Optical data storage with electron trapping materials using M-ary data channel coding

Earman, Allen M.

doi:10.1117/12.137530

Cited by 19 publications

(7 citation statements)

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“…We see from Table II that a d 1 = d 2 = 2, k 1 = k 2 = 10 ternary RLL sequence has a capacity that is slightly higher than 0.75 user bits per channel bit. 4 In Appendix A we have listed all of the 375 possible 15-symbol long 2,10-constrained sequences that both begin and end with fewer than nine '0's. These sequences will become ternary d 1 = d 2 = 2, k 1 = k 2 = 10 sequences if we let the symbol 'x' assume either of the values '1' or '2'; there are a total of 4254 such 15-digit long, ternary RLL sequences.…”

Section: Ternary Rll Sequences and Modulation Codesmentioning

confidence: 99%

“…ML-RLL modulation codes have been discussed previously in the technical literature. [1,2,3,4] The theoretical capacities, C(d 1 , d 2 ; k), and maximum efficiencies E m (d 1 , d 2 , k) of several ternary RLL sequences under the conditions d 1 ≤ d 2 , and k 1 = k 2 = k are listed in Table II. As a means of illustrating ternary RLL modulation we shall discuss the case d 1 = d 2 = 2.…”

Section: Ternary Rll Sequences and Modulation Codesmentioning

confidence: 99%

“…Reference [4] proposes the use of PPM recording to write marks corresponding to ML-RLL sequences onto an optical storage medium. This scheme is basically identical to that illustrated in Fig.…”

Section: Recording Multi-level Rll Sequencesmentioning

confidence: 99%

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Recording of multilevel run-length-limited modulation signals

Howe

2004

SPIE Proceedings

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We discuss the use of pulse length modulated recording of run-length-limited sequences of p-ary digits p i ∈ {0, 1, …, p-1}; p ≥ 3, to effect the physical representation of digital data on a storage medium that supports three or more distinct recording levels, or types of marks. p-ary run-length-limited modulation codes that facilitate the implementation of the modulation technique are also described. We also introduce a novel error correction coding technique that enables detecting/correcting errors in the values of the non-'zero' digits in the p-ary run-length limited sequence recovered from the storage medium. Modulation and Modulation Coding:Modulation is a process that produces a physical representation of logical information. In digital recording, the logical information of interest, also called 'user data', is in the form of binary digits ('bits') that usually occur in groups of length eight (i.e., eight-tuples of bits) called 'bytes'. The user data is usually presented to the data storage system as a 'file' which consists of one or more multi-byte blocks called 'sectors' (sectors generally comprise 512, 1024 or 2048 bytes of user data as well as several additional bytes of system information, e.g., information that identifies the location that the sector will occupy on the storage medium, error correction code parity information, etc.). Prior to actually recording a sector on the storage medium, the logical sequence of bytes must be represented as a physical entity, e.g., a time-varying electrical voltage or waveform. There are many types of modulation in use today. For example, in communications applications, individual bytes, or groups of bytes, of user data may be represented as different frequencies (frequency modulation), as different phases of a fixed-frequency carrier (quadrature phase modulation), as different pulse amplitudes in a pulse waveform (pulse amplitude modulation), etc. In some modulation techniques, the sequence of binary user data may first be transformed into a different sequence of bits, that exhibits certain properties, before creating the physical representation of the logical data. This latter transformation of binary sequences is performed to facilitate the realization of the physical representation of the user data and is known as 'modulation coding'. Binary RLL Modulation:Conventional digital data storage systems, such as magnetic disks/tapes and optical discs, carry information on their storage medium via modulation techniques that utilize only two types of marks (in the sequel we shall refer to this as bilevel recording). A recorded magnetic storage medium consists of a substrate coated with a thin layer of magnetic material having small regions that are magnetized in one of two oppositely directed orientations; either positive or negative voltage pulses occur when the magnetic playback head traverses the boundaries of these oppositely magnetized regions (the readout pulse polarity depends on the direction of the magnetization change that occurs at a boundary). Recorded phas...

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Section: Ternary Rll Sequences and Modulation Codesmentioning

confidence: 99%

Section: Ternary Rll Sequences and Modulation Codesmentioning

confidence: 99%

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Recording of multilevel run-length-limited modulation signals

Howe

2004

SPIE Proceedings

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“…It is therefore imperative that new approaches beyond traditional magnetic and solid-state data storage are developed to meet this demand. One of the most promising solutions is optical data storage which has been investigated in a variety of different approaches and using a range of different materials [3][4][5]. Importantly, optical data storage permits multilevel encoding [3].…”

Section: Introductionmentioning

confidence: 99%

“…One of the most promising solutions is optical data storage which has been investigated in a variety of different approaches and using a range of different materials [3][4][5]. Importantly, optical data storage permits multilevel encoding [3]. Multilevel encoding allows for the storage capacity to be increased by writing more than one bit per point.…”

Section: Introductionmentioning

confidence: 99%

Towards rewritable multilevel optical data storage in single nanocrystals

et al. 2018

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Novel approaches for digital data storage are imperative, as storage capacities are drastically being outpaced by the exponential growth in data generation. Optical data storage represents the most promising alternative to traditional magnetic and solid-state data storage. In this paper, a novel and energy efficient approach to optical data storage using rare-earth ion doped inorganic insulators is demonstrated. In particular, the nanocrystalline alkaline earth halide BaFCl:Sm is shown to provide great potential for multilevel optical data storage. Proof-of-concept demonstrations reveal for the first time that these phosphors could be used for rewritable, multilevel optical data storage on the physical dimensions of a single nanocrystal. Multilevel information storage is based on the very efficient and reversible conversion of Sm to Sm ions upon exposure to UV-C light. The stored information is then read-out using confocal optics by employing the photoluminescence of the Sm ions in the nanocrystals, with the signal strength depending on the UV-C fluence used during the write step. The latter serves as the mechanism for multilevel data storage in the individual nanocrystals, as demonstrated in this paper. This data storage platform has the potential to be extended to 2D and 3D memory for storage densities that could potentially approach petabyte/cm levels.

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Randomly Distributed Plasmonic Hot Spots for Multilevel Optical Storage

et al. 2018

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Multilevel optical storage is regarded as one efficient way to achieve higher capacity. In this paper, a kind of multilevel optical storage is presented by encoding the plasmonic hot spots among coupling gold nanorods (GNRs). The hot spots not only lower the recoding energy, but enhance two-photon-induced luminescence (TPL) intensity of the GNRs adjacent to hot spots significantly. From the numerical simulations based on finite-difference time-domain technique, it can be seen that the existence of hot spots expands the range of TPL intensity and makes a steeper function of TPL intensity distribution than isolated GNRs. The multilevel optical storage is performed experimentally in the GNR−poly(vinyl alcohol) (PVA) films with optical density (OD) = 3, 12, and 24. The six-level optical storage with high quality could be fulfilled with ultralow energy of only a few picojoule per pulse in the GNR−PVA films of OD = 12. This work can be the building blocks for the cold data storage in Big Data era.

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Optical data storage with electron trapping materials using M-ary data channel coding

Cited by 19 publications

References 0 publications

Recording of multilevel run-length-limited modulation signals

Recording of multilevel run-length-limited modulation signals

Towards rewritable multilevel optical data storage in single nanocrystals

Randomly Distributed Plasmonic Hot Spots for Multilevel Optical Storage

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