Activation of oxygen molecules by 1070 nm laser radiation in aerated solvents.

Population of the chemically active singlet (0) state of molecular oxygen occurring due to direct laser excitation of the (1)←-(0) transition has been observed for the first time, to the best of our knowledge, in oxygen molecules dissolved in organic solvents saturated with air under natural conditions (room temperature and normal atmospheric pressure). The data were obtained in 1 cm spectrophotometric cells due to the application of a set of high-power IR fiber and diode lasers. The rate of laser generation of the singlet ((0)) states in oxygen molecules was monitored by a chemical trapping method.

Measurement of high-birefringent spun fiber parameters using short-length fiber Bragg gratings.

Spectral polarization characteristics of short-length fiber Bragg gratings UV-written in a highly-birefringent spun-fiber have been investigated. Based on the analysis of the characteristics the technique for measuring the built-in linear phase birefringence as well as the spin period in this fiber type has been suggested. In this method the birefringence dispersion is excluded and therefore the built-in linear phase birefringence can be measured with an improved accuracy.

Watt-level, continuous-wave bismuth-doped all-fiber laser operating at 1.7 μm.

A watt-level all-fiber laser radiating at the wavelength of 1.7 μm in a continuous-wave regime was developed by using bismuth-doped high-germania optical fiber. A maximum slope efficiency of 33% with respect to the launched pump power was achieved.

High-beam quality, high-efficiency laser based on fiber with heavily Yb(3+)-doped phosphate core and silica cladding.

We have fabricated and tested a composite fiber with an Yb(3+)-doped phosphate glass core and silica cladding. Oscillation with a slope efficiency of 74% was achieved using core pumping at 976 nm with fiber lengths of 48-90 mm in a simple laser configuration, where the cavity was formed by a high-reflectivity Bragg grating and the cleaved fiber end. The measured M(2) factors were as low as 1.

Millijoule pulse energy 100-nanosecond Er-doped fiber laser.

We report, for the first time to our knowledge, on a single-mode millijoule-level 100-nanosecond Er-doped fiber laser operating near 1550 nm. The system features a newly developed 35-μm-core Yb-free double-clad Er-doped fiber based on P(2)O(5)-Al(2)O(3)-SiO(2) glass matrix and produces pulses with energy as high as 1 mJ at repetition rates of 1-10 kHz.