X-ray Generation

   Femtosecond laser produced plasmas are violent objects with extreme conditions of temperature and pressure and so it is a bright source of electromagnetic radiation and high charge state ions with energies extending from fraction of an electron volt to million electron volts (MeV). Usual electron temperatures are as high as a few hundred keVs.
   We are looking at the generation, optimisation and applications of fs X-ray sources. This physics underlying the efficient laser-plasma coupling schemes, plasma heating and X-ray generation are being investigated with a number of low Z and high Z targets. The main objective of the present experiments is to provide a predictable X-ray source for applications in time resolved pump-probe experiments. Extremely short pulse durations and large flux can be made use of to study the lattice dynamics and transient chemical reaction dynamics. The very low exposure dose compared to continuous sources is useful for imaging living cells.

   Through High Harmonic Generation, femtosecond or sub-femtosecond coherent pulses are generated in the VUV to soft X-ray region with laser intensities of the order of 10¹⁵-10¹⁶ W/cm². There is excellent progress in this area across the world, but phase matching of the generated field with the fundamental is one of the challenges towards attaining maximum efficiency. Here in SILIS we are looking at various phase matching schemes using modulated capillary wave guides and capillary discharges and we hope to provide the beam for applied research in science and technology.