Optimization for high repetition rate pulse Raman laser

Patent metadata

Field	Value
Publication number	US-11522333-B2
Application number	US-202117201476-A
Country	US
Kind code	B2
Filing date	Mar 15, 2021
Priority date	Oct 13, 2020
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A high repetition rate pulse laser including a linear cavity having a first direction and a second direction opposite to the first direction is disclosed. The pulse laser includes, along the first direction, a first optical component, a gain and Raman medium, an acousto-optic crystal, a first lithium triborate (LBO) crystal and a second optical component. The first optical component allows a pumping light incident in the first direction to transmit therethrough. The gain and Raman medium receives the pumping light from the first optical component, and generates a first infrared base laser light having a first wavelength and a second infrared base laser light having a second wavelength. The acousto-optic crystal receives a radio frequency control signal from a radio frequency controller, wherein the radio frequency control signal has a signal period including a low level period and a high level period.

First claim

What is claimed is:

1. A high repetition rate pulse laser including a linear cavity having a first direction and a second direction opposite to the first direction, comprising along the first direction:
a first optical component allowing a pumping light incident in the first direction to transmit therethrough;
a gain and Raman medium receiving the pumping light from the first optical component, and generating a first infrared base laser light having a first wavelength and a second infrared base laser light having a second wavelength;
an acousto-optic crystal receiving a radio frequency control signal from a radio frequency controller, wherein the radio frequency control signal has a signal period including a low level period and a high level period, and the acousto-optic crystal undergoes a corresponding turn-on time to allow any light to pass therethrough during the low level period;
a first lithium triborate (LBO) crystal receiving the first and the second infrared base lasers, and generating a visible laser light having a third wavelength; and
a second optical component, wherein:
the first optical component has a first high reflectivity for a first wave band covering the first and the second wavelengths in respect of the second direction and a second high reflectivity for a second wave band covering the third wavelength;
the gain and Raman medium has a first high transmittance for the first wave band and a third high reflectivity for the second wave band in respect of the second direction;
the second optical component has a fourth high reflectivity for the first wave band and an initial transmittance, and when an intensity of the visible laser light reaches a threshold, the second optical component has a second high transmittance for the second wavelength in respect of the first direction so as to release an output laser pulse along the first direction; and
the intensity of the visible laser light achieves the threshold during the turn-on time of the acousto-optic crystal.

2. The pulse laser device according to claim 1 , wherein the gain and Raman medium includes a neodymium doped vanadate and the second infrared base laser light is generated via a self-stimulated Raman scattering.

3. The pulse laser device according to claim 1 , wherein the first wave length and the second wavelength are approximately 1064 nm and 1176 nm respectively.

4. The pulse laser device according to claim 1 , wherein the third wavelength is approximately 588 nm or 532 nm when the first LBO is a doubling harmonic generation crystal.

5. The pulse laser device according to claim 1 , wherein the third wavelength is approximately 549 nm when the first LBO crystal is a sum frequency generation crystal.

6. The pulse laser device according to claim 1 , wherein the linear cavity further comprises a second LBO crystal disposed between the acousto-optic crystal and the first LBO crystal.

7. The pulse laser device according to claim 6 , wherein the second LBO crystal is one of a doubling harmonic generation crystal and a sum frequency generation crystal.

8. The pulse laser device according to claim 6 , wherein the linear cavity further comprises a third LBO crystal disposed between the first and the second LBO crystals.

9. The pulse laser device according to claim 8 , wherein the third LBO crystal is one of a doubling harmonic generation crystal and a sum frequency generation crystal.

10. A linear cavity for generating a high repetition rate laser light, comprising along a first direction:
a first optical component allowing a pumping light incident in the first direction to transmit therethrough;
a gain and Raman medium receiving the pumping light from the first optical component, and generating a first infrared base laser light having a first wavelength and a second infrared base laser light having a second wavelength;
an acousto-optic crystal receiving a radio frequency control signal from a radio frequency controller, wherein the radio frequency control signal has a signal period including a low level period and a high level period, and the acousto-optic crystal undergoes a corresponding turn-on time to allow any light to pass therethrough during the low level period;
a first lithium triborate (LBO) crystal receiving the first and the second infrared base lasers, and generating a first visible laser light having a third wavelength;
a second LBO crystal receiving the first and the second infrared base lasers, and generating an ultraviolet laser light having a fourth wavelength; and
a second optical component, wherein:
the first optical component has a first high reflectivity for a first wave band covering the first and the second wavelengths in respect of a second direction opposite to the first direction and a second high reflectivity for a second wave band covering the third and the fourth wavelengths;
the gain and Raman medium has a first high transmittance for the first wave band and a third high reflectivity for the second wave band in respect of the second direction;
the second optical component has a fourth high reflectivity for the first wave band and an initial transmittance, and when an intensity of the ultraviolet laser light reaches a threshold, the second optical component has a second high transmittance for the second wavelength in respect of the first direction, so as to release an output laser pulse along the first direction; and
the intensity of the first visible laser light achieves the threshold during the turn-on time of the acousto-optic crystal.

11. The linear cavity according to claim 10 , wherein the gain and Raman medium includes a neodymium doped vanadate and the second infrared base laser light is generated via a self-stimulated Raman scattering.

12. The linear cavity according to claim 10 , wherein the first wave length and the second wavelength are approximately 1064 nm and 1176 nm respectively.

13. The linear cavity according to claim 10 , wherein the first LBO crystal and the second LBO crystal are a sum frequency generation crystal and a doubling harmonic generation crystal respectively when the first wavelength is twice as long as the third wavelength.

14. The linear cavity according to claim 10 , wherein the first LBO crystal and the second LBO crystal are a doubling harmonic generation crystal and a sum frequency generation crystal respectively when the second wavelength is twice as long as the third wavelength.

15. The linear cavity according to claim 10 , further comprising a third LBO crystal disposed between the gain and Raman medium and the first LBO crystal, receiving the first and the second infrared base laser lights, and generating a second visible laser having a fifth wavelength falling in the second wave band.

16. A high repetition rate pulse laser including a linear cavity having a first direction and a second direction opposite to the first direction, comprising along the first direction:
a first optical component receiving a pumping light incident in the first direction, and allowing the pumping light to transmit therethrough, wherein the pumping light has a first wavelength;
a gain medium receiving the pumping light from the first optical component, and generating a base laser light having a second wavelength;
an acousto-optic crystal receiving the base laser light from the gain medium, and receiving a radio frequency control signal to determine whether the acousto-optic crystal is at a transparent condition or a non-transparent condition based on the radio frequency control signal; and
a second optical component configured to form therebetween a laser resonant cav

Assignees

• National Yang Ming Chiao Tung Univ

Inventors

• Chen Yung-Fu
• Liang Hsing-Chih
• Tsou Chia-Han

Classifications

• H01S3/117 Primary

  using intracavity acousto-optic devices · CPC title

• H01S3/1022

  by controlling the optical pumping · CPC title

• H01S3/1673

  YVO4 [YVO] · CPC title

• H01S3/109

  Frequency multiplication, e.g. harmonic generation · CPC title

• H01S3/09415

  the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping · CPC title