Aluminum oxide single crystals doped with magnesium and carbon and having aggregate vacancy defects are proposed
for volumetric fluorescent bit-wise data storage. A unique optical recording technique, which utilizes sequential two-photon
absorption and incoherent confocal fluorescence detection, is utilized for nondestructive readout. The new
medium is exceptionally environmentally and temporally stable and can be recorded with diode lasers. Recent static and
dynamic test stand results are reported, including demonstration of 20 layers of data and random mark-length recording
with a clear "eye pattern" and satisfactory carrier-to-noise ratio.
Recording and readout in two-photon absorbing Al<sub>2</sub>O<sub>3</sub>:C,Mg optical data storage media was investigated for crystals having different concentrations of color centers and for two orientations of the crystal optical c-axis. The writing and reading efficiency of the media was increased by taking into account the anisotropy of optical absorption and by rotating the laser light polarization vector synchronously with the disk rotation. The parameters for writing and non-destructive reading of the bits in the volume of a single crystal disk are reported.
Spectroscopic properties of new aluminum oxide crystals for volumetric optical data storage are investigated. Magnesium impurity and double oxygen vacancy defects are responsible for the main optical properties of the new material. Sequential two-photon absorption and ionization of color centers followed by capture of a free electron on a deep trap is a suggested mechanism for writing information. One-photon absorption and non-destructive readout using reconstruction of recorded holograms or a confocal fluorescence detection scheme are proposed.
Two-photon absorption in new aluminum oxide single crystals is used for recording single bits in multiple layers while one-photon absorption and a confocal fluorescence detection scheme is applied for data readout.
Holographic recording is tested using new Al<sub>2</sub>O<sub>3</sub>:C,Mg single crystals. Plane holograms were recorded using 442 nm pulsed laser light from an optical parametric oscillator and were read non-destructively with a 442 nm He-Cd laser.
Conference Committee Involvement (1)
Optical Data Storage 2014
18 August 2014 | San Diego, California, United States