CN204349202U - Wide temperature low noise frequency-multiplication solid state laser - Google Patents

Abstract

The utility model relates to a wide temperature and low noise frequency doubling solid-state laser, which belongs to the technical field of lasers. A wide-temperature low-noise frequency-doubled solid-state laser, comprising a semiconductor laser and an optical coupling system, a volume grating and a laser resonator arranged in sequence with the direction of the pumping light emitted by the semiconductor laser on the same optical axis; the laser resonator is controlled by laser gain It is composed of dielectric crystal, nonlinear frequency doubling crystal and birefringent crystal. In the utility model, a volume grating is used to lock the wavelength, so that the wavelength of the semiconductor laser is stabilized at the absorption peak of the crystal and the line width is narrowed, thereby improving the stability of the absorption depth in the laser crystal and making the longitudinal mode stability in the laser resonator improve, thereby extending the low-noise temperature range.

Description

Wide temperature low noise frequency doubled solid-state laser

technical field

The utility model relates to a laser, in particular to a frequency-multiplied solid laser with wide temperature and low noise.

Background technique

At present, the intracavity frequency doubling laser in the visible band is used to pump Nd:YVO4 or Nd:YAG to receive and emit laser in the infrared band, and then pass through a nonlinear crystal such as KTP to generate visible laser light. The intracavity frequency-doubling laser disclosed by our company includes a pump source and a resonant cavity. The pump source is an ordinary semiconductor laser with an unlocked wavelength. The front end of the resonator is coated to form a front cavity mirror, and the rear end of the resonator is coated to form a rear cavity mirror. The resonant cavity includes a laser gain medium and a nonlinear frequency doubling crystal, and the birefringent crystal is processed into the polarization state of the fundamental frequency light and the frequency doubling light to realize various lasers with different performances. The components are bonded together by gluing or optical glue. This product has high output power stability against temperature, low noise, and highly polarized output, and it has already been commercialized.

However, the disadvantage of this product at present is that the laser crystal absorption bandwidth is narrow and sharp, and the absorption efficiency is low, while the spectral width of the output beam of the pump semiconductor laser is about 1-2nm when it is in normal free operation, and the central wavelength is respectively There is a drift of about 0.24 nm/°C with temperature and a drift of about 0.07 nm/mA with current. This makes the stability of the output power and wavelength in different states will be poor when the temperature or current is changed, which will affect the stability of the longitudinal mode in the cavity, and then affect the noise performance of the laser.

Utility model content

The purpose of the utility model is to solve the above problems and provide a wide temperature and low noise frequency doubling solid-state laser, the longitudinal mode in the cavity has good stability and low noise.

The purpose of this utility model is achieved in that:

A wide-temperature low-noise frequency-multiplied solid-state laser is characterized in that it includes a laser pumping system and a laser resonator; the laser pumping system includes a semiconductor laser and sequentially on the same optical axis as the pumping light emitted by the semiconductor laser. An optical coupling system, a volume grating and a focusing optical system are set; the laser resonant cavity is composed of a laser gain medium crystal, a nonlinear frequency doubling crystal and a birefringent crystal.

Wherein, the wavelength range of the laser light emitted by the semiconductor laser is 800nm-1000nm.

Wherein, the optical coupling system is a single optical lens or an optical lens group.

Wherein, the volume grating is a volume Bragg grating.

Wherein, the diffraction efficiency of the volume grating is 1%-50%.

Wherein, the output beam of the semiconductor laser is incident on the volume grating vertically or at an inclination angle smaller than 90°.

Wherein, the optical coupling system, the volume grating and the focusing optical system are coated with an anti-reflection film.

Wherein, the laser gain medium crystal is Nd:YVO4 crystal; the nonlinear frequency doubling crystal is KTP crystal; the birefringent crystal is a 1/4 wave plate or 1/8 wave plate of fundamental frequency light, or the Birefringent crystals are 1/2 wave plates or full wave plates for frequency doubled light.

Wherein, the laser gain medium crystal, the nonlinear frequency doubling crystal and the birefringent crystal are respectively coated with a front cavity mirror film, an anti-reflection film and a rear cavity mirror film.

Wherein, the laser gain medium crystal, the nonlinear frequency doubling crystal and the birefringent crystal are respectively bonded by glue or optical glue.

The beneficial effects of the utility model are: in the laser, the volume grating is used to lock the wavelength, so that the wavelength of the semiconductor laser is stabilized at the absorption peak of the crystal and the line width is narrowed, thereby improving the stability of the absorption depth in the laser crystal, making the laser The stability of the longitudinal mode in the resonator is improved, thereby expanding the temperature range of low noise.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Detailed ways

Below in conjunction with specific embodiment and accompanying drawing, further elaborate the utility model.

As shown in FIG. 1 , a wide-temperature low-noise frequency-doubled solid-state laser includes a laser pumping system 1 and a laser resonator 2 .

The laser pumping system 1 includes a semiconductor laser 11 and an optical coupling system 12 , a volume grating 13 and a focusing optical system 14 arranged in sequence on the same optical axis as the direction of the pump light emitted by the semiconductor laser 11 . Wherein, the wavelength range of the laser light emitted by the semiconductor laser 11 is 800nm-1000nm; the optical coupling system 12 can be a single optical lens or an optical lens group; the volume grating 13 is specifically a volume Bragg grating with a diffraction efficiency of 1%-50%. The output beam of the semiconductor laser 11 is incident on the volume grating 13 vertically or at an inclination angle smaller than 90°. The optical coupling system 12 , the volume grating 13 and the focusing optical system 14 are all coated with an anti-reflection film.

