Spatio-spectral characterization of ultrashort-pulse laser with wavelength-scanning ptychography

Spatio-spectral measurement of ultrashort-pulse beam is very important for the performance optimization of laser facilities. A reference-free, spectrally resolved measurement method based on ptychography with an advanced iterative algorithm for high-precision synthesis of full-spectrum data is proposed. We designed an integrated measurement device with robust implementation and high reliability. The device was successfully applied in a target chamber of a terawatt-class ultrashort-pulse laser facility. The spatio-spectral complex amplitude of a complicated pulsed laser was accurately reconstructed with high spatial resolution of 11 μm and some wavelength-dependent spatial phase characteristics in the laser pulse were identified. This method offers a promising approach for advanced beam characterization of high-power femtosecond laser system.