We study numerically and analytically the role of the combined effect of self-focusing, geometrical focusing, and the plasma defocusing in the formation of the fluorescence signal during the filamentation of a Ti:sapphire laser pulse in nitrogen molecular gas. Results of numerical simulations are used to estimate the number of excited ions in the focal volume, which is proportional to the fluor...

We demonstrate coherent control of the optical transition of single nitrogen-vacancy defect centers in diamond. On applying short resonant laser pulses, we observe optical Rabi oscillations with a half period as short as 1 ns, an order of magnitude shorter than the spontaneous emission time. By studying the decay of Rabi oscillations, we find that the decoherence is dominated by laser-induced s...

We report on the development of a photoacoustic sensor for the detection of formaldehyde (CH(2)O) using a thermoelectrically cooled distributed-feedback quantum cascade laser operating in pulsed mode at 5.6 μm. A resonant photoacoustic cell, equipped with four electret microphones, is excited in its first longitudinal mode at 1,380 Hz. The absorption line at 1,778.9 cm(-1) is selected for CH(2)...

With an approach of controlling the nonlinearity of medium rather than the light field, the effect of field-free molecular alignment on filamentation and resulting white-light generation is studied. This is done by measuring the rotational wavepacket evolution of nitrogen molecules after passing of a femtosecond laser pump pulse by observing the nonlinear propagation dynamics of a variably dela...

Articles you may be interested in The electronic properties of a two-electron multi-shell quantum dot-quantum well heterostructure Enhanced tunnel transport in disordered carbon superlattice structures incorporated with nitrogen Nonlinear transport in quantum-cascade lasers: The role of electric-field domain formation for the laser characteristics Electrical conductivity enhanced dielectric and...

We investigated the optical emission features of plasmas produced by 800 nm, 40 fs ultrafast laser pulses on a carbon target in the presence of ambient helium or nitrogen gases at varied pressures. Fast photography employing intensified charge coupled device, optical emission spectroscopy, and temporally spatially resolved optical time of flight emission spectroscopy were used as diagnostic too...

We show that a novel material InNAsP grown on InP is superior for long-wavelength microdisk lasers (and so expected for edge-emitting lasers) because of its larger conduction band offset from the addition of a small amount of nitrogen (0.5%–1%). The maximum temperature of operation for an InNAsP–GaInAsP microdisk laser is 70 C, which is about 120 C higher than that of a similar laser fabricated...

Optical waveguiding LiNbO3 film was grown on ~001!-oriented crystalline SiO2 substrate by pulsed laser deposition. The film is highly ~012! textured and has smooth surface. Its photoluminescence ~PL! spectra were obtained by using the 514.4 nm line excitation of Ar laser, displaying a broad band peaked at 2.2 eV at room temperature and three well-resolved luminescent bands peaked at 2.3, 2.2, a...

Evaporation kinetics of fused silica were measured up to ≈3000K using CO(2) laser heating, while solid-gas phase chemistry of silica was assessed with hydrogen, air, and nitrogen. Enhanced evaporation in hydrogen was attributed to an additional reduction pathway, while oxidizing conditions pushed the reaction backwards. The observed mass transport limitations supported use of a near-equilibrium...

The task of wear resistance improvement for bearing steels working at high loads in water medium was solved by laser alloying with Sn. The modified zone contains up t o 22 wt.% Sn, which is used as a solid lubricant during exploitation. As a result the bearing race's durability is increased 2.5 times. The combination of laser alloying from a nitrogen jet with surface plastic deformation (SPD) w...