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

Physical Review A

Efficient phase conjugation via two-photon coherence in an optically dense crystal

Byoung Seung HAM, Philip Hemmer, M. S. Shahriar

Published Apr 1, 1999• 36 citations
Publisher

Abstract

We demonstrate efficient phase conjugation in an inhomogeneously broadened rare-earth doped crystal using electromagnetically induced transparency. The observed frequency conversion efficiency of the phase conjugate in energy over a backward pump beam is as high as 10% with \ensuremath{\sim}1/4 of maximal Raman coherence. This efficient phase conjugation has potential applications of nonlinear optical processes such as frequency up-conversion and Raman excited spin-echo optical memory.

DOI
10.1103/physreva.59.r2583

Related papers

Efficient phase conjugation using Raman dark resonances in an optically dense crystal

Byoung Seung HAM, Philip Hemmer, M. S. Shahriar

Summary form only given. In a three-level system, optical refractive indices can be changed due to the atom-field interactions. Especially in a short time scale (t/spl Lt/ /spl gamma/), a resonant strong electromagnetic field can change the absorption coefficient strongly so that another resonant electromagnetic field which has a different frequency can pass through without experiencing any absorption in an optically dense medium. This phenomenon is called electromagnetically induced transparency (EIT). There have been many studies of EIT in atomic vapors and solids for potential applications to nonlinear optical processes such as enhanced four-wave mixing, lasers without inversion, frequency up-conversion lasers, and optical memory. We report efficient phase conjugation based on EIT in an in homogeneously broadened solid system of Pr/sup 3+/ doped yttrium silicate.

Conference on Lasers and Electro-Optics•Jan 20, 2003•0 citations

Efficient generation of Raman echo and time-domain optical data storage by electromagnetically induced transparency

Myung K. Kim, Philip Hemmer, Byoung Seung HAM +1 more

We have observed excitation of spin echoes and spin free induction decay (FID) by electromagnetically induced transparency (EIT) in an optically dense solid sample. The experiments are done in a double-lambda system of 605.7 nm 3H4 - 1D2 transition of Pr3+:Y2SiO5, where the 10.2 MHz ground state spin coherence is excited by low-power resonant Raman pulses. It has been shown that the spin coherence, including spin echo, is equivalent to the transparent state of EIT, and therefore a high efficiency is expected for such resonant Raman-excited spin echo. The observed efficiency of spin echo is as high as 75% of the FID signal at 5K. A background-free detection scheme is used based on EIT and enhanced nondegenerate four-wave mixing. The technique is applied in the frequency-selective time-domain optical data storage, that utilizes the spin as well as the optical inhomogeneous spectral widths. The data storage scheme is analogous to the stimulated spin echo with resonant Raman excitation of the spin coherence. We verify that the write window is determined by the spin T2 which is much longer than the optical T2, especially at higher temperature. We find that the spin dephasing time T2 is almost constant at approximately 500 microseconds in the range of 2 to approximately 6 K, whereas the optical T2 decreases rapidly, by a factor of approximately 50, above 4 K. These results will be useful in the development of high capacity time-domain optical data storage operating at higher temperature.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Nov 5, 1998•1 citation

Efficient and coherent frequency conversions and nonlinear interference in optical parametric and atomic Raman processes

Yu Ding

By implementing a parametric down-conversion process with a strong signal field injection, we demonstrate that frequency down-conversion from pump photons to idler photons can be a coherent process. Contrary to a common misconception, we show that the process can be free of quantum noise. With an interference experiment, we demonstrate that coherence is preserved in the conversion process. This technique could lead to a high-fidelity quantum state transfer from a high-frequency photon to a low-frequency photon and connect a missing link in quantum networks. Coherent and efficient nonlinear interaction and frequency conversion are of great interest in many areas of quantum optics. Traditionally, the low efficiency of Raman scattering is improved by a high-finesse optical resonator or stimulated Raman conversion. It was recently found that the atomic spin wave initially built through electromagnetically induced transparency or a weak Raman process can actively enhance the Raman frequency conversion. An experimental demonstration of an efficient Raman conversion scheme with coherent feedback of both pump and Stokes fields is presented. The temporal profile of the generated Raman pulse shows that the coherence time of the atomic spin wave is $\sim$1.8 ms. A laser-like power threshold is observed and its low threshold is attributed to the long coherence time of the atomic spin wave. The mechanism of the conversion enhancement process is discussed and the conversion efficiency of a single pass of the beams is compared with that of double passes. Finally, a beat signal is observed between the two Stokes fields and its Fourier transform shows that the frequency difference is caused by the AC Stark effect. Precision phase measurement is traditionally restricted by the standard quantum limit. However, this limit is not as fundamental as the Heisenberg limit and can be circumvented by use of nonclassical quantum states and structure modification of the interferometers. Several examples of nonlinear interferometers are proposed and implemented. The wave propagation equations for the nonlinear interferometers are solved. The interference fringes are measured and compared with that of linear interferometers. The first nonlinear interferometer presented is based on second harmonic generation and degenerate parametric down-conversion. The second nonlinear interferometer is composed of two parametric amplifiers. The idea of nonlinear beam splitters is introduced as an analogy to traditional beam splitters. We show that a nonlinear interferometer can be built alternatively by using only one parametric amplifier. Type II phase-matched crystals can be used to increase the amplification factor. An interferometer based on a Raman amplifier is analyzed for its application to sensitive magnetic field measurement.

