Vladimir N. Zagorodnev

Near-infrared luminescence of RbPb2Cl5:Bi crystals.

A wideband near-IR (NIR) luminescence centered at 1080 nm was found in a RbPb(2)Cl(5):Bi single crystal grown by the Bridgman technique. Absorption, luminescence, and excitation of luminescence spectra were investigated at room and cryogenic temperatures. The luminescence was proposed to be due to the (3)P(1)-->(3)P(0) transition in Bi(+) ion.

Optical spectroscopy of the RbPb 2 Cl 5 :Dy 3+ laser crystal and oscillation at 5.5 μm at room temperature

Oscillation at 5.5μm wavelength has been investigated in the low-phonon, moisture-resistant RbPb2Cl5:Dy3+ crystal in free-running mode at room temperature. In line with our knowledge this is the longest laser wavelength for a rare-earth doped crystal that does not require any special precautions for survival. Spectra and kinetics of luminescence of the new laser crystal were investigated under pumping to 1.3 μm absorption band, corresponding to lasing experiments. Emission cross sections were determined for mid-IR transitions. It was found that emission cross section on the 6H9/2+6F11/2→6H11/2 laser transition at 5.5 μm wavelength is as high as 0.6×10−20cm2.

Single-mode microstructured optical fiber for the middle infrared

Microstructured crystalline optical fiber from silver halides is described. Both experimental and theoretical evidences are presented to establish that the fiber is effectively single mode at wavelength 10.6 micro m with numerical aperture NA=0.16 and optical losses of approximately 2 dB/m. Crystalline microstructured optical fibers offer key advantages over step-index optical fibers from silver halide crystals. The wide transmission range of wavelengths 2-20 micro m provides great potential for applications in spectroscopy and for the development of a range of new crystalline-based nonlinear optical fibers.

Preparation and optical properties of rare-earth-activated alkali metal lead chlorides

High-purity MPb2Cl5 (M = K, Rb) and MPbCl3 (M = Rb, Cs) salts were prepared by directional solidification and zone melting of stoichiometric mixtures. The Bridgman method was used to grow crystals of rare-earth-activated double salts: KPb2Cl5:(Tb3+, KPb2Cl5:(Tb3+, Tm3+), KPb2Cl5:Dy3+, KPb2Cl5:Pr3+, RbPb2Cl5:Dy3+, and RbPb2Cl5:Pr3+. Analysis of their room-temperature IR absorption and luminescence spectra suggests that these crystals are potential materials for mid-IR solid-state lasers.

Preparation of Pr- and Dy-Doped Rb1 − xMxPb2Cl5 − yBry (M = K, Cs) crystals

We have demonstrated for the first time the possibility of preparing high-purity and praseodymium- and dysprosium-doped solid solutions based on lead halides and alkali metals: Rb1 − xCsxPb2Cl5, Rb1 − xCsxPb2Br5, Rb1 − xKxPb2Cl5, and RbPb2Cl5 − yBry. According to X-ray diffraction data, Rb1 − xCsxPb2Cl5 and Rb1 − xCsxPb2Br5 crystals in the solid solution range are isostructural with the constituent double salts RbPb2Cl5 and RbPb2Br5, respectively. The double salt Rb0.5K0.5Pb2Cl5 is isostructural with KPb2Cl5, and the double mixed salt RbPb2Cl2.5Br2.5 is isostructural with RbPb2Br5. The Pr3+ and Dy3+ concentrations in crystals of the solid solutions and mixed salts were determined by inductively coupled plasma mass spectrometry (ICP-MS). In the Rb1 − x (Cs, K)xPb2Hal5 (Hal = Cl, Br) solid solutions, the dopants were observed to be nonuniformly distributed over the host. According to ICP-MS analysis data and absorption spectra, the Pr3+ and Dy3+ concentrations in the RbPbCl2.5Br2.5 crystals were higher than those in RbPb2Br5.

Oscillation on the RbPb 2 Cl 5 :Pr 3+ Crystal within the 2.31–2.59 μm emission band

Pulsed oscillation due to the ³F₃ - ³H₅ transition was investigated in RbPb₂Cl₅:Pr³⁺ crystal. Lifetime of the upper laser level and peak emission cross section was estimated to be 0.11 ms and 1.7middot10^-19 cm² correspondingly.

Singlemode leakage channel fiber for the middle infrared

We fabricated leakage channel microstructured crystalline fiber (MCF) from solid solution AgClxBr1-x for middle IR with one ring of six rods and large mode field area 13 600 μm2 for the first time. Experiments proved that MCF is effectively single mode at 10.6 μm wavelength, which corresponds to numerical simulation. Measured optical losses are 8 dB/m.

Singlemode crystalline fibers for the middle infrared

Microstructured and step-index fibers from silver halides singlemode at 10.6 mum and 5.5 mum are demonstrated. Experimental and theoretical evidences are presented to establish that the step-index fibers are singlemode at 10.6 mum.

Spectroscopy of RbPb 2 Cl 5 :Pr 3+ Laser Crystal in Near- and Mid-IR

Nature of spectral broadening of absorption bands corresponding to f-f transitions in Pr3+ ion is investigated by low temperature absorption spectroscopy and selective laser spectroscopy.

The 5.5 μm-wavelength oscillation in the Dy3+:RbPb2Cl5 crystal at room temperature

New laser transition for 5.5 μm wavelength range was discovered in the moisture-resistant Dy3+:RbPb2Cl5 crystal. Pulse oscillation in free running mode was obtained under YAG:Nd laser pumping at 1.3 μm. Lasing slope efficiency was as high as 1% at room temperature. In line with our knowledge it is the longest laser wavelength for a rare earth doped crystal which does not require any special precautions to be survived.