frequency pulse laser, and a first half-wave plate, a first frequency doubling crystal, a first sum-frequency crystal, a first beam splitter, and a second beam splitter arranged sequentially along the output beam direction of the 1064nm fundamental frequency pulse laser. The 1064nm infrared laser pulse emitted by the 1064nm fundamental frequency pulsed laser passes through the first half-wave plate and then through the first frequency doubling crystal to generate a 532nm green laser pulse. The 1064nm infrared laser pulse and the 532nm green laser pulse then pass through the first sum-frequency crystal to generate a 355nm ultraviolet laser pulse. The 1064nm infrared laser pulse, the 532nm green laser pulse, and the 355nm ultraviolet laser pulse all pass through the first beam splitter. The 355nm ultraviolet laser pulse is reflected by the first beam splitter and then enters the optical parametric oscillator and frequency doubling device. The 532nm green laser pulse is transmitted through the first beam splitter and then reflected by the second beam splitter. The 1064nm infrared laser pulse is transmitted through the first and second beam splitters and then enters the sum-frequency device.

[0009] The optical parametric oscillation and frequency doubling device includes a first reflecting mirror, a second half-wave plate, a first cavity mirror, a first parametric crystal, a second parametric crystal, a second cavity mirror, a third beam splitter, a second frequency doubling crystal, a fourth beam splitter, and a second reflecting mirror. The 355nm ultraviolet laser pulse, after being reflected by the first mirror and then passing through the second half-wave plate, serves as the pump light for the optical parametric oscillation (OPO) process. It then passes through the first cavity mirror and enters the first and second parametric crystals, where the OPO process generates a 1427nm idler light and a 472nm blue laser pulse as a signal light. The 472nm blue laser pulse and the 355nm ultraviolet laser pulse pass through the second cavity mirror. The 355nm ultraviolet laser pulse is reflected by the third beam splitter. The 472nm blue laser pulse, after being transmitted through the third beam splitter, serves as the fundamental frequency light and enters the second frequency doubling crystal, where it is frequency-doubled to generate a 236nm deep ultraviolet laser pulse. The 472nm blue laser pulse is reflected by the fourth beam splitter. The 236nm deep ultraviolet laser pulse, after being transmitted through the fourth beam splitter and then reflected by the second mirror, enters the summing and frequency conversion device.

[0010] The frequency-splitting device includes a delay unit, a beam combiner, a second frequency-splitting crystal, and a beam splitter. The 1064nm infrared laser pulse, after passing through the delay unit, and the 236nm deep ultraviolet laser pulse, pass through the beam combiner and enter the second frequency-splitting crystal to generate a 193nm vacuum ultraviolet laser pulse. The 193nm vacuum ultraviolet laser pulse, the 236nm deep ultraviolet laser pulse, and the 1064nm infrared laser pulse are then split into three beams by the beam splitter, thereby obtaining the 193nm vacuum ultraviolet laser pulse output.

[0011] Compared with existing technologies, the present invention has the following advantages:

[0012] 1. Using a mature 1064nm laser as the fundamental frequency light for nonlinear frequency conversion ensures good stability and guarantees phase matching in subsequent wavelength conversion processes. The 1064nm laser can output high-energy, high-peak-power fundamental frequency light pulses, guaranteeing the power density required for nonlinear conversion and obtaining high-efficiency 193nm deep ultraviolet laser, making it highly practical.

[0013] 2. The device has a compact overall structure, which is conducive to miniaturization and easy maintenance;

[0014] 3. Employing all-solid-state laser technology, the output 193nm wavelength beam has good quality and coherence. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the 193nm wavelength vacuum ultraviolet all-solid-state pulsed laser of the present invention.

[0016] In the diagram: A - 1064nm fundamental frequency pulse and its third frequency harmonic laser generation device; B - optical parametric oscillator and frequency doubling device; C - sum frequency device; 1 - 1064nm fundamental frequency pulse laser; 2 - first half-wave plate; 3 - first frequency doubling crystal; 4 - first sum frequency crystal; 5 - first beam splitter; 6 - second beam splitter; 7 - first reflector; 8 - second half-wave plate; 9 - first cavity mirror; 10 - first parametric crystal; 11 - second parametric crystal; 12 - second cavity mirror; 13 - third beam splitter; 14 - second frequency doubling crystal; 15 - fourth beam splitter; 16 - fourth reflector; 17 - delayer; 18 - beam combiner; 19 - second sum frequency crystal; 20 - beam splitter prism. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings, but these should not be construed as limiting the scope of protection of the present invention.

