The City University of New York

Other

Vladimir Petricevic

Robert R Alfano

Alexey Bykov

Swapan Kumar Gayen

Mikhail Sharonov

A laser medium includes a single crystal of chromium-doped LiScInGeSiO, where 0&#x2266;x&#x2266;1 and 0&#x2266;y&#x2266;1. Preferably, x and y are not both 0. A laser, such as a tunable near infrared laser, can contain the laser medium.

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A method is described to improve and produce purer Cr-doped laser materials and lasers with reduced co-incorporation of chromium in any other valence states, such as Cr, Cr, Cr, and Cr. The method includes: 1) certain crystals of olivine structure with large cation (Ca) in octahedral sites such as Cr:CaGeO, Cr:CaSiO, Cr:CaGeSiO(where 0&#x3c;x&#x3c;1), and/or 2) high-temperature solution growth techniques that enable the growth of the crystals below the temperature of polymorphic transitions by using low melting point solvent based on oxide, fluoride and/or chloride compounds. Purer Cr-doped laser materials are characterized by a relatively high concentration of Cr-lasing ion in crystalline host that makes these materials suitable for compact high power (thin disk/wedge) NIR laser applications.

Tetravalent chromium doped laser materials and NIR tunable lasers

A laser medium includes a single crystal of Cr:MgMSiAO, where, where M is a bivalent ion having an ionic radius larger than Mg, and A is a tetravalent ion having an ionic radius larger than Si. In addition, either a) 0&#x2266;x&#x3c;2 and 0&#x3c;y&#x3c;1 or b) 0&#x3c;x&#x3c;2 and y is 0 or 1 with the proviso that if M is Caand x=1 then y is not 0. The laser medium can be used in a laser device, such as a tunable near infrared (NIR) laser.

A laser-medium in the form of a dielectric crystal or glass doped with tetravalent chromium. The dielectric crystals are of olivine-like structure such as germanates of formula (A) (RE)GeO.sub.4 where (A=Na or Li, RE=Y, Lu or Gd), crystals of willemite structure Zn.sub.2 (Si or Ge)O.sub.4 tetrahedral sites, or any other single-crystal or polycrystalline compound containing the (Si.Ge)O.sub.4 tetrahedra in its crystal lattice, such as Ca.sub.3 La.sub.2 (SiO.sub.4).sub.6 and crystals such as YAG (Y.sub.3 Al.sub.5 O.sub.12).

Tetravalent chromium (Cr.sub.4+) as a laser-active ion for tunabale

A laser system in which the laser medium is a single crystal of Cr.sub.3+ :Mg.sub.2 SiO.sub.4 is disclosed. In one embodiment, the system comprises a single crystal of chromium doped forsterite and a cavity which includes a pair of 30 cm. radius mirror having high transmission at 543 nm (the pump wavelength) and high reflectivity in the 1150-1350 nm range. Room temperature vibronic pulsed laser action is obtained with this cavity. Laser action has been observed at 1235 nm and a bandwidth of 25 nm. The wavelength range is suitable for transmission through optical fibers and is useful in laser ranging and remote sensing. Because of the ultrawide fluorescence bandwidth and a 15 fluoroescence lifetime the system is suitable for high intensity, tunable, cw, Q switched mode locked operation. In the mode locked operation pulses as short as 10-500 femtosecond may be generated. A number of different embodiments of the invention are described.

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New York, NY, United States of America

Vladimir Petricevic