SLAM: Super laser array memory

• Forschungsstelle: EU FRP
• Projektnummer: 00.0482
• Projekttitel Englisch: SLAM: Super laser array memory

Schlüsselwörter (Englisch)

Optical disk; superresolution; optical memory;
Information Processing; Information Systems; Innovation; Technology Transfer

Alternative Projektnummern (Englisch)

EU project number: IST-2000-26479

Forschungsprogramme (Englisch)

EU-programme: 5. Frame Research Programme - 1.2.8 Generic R&D activities

Kurzbeschreibung (Englisch)

See abstract

Partner und Internationale Organisationen (Englisch)

Coordinator: TU Delft (NL)

Abstract (Englisch)

The proposed research aims at the introduction of robust super high-density optical recording systems based on optical near-field related scanning methods with a dramatically increased reading/recording gap between the source and information layer.

The near-field method, in contrast with classic optical recording techniques, does not present a fundamental limit on the spatial density. The drastic enlargement of the air gap between probe and information layer will be achieved by developing a super-resolution technique combined with (coherent) detection of the phase of the reflected light in the far field. A larger spatial density will also be obtained by mircostructuring the information pits and by using a priori information present in the recorded signal. In addition to that, attention is paid to waveguide-based phase profile discrimination. The proposed removable optical recording systems will be crucial for the distribution of enormous amounts of information in a cheap an reliable way. By using several heads in parallel, the required data rate extension is easily obtained.

Objectives:
The objective is to demonstrate the feasibility and show the potential implementation of a robust optical storage system related to the optical near-field technique. The main drawback of a classical near-field optical head, its extremely small air gap, must be avoided. A dramatic increase in the air gap height should be obtained and, in the opinion of the proposers, this could be done by using super-resolution techniques, by making use of a priori information about the data stream, by implementing a potential coherent detection of the phase of the field reflected towards the probe and by micro -structuring the information pits.

An optimum implementation of all these measures requires a detailed analysis of the electromagnetic field in the volume between the optical head and the information layer and an extensive theoretical and experimental study of the reading and recording properties of such an optical system.

Work description:
The research will focus on methods to drastically increase the gap between the exit surface of the optical head and the information layer so that a robust optical system is obtained which can record and play back removable discs with an extremely high information density.

To reach this ambitious goal, a detailed theoretical and experimental analysis of the following topics is needed:
- Study of the internal EM-field exiting from the optical head and expanding towards the information layer.
- The interaction of the EM-field with the optical information layer as a function of the gap width, both under reading and recording conditions.
- Design of a super-resolution filter to drastically enhance the information density on the optical disc- Study of the super-resolution effect which can be expected if a priori knowledge about the structure of the information pits is available; emphasis on the detection of the phase of the reflected field. Shift of the optical pass-band to a high-frequency carrier.
- Study of deposited structures on the information 'pits' of the disc and on the exit surface of the laser to enhance the modulation depth of the detected signal (microstructuring).
- Use of several laser sources (array) to achieve parallel recording with a much higher data transfer rate and a study of cross-talk effects.
- Study of the merits of detecting laser current and/or laser light variations under the influence of the (coherent) optical flux returned by the information.
- Experimental study of the system properties in reading and recording mode; characterisation of the optical media properties and assessment of the robustness of the entire optical system plus media.

Datenbankreferenzen (Englisch)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 00.0482