[0018] like Figure 1As shown, this invention relates to a 193nm wavelength vacuum ultraviolet all-solid-state pulsed laser, comprising three parts: a 1064nm fundamental frequency pulse and its third harmonic laser generation device A, an optical parametric oscillator and its frequency doubling device B, and a sum-frequency device C. Specific implementation details are as follows:

[0019] The 1064nm fundamental frequency pulse and its third harmonic laser generating device A includes a 1064nm fundamental frequency pulse laser 1, and a first half-wave plate 2, a first frequency doubling crystal 3, a first sum-frequency crystal 4, a first beam splitter 5, and a second beam splitter 6, which are placed sequentially along the output beam direction of the 1064nm fundamental frequency pulse laser.

[0020] Wherein: the 1064nm fundamental frequency pulsed laser 1 is a pulsed laser oscillator or pulsed laser amplifier using neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal or neodymium-doped yttrium vanadate (Nd:YVO4) crystal as the gain medium; the first half-wave plate 2 is a 1064nm half-wave plate coated with a 1064nm anti-reflection film; the first frequency-doubling crystal 3 is any crystal capable of second-harmonic conversion of the 1064nm laser, and both of its light-transmitting surfaces are coated with 1064nm and 532nm anti-reflection films; the first frequency-doubling crystal 3 is any crystal capable of second-harmonic conversion of the 1064nm laser, and both of its light-transmitting surfaces are coated with 1064nm and 532nm anti-reflection films; the first half-wave plate 2 is a 1064nm half-wave plate coated with a 1064nm and 532nm anti-reflection film ... half-wave plate; the first half-wave plate 3 is a 1064nm half-wave plate coated with a 1064nm half-wave plate; the first half-wave plate 3 is a 1064nm half-wave plate coated with a 1064 The sum-frequency crystal 4 is any crystal capable of sum-frequency conversion between 1064nm and 532nm lasers. Both light-transmitting surfaces of the crystal are coated with anti-reflection films of 1064nm, 532nm, and 355nm. The front surface of the first beam splitter 5 is coated with a 355nm high-reflection film and anti-reflection films of 1064nm and 532nm, and the rear surface is coated with anti-reflection films of 1064nm and 532nm. The front surface of the second beam splitter 6 is coated with a 532nm high-reflection film and an anti-reflection film of 1064nm, and the rear surface is coated with an anti-reflection film of 1064nm.

[0021] The 1064nm infrared laser pulse emitted by the 1064nm fundamental frequency pulsed laser 1 passes through the first half-wave plate 2 and then through the first frequency doubling crystal 3 to generate a 532nm green laser pulse. The 1064nm infrared laser pulse and the 532nm green laser pulse then pass through the first sum-frequency crystal 4 to generate a 355nm ultraviolet laser pulse. The 1064nm infrared laser pulse, the 532nm green laser pulse, and the 355nm ultraviolet laser pulse all pass through the first beam splitter 5. The 355nm ultraviolet laser pulse is reflected by the first beam splitter 5 and then enters the optical parametric oscillator and frequency doubling device B. The 532nm green laser pulse is transmitted through the first beam splitter 5 and then reflected by the second beam splitter 6. The 1064nm infrared laser pulse is transmitted through the first beam splitter 5 and the second beam splitter 6 and then enters the sum-frequency device C.

[0022] The optical parametric oscillation and frequency doubling device B includes a first reflecting mirror 7, a second half-wave plate 8, a first cavity mirror 9, a first parametric crystal 10, a second parametric crystal 11, a second cavity mirror 12, a third beam splitter 13, a second frequency doubling crystal 14, a fourth beam splitter 15, and a second reflecting mirror 16.

