Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

International Conference on Optoelectronic Science and Engineering '90

Real-time all-optical associative memory

Tuan-Sun Lu

Published Jul 1, 1990• 1 citation
Publisher

Abstract

We have proposed and demonstrated a real-time all-optical associative memory system which combines Fe:LiNbO3 crystal holographic memory element and phase conjugate mirror (PCM). The PCM was produced by BaTiO3 crystal self-pumped phase conjugate whose reflectivity is enhanced by two-wave mixing. Analysis and preliminary experiments are given.

DOI
10.1117/12.2294871

Related papers

Holographic associative memory using a coherently induced double phase conjugate mirror

Xiudong Sun, Zhongxiang Zhou, Yan Li +3 more

We demonstrate a new method to implement holographic associative memory based on a coherently induced double phase conjugate mirror that has phase-conjugate reflectivity larger than unity for weak reference signal over a large range of pumping-reference intensity ratio. The phase conjugator, operated with a copper-doped KNSBN crystal, serves as a novel nonlinear feedback and gain element for the associative memory system. A vanadium-doped KNSBN crystal as storage medium improves the response speed of the holographic recording process. A stored image has been completely retrieved when a partial input addresses the associative memory system.

Optical Engineering•Aug 1, 1996•3 citations

Real-time programmable holographic optical resonators

Dana Z. Anderson

A programmable optical resonator is one in which a hologram assumes the role of one of the mirrors of an ordinary optical resonator. A holographic recording medium allows the optical electric field eigenmodes of the resonator to be user-defined. Interest in this kind of resonator stems from their potential as associative optical memories. When the holographic medium is a photorefractive or other real-time recording medium, the resonator can learn, recall, and forget programmed information. Recall is achieved by placing a gain medium, such as an externally pumped photorefractive crystal, inside the resonator. The gain medium excites eigenmodes of the resonator. Using LiNbO3 as the recording medium and pumped BaTiO3 as the gain medium we have been able to store and recall complicated images as eigenmodes of a resonator.

Conference on Lasers and Electro-Optics•Jan 1, 1986•0 citations

Anisotropic Four-Wave Mixing in Optical Waveguides

Detlef Kip, Eckhard Krätzig

Photorefractive crystals like LiNbO3, KNbO3 or BaTiO3 are suitable media for frequency degenerate two- and four-wave mixing allowing for amplification and phase conjugation of coherent light beams [1, 2].

Photorefractive Effects, Materials, and Devices•Jan 1, 1993•0 citations

Stationary Photorefractive Self-Pump Phase-Conjugation with Stimulated Backward Scattering in LiNbO 3 :Fe Crystals

Jingjun Xu, Xin-zheng Zhang, Qian Sun +4 more

Stationary photorefractive self-pumped phase-conjugation with one four-wave-mixing interaction region, stimulated by the photorefractive amplified backward scattering, is obtained in LiNbO 3 :Fe crystals, in which the strong backward scattered light is gotten by putting a scattering particle on the backface of the sample. Even though its reflectivities are not high (its temporal and stationary reflectivities are 10% and 3%, respectively), due to the low electrooptic coefficients of LiNbO 3 :Fe crystals, our experimental results prove that this mechanism is effective and simple comparing with the "cat" self-pumped phase-conjugator.

Chinese Physics Letters•Jan 1, 1999•2 citations

Photorefractive adaptive transmission system

S. Mailis, Nikolaos A. Vainos

A photorefractive system based on the combined operation of a strontium barium niobate input amplifier and a self-pumped barium titanate phase-conjugator crystal is presented and analyzed. Amplified real-time phase-conjugate wave-front generation in this system is demonstrated. The system's ability to all-optically, temporally modulate a weak probe signal and to transmit it back to its source by means of amplified dynamic phase conjugation demonstrates its potential in adaptive optical transmission schemes.

Applied Optics•Dec 10, 1993•5 citations

Time reversal by an interferometer with coupled phase-conjugate reflectors

M. D. Ewbank, Jack Feinberg, P. Yeh +1 more

A new type of interferometer has been constructed that uses a beam splitter and two self-pumped BaTiO(3) crystals as phase-conjugate reflectors in place of the usual interferometer mirrors. Counterpropagating beams of light are spontaneously generated between the two crystals, coupling the pair of phase conjugators. This optical oscillation locks the relative phase of the two phase-conjugate reflections such that they recombine at the beam splitter to form only a single beam as though they were truly time-reversed waves.

Optics Letters•Jun 1, 1985•39 citations
We have proposed and demonstrated a real-time all-optical associative memory system which combines Fe:LiNbO3 crystal holographic memory element and phase conjugate mirror (PCM). The PCM was produced by BaTiO3 crystal self-pumped phase conjugate whose reflectivity is enhanced by two-wave mixing. Analysis and preliminary experiments are given.
We demonstrate a new method to implement holographic associative memory based on a coherently induced double phase conjugate mirror that has phase-conjugate reflectivity larger than unity for weak reference signal over a large range of pumping-reference intensity ratio. The phase conjugator, operated with a copper-doped KNSBN crystal, serves as a novel nonlinear feedback and gain element for the associative memory system. A vanadium-doped KNSBN crystal as storage medium improves the response speed of the holographic recording process. A stored image has been completely retrieved when a partial input addresses the associative memory system.
A programmable optical resonator is one in which a hologram assumes the role of one of the mirrors of an ordinary optical resonator. A holographic recording medium allows the optical electric field eigenmodes of the resonator to be user-defined. Interest in this kind of resonator stems from their potential as associative optical memories. When the holographic medium is a photorefractive or other real-time recording medium, the resonator can learn, recall, and forget programmed information. Recall is achieved by placing a gain medium, such as an externally pumped photorefractive crystal, inside the resonator. The gain medium excites eigenmodes of the resonator. Using LiNbO3 as the recording medium and pumped BaTiO3 as the gain medium we have been able to store and recall complicated images as eigenmodes of a resonator.
Stationary photorefractive self-pumped phase-conjugation with one four-wave-mixing interaction region, stimulated by the photorefractive amplified backward scattering, is obtained in LiNbO 3 :Fe crystals, in which the strong backward scattered light is gotten by putting a scattering particle on the backface of the sample. Even though its reflectivities are not high (its temporal and stationary reflectivities are 10% and 3%, respectively), due to the low electrooptic coefficients of LiNbO 3 :Fe crystals, our experimental results prove that this mechanism is effective and simple comparing with the "cat" self-pumped phase-conjugator.
A photorefractive system based on the combined operation of a strontium barium niobate input amplifier and a self-pumped barium titanate phase-conjugator crystal is presented and analyzed. Amplified real-time phase-conjugate wave-front generation in this system is demonstrated. The system's ability to all-optically, temporally modulate a weak probe signal and to transmit it back to its source by means of amplified dynamic phase conjugation demonstrates its potential in adaptive optical transmission schemes.
A new type of interferometer has been constructed that uses a beam splitter and two self-pumped BaTiO(3) crystals as phase-conjugate reflectors in place of the usual interferometer mirrors. Counterpropagating beams of light are spontaneously generated between the two crystals, coupling the pair of phase conjugators. This optical oscillation locks the relative phase of the two phase-conjugate reflections such that they recombine at the beam splitter to form only a single beam as though they were truly time-reversed waves.