Highly efficient parametric amplification of optical beams. I. Optimization of the profiles of interacting waves in parametric amplification

Design of a highly stable, high-conversion-efficiency, optical parametric chirped-pulse amplification system with good beam quality

“…The maximum OPCPA conversion efficiency is obtained when the rate of energy transfer from the pump to the signal and idler is such that all spatial and temporal points in the pulse reach peak conversion simultaneously. Maximizing the conversion efficiency thus requires the use of complementary shapes for the seed and pump spatial and temporal profiles, as described by Begishev et al 8,9 Appropriate seed temporal shapes can be approximated by spectral shaping 10 or other pulse-shaping techniques. 11,12 Ross et al 12 described a multiple-stage OPCPA design that allows significant reconversion in the preamplifier stages in order to produce an approximately complementary seed shape for use with a temporally Gaussian shaped pump in the final power-amplifier stage.…”

Non-Hermitian Dynamics Mimicked by a Hermitian Nonlinear System

“…A spatiotemporal asynchronocity of these power oscillations -due to the inhomogeneous transverse intensity profiles that are characteristic of real laser beams -is highly detrimental to the efficiency of the integrated power exchange, as they result in nonuniform conversion. This is a main limiting factor in optical parametric amplification (OPA) [5][6][7], a nonlinear process used to extend the frequency range of modern ultrafast laser systems. As a result, OPA, while an indispensable tool for ultrafast, strong-field, and relativistic optical science [8][9][10][11], is considerably less efficient than laser amplification [9,12].…”

“…Our example addresses the OPA efficiency problem: the inhomogeneous spatial and temporal intensity profiles of real laser beams make uniform pump depletion unfeasible in OPA, since sensitivity of the field power exchange cycle period to initial pump and signal photon number makes the length for full conversion vary with transverse coordinate. Historically, flattop or conformal laser profile shaping has been proposed, and in a few cases achieved, to synchronize power oscillations across the spatiotemporal coordinate and improve conversion efficiency [6,7,[31][32][33][34]. However, as shaping is usually impractical, low pump-to-signal energy conversion efficiencies of a few to twenty percent plague most OPA systems [12].…”

“…0 d eff n s c F{E p (t)E * i (t)} − ik s (ω)E s (ω) (5) d z E p (ω) = i ω p,0 d eff n p c F{E s (t)E i (t)} − ik p (ω)E p (ω)(6) …”

High-conversion-efficiency optical parametric chirped-pulse amplification system using spatiotemporally shaped pump pulses

“…This has several implications: First, careful tailoring of the pump and seed spatiotemporal profiles is required to achieve high optical parametric amplification (OPA) conversion efficiency. 6,7 Second, even slight variations in the pump intensity can result in large amplification-factor fluctuations, potentially leading to significant spatial and spectral modulation and large overall energy fluctuations in the amplified broadband output pulse. It has been shown that, for a narrow range of pump intensities and a particular interaction length, saturation in the OPA process can be observed, reduc-…”