[0023] Wherein: the incident surface of the first reflecting mirror 7 is coated with a 355nm high-reflectivity film and is placed at 45° to the laser axis; the second half-wave plate 8 is a 355nm half-wave plate coated with a 355nm anti-reflection film; the front surface of the first cavity mirror 9 is coated with 355nm and 1427nm anti-reflection films, and the rear surface is coated with 355nm, 1427nm anti-reflection films and a 472nm high-reflectivity film; the first parametric crystal 10 and the second parametric crystal 11 are identical, being any crystal capable of converting 355nm pump light into 472nm signal light and 1427nm idle light through an optical parametric oscillation (OPO) process, with each crystal having two light-transmitting surfaces coated with 355nm, 472nm, and 1427nm anti-reflection films, and these two crystals are placed in a cross-complementary symmetrical arrangement relative to the OPO pump laser axis to compensate for the walk-off effect of the 355nm pump light; The second cavity mirror 12 has a front surface coated with anti-reflection films of 355nm and 1427nm and a partial transmission film with a transmittance of 30% at 472nm, and a rear surface coated with anti-reflection films of 472nm, 355nm, and 1427nm; the third beam splitter 13 has a front surface coated with a high-reflection film of 355nm and an anti-reflection film of 472nm, and a rear surface coated with a 472nm anti-reflection film, and is placed at a 45° angle to the laser axis; the second frequency-doubling crystal 14 is any crystal capable of performing second-harmonic conversion on 472nm laser light, and both light-transmitting surfaces of the crystal are coated with anti-reflection films of 472nm and 236nm; the fourth beam splitter 15 has a front surface coated with a high-reflection film of 472nm and an anti-reflection film of 236nm, and a rear surface coated with a 236nm anti-reflection film, and is placed at a 45° angle to the laser axis; the incident surface of the second reflector 16 is coated with a high-reflection film of 236nm and is placed at a 45° angle to the laser axis.

[0024] The 355nm ultraviolet laser pulse, after being reflected by the first reflecting mirror 7 and then passing through the second half-wave plate 8, serves as the pump light for the optical parametric oscillation (OPO) process. It then passes through the first cavity mirror 9 and enters the first parametric crystal 10 and the second parametric crystal 11, where the OPO process generates a 1427nm idler light and a 472nm blue laser pulse as the signal light. The 472nm blue laser pulse and the 355nm ultraviolet laser pulse then pass through the second cavity mirror 12. The 355nm ultraviolet laser pulse is reflected by the third beam splitter 13; the 472nm blue laser pulse is transmitted through the third beam splitter 13 and enters the second frequency doubling crystal 14 as the fundamental frequency light, where it is frequency-doubled to generate a 236nm deep ultraviolet laser pulse; the 472nm blue laser pulse is reflected after passing through the fourth beam splitter 15; the 236nm deep ultraviolet laser pulse is transmitted through the fourth beam splitter 15 and then reflected by the second mirror 16 before entering the summing frequency device.

[0025] The frequency-splitting device includes a delay unit 17, a beam combiner 18, a second frequency-splitting crystal 19, and a beam splitter 20.

[0026] Wherein: the delayer 17 is any device capable of delaying a 1064nm laser pulse, used to make the 1064nm laser pulse coincide with the 236nm laser pulse in the time domain; the front surface of the beam combiner 18 is coated with a 1064nm anti-reflection film, and the rear surface is coated with a 1064nm anti-reflection film and a 236nm high-reflection film, and is placed at 45° to the laser axis; the second sum-frequency crystal 19 is any crystal capable of sum-frequency conversion of 1064nm and 236nm lasers, and both light-transmitting surfaces of the crystal are coated with 1064nm, 236nm and 193nm anti-reflection films; the incident surface and the exit surface of the beam splitter 20 are both coated with 1064nm, 236nm and 193nm anti-reflection films.

[0027] The 1064nm infrared laser pulse, after passing through the delay unit 17, and the 236nm deep ultraviolet laser pulse, enter the second sum-frequency crystal 19 through the beam combiner 18 to generate a 193nm vacuum ultraviolet laser pulse. The 193nm vacuum ultraviolet laser pulse, the 236nm deep ultraviolet laser pulse, and the 1064nm infrared laser pulse are split into three beams by the beam splitter prism 20, thereby obtaining the 193nm vacuum ultraviolet laser pulse output.

