Persistent spectral hole burning and optical data processing

1993 ◽  
Author(s):  
Karl K. Rebane
Keyword(s):  
Data Processing ◽  
Optical Data ◽  
Hole Burning ◽  
Spectral Hole Burning ◽  
Optical Data Processing ◽  
Spectral Hole

Spectral Data Storage Using Rare-Earth-Doped Crystals

MRS Bulletin ◽  
1999 ◽  
Vol 24 (9) ◽  
pp. 46-50 ◽  
Author(s):  
Eric S. Maniloff ◽  
Alan E. Johnson ◽  
Thomas W. Mossberg
Keyword(s):  
Rare Earth ◽  
Absorption Line ◽  
Data Storage ◽  
Optical Data Storage ◽  
Optical Data ◽  
Hole Burning ◽  
Spectral Hole Burning ◽  
Line Broadening ◽  
Spectral Hole ◽  
Rare Earth Doped

Conventional optical data-storage techniques, such as magneto-optic disks and CD-ROMs, record a single bit of information at each particular substrate location. In order to produce the gigabyte-class storage substrates demanded by today's computers using such conventional technologies, access to tens of billions of individual material locations is required. This brute-force approach to optical data storage has produced impressive results. However, there is increasing interest in methods for more efficiently accessing storage materials. One approach is to record multiple bits at a single storage-material location. This can be accomplished by multiplexing the bits spectrally, using differing optical frequencies to record data bits. It has been realized for over 20 years that when certain materials are cooled to appropriate temperatures, typically below 20 K, the possibility of spectrally multiplexing large numbers of bits in a single material location arises. Although this approach, known as spectral hole-burning, has been proposed as a data-storage mechanism, to date it has primarily been used as a tool to study material properties. Rare-earth-doped crystals have been demonstrated to have properties that lend themselves to a variety of different spectral hole-burning-based data-storage applications. In this article, we will review the principles of spectral hole-burning, discuss some specific material systems in which spectral hole-burning is of particular interest, and describe methods for producing high-capacity, high-data-rate spectral memories.Spectral hole-burning, and spectral memories based on spectral hole-burning, depend on a material property referred to as inhomogeneous absorption line broadening. Materials exhibiting this property contain active atoms or molecules that individually respond to (absorb) very specific frequencies of light, but the collective response of all of the material's active atoms or molecules covers a spectral region that is broad compared with the response of a particular active atom or molecule. Inhomogeneous absorption line broadening is caused by local variations in the structure of the host, which in turn lead to variations in the electronic levels of the active atoms or molecules. The absorption linewidth of an individual absorber is referred to as the homogeneous linewidth Γh, and the absorption width of a collection of inhomogeneously broadened absorption centers is referred to as the inhomogeneous linewidth Γi. Application of monochromatic light to such a material has the effect of exciting only a very small subset of active absorbing atoms—those residing in the illuminated spatial volume within a homogeneous width of the exciting light's specific frequency. If the frequency of the imposed light is shifted, a different subset of active absorbing atoms in the illuminated volume responds.

Memory and neural networks on the basis of color centers in solids

2009 ◽  
Vol 390 (11) ◽  
Author(s):  
Albrecht Winnacker ◽  
Andres Osvet
Keyword(s):  
Neural Networks ◽  
High Speed ◽  
Optical Data ◽  
Color Centers ◽  
Hole Burning ◽  
Spectral Hole Burning ◽  
Data Recording ◽  
Spectral Hole ◽  
Set Up ◽  
High Degree

Abstract Optical data recording is one of the most widely used and efficient systems of memory in the non-living world. The application of color centers in this context offers not only systems of high speed in writing and read-out due to a high degree of parallelism in data handling but also a possibility to set up models of neural networks. In this way, systems with a high potential for image processing, pattern recognition and logical operations can be constructed. A limitation to storage density is given by the diffraction limit of optical data recording. It is shown that this limitation can at least in principle be overcome by the principle of spectral hole burning, which results in systems of storage capacities close to the human brain system.

FEMTOSECOND SPECTRAL HOLE-BURNING IN GaAs/AlGaAs MULTIPLE QUANTUM WELLS

1987 ◽  
Vol 48 (C5) ◽  
pp. C5-511-C5-515 ◽  
Author(s):  
J. L. OUDAR ◽  
J. DUBARD ◽  
F. ALEXANDRE ◽  
D. HULIN ◽  
A. MIGUS ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Multiple Quantum Wells ◽  
Hole Burning ◽  
Spectral Hole Burning ◽  
Multiple Quantum ◽  
Spectral Hole

Investigation of the V4+-Centre in 6H- and 4H-SIC by the Method of Spectral-Hole Burning

1998 ◽  
Vol 512 ◽  
Author(s):  
C. Hecht ◽  
R. Kummer ◽  
A. Winnacker
Keyword(s):  
Electronic Properties ◽  
Room Temperature ◽  
Hole Burning ◽  
Band Offset ◽  
Spectral Hole Burning ◽  
Type Ii ◽  
Thermally Stable ◽  
Spectral Hole

ABSTRACTIn the context of spectral-hole burning experiments in 4H- and 6H-SiC doped with vanadium the energy positions of the V4+/5+ level in both polytypes were determined in order to resolve discrepancies in literature. From these numbers the band offset of 6H/4H-SiC is calculated by using the Langer-Heinrich rule, and found to be of staggered type II. Furthermore the experiments show that thermally stable electronic traps exist in both polytypes at room temperature and considerably above, which may result in longtime transient shifts of electronic properties.

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