Temporally resolved Raman backscattering diagnostic of high intensity laser channeling

The implementation of an innovative technique for measuring the propagation of intense laser pulses through plasma channels is described. At high laser intensities, temporally resolved stimulated Raman backscattering can be used to diagnose both the electron density and the laser intensity inside the plasma channel, observations which are not possible using other techniques. This diagnostic is demonstrated in experiments using an open-ended capillary in which a plasma channel was created. The plasma channel was generated using either an electrical discharge or laser ablation by a second laser pulse.