We report experimental results showing novel features in photo-darkening and photo-bleaching of a heavily-doped Ytterbium silica fiber exposed to in-core 977-nm 543-nm irradiation. It is shown that pumping the at resonant wavelength leads an increase absorption spectrally wide range (400–1000 nm, photo-darkening) simultaneous decrease (Yb 3+ ) coefficient near ∼ 1 μm (resonant photo-bleaching). Such character spectra transformations allows us propose they are signature light-induced Yb → 2+...

A new effect for a CW-pumped ytterbium fiber laser (YFL), self-induced line sweeping (SLLS), is reported. The effect's main characteristic ``adiabatic'' movement (seconds) of the from shorter to longer wavelengths, spanning over spectral interval as large 7 nm, followed by its instantaneous bounce backward. SLLS regime observed nearly above YFL threshold, in excess pump power up 70% threshold value, whereas at higher pumps it replaced common chaotic bursts time domain. seems appear owing use...

The characteristics of a : ZnSe laser in scheme with transverse pumping by nonchain electric-discharge HF at room temperature are studied. Doping crystals ions was performed diffusion simultaneously through two surfaces under the conditions thermodynamic equilibrium. It is found that pulses modulated short spikes ( half maximum low pump energies), whose number decreases and modulation depth increases as energy to threshold value. A pulse achieved duration (at high energies); possibility...

An investigation was made of the spectral, luminescence, and lasing properties gadolinium scandium gallium garnet (GSGG) crystals activated with neodymium chromium ions in which efficiency transfer excitation from to is considerably higher than YAG:Nd3+:Cr3+. It found that parameter characterizing probability an elementary Cr3+–Nd3+ interaction event for GSGG twenty times YAG twice garnet. Investigations were free parameters GSGG:Nd3+:Cr3+ it maximum differential GSGG:Nd3+. concluded...

We report a study of the attenuation spectra transformations for series Bismuth (Bi) doped silica fibers with various contents emission-active Bi centers, which arise as result irradiation by beam high-energy electrons. The experimental data reveal substantial decrease concentration associated presence Germanium in glass, at increasing dose (the resonant-absorption bleaching effect germano-silicate fiber). In contrast, spectral changes that appear alumino-silicate fiber have through...

The nonlinear transmission of light by single-wall carbon nanotube suspensions in D2O at a wavelength 1.54 μm is studied. For the 250-ns probe pulse and 40-MW cm-2 maximum intensity radiation incident on cell, decrease absorption coefficient was 3.6 cm-1 while weak field 17 cm-1. Q-switching self-mode locking were obtained pulsed Er3+ : glass laser using cell with suspension as passive filter.

A study was made of the spectral, luminescence, and lasing properties an yttrium scandium gallium garnet crystal activated with chromium erbium. The lifetimes Stark sublevels some levels Er3+ were determined schemes these constructed. It established that, in addition to "forward" energy transfer, there also reverse process Er3+→Cr3+. mechanism interaction its microscopic constants determined. erbium concentrations could be varied within wide limits without significant deterioration...

An investigation is reported of the spectral, luminescence, and lasing properties a Gd3Ga5O12 crystal activated with chromium neodymium ions. The high efficiency energy transfer process from to ions demonstrated. For example, probability an elementary Cr3+–Nd3+ interaction event in was 12 times higher than that Y3Al5O12 crystal. It found sensitization ion luminescence by can increase severalfold characteristics cw pulsed lasers. free-lasing parameters shows ultimate differential...

The superluminescence of a Fe2+:ZnSe crystal was obtained in the region from 4.6 to 4.7 μm upon transverse pumping by high-power laser radiation at 2.94 μm. pulse energy ∼1 mJ 15-mJ pulse. A ZnSe doped with Fe2+ ions diffusion method under conditions thermodynamic equilibrium phases.

A modeling of an all-fiber self-Q-switched Erbium laser is developed, implying that the mechanism self-Q-switching power-dependent thermo-induced lensing in fiber stems from excited-state absorption at wavelength.

A new physical effect lying in the generation of an electrical signal (ES) upon interaction IR laser radiation with water surface at a fluences lower than plasma formation threshold is studied. An ES amplitude exceeding 15 V detected. one-to-one relationship between observed and bulk explosive boiling established, qualitative interpretation proposed. In case irradiation open surface, generated due to accompanied by evacuation splashing layer, destruction double electric layer on spread...

A laser continuously tunable in the range 766–820 nm was constructed. It utilizes an electronic–vibrational transition chromium a gadolinium scandium gallium garnet crystal kept at room temperature and subjected to nonselective flashlamp pumping.

Fabrication details and basic characteristics of a set novel multimode hafnia-yttria-alumina-silicate (HYAS) core-glass based fibers, one which is co-doped with bismuth (Bi), for the mid-IR (> 2 µm) spectral range are reported. It demonstrated that fibers this type possess low fundamental loss in beyond µm, lowered by fewer times as compared to conventional silica-based ones, even at moderate (units mol.%) co-doping hafnium. This makes them attractive versatile applications. Furthermore,...

Spectral-kinetic characteristics of the cathodoluminescence Fe2+ : ZnSe single crystals are studied at T=300 and 80 K. These correspond to IR luminescence spectrum kinetics ions in optically excited into impurity absorption band. The obtained results open a real possibility pumping lasers by hot electrons.

A model is proposed of passive Q switching in a laser by crystal switch with phototropic centres. Expressions for the output energy and duration giant pulse are derived taking account geometric factor representing distribution orientations these centres relative to lattice switch. The calculated results agreement those obtained an experimental investigation neodymium form doped LiF :F2- or Cr4+ : YAG crystal.

An investigation was made of changes in the profile and state polarisation a short (25 ns) resonant light pulse (λ ~ 1.06 μm) during its propagation YAG : Cr4+ crystal. The experimental results were good agreement with theory which absorption by impurity centres crystal is described phenomenologically as consequence interaction three orthogonal groups linear dipoles. result demonstrated fleasibility controlling propagating through polariser — system. application single-frequency to this...

A laser is described utilizing neodymium phosphate glass, an unstable resonator, and Q switching by stimulated Brillouin scattering. It was found that occurred when the resonator changed over from to a stable configuration. Wavefront reversal then caused lasing take place in lowest-order mode, radiation having diffraction-limited divergence completely filling 6.3 mm diameter of active element.

Self-mode locking is achieved in a F2-:LiF laser pumped by cw fibre using new passive switch based on single-wall carbon nanotubes.

By the example of absorbing liquids (water, ethanol) irradiated by erbium laser pulses (λ = 2.94 μm), possibility was experimentally demonstrated for detecting displacement evaporation front phase shift (delay) acoustic response to a high-frequency (ω > 0.1 GHz) modulation pulse with duration τ 1/ω.

Abstract The influence of free electrons in Fe 2+ : ZnSe crystals on the nonlinear transmission high-power laser radiation with a wavelength 2940 nm at room and low temperatures is experimentally found. samples additionally doped Al are used. an sample electron conduction strong (peak intensity about 4.6 MW cm −2 ) field almost same as weak both temperatures. absence increase this under action explained by increasing absorption saturation due decrease lifetime excited state . related to...

The linear and nonlinear transmission of crystals is measured at a wavelength in the temperature range . It found that, with increasing from to , decreases case incident radiation an intensity increases At almost coincides transmission. spectra temperatures 22 are presented.