Three-wavelength laser device without gain competition

Abstract

The invention discloses a three-wavelength laser device without gain competition and belongs to the technical field of laser. The prior art has the problems of intense gain competition between different transition spectral lines, large waste heat generation amount of the laser device, and high Stokes frequency shift and low Stokes efficiency of pump light photons and laser photons. The three-wavelength laser device consists of a long resonant cavity and a short resonant cavity, wherein the short resonant cavity is formed in the long resonant cavity; the long resonant cavity and the short resonant cavity share a light path and an output coupling mirror; a pump is positioned on the light path outside a total reflecting mirror of the long resonant cavity; a condensing mirror is positioned on the light path between laser crystals of the long resonant cavity and the short resonant cavity and outside the total reflecting mirror of the short resonant cavity; the pump is an 885nm semiconductor laser pump or an 888nm semiconductor laser pump; the laser crystal of the long resonant cavity is a non-bonded laser crystal and generates quasi-three-energy-level laser lambda 1; and the laser crystal of the short resonant cavity is a bonded self-Raman laser crystal and generates four-energy-level laser lambda 2 and self-Raman laser lambda 3. The three-wavelength laser device is used for obtaining three-wavelength laser, and the three-wavelength laser serves as fundamental frequency light to obtain new wavelength laser by frequency mixing.

Description

technical field [0001] The invention relates to a three-wavelength laser without gain competition, which realizes simultaneous stable and high-efficiency output of quasi-three-level laser, four-level laser and first-order Stokes self-Raman laser in the form of series pumping, and belongs to the field of laser technology . Background technique [0002] The wavelengths of some special bands can be obtained by nonlinear frequency mixing (frequency doubling, sum frequency, and difference frequency) of three-wavelength lasers. For example, the 480-520nm band, which is the same as the emission band of the argon ion laser; another example, 550-600nm, which is widely used in the fields of spectral analysis, military, astronomical observation, laser guide stars, etc.; and the THz generated by the difference frequency The wave band has broad application prospects in the fields of non-destructive detection of organisms, environmental monitoring and communication. [0003] The known t...

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Problems solved by technology

[0004] There are following deficiencies in the described known technology: one, because the different transition spectral line emission cross sections of the same neodymium-doped laser crystal differ greatly, for example, 1.06 μ m (1079.5nm) and 0.9 μ m (930nm) wavelength emission cross sections differ by 10 ~ 20 times, see the table below,

[0006] There is a very strong gain competition between different transition lines. Therefore, the known technology uses the same laser gain medium to simultaneously realize the three-wavelength laser output of 1341.4nm, 1079.5nm and 930nm, which can easily cause the intensity of the two wavelengths of laser light to be enhanced while the other The light intensity of one wavelength laser is weakened, that is, the consequences of rising and falling, making it difficult for the lasers of the three wavelengths to oscillate stably at the same time; secondly, both 1341.4nm and 1079.5nm are four-level lasers. 4 f 5 / 2 - 4 f 3 / 2 A large amount of waste heat is generated during the non-radiative transition process, which reduces the stability of the laser. In addition, the pumping method of this scheme is ordinary pumping, which will also generate more waste heat. Third, when using 803nm semiconductor laser pumping, the pumping There is a large Stokes frequency shift between light photons and laser photons and a low Stokes efficiency

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