Two-wavelength double heterodyne interferometry is applied for topographic measurements on optically rough target surfaces. A two-wavelength He-Ne laser and a matched grating technique are used to improve system stability and to simplify heterodyne frequency generation.

l'he demonstration of large soft x-ray a~nplification in a discharge-created plasma has opened a new patfito the development of compact and practical soft x-ray lasers. We review our progress in the development and study of these ultrashort wavelenglh lams. The field has advanced from the fust observation of large amplificatiod in a discharge-created plasma in Ne-like Ar [J.J. Rocca, V.N. Shlya...

BACKGROUND The use of photoactivated disinfection has had a significant medical and technological effect in bacterial inactivation, as an alternative to conventional antimicrobial methods. The main goal of this study was to investigate the effect of photoactivated disinfection on Streptococcus mutans, when Radachlorin(®) was used as a photosensitizer. METHODS Streptococcus mutans samples of t...

Simultaneous frequency and amplitude stabilization of a commercial internal-mirror He-Ne laser by a new simple method is reported. In this method, the back beam intensity of one polarization of the orthogonally polarized modes is fed back as a heater current to control the cavity length of the laser. The relative frequency stability and amplitude stability achieved are, respectively, +2.5 X 10-...

A suggestion for the generation of extreme-ultraviolet (XUV) laser radiation based on tunneling ionization and subsequent electron excitation of Deltan not equal 0 transitions is described. The favorable scaling of the required intensity of the pump laser with the output XUV wavelength is compared with that exhibited by XUV lasers ased on Deltan = 0 transitions. Calculations for Be-like Ne pred...

The lifetime of interatomic Coulombic decay (ICD) [L. S. Cederbaum et al., Phys. Rev. Lett. 79, 4778 (1997)] in Ne2 is determined via an extreme ultraviolet pump-probe experiment at the Free-Electron Laser in Hamburg. The pump pulse creates a 2s inner-shell vacancy in one of the two Ne atoms, whereupon the ionized dimer undergoes ICD resulting in a repulsive Ne+(2p(-1))-Ne+(2p(-1)) state, which...

We describe a collisional radiative code to simulate the Ne-like and F-like resonance lines emitted from laser produced plasmas. Ions and excited levels densities are calculated by solving rate equations using an implicit-finite difference method for steady state, quasi steady state and time-dependent conditions. The code calculates intensities of Ne-like 1s22s22p6 → 1s22s22p5nl and F-like 1s22...

A fiber sensor system based on high-birefringence optical fiber and a frequency-stabilized He-Ne Zeeman laser (lambda = 0.6328 microm) has been demonstrated. The small path-length changes of interest are extracted from the amplitude or phase of the laser beat frequency by using either the phase-sensitive detection or the phase-demodulation technique. A minimum detectable optical phase delay of ...

He-Ne laser irradiation (0.01 -6 3/cm3) of the blood and neutrophile suspension in vitrowas shown to modulate reactive oxygen species (RDS ) product ion in healthy donors. Intravascular laser irradiation of the blood ( 5 mW, 30 minutes, daily) of the patients with chronic gastric ulcer during first 5 days resulted in increasing stimul-k-duced ROS production in patients with the low initial chem...

Mid-infrared laser lines observed in hydrogen/rare gas discharges are assigned to three-body recombination processes involving an electron, a rare gas (He or Ne) atom, and the triatomic hydrogen ion (H(3)(+)). Calculations of radiative transitions between neutral H(3) Rydberg states support this interpretation, and link it to recent results for hydrogenic∕rare gas afterglow plasmas. A mechanism...