Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Fabrication and plasma spectroscopy of PLD thin film deposition for power-gated holeburning

Zameer U. Hasan, Francisco J. Bezares, Jhisook Park, Mike Campanell, Muhammed Aly

Published Feb 8, 2007• 1 citation

Abstract

The fabrication of spectral storage materials presents a great challenge of tailoring the optical properties of a solid at the atomic scale. We show that by a careful choice of a host material and the luminescent rare earth centers created in it, thin film structures can be fabricated using pulsed laser deposition. It is shown that these structures can be tailored to satisfy the material requirements for the power-gated spectral holeburning, one of the most successful techniques for the spectral storage. In the form of multilayer thin film structures, these tailored materials can provide surface storage densities exceeding a terabit per square inch. Possibilities of tailoring new rare earth centers that can further multiply the storage densities have been discussed. Experimental data has been presented for the fabrication and characterization of such impurity based europium centers in MgS and CaS by chemically controlled pulsed laser deposition.

DOI: 10.1117/12.716386

Related papers

Pulsed laser deposited thin films of sulfides for high-density memory storage

J. L. Park, Levent Biyikli, Mohamed F. Aly +1 more

For frequency domain storage rare earth doped sulfide show the most promising characteristics of any spectral holeburning material known. They provide the desired density of storage with a remarkable stability of memory against storage, read- out, and thermal surges. Problems associated with the fabrication of a prototype device not only require a careful consideration of design parameters but also raise some interesting questions regarding the material characteristics and the holeburning mechanism. This paper gives the status of our efforts in the direction of making thin films of MgS and CaS doped with Eu suitable for spectral holeburning based optical storage using the Pulsed Laser Vapor Deposition (PLD) technique.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIENov 22, 19990 citations

Thin films of sulfides for high-density optical storage by photon-gated hole burning

Mohamed F. Aly, Levent Biyikli, Sameh I. Dardona +2 more

In the form of micro-particles europium doped alkaline earth sulfides have been shown to exhibit high density of permanent spectral holes. The photon-gated spectral holeburning (PGHB) in these systems provided the most promising characteristics of any material known to date. These spectral holes can be used as optical memory. However, for any optical storage device either large size single crystals or thin films are required. Thin films of these materials are grown by Pulsed Laser Deposition (PLD) technique. This fast and simple growth technique is superior the single crystal growth or the molecular beam epitaxy (MBE) as far as the holeburning properties are concerned. Transparent glassy MgS:Eu and CaS:Eu films have been grown and tested for the spectral holeburning properties. Critical parameters such as the relative concentration of Eu2+ and Eu3+, and optical quality of thin films have been investigated. Int his paper we report on the growth and the high-density optical holeburning in these films. The density of spectral holes has been further increased by burning in multiple Eu-centers in a material and by depositing multiple layers of thin films of different materials in a stack.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIENov 29, 20002 citations

Atomic tailoring for ultra-dense multi-layer spectral memories

Z. Hasan, J. L. Park, Francisco J. Bezares +1 more

Spectral Storage using optical holeburning has the potential of providing ultrahigh densities approaching terabits per square inch. The progress on multilayer spectral storage in Eu-doped sulfides has been presented. It is shown that atomic scale tailoring of these structures is possible in order to design several different europium optical centers. In the spectrum of these centers, ultrahigh density storage can be achieved with the simultaneous optimization of other performance parameters. Results are also presented for tailoring the barrier and the capping layers.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEFeb 9, 20061 citation

Challenges for ultra-high density spectral storage

Zameer U. Hasan

ABSTRACT A review of the status of ultra-high density spectral storage has been presented. Keywords: Ultra-High Density Spectral Storage, Spectral Memories, Terabits Storage, Spectral Holeburning, Optical Holeburning, Multi-layer Th infilm, Power-Gated Holeburning, Optical Materials, Rare Earths 1. INTRODUCTION Spectral Storage offers the highest possible storage densities thus far. Terabits per square inch and even more have been shown to be possible, in principle. Spectral storage is unlike any other type of storage. Magnetic, holographic, multi-layer storage [1], etc., are all macroscopic scale storage in the sense that the macroscopic properties of the recording material are transformed to record a series of zeros and ones. Spectral storage is at the atomic or microscopic scale. A small number of atoms in a solid-state medium are used to store a bit of information. This is responsible for the high storage density of spectral storage. A cubic micron of solid has ~10 18

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEFeb 7, 20080 citations

Photoluminescence and spectral holeburning in europium-doped MgS nanoparticles

Zameer U. Hasan, Sameh I. Dardona, Aras Konjhodzic

Luminescence and power-gated spectral holeburning studies have been performed on Eu-doped MgS nanoparticles. These particles are atomically tailored to produce and control the relative concentration of Eu(2+) and Eu(3+), which is necessary for power-gated holeburning. The spectral holes are permanent at low temperatures. Optical studies show that the electron-phonon coupling is stronger in nanoparticles than in thin films or microparticles of the same material. This is the reason for inherently broader spectral holes in nanoparticles as compared to microparticle or thin-film samples. Temperature broadening of spectral holes in nanoparticles follows a T(2.4) behavior, a faster rate than thin films or microparticles. This behavior can be attributed to the glassy nature of the particles produced.

The Journal of Chemical PhysicsDec 8, 20055 citations

Power-gated spectral holeburning in MgS:Eu2+, Eu3+: A case for high-density persistent spectral holeburning

Z. Hasan, Levent Biyikli, P. I. Macfarlane

We present the case of photoionization-induced holeburning in rare-earth-doped II–VI compounds for high-density persistent holeburning. In this case, the photoproduct of holeburning is distributed across the entire zero-phonon line. This maximizes the total number of possible spectral holes that can be burned into an inhomogeneous line as well as produces holes that are photoerasable. Experimental data on photon-gated holeburning in MgS:Eu2+, Eu3+ are presented. With the proper choice of the host electronic band structure, the optically active rare-earth ion and its electronic transitions involved in the holeburning process, to the best of our knowledge we have observed the highest number of photon-gated holes ever burned in a single electronic transition. The features of these holes are that they suffer no detectable erasure after several thousands of read cycles, they survive thermal cycling to ∼150 K, and they are completely photoerasable. A special case of photon-gated holeburning, power-gated holeburning, was employed to demonstrate that, in such systems, a single laser can be used for burning, reading, and erasing of the spectral holes.

Applied Physics LettersJun 29, 199820 citations