Recording by microexplosion and two-photon reading of three-dimensional optical memory in polymethylmethacrylate films

We report the recording of a three-dimensional (3D) pattern in bulk polymet hyl metacrylate (PMMA) films by microexplosion induced by a tightly focused (numerical aperture of oil-immersion objective was 1.3) single laser shot. Recording was done by picosecond (ps) single-pulse irradiation at 532 nm a nd by femtosecond at a 400 nm wavelength. The light-induced damage threshol d of PMMA was found at similar to 4 MW/cm(2) for ps damaging. Readout of th e 3D pattern was carried out by the recording of the transmission and the p hotoluminescence (PL) of bits. We demonstrate the possibility exciting PL o f the optically damaged area inside the PMMA by one- and two-photon absorpt ion. (C) 2000 American Institute of Physics. [S0003-6951(00)03208-3].