Multilevel data writing in nanoporous glass by a few femtosecond laser pulses.

Abstract

Multidimensional data recording inside nanoporous high-silica glass by a femtosecond laser beam has been investigated. It is shown that three femtosecond laser pulses at pulse repetition rates up to 1MHz are sufficient for recording 3bits of information inside nanoporous glass, which is an order of magnitude lower than the number of pulses required for data writing in silica glass and provides a corresponding gain in the data writing speed. Multilayer data recording and reading were demonstrated providing the storage density corresponding to the capacity of 25GB in the optical compact disc form factor. An outstanding thermal stability of the proposed optical data storage is confirmed by the 24h long heat treatment at 700°C, which could not damage the recorded data.