Characterization of a liquid-crystal ultrafast pulse shaper for ultra-broadband applications

By combining broadband common-path spectral interferometry with an iterative fitting algorithm the phase response of a liquid-crystal spatial light modulator has been characterized from 400 to 770 nm, equivalent to a frequency bandwidth of 0.36 PHz. The resulting calibration not only maps the response of the device as a function of wavelength and voltage, but also provides sufficient information to recover the thickness of the liquid-crystal cell and the wavelength dependent refractive index of the liquid-crystal. The technique has applications in amplitude and phase shaping of pulses from broadband super-continuum and optical parametric oscillator/amplifier sources.