V. P. Mikhailov

Pulsed laser operation of Yb-doped KY(WO 4 ) 2 and KGd(WO 4 ) 2

Spectroscopic properties and laser performance of Y b-doped tungstates at pulsed Ti:sapphire laser pumping are reported. Room-temperature lasing near 1025nm is demonstrated in Yb:KY(WO(4))(2) and Yb:KGd(WO(4))(2), with a slope efficiency as great as 86.9%.

Diode-pumped CW lasing of Yb:KYW and Yb:KGW

Abstract Room temperature CW laser action of Yb 3+ -doped KY(WO 4 ) 2 and KGd(WO 4 ) 2 crystals at 1026–1044 nm has been demonstrated under pumping by 980 nm fiber-coupled InGaAs laser diode. A slope efficiency of Yb lasers up to 53% has been obtained.

Absorption and luminescence of tetrahedral Co2+ ion in MgAl2O4

Abstract Optical absorption, luminescence, saturation of absorption and lifetime measurements have been carried out on Co-doped MgAl 2 O 4 . The crystal field parameter Dq of 400 cm -1 and the Racah parameters B of 730 cm -1 and C of 3500 cm -1 are estimated for the tetrahedral Co 2+ ion. Luminescence bands observed in the visible at 660 nm and in the near infrared at 880 and 1270 nm are assigned to transitions from the 4 T 1 ( 4 P) level to the lower levels 4 A 2 ( 4 F), 4 T 2 ( 4 F), and 4 T 1 ( 4 F), respectively. Strong luminescence quenching due to nonradiative decay processes is observed. Saturation of Co 2+ absorption at 540 nm is measured and the absorption cross section is estimated to be (2.1 ± 0.2) × 10 -19 cm 2 .

Optical absorption and nonlinear transmission of tetrahedral V3+ (d2) in yttrium aluminum garnet

Abstract The saturation of the optical absorption in V 3+ : YAG crystal is investigated. The absorption cross section of tetrahedral V 3+ at 1.08 μm is estimated to be 8.2±2.5x10 -18 cm 2 . Q -switching and passive mode-locking for a number of solid state lasers with wavelengths at 747 nm, 780 nm, 1.06 μm and 1.34 μm have been obtained with a V 3+ :YAG saturable absorber.

Chromium-doped forsterite as a solid-state saturable absorber

Saturation of near-infrared absorption in Mg(2)SiO(4):Cr is observed, and the absorption cross section at 1.08 microm is estimated to be sigma(alpha) = (2.3 +/- 0.3) x 10(-18) cm(2). Q switching and passive mode locking of a Nd:YAG laser have been realized with a Mg(2)SiO(4):Cr saturable absorber.

Cr 2+ :ZnSe and Co 2+ :ZnSe saturable-absorber Q switches for 1.54-µm Er:glass lasers

Passive Q switching of Er:glass lasers has been demonstrated with Cr(2+):ZnSe and Co(2+):ZnSe saturable absorbers. A pulse duration of ~50ns and an output pulse energy of 5 mJ were obtained with both Co:ZnSe and Cr:ZnSe passive shutters. A Q-switched conversion efficiency of as much as 26% was obtained for Cr:ZnSe. Theoretical modeling exhibits satisfactory agreement with experimental data.

Spectroscopy and excited-state absorption of Ni2+-doped MgAl2O4

Abstract Luminescence, ground-state and excited-state absorption and lifetime measurements on Ni2+-doped MgAl2O4 were performed. Excited-state absorption bands at 1700 nm in the near infrared and at 750 and 580 nm in the visible region due to the transitions from the 3T2 (3F) metastable state to the 3T1(3F), 1T2(1D), and 3T1(3P) states were observed and ESA cross sections were determined. The 3T2-3T1(3F) ESA band overlaps with the emission band and prevents lasing of Ni2+ : MgAl2O4 at room temperature.

Fluorescence dynamics, excited-state absorption, and stimulated emission of Er 3+ in KY(WO 4 ) 2

The fluorescence dynamics from excited states of Er3+ in KY(WO4)2 are compared with Judd–Ofelt-theory calculations, and spectroscopic parameters of the promising laser transitions from the 4I13/2,4I11/2, and 4S3/2 levels are determined. The cw excited-state absorption spectra of Er3+-doped KY(WO4)2 are measured with a pump-and-probe technique and analyzed in the spectral range from 500 nm to 1800 nm. Energy transfer between Yb3+ and Er3+ ions in codoped KY(WO4)2 is investigated. Laser action near 1.54 μm under Ti:sapphire and diode-laser pumping is obtained in Er,Yb:KY(WO4)2.

Spectroscopy, excited-state absorption and stimulated emission in Pr3+-doped Gd2SiO5 and Y2SiO5 crystals

Abstract Spectroscopic measurements on Pr 3+ -doped Gd 2 SiO 5 and Y 2 SiO 5 crystals were performed. Cross-sections of excited-state absorption (ESA) from the 3 P 0 level of Pr 3+ were estimated in both crystals. Stimulated emission in the red spectral region on the 3 P 0 - 3 F 2 transition was detected in Pr 3+ :Gd 2 SiO 5 . Poor pumping efficiency due to the strong ESA prevents lasing from the 3 P 0 level in both silicates.

Z-scan measurements of nonlinear refraction and Kerr-lens mode-locking with Yb3+:KY(WO4)2

The nonlinear refractive index n2 of Yb3+:KY(WO4)2 crystal has been measured using picosecond Z-scan technique. The magnitude of n2 was found to be 8.7 × 10−16 cm2/W at wavelength of 1.08 μm. The numerical modeling based on fluctuation model showed a great potential of this crystal as active medium for Kerr-lens mode-locking.