M. I. Timoshechkin

Spectroscopic and lasing properties of calcium niobium gallium garnet activated with Cr3+ and Nd3+

An investigation was made of the luminescence and lasing spectra of a calcium niobium gallium garnet crystal activated with Cr3+ and Nd3+ ions. An effective nonradiative energy transfer from the chromium to the neodymium ions was discovered. The probability of an elementary Cr→Nd interaction event was determined. A detailed study was made of the Stark structure of the ground (4I9/2) and metastable (4F3/2) levels of Nd3+. Selective laser excitation was used to identify four main optical Nd3+ centers for which the splitting schemes of the 4I9/2 and 4F3/2 levels were constructed. Lasing was observed at 300 K as a result of the 4F3/2→4I11/2 transition in crystals activated with Cr3+ and Nd3+.

Growth and luminescence of epitaxial Yb{sub 0.3}Er{sub x}Gd{sub 2.7-x}Ga{sub 5}O{sub 12} films

A series of (Gd,Yb,Er){sub 3}Ga{sub 5}O{sub 12} films with a variable Er content was grown on Gd{sub 3}Ga{sub 5}O{sub 12} substrates with the (111) orientation by liquid-phase epitaxy from a supercooled PbO - B{sub 2}O{sub 3} melt. Variation of the film growth from sample to sample, grown under the same conditions, was explained by degradation of the molten solution. The violet colour of the first film of the series was attributed to enhanced capture, from the molten solution, of lead and platinum impurity ions and also to characteristics of charge compensation of these ions at high growth rates. Blue - green luminescence was observed for films with erbium content in excess of 0.01 at.%. (active media)A series of (Gd,Yb,Er)3Ga5O12 films with a variable Er content was grown on Gd3Ga5O12 substrates with the (111) orientation by liquid-phase epitaxy from a supercooled PbO — B2O3 melt. Variation of the film growth from sample to sample, grown under the same conditions, was explained by degradation of the molten solution. The violet colour of the first film of the series was attributed to enhanced capture, from the molten solution, of lead and platinum impurity ions and also to characteristics of charge compensation of these ions at high growth rates. Blue — green luminescence was observed for films with erbium content in excess of 0.01 at.%.

Efficient laser operation of Cr,Nd:GGG crystals at 1.331 and 1.423 um

Spectroscopic and laser properties of Cr,Nd:GGG and Nd:YAG crystals in the 1.3 - 1.45 micrometers wavelength range have been compared. Flashpumped Cr,Ce,Nd:GGG laser operating at 1.331 micrometers with total efficiency up to 3% and average output power of 65 W has been developed. For the first time to our knowledge oscillation at 1.4237 micrometers wavelength in Cr,Nd:GGG crystal have been obtained. Output energy of 2.3 J at this eyesafe wavelength with total efficiency of 1.23% have been obtained for flashpumped Cr,Ce,Nd:GGG laser in free-running mode. Average output power of 21.6 W at 13 Hz repetition rate have been achieved. Cr,Nd:GGG crystals advantages for 1.4 micrometers lasing compared to Nd:YAG crystals are discussed.

Large single crystals of neodymium and chromium co-doped gadolinium gallium garnet for efficient solid state lasers

The paper treats the problems of growth of large defectless single crystals of gadolinium- gallium garnet (GGG) doped with chromium, cerium, and neodymium, up to 65 mm in diameter and 130 mm long. The influence of UV radiation of the pump flashlamp on the formation of stable color centers in GGG-crystals co-doped with Cr, Ce, and Nd-ions was investigated. The processes of a nonradiative energy transfer from Cr to Nd ions in GGG were analyzed. The lasing properties of the GGG:Nd and GGG:Cr,Ce,Nd crystals were studied at 4F3/2 yields 4I11/2 and 4F3/2 yields 4I13/2 transitions. On the basis of grown crystals efficient lasers with the wavelengths of 1.06 and 1.33 micrometers are developed.

Multipurpose two-wavelength surgical laser

Prototype of a commercial laser system, capable of performing various surgical operations, was developed and produced. The laser unit can emit, separately or simultaneously, radiation with wavelengths 1.06 and 2.1 (mu) at an average power up to 30 and 6.5 W correspondingly. The construction of an optical scheme and power supply gives wide flexibility of the laser output parameters. Possible medical applications of the 1 - 2 micron laser system are considered.