DPSS

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DPSS ( diode pumped solid state ; also DPSSL ) is the abbreviation for a solid-state laser pumped with the radiation from diode lasers . Diode-pumped solid-state lasers are increasingly replacing the previously common solid-state lasers pumped with gas discharge lamps.

construction

The laser crystal of the solid-state laser is usually a yttrium-aluminum-garnet (YAG) crystal (host crystal) in disk, plate, fiber or rod form that is doped with erbium , ytterbium or neodymium . However, other host crystals are also used, such as: YAlO 3 (YALO), YVO 4 (yttrium vanadate), YLiF 4 (YLF), tungstates (KGd (WO 4 ) 2 , KY (WO 4 ) 2 ), as well as sapphire and zinc chalcogenides.

The doping results in different pump and emission wavelengths:

  • Ytterbium: diode laser pump wavelength at 930 ... 945 nm, emission at 1029 nm
  • Neodymium: pumps at 808 nm or 888 nm, emission at 1064 nm
  • Erbium: pumping at 980 nm, emission (or amplification, see EDFA ) at 1550 nm

Compared to pumping with gas discharge lamps, pumping with diode laser radiation offers several advantages:

  • the electrical-optical efficiency of diode lasers is higher than that of flash lamps
  • the pump lasers only generate the wavelength that is used to excite the laser medium - this reduces heating
  • the lower heating leads to higher power densities and better beam quality due to lower thermal stresses
  • the laser diodes have a longer service life than gas discharge lamps

The disadvantage of a DPSS laser is its high purchase price due to the relatively expensive laser diodes.

Diode pumped z. B. Nd: YAG lasers ( laser pointer ), in which the 1064 nm line of the neodymium -doped crystal is frequency-doubled with the aid of a KTP crystal, so that laser radiation with a wavelength of 532 nm is available.

Disk lasers and fiber lasers are principally DPSS lasers.