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Line shape analysis of O 2 in air at high temperature is reported using a spectrometer based on a DFB-diode laser. Measurements for the R Q( N =11) and the R R( N =5) magnetic dipole transitions of the b 1 Σ g + ( ν ′=0)← X 3 Σ g − ( ν ′′=0) band at 761 nm are performed at atmospheric pressure from room temperature up to 900°C. Four parameters are extracted and analysed giving evidence of the possibility of measuring gas temperature and O 2 concentration with the laser method.

LiNbO(3) single-crystal fibers with diameters of 63 and 230 mum were grown, and the second-harmonic-generation (SHG) process was studied with femtosecond laser pulses perpendicularly focused to the fiber. SHG occurred without collinear phase matching, leading to wavelength-independent overall conversion efficiency, unlike in a bulk crystal. The scattering pattern of the second harmonic exhibited an intense forward peak and an almost-uniform, less-intense distribution around the fiber, owing to trapping in high-Q whispering modes. Implementation of a second-order autocorrelator with the 63-mum fiber demonstrates its application potential.