Determination of spectral width and chirp of ultrashort light pulses by analysis of second harmonic beam divergence

The Real-Time Temporal and Spatial Diagnostics of Ultrashort High-Power Laser Pulses using an All-Reflective Single-Shot Autocorrelator

“…With the measured pulse duration of 23 fs for a sech 2 pulse shape, the value of the time-bandwidth product ∆t∆ν is 0.576, indicating that the laser pulse is not bandwidthlimited [16]. The diverging image of the SH signal observed in the CCD located 25 or 30 cm from the crystal could be evidence of positive chirp [17]. Further investigation and optimization are required.…”

Simple ultrashort light pulse chirp measurement device

“…of sum-frequency generation. The width of the secondharmonic beam ∆x is proportional to the pulse duration τ , provided the beam diameter d is large enough [2]:…”

“…Ultrashort light pulse characterization, which in general includes determination of the temporal dependence of the instantaneous frequency (chirp) or, equivalently, spectral phase, is a difficult and complicated task [1][2][3][4][5][6][7][8][9][10][11][12][13]. Our previous theoretical analysis has shown that the well-known nonlinear autocorrelator based on noncolinear second-harmonic generation (SHG) [13], in addition to pulse duration measurements, can provide measurements of the chirp of a fs pulse [2,4,13]. The SHG autocorrelation method has been verified experimentally with femtosecond pulses produced by the Ti:sapphire laser system based on the Colliding Pulse Amplification (CPA) scheme [7].…”