Saturday, October 23, 1999
Joint SPIE and Department of Electrical and Electrical Engineering Seminar, The University of Hong Kong (Hong Kong, Hong Kong)
Using femtosecond laser pulses we study the effects of intense laser radiation on transparent materials. By tightly focusing these laser pulses below the surface of transparent materials, we initiate highly nonlinear absorption processes which produce a dense, highly-excited plasma inside the sample. The high density, tightly-confined plasma leads to a micron-sized explosion within the material, with temperatures and pressures approaching stellar conditions. We have recently shown that it is possible to create internal submicron-sized structures by optically initiating microexplosions inside transparent solids. We have demonstrated three-dimensional data-storage densities of 17 Gbits/cm^3. Other applications of this technique include photonic bandgap materials and three dimensional diffractive optical elements. The extreme conditions produced in microexplosions provide a microscopic laboratory for studying the equation of state of materials at high temperature and pressure. Microexplosions may also find applications in in ophlalmology, subsurface skin surgery, and biological experiments.