Abstract

Knowledge of the space-time properties of ultrafast laser pulses is necessary both for characterizing spatiotemporal distortions and for applications using structured beams. In the past, such characterization has relied mainly upon measurements of linear interference between an ‘unknown' pulse and a ‘reference' pulse [1]. To measure the unknown pulse, the reference must be spatially homogeneous, and its amplitude and phase must be characterized independently. In addition, the linear interference measurement has been confined to the visible and near-infrared regions of the spectrum due to the wavelength range of CCD and CMOS detectors. Our recent work has shown that nonlinear excitation of photocarriers in a silicon-based image sensor can provide a sub-cycle temporal gate, which can be used to characterize optical waveforms in the mid-IR [2]. Here, we show that by using a scanning geometry, the two-dimensional sensor allows the space, time and polarization properties to be characterized simultaneously. We demonstrate the technique through the measurement of few-cycle Bessel-Gaussian and vector waveforms.

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