Claims

1. A 193nm wavelength vacuum ultraviolet all-solid-state pulsed laser, characterized in that: It consists of three parts: a 1064nm fundamental frequency pulse and its third harmonic laser generation device (A), an optical parametric oscillator and frequency doubling device (B), and a frequency summing device (C); The 1064nm fundamental frequency pulse and its third frequency harmonic laser generating device (A) is used to generate a 1064nm infrared laser pulse and a 355nm ultraviolet pulse laser generated by the third frequency harmonic process, and transmits the 355nm ultraviolet pulse laser to the optical parametric oscillator and frequency harmonic device (B), and transmits the remaining 1064nm infrared laser pulse to the sum frequency device (C). The optical parametric oscillation and frequency doubling device (B) includes a first reflecting mirror (7), a second half-wave plate (8), a first cavity mirror (9), a first parametric crystal (10), a second parametric crystal (11), a second cavity mirror (12), a third beam splitter (13), a second frequency doubling crystal (14), a fourth beam splitter (15), and a second reflecting mirror (16). The 355nm ultraviolet laser pulse, after being reflected by the first mirror (7) and then passing through the second half-wave plate (8), serves as the pump light for the optical parametric oscillation (OPO) process. It then passes through the first cavity mirror (9) and enters the first parametric crystal (10) and the second parametric crystal (11), generating a 1427nm idler light and a 472nm blue laser pulse as signal light through the OPO process. The 472nm blue laser pulse and the 355nm ultraviolet laser pulse, after passing through the second cavity mirror (12), are then... The 355nm ultraviolet laser pulse is reflected by the third beam splitter (13); the 472nm blue laser pulse is transmitted through the third beam splitter (13) and enters the second frequency doubling crystal (14) as the fundamental frequency light, generating a 236nm deep ultraviolet laser pulse after frequency doubling; the 472nm blue laser pulse is reflected after passing through the fourth beam splitter (15); the 236nm deep ultraviolet laser pulse is transmitted through the fourth beam splitter (15) and then reflected by the second mirror (16) before entering the summing device (C); The first parametric crystal (10) and the second parametric crystal (11) are identical and are placed in a cross-complementary symmetrical arrangement relative to the OPO pump laser axis to compensate for the walk-off effect of the 355nm pump light; the sum-frequency device (C) includes a delayer (17), a beam combiner (18), a second sum-frequency crystal (19), and a beam splitter (20). After the 1064nm infrared laser pulse passes through the delay unit (17), it and the 236nm deep ultraviolet laser pulse pass through the beam combiner (18) and enter the second sum-frequency crystal (19) to generate a 193nm vacuum ultraviolet laser pulse. After the 193nm vacuum ultraviolet laser pulse passes through the beam splitter (20), it is separated from the 236nm deep ultraviolet laser pulse and the 1064nm infrared laser pulse and then output.

2. The 193nm wavelength vacuum ultraviolet all-solid-state pulsed laser according to claim 1, characterized in that: The 1064nm fundamental frequency pulse and its third frequency harmonic laser generating device (A) includes a 1064nm fundamental frequency pulse laser (1), and a first half-wave plate (2), a first frequency harmonic crystal (3), a first sum frequency crystal (4), a first beam splitter (5), and a second beam splitter (6) arranged sequentially along the output beam direction of the 1064nm fundamental frequency pulse laser (1). The 1064nm infrared laser pulse emitted by the 1064nm fundamental frequency pulse laser (1) passes through the first half-wave plate (2) and then through the first frequency doubling crystal (3) to generate a 532nm green laser pulse. The 1064nm infrared laser pulse and the 532nm green laser pulse then pass through the first sum-frequency crystal (4) to generate a 355nm ultraviolet laser pulse. The 1064nm infrared laser pulse, the 532nm green laser pulse, and the 355nm ultraviolet laser pulse all pass through the first beam splitter (5). The 355nm ultraviolet laser pulse is reflected by the first beam splitter (5) and then enters the optical parametric oscillator and frequency doubling device (B). The 532nm green laser pulse is transmitted through the first beam splitter (5) and then reflected by the second beam splitter (6). The 1064nm infrared laser pulse is transmitted through the first beam splitter (5) and the second beam splitter (6) and then enters the sum-frequency device (C).

