Radio frequency CO2 laser device and unstable-waveguide mixing chamber thereof

The invention discloses a radio frequency CO2 laser device and an unstable-waveguide mixing chamber thereof. The unstable-waveguide mixing chamber comprises a waveguide system and an optical feedback system. The waveguide system comprises a pair of plate electrodes, the optical feedback system comprises a first resonance chamber lens and a second resonance chamber lens that are arranged opposite to two longitudinal tail ends of the pair of plate electrodes, a first waveguide extension block is arranged between one longitudinal tail end of the pair of plate electrodes and the first resonance chamber lens, the first waveguide extension block extends in a longitudinal direction toward the first resonance chamber lens, and therefore waveguide length is increased; the first waveguide extension block is made of a metal material or an electrical insulating material; when the first waveguide extension block is made of the metal material, and an electrical insulator is arranged between the first waveguide extension block and the pair of plate electrodes so as to insulate the first waveguide extension block from the pair of plate electrodes. Via the above structure, coupling loss of laser beams between the electrodes and a resonance chamber can be reduced, and pollution and damage brought to resonance chamber lenses by plasma electro-discharge can be kept at a low level.