Metal vapor laser

Metal vapor lasers belong to the group of gas lasers in which the radiating medium is in the gaseous or vapor phase. The best-known metal vapor laser is the copper vapor laser , there are also metal vapor lasers that work with the elements lead , calcium , gold , manganese , selenium , thallium or indium . They are mostly operated in a pulsed manner.

Helium - cadmium - and helium-selenium vapor lasers can also be operated in a continuous wave in a direct current glow discharge. The necessary metal vapor partial pressure is generated in a furnace (250-350 ° C) on the anode side of the discharge. The vapor diffuses into the discharge capillary (inner diameter approx. 1.5 mm) and migrates to the cathode side . Prior to the cathodic electrode a is condensation trap for the metal vapor is provided to protect the laser Brewster window from deposits. The excitation of the metal atoms in the upper laser state occurs through collisions with highly excited helium atoms (energetically close to the ionization energy), which are de-excited into a metastable state. The ground state of the helium atoms is restored by impacts with the capillary wall. Due to the complexity of the metal atoms and the multitude of electronic states, a multitude of laser levels have been detected in these metal vapor lasers, ranging from infrared to ultraviolet .

Typical wavelengths

• Gold vapor laser: 312 nm, 627.8 nm
• Copper vapor laser: 510.6 nm, 578.2 nm
• Helium-cadmium vapor laser: 325 nm, 442 nm