V A Mikhailov

Lasing in a Tm:Ho:Yb3Al5O12crystal pumped into the3H6-3F4transition

A growth technology has been developed, and a Tm:Ho:Yb3Al5O12 laser crystal of high optical quality has been grown by Czochralski method. Its spectral and luminescent characteristics are studied. Lasing at a wavelength of 2100 nm is obtained under pumping into the absorption line on the 3H6 – 3F4 transition of the Tm3+ ion at a wavelength of 1678 nm. The slope and total (optical) efficiencies of the laser at an output power of up to 320 mW reach 41% and 30%, respectively.

Influence of synthesis conditions on optical losses in aluminoborophosphate laser glass

The influence of the duration of melting, the purity of the reagents used for synthesis, and the material of crucibles on the optical losses in laser neodymium high-strength aluminoborophosphate glass has been investigated. The obtained results have demonstrated that the main reason of emerging of optical losses at the lasing wavelength in the glass under study is the interaction of the crucible material with the aluminoborophosphate melt which is aggressive at a synthesis temperature of 1350°C.

Diode-pumped lasers based on oxide crystals

The main results of experimental investigation of basic physical, spectroscopic and laser properties of Nd:GdVO4, Nd:YVO4, Nd:LaSc3(BO3)4, Tm:GdVO4 and other oxide crystals are discussed. The problem of obtaining of high efficient CW lasing on fundamental and second harmonic wavelengths using optimized laser resonators including microchip configuration is studied.

Spectroscopy of the Tm:Sc2SiO5 laser crystal in different orientations

Six absorption bands of Tm3+:Sc2SiO5 crystal have been investigated by decomposing each absorption band into a series of Lorentzian peaks. Polarized light of two polarizations was transmitted in three perpendicular directions through a crystal shaped as a parallelepiped with polished faces. The results are presented in the form of tables containing the parameters of the found Lorentzian peaks: central wavelength, width, and height.

Study of the formation of a microrelief on ZnSe- and CdSe-crystal surfaces ablated by excimer KrF-laser radiaton

One-dimensional gratings with a period of are formed on the surfaces of CdSe and ZnSe crystals ablated by two interfering radiation beams of a nanosecond excimer KrF laser. Investigated are the dependences of the shape and depth of gratings on the energy density under irradiation by a single pulse, and on the number of pulses at a given energy density. The maximum grating depth is estimated as of the period. By forming a one-dimensional grating with a period of and a depth of on the CdSe-crystal surface, this surface becomes antireflective at a wavelength of . The surface reflectivity is reduced by 88 %. A possibility of forming two-dimensional gratings having periods of 1 and is demonstrated.

Acousto-optic Q-switched Tm:Ho:YbAG laser pumped at 1678 nm

Acousto-optic Q-switched lasing has been obtained for the first time in a Tm:Ho:YbAGcrystal. The laser output power is analyzed as a function of the laser pulse repetition rate. It is found that at rates above 30 kHz the laser slope efficiency reaches maximum values (~20 to 30%), comparable with the efficiency in the cw mode. The shortest laser pulse width is about 40 ns, and the average output power reaches about 80mW.

The study of a Tm:YbAG laser pumped at 1678 nm

The laser crystal Tm3+:Yb3Al5O12 (Tm:YbAG) was grown by the Czochralski method and was investigated under pumping by a Raman-shifted erbium fiber laser at a wavelength of 1.678 um. Absorbance and luminescence spectra were recorded and the luminescence lifetime of the upper lasing level 3F4 was measured to be 4,7 ms. Lasing of this crystal at a wavelength of 2.02 um was obtained for the first time. The laser slope efficiency reached 41% at the output power up to 330 mW at room temperature.

Lasing in a Tm : Yb{sub 3}Al{sub 5}O{sub 12} crystal pumped at 1.678 μm

The Yb3Al5O12 (YbAG) crystal is proposed as a matrix of Tm3+-doped laser elements for two-micron lasers. A Tm : YbAG crystal of high optical quality is grown by the Czochralski method and its spectral and luminescent characteristics are studied. The luminescence decay time for the upper laser level 3F4 is measured to be 4.7 ms. Lasing in this crystal pumped by a 1.678-μm fibre laser is obtained at a wavelength of 2.02 μm for the first time. The total and slope efficiencies of the laser at room temperature and an output power up to 330 mW reach 33% and 41%, respectively.

Study of Tm : Sc{sub 2}SiO{sub 5} laser pumped into the {sup 3}H{sub 6} – {sup 3}F{sub 4} transition of Tm{sup 3+} ions

The Tm3+ : Sc2SiO5 crystals of optical quality are grown by the Czochralski method. Lasing at a wavelength of ~1.98 μm is obtained in an active element made of a grown crystal under pumping by an erbium Raman fiber laser at a wavelength of 1.678 μm. The slope efficiency of the laser reaches 42% at an output power up to 320 mW.The Tm{sup 3+} : Sc{sub 2}SiO{sub 5} crystals of optical quality are grown by the Czochralski method. Lasing at a wavelength of ∼1.98 μm is obtained in an active element made of a grown crystal under pumping by an erbium Raman fiber laser at a wavelength of 1.678 μm. The slope efficiency of the laser reaches 42% at an output power up to 320 mW. (lasers)

A 913-nm diode-pumped quasi-three-level Nd{sup 3+}:Gd{sub 0.7}Y{sub 0.3}VO{sub 4} laser

Lasing parameters of a mixed Nd{sup 3+}:Gd{sub 0.7}Y{sub 0.3}VO{sub 4} vanadate crystal emitting at the 913-nm {sup 4}F{sub 3/2}-{sup 4}I{sub 9/2} laser transition are studied. The output power of up to 600 mW was obtained upon longitudinal diode pumping for the absolute and slope laser efficiencies of {approx}13% and {approx}17%, respectively. (lasers)