Internal cavity and external cavity mixing type non-linear frequency conversion ultraviolet laser

Abstract

The invention discloses an internal cavity and external cavity mixing type non-linear frequency conversion ultraviolet laser. The internal cavity and external cavity mixing type non-linear frequency conversion ultraviolet laser comprises a pumping source, an energy transmitting optical fiber, a focusing and coupling system, a laser total reflection mirror, a gain medium crystal, a Q switch, a laser output mirror, a harmonic mirror, a frequency doubling crystal, a focusing mirror and a frequency tripling crystal, wherein pump light output by the pumping source is transmitted to the gain medium crystal through the energy transmitting optical fiber and the focusing and coupling system, laser light then can oscillate in a base-frequency light resonant cavity formed by the laser total reflection mirror and the laser output mirror, pulsing base-frequency light is generated under the modulating action of the Q switch, frequency doubling light is generated every time when the base-frequency light passes through the frequency doubling crystal in the base-frequency light resonant cavity, the frequency doubling light and the base-frequency light are focused in the frequency tripling crystal after passing through the focusing mirror, and then frequency tripling laser light is generated. According to the internal cavity and external cavity mixing type non-linear frequency conversion ultraviolet laser, frequency doubling inside the cavity and frequency tripling outside the cavity are utilized, high power density of the base-frequency light in the cavity is utilized, the conversion rate during frequency doubling is improved, and long-term stability of a system is guaranteed due to the fact that the frequency tripling process is achieved outside the resonant cavity.

Description

technical field [0001] The invention relates to the technical field of lasers, specifically a kind of internal and external cavity mixed nonlinear frequency that utilizes the high power density of the fundamental frequency light in the cavity, improves the conversion rate of the frequency doubling process, and ensures the long-term stability and high efficiency of the system. Change UV laser. Background technique [0002] LD-pumped all-solid-state lasers have made great progress since 1980. Ultraviolet lasers have been a research hotspot because of their applications in fluorescence detection, fine processing and lithography. The process of processing materials with ultraviolet light is called photoetching effect, because the high-energy photons of ultraviolet light can directly destroy the chemical bonds of materials. It is a "cold" processing process, and the heat-affected area is minimal. In contrast, visible and infrared lasers use heat focused on the processing site to...

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Problems solved by technology

[0006] The conversion rate of complete external cavity triple frequency is low, and the current conversion rate from fundamental frequency light to ultraviolet laser is less than 40%. This is due to the low optical power density of external cavity laser and the low efficiency of double frequency, resulting in The power of the green laser is weak, which seriously affects the conversion rate of the subsequent triple frequency

[0007] The complete inner cavity frequency tripler has poor stability. This method of placing the frequency doubler crystal and the frequency tripler crystal in the resonant cavity of the fundamental frequency light at the same time can improve the conversion rate, but this method has poor stability of the optical path and is likely to cause frequency tripler. The optical damage of the crystal, and the ultraviolet crystal needs to be replaced and moved regularly, and placing the triple frequency crystal in the cavity will affect the stability of the later optical path

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