The laser resonator 2 is formed by bonding a laser gain medium crystal 21 , a nonlinear frequency doubling crystal 22 and a birefringent crystal 23 by gluing or optical glue. Among them, the laser gain medium crystal 51 specifically uses Nd:YVO4 crystal, the nonlinear frequency doubling crystal 52 specifically uses KTP crystal, and the refraction crystal 53 is a 1/4 wave plate or a 1/8 wave plate of the fundamental frequency light, and can also be a frequency doubling 1/2 wave plate or full wave plate of light. The components in the laser resonator 5 are bonded by gluing or optical glue. The front end surface of the laser gain medium crystal 21 is coated with a front cavity mirror film consisting of a 1064nm high reflection film, a 532nm high reflection film and an 808nm anti-reflection film, and the rear end surface is coated with two anti-reflection films of 1064nm and 532nm . The front and rear end faces of the nonlinear frequency doubling crystal 22 are coated with two types of anti-reflection coatings of 1064nm and 532nm. Two kinds of anti-reflection coatings of 532nm and 1064nm are coated on the front surface of the birefringent crystal 23, and a rear cavity mirror film composed of a high-reflection coating of 1064nm and an anti-reflection coating of 532nm is coated on the rear end surface.

In the aforementioned wide-temperature low-noise frequency-doubled solid-state laser, the semiconductor laser is used as the pumping source of the laser pumping system to emit pumping light. The light is shaped into parallel light by the optical coupling system and then enters the volume Bragg grating. Most of the light will pass through the volume Bragg grating. Bragg grating, and a part of the light beam in the wavelength range of (809±0.5)nm is reflected back into the semiconductor laser. Due to the selectivity of the volume Bragg grating to specific wavelengths, an external cavity with wavelength selective properties is formed, and part of the light fed back will form a stable oscillation between the rear end facet of the semiconductor laser chip and the Bragg grating, realizing wavelength locking. The locked pump light enters the laser gain medium crystal through the focusing optical system. A resonant cavity is formed between the front cavity mirror film coated on the front surface of the laser gain medium crystal and the rear cavity mirror film coated on the rear end surface of the birefringent crystal, and a nonlinear frequency doubling crystal is inserted in the resonant cavity to generate a 532nm low-noise Intra-cavity frequency doubled green light output.

Since the Bragg grating can lock the output wavelength of the semiconductor laser, the output spectrum of the laser pump system basically does not change with the temperature, thus obtaining a stable spectral output, which is locked at the peak absorption wavelength of the laser gain medium crystal and the line width Compression, thereby improving the stability of the absorption depth of the pump light in the laser gain medium crystal, improving the stability of the longitudinal mode in the laser resonator, and widening the temperature range of low noise.

Claims (10)

1. a wide temperature low noise frequency-multiplication solid state laser, is characterized in that, comprises laser pumping system (1) and laserresonator (2); Described laser pumping system (1) comprise semiconductor laser (11) and the pump direction that sends with this semiconductor laser (11) with the optical coupling system (12) set gradually of optical axis, body grating (13) and Focused Optical system (14); Described laserresonator (2) is made up of gain medium crystal (21), frequency doubling non-linear's crystal (22) and birefringece crystal (23).

2. wide temperature low noise frequency-multiplication solid state laser according to claim 1, is characterized in that, the wave-length coverage of the laser that described semiconductor laser (11) is launched is 800nm ~ 1000nm.

3. wide temperature low noise frequency-multiplication solid state laser according to claim 1, is characterized in that, described optical coupling system (12) is single optical lens or optical lens group.

4. wide temperature low noise frequency-multiplication solid state laser according to claim 1, it is characterized in that, described body grating (13) is Volume Bragg grating.

5. wide temperature low noise frequency-multiplication solid state laser according to claim 1, is characterized in that, the diffraction efficiency of described body grating (13) is 1%-50%.

6. wide temperature low noise frequency-multiplication solid state laser according to claim 1, is characterized in that, the output beam of described semiconductor laser (11) is vertical or incide on body grating (13) with the inclination angle being less than 90 °.

7. wide temperature low noise frequency-multiplication solid state laser according to claim 1, is characterized in that, described optical coupling system (12), body grating (13) and Focused Optical system (14) are all coated with anti-reflection film.

8. wide temperature low noise frequency-multiplication solid state laser according to claim 1, is characterized in that, described gain medium crystal (21) is Nd:YVO4 crystal; Described frequency doubling non-linear's crystal (22) is ktp crystal; Described birefringece crystal (23) is quarter wave plate or 1/8 wave plate of fundamental frequency light, or described birefringece crystal (23) is 1/2 wave plate or the full-wave plate of frequency doubled light.

9. wide temperature low noise frequency-multiplication solid state laser according to claim 1, it is characterized in that, described gain medium crystal (21), frequency doubling non-linear's crystal (22) and birefringece crystal (23) are coated with front cavity mirror film, anti-reflection film and Effect of Back-Cavity Mirror film respectively.

10. wide temperature low noise frequency-multiplication solid state laser according to claim 1, it is characterized in that, described gain medium crystal (21), between frequency doubling non-linear's crystal (22) and birefringece crystal (23) respectively by gummed or optical cement bonding.