(c) Dr Paul Kinsler. [Acknowledgements & Feedback]

# Carrier Shocking (2003-)

This work was done in conjunction with Prof. GHC New and graduate student J.C.A. Tyrrell and S.B.P. Radnor in the Department of Physics at Imperial College.

This description is under construction

The self-steepening of an optical pulse envelope was first studied by DeMartini \emph{et al.} in 1967, and is a well-known phenomenon associated with self-phase modulation. Surprisingly, however, the possibility of shock formation on the optical carrier was considered even earlier in a 1965 paper by Rosen, who showed that, for a third order ($\chi^{(3)}$) nonlinearity, a field discontinuity (or shock) can develop under certain circumstances after a finite distance of propagation. Before a carrier shock forms, or before its onset is halted by (e.g.) dispersion or the nonlinear response time, the carrier-wave undergoes self-steepening. This carrier self-steepening/ shocking phenomenon received little attention for more than 30 years, until it was revisited in the 1990s by Flesch \emph{et al.} \cite{Flesch-PM-1996prl,Gilles-MV-1999pre}, who performed Finite Difference Time Domain (FDTD) simulations of the process.

Following initial investigations by J.C.A. Tyrrell, we studied the effect of linear dispersion on carrier shocking, now published in Phys. Rev. E. This has led on to other topics. The first is the use of carrier shocking as a process with which to probe the uni-directional approximation of propagating optical pulses. The second is the use of near-shocked (self-steepened) waveforms as drivers for High Harmonic Generation. Here the steep field gradients enhance the spectral cut-off, and the pulse profiles can generate shorter XUV bursts. Further, since carrier shocking is a rather general process, occurring (at least in principle) for all nonlinear orders, we can use $\chi^{(2)}$ self-steepened pulses to break the inversion symmetry of the driving field, and produce more isoalated XUV bursts.

Background References:
1. Demartini-TGK, Phys. Rev. (1967).
2. Rosen, Phys. Rev. (1965).
3. Flesch, P, Moloney, Phys. Rev. Lett. (1996),
Gilles, Moloney, V, Phys. Rev. E (1999).
4. Kinsler, Radnor, Tyrrell, New, Phys. Rev. E (2007).
5. Kinsler, submitted to JOSA B (2007).
6. Radnor, Chipperfield, Kinsler, New, in preparation (2007).

( Research homepage; )
Date=18 20011117 Author=P.Kinsler Created=20011117

LOGBUG