Under certain conditions, powerful ultrashort laser pulses can form greatly extended, propagating filaments of concentrated high intensity in gases, leaving behind a very long trail of plasma. Such filaments can be much longer than the longitudinal scale over which a laser beam typically diverges by diffraction, with possible applications ranging from laser-guided electrical discharges to high ...

A new laser technology which achieves nearly 100 nm quasi-continuous tuning using only injection current control in a four-section Grating-Coupler, Sampled-Reflector (GCSR) laser was used to simultaneously detect CO and CO2 in room-temperature gas mixtures. The same GCSR laser was used to perform in-situ measurements of CO, H2O, and OH in the exhaust gases of a methane/air flame. This laser is ...

We report on experiments simulating chemical processes in early Earth’s atmosphere initiated by events with high-energy density, e.g. lightning or impact of extraterrestrial objects. Large-scale laser spark was created in the mixture of molecular gases (N2, H2O, CO or CO2) in the high-power laser laboratory PALS. Transient chemical composition was analyzed in-situ by optical emission spectrosco...

Various applications, such as pollution monitoring, toxic-gas detection, non invasive medical diagnostics and industrial process control, require sensitive and selective detection of gas traces with concentrations in the parts in 10 (ppb) and sub-ppb range. The recent development of quantum-cascade lasers (QCLs) has given a new aspect to infrared laser-based trace gas sensors. In particular, si...

Recent advances in room-temperature, near-IR and visible diode laser sources for tele-communication, high-speed computer networks, and optical data storage applications are enabling a new generation of gas-dynamic and combustion-flow sensors based on laser absorption spectroscopy. In addition to conventional species concentration and density measurements, spectroscopic techniques for temperatu...

A Pound-Drever-Hall (PDH)-based mode-locked cavity-enhanced sensor system was developed using a distributed feedback diode laser centered at 1.53 µm as the laser source. Laser temperature scanning, bias control of the piezoelectric ceramic transducer (PZT) and proportional-integral-derivative (PID) feedback control of diode laser current were used to repetitively lock the laser modes to the cav...

The formation of plasma channels with nonuniformity of about ± 3.5% has been demonstrated. The channels had a density of 1.2×10 cm with a radius of 15 μm and with length ≥ 2.5 mm. The channels were formed by 0.3 J, 100 ps laser pulses in a nonflowing gas, contained in a cylindrical chamber. The laser beam passed through the chamber along its axis via pinholes in the chamber walls. A plasma chan...

Laser initiated, free standing discharge channels offer many attractive advantages for the transport and focusing of intense ion beams [1, 2]. Discharge plasmas can neutralize both current and space charge of such beams, while the azimuthal magnetic field provides strong focusing all the way through the channel. Experiments at GSI have produced 50 cm long stable plasma channels with peak curren...

In spite of the fact that more than five decades have passed since the invention of laser, some topics of laser-matter interaction still remain incompletely studied. One of such topics is plasma impact on the overall phenomenon of the interaction and its particular OPEN ACCESS Micromachines 2014, 5 1345 features, including influence of the laser-excited plasma re-radiation, back flux of energet...

A vertical cavity surface-emitting laser was studied for gas-sensing applications. Properties of the 962-nm laser that were measured include side-mode suppression, wavelength tuning with temperature and current, power versus injection current, and the amplitude noise spectrum. With wavelength modulation spectroscopy, a rms noise level of 2 x 10(-4) absorbance units was achieved. The large curre...