3. The 193nm wavelength vacuum ultraviolet all-solid-state pulsed laser according to claim 2, characterized in that: The 1064nm fundamental frequency pulsed laser (1) is a pulsed laser oscillator or pulsed laser amplifier using neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal or neodymium-doped yttrium vanadate (Nd:YVO4) crystal as the gain medium; the first half-wave plate (2) is a 1064nm half-wave plate coated with a 1064nm anti-reflection film; the first frequency doubling crystal (3) is any crystal capable of performing second-harmonic conversion on the 1064nm laser, and both of its light-transmitting surfaces are coated with 1064nm and 532nm anti-reflection films; the first and The frequency crystal (4) is any crystal capable of sum-frequency conversion of 1064nm and 532nm lasers. Both light-transmitting surfaces of the crystal are coated with anti-reflection films of 1064nm, 532nm and 355nm. The front surface of the first beam splitter (5) is coated with a 355nm high-reflection film and anti-reflection films of 1064nm and 532nm, and the rear surface is coated with anti-reflection films of 1064nm and 532nm. The front surface of the second beam splitter (6) is coated with a 532nm high-reflection film and an anti-reflection film of 1064nm, and the rear surface is coated with an anti-reflection film of 1064nm.

4. The 193nm wavelength vacuum ultraviolet all-solid-state pulsed laser according to any one of claims 1-3, characterized in that: The incident surface of the first reflecting mirror (7) is coated with a 355nm high-reflection film; the second half-wave plate (8) is a 355nm half-wave plate coated with a 355nm anti-reflection film; the front surface of the first cavity mirror (9) is coated with 355nm and 1427nm anti-reflection films, and the rear surface is coated with 355nm, 1427nm anti-reflection films and a 472nm high-reflection film; the first parametric crystal (10) and the second parametric crystal (11) are completely identical, and are any crystal capable of converting 355nm pump light into 472nm signal light and 1427nm idle light through an optical parametric oscillation (OPO) process, and both of their light-transmitting surfaces are coated with 355nm, 472nm and 1427nm anti-reflection films; the front surface of the second cavity mirror (12) is coated with a 355nm, 472nm and 1427nm high-reflection film. The front surface of the third beam splitter (13) is coated with a 355nm and 1427nm antireflection film and a 472nm partial transmission film with a transmittance of 30%, and the rear surface is coated with a 472nm, 355nm and 1427nm antireflection film; the front surface of the third beam splitter (13) is coated with a 355nm high reflectivity film and a 472nm antireflection film, and the rear surface is coated with a 472nm antireflection film; the second frequency doubling crystal (14) is any crystal capable of performing frequency doubling conversion on 472nm laser, and both light-transmitting surfaces of the crystal are coated with 472nm and 236nm antireflection films; the front surface of the fourth beam splitter (15) is coated with a 472nm high reflectivity film and a 236nm antireflection film, and the rear surface is coated with a 236nm antireflection film; the incident surface of the second reflector (16) is coated with a 236nm high reflectivity film.

5. The 193nm wavelength vacuum ultraviolet all-solid-state pulsed laser according to any one of claims 1-3, characterized in that: The delay device (17) is any device capable of delaying a 1064nm infrared laser pulse, used to make the 1064nm infrared laser pulse coincide with the 236nm laser pulse in the time domain; the front surface of the beam combiner (18) is coated with a 1064nm anti-reflection film, and the rear surface is coated with a 1064nm anti-reflection film and a 236nm high-reflection film; the second sum-frequency crystal (19) is any crystal capable of sum-frequency conversion of 1064nm and 236nm lasers, and both light-transmitting surfaces of the crystal are coated with 1064nm, 236nm and 193nm anti-reflection films; the incident surface and the exit surface of the beam splitter (20) are coated with 1064nm, 236nm and 193nm anti-reflection films.

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