Thermal Effects in Up-Conversion Luminescence NaYF: Tm, Yb Core-Shell Nanoparticles in the Temperature Range of 18-312 K.

This work demonstrates the temperature (18-312 K) impact on Tm up-conversion luminescence in core-shell structured NaYF:Tm, Yb nanoparticles excited at 976 nm. As the temperature decreases from room temperature to 18 K, Tm up-conversion luminescence bands intensities greatly increase, an average of 60-fold, emitting intense blue and ultraviolet radiation. Tm up-conversion luminescence spectra measurements at different temperatures reveal that three thermal quenching mechanisms are responsible for observed variations in Tm up-conversion luminescence spectra.

High-order harmonics generation in Cd and Pd laser-induced plasmas.

We demonstrate the generation of high-order harmonics of laser pulses in palladium and cadmium plasmas. We adjusted the wavelength of driving pulses to investigate the resonance enhancement in different ranges of extreme ultraviolet region. The summation of incommensurate waves during the two-color pump of Pd and Cd plasmas allowed the generation of a broader range of harmonics.

Sol-Gel Synthesis of Translucent and Persistent Luminescent SiO@ SrAlO Eu, Dy, B Materials.

This publication offers an economically promising method of persistent luminescent silicate glass synthesis that does not involve high temperatures or ready-made (separately synthesized) PeL particles. In this study, we demonstrate the formation of SrAlO doped with Eu, Dy, and B in a SiO glass structure using the one-pot low-temperature sol-gel synthesis method. By varying the synthesis conditions, we can use water-soluble precursors (e.

Investigation of Nonlinear Optical Processes in Mercury Sulfide Quantum Dots.

The authors report the third-harmonic generation, nonlinear refraction, and nonlinear absorption in HgS quantum dot (QD) suspensions and films using the nanosecond and femtosecond pulses. High conversion efficiency (7 × 10) towards the third harmonic (TH) of the 900-1700 nm, 150 fs laser in the thin (70 nm) films containing HgS QDs deposited on the glass substrates is obtained. The authors analyze spectral dependencies of the TH, nonlinear refractive indices, and nonlinear absorption coefficients of QDs in the 500-1700 nm range and discuss the relation between the TH process and the low-order nonlinear optical properties of these quantum dots.

Third-order optical nonlinearities of exfoliated BiTe nanoparticle films in UV, visible and near-infrared ranges measured by tunable femtosecond pulses.

We characterize the nonlinear optical properties of synthesized BiTe nanoparticle-contained thin films using the tunable femtosecond laser in the spectral range of 400-1000 nm. These nanoparticles possess a strong saturable absorption and positive nonlinear refraction (-6.8×10 cm W in the case of 500 nm, 150 fs probe pulses, and 3×10 cm W in the case of 400 nm, 150 fs probe pulses, respectively).

Nonlinear Absorption and Refraction of Picosecond and Femtosecond Pulses in HgTe Quantum Dot Films.

We report measurements of the saturated intensities, saturable absorption, and nonlinear refraction in 70-nm thick films containing 4 nm HgTe quantum dots. We demonstrate strong nonlinear refraction and saturable absorption in the thin films using tunable picosecond and femtosecond pulses. Studies were carried out using tunable laser pulses in the range of 400-1100 nm.

Up-Conversion Luminescence Processes in NaLaF Doped with Tm and Yb and Dependence on Tm Concentration and Temperature.

In this work, luminescence processes in polycrystalline NaLaF:Tm and NaLaF:Tm,Yb materials were studied. Luminescence spectra and decay kinetics measurements were performed for NaLaF doped with various Tm concentrations (0.01, 0.