Disc Properties
Mempile's TeraDisc technology uses specially-engineered chromophores encased within a special transparent acrylic matrix. This plastic is designed for robust commercial production using injection-molding, and for use with drive technology similar to that of DVD recorders.
Using a red laser on Mempile's current media, the TeraDisc can record 200 DVD-like virtual layers resulting in close to 1 TB of data. With the refinements expected over time, the number of data layers will be substantially increased and other attributes like mark size and spacing decreased. Capacities of 5 TB can be expected.
Drive Components include:
• CD-like system for tracking
• Red read/write modelocked picosecond laser
• Sensitive detector for read signal (450-600 nm)
• Two dichroic elements
• Focus offset control (to pick the desired working layer)
• Independent servo systems for the tracking and read/write lasers
• Variable spherical aberration correction
The Optical Pickup Unit
The optical pickup unit is being specially designed for precise positioning such that the head can be moved radially and vertically, always perpendicular to the recording surface. The collection and detection system is nearly standard.
The Optical and Mechanical Systems
The optical data storage industry has invested enormous resources on research and development over the last few decades, and Mempile leverages the fruits of this work in the drive design. The optomechanical systems required for disc clamping and movement, disc-head alignment, data encoding and decoding, data tracking and many other subsystems, can all be taken from existing systems with little or no modification. Even methods to lock on to and address multiple layers of information have been developed in the past (e.g. for DVD-9). The Mempile approach does not require exotic optical components previously untested in commercial optical storage, such as spatial light modulators, immersion lenses, or confocal optics. Rather, standard components are used, with the addition of a robust and simple method of variable spherical aberration correction. The use of two-photon reading means that fluorescence signal is emitted only from the addressed data point, and therefore spatial filtering optics are not required.
