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Suppression of Cubic Nonlinearity in Second-Harmonic Generation of Ultrahigh-Intensity Laser Pulses by Initial Frequency Chirp

We demonstrated that a frequency chirp initially introduced to a fundamental pulse can be used to effectively suppress the cubic nonlinear effect in type I second-harmonic generation with ultrahigh-intensity laser pulses. The energy conversion efficiency can be increased by a factor of 1.23 with good temporal and spatial profiles of second-harmonic pulse in comparison with conventional schemes of second-harmonic generation.