Adaptive compression of tunable pulses from a non-collinear-type OPA to below 16 fs by feedback-controlled pulse shaping

Dispersion control in a 100-kHz-repetition-rate 35-fs Ti:sapphire regenerative amplifier system

“…According to the Nyquist theorem, the phase difference between two adjacent pixels should not exceed [18]. For a purely quadratic, cubic, or quartic phase distribution, this implies -in our case-a limitation of 5.10 fs , 5.10 fs , and 8.10 fs , respectively, for the maximum SOD, TOD, and FOD applicable.…”

“…We focus the beam in a nonlinear crystal (BBO, 20 m) and record the resulting second harmonic (SH) as a feedback signal. Adjustment of the voltage of each pixel for maximum SH represents an optimization problem which is solved with an evolutionary algorithm [4], [14], [18]. Convergence of the procedure [ Fig.…”

Evolutionary algorithms and their application to optimal control studies

“…For substantially shorter pulses, especially in the sub-20 fs range, more care must be taken to satisfy these approximations. Replacing the lenses by spherical or cylindrical mirrors, as demonstrated in section 2.5 as well as in chapter 5, avoids these problems and ensures dispersion-free operation [61][62][63][64][65]. Phase-only filters which have the advantage of being inherently loss-free are used in many pulse shaping experiments.…”

Spectral phase shaping for non-linear spectroscopy and imaging

“…A phase profile applied to the incoming pulse with that maximizes the second harmonic intensity, has the opposite sign of the original phase profile [92]. The optimization is done by parameterization of the phase in orders of (ω-ω 0 ) [93]:…”

“…The optimization loop is based on a genetic or evolutionary algorithm [94] which uses a set of random values for c k for the first generation. The next generation consists of a mixture of the values of c k for the best measured cases, together with random variations (mutations) to find the optimum values of c k [93]. Here a thin (10 µm) BIBO crystal is used as SHG crystal.…”