Linear techniques of phase measurement by femtosecond spectral interferometry for applications in spectroscopy

Although nonlinear methods can provide only the amplitude and the phase of an isolated ultrashort pulse, Linear techniques can yield such measurements with a much better sensitivity and reliability when a reference pulse is available. We demonstrate two such methods, dual-quadrature spectral interferometry and Fourier-transform spectral interferometry. These techniques are simple to implement, very sensitive, and provide a complete measurement of the complex electric field, E(omega), as a continuous function of frequency. (C) 1995 Optical Society of America