Inline UV pulse synthesizer

We demonstrated an inline synthesizer for generating ultrashort pulses in the ultraviolet (UV) range. The inline UV pulse synthesizer comprised three nonlinear crystals located in the propagation path of the fundamental driving laser pulse. Second-harmonic signals with central wavelengths of 420, 375, and 345 nm were generated in turn in the three BBO crystals, resulting in a synthesized UV pulse subsequent to the final nonlinear crystal. Its temporal amplitude and phase could be manipulated easily by changing the relative positions of the crystals, allowing for flexibility of the waveform. The minimum pulse duration of the synthesized UV pulse was 4.7 fs, which was close to the Fourier-transform-limited pulse duration. This ultrashort UV pulse with 19 $$ J energy can be utilized in various applications such as high harmonic generation and frustrated tunneling ionization.