L E Li

Properties of Nd 3+ -doped and undoped tetragonal PbWO 4 ,NaY(WO 4 ) 2 , CaWO 4 , and undoped monoclinicZnWO 4 and CdWO 4 as laser-active and stimulated Ramanscattering-active crystals

Spectroscopic, laser, and chi((3)) nonlinear optical properties of tetragonal PbWO(4), NaY(WO(4))(2), CaWO(4), and monoclinic CdWO(4) and ZnWO(4) were investigated. Particular attention was paid to Nd(3+)-doped and undoped PbWO(4) and NaY(WO(4))(2) crystals. Their absorption and luminescence intensity characteristics, including the peak cross sections of induced transitions, were determined. Pulsed and continuous-wave lasing in the two 4F(3/2)-->4I(11/2) and 4F(3/2)-->4I(13/2) channels was excited. For these five tungstates, highly efficient (greater than 50%) multiple Stokes generation and anti-Stokes picosecond generation were achieved. All the observed scattered laser components were identified. These results were analyzed and compared with spectroscopic data from spontaneous Raman scattering. A new crystalline Raman laser based on PbWO(4) was developed for the chi((3)) conversion frequency of 1-microm pump radiation to the first Stokes emission with efficiency up to 40%. We classify all the tungstates as promising media for lasers and neodymium-doped crystals for self-stimulated Raman scattering lasers.

Nanocrystalline zinc oxide: Pyrolytic synthesis and spectroscopic characteristics

Nanocrystalline and microcrystalline ZnO powders are synthesized by the pyrolysis of organic zinc salts in the presence of a reducing catalyst represented by a porous cellulose carrier. The specimens obtained are characterized by X-ray powder diffraction, energy dispersive analysis, scanning electron microscopy, and pulse cathodoluminescence. Lasing characteristics of the specimens are studied. The synthesis conditions, under which specimens with the crystallite morphology optimal for a low-threshold lasing are obtained, are found.

High-temperature lasing in ZnO microcrystallites

High-temperature studies of the luminescence and lasing spectra parameters of the main UV bands (spontaneous luminescence and lines of stimulated-emission mode structure) and the recombination band of electron-hole plasma in zinc oxide microcrystallites have been performed. ZnO microcrystallites of tetrapod morphology, characterized by type-II lasing (microlasers), have been chosen as objects of study [1]. The temperature behavior of a number of key parameters related to specific features of microlasing is investigated.

New Nd{sup 3+}:CaLu{sub 2}F{sub 8} laser crystal containing lutetium

A new Nd3+:CaLu2F8 fluoride laser crystal with a disordered structure was produced. A preliminary investigation was made of its absorption and luminescence characteristics, and cw lasing (4F3/2 → 4I11/2 channel) of the Nd3+ activator ions was achieved.

Quasi-cw Pr{sup 3+} : LiYF{sub 4} laser with {lambda}= 0.6395 {mu}m and an average output power of 2.3 W

A quasi-cw flashlamp-pumped Pr3+ : LiYF4 laser was developed. It emits in the red part of the spectrum (λlas=0.6395 μm) and it is repetitively pulsed. Its average output power is 2.3 W at a repetition rate of f=10 Hz and 650 mW at f=50 Hz.