Phase Change Cycling for Erasable Optical Storage Driven by Ultrashort Laser Pulses

Reversible phase transitions between the amorphous and the crystalline states have been induced in Sb 0.93 Ge 0.07 thin films by irradiation with picosecond laser pulses of different energy densities. It is shown for the first time that a material can be repetitively cycled between both states by means of ultrashort pulsed laser irradiation. The phase transformation involves optical contrast thus demonstrating that erasable phase change optical storage driven by ultrashort laser pulses is feasible.