•Jan 1, 2014•0 citations

Frequency-selective time-domain optical data storage by electromagnetically induced transparency in a rare-earth-doped solid

Byoung Seung HAM, M. S. Shahriar, M. K. Kim +1 more

We report the experimental observation of optical data storage by frequency-selective stimulated spin echoes based on electromagnetically induced transparency in an inhomogeneously broadened rare-earth-doped solid. We find that the spin dephasing time T(2) is almost constant in the range 2-6 K, whereas the optical T(2) shortens rapidly above 4 K. This experiment demonstrates the potential of spin echoes excited by electromagnetically induced transparency for higher-capacity optical data storage at higher temperature.

Optics Letters•Dec 15, 1997•139 citations

Low threshold, highly efficient phase conjugation using optical coherent transients

Randy R. Reibel, Jason K. Brasseur

We discuss and demonstrate two approaches to achieving low threshold, highly efficient phase conjugation using optical coherent transients in rare-earth ion doped crystals. One approach utilizes coherent media inversion and the other utilizes integration gain.

Conference on Lasers and Electro-Optics•Jan 1, 2004•0 citations

Efficient Nonlinear Frequency Conversion with Maximal Atomic Coherence

Maneesh Jain, Hui Xia, G. Y. Yin +2 more

We demonstrate efficient nonlinear frequency conversion in atomic Pb vapor under conditions where the linear susceptibility and the effective nonlinear susceptibility are of the same order. This is accomplished by using electromagnetically induced transparency to prepare a near-maximal atomic coherence on a Raman transition. This strongly driven transition is used to convert an intense laser beam from 425 to 293 nm with an efficiency of $\ensuremath{\sim}40%$.

Physical Review Letters•Nov 18, 1996•395 citations
We demonstrate efficient phase conjugation in an inhomogeneously broadened rare-earth doped crystal using electromagnetically induced transparency. The observed frequency conversion efficiency of the phase conjugate in energy over a backward pump beam is as high as 10% with \ensuremath{\sim}1/4 of maximal Raman coherence. This efficient phase conjugation has potential applications of nonlinear optical processes such as frequency up-conversion and Raman excited spin-echo optical memory.
Summary form only given. In a three-level system, optical refractive indices can be changed due to the atom-field interactions. Especially in a short time scale (t/spl Lt/ /spl gamma/), a resonant strong electromagnetic field can change the absorption coefficient strongly so that another resonant electromagnetic field which has a different frequency can pass through without experiencing any absorption in an optically dense medium. This phenomenon is called electromagnetically induced transparency (EIT). There have been many studies of EIT in atomic vapors and solids for potential applications to nonlinear optical processes such as enhanced four-wave mixing, lasers without inversion, frequency up-conversion lasers, and optical memory. We report efficient phase conjugation based on EIT in an in homogeneously broadened solid system of Pr/sup 3+/ doped yttrium silicate.
We have observed excitation of spin echoes and spin free induction decay (FID) by electromagnetically induced transparency (EIT) in an optically dense solid sample. The experiments are done in a double-lambda system of 605.7 nm 3H4 - 1D2 transition of Pr3+:Y2SiO5, where the 10.2 MHz ground state spin coherence is excited by low-power resonant Raman pulses. It has been shown that the spin coherence, including spin echo, is equivalent to the transparent state of EIT, and therefore a high efficiency is expected for such resonant Raman-excited spin echo. The observed efficiency of spin echo is as high as 75% of the FID signal at 5K. A background-free detection scheme is used based on EIT and enhanced nondegenerate four-wave mixing. The technique is applied in the frequency-selective time-domain optical data storage, that utilizes the spin as well as the optical inhomogeneous spectral widths. The data storage scheme is analogous to the stimulated spin echo with resonant Raman excitation of the spin coherence. We verify that the write window is determined by the spin T2 which is much longer than the optical T2, especially at higher temperature. We find that the spin dephasing time T2 is almost constant at approximately 500 microseconds in the range of 2 to approximately 6 K, whereas the optical T2 decreases rapidly, by a factor of approximately 50, above 4 K. These results will be useful in the development of high capacity time-domain optical data storage operating at higher temperature.
By implementing a parametric down-conversion process with a strong signal field injection, we demonstrate that frequency down-conversion from pump photons to idler photons can be a coherent process. Contrary to a common misconception, we show that the process can be free of quantum noise. With an interference experiment, we demonstrate that coherence is preserved in the conversion process. This technique could lead to a high-fidelity quantum state transfer from a high-frequency photon to a low-frequency photon and connect a missing link in quantum networks. Coherent and efficient nonlinear interaction and frequency conversion are of great interest in many areas of quantum optics. Traditionally, the low efficiency of Raman scattering is improved by a high-finesse optical resonator or stimulated Raman conversion. It was recently found that the atomic spin wave initially built through electromagnetically induced transparency or a weak Raman process can actively enhance the Raman frequency conversion. An experimental demonstration of an efficient Raman conversion scheme with coherent feedback of both pump and Stokes fields is presented. The temporal profile of the generated Raman pulse shows that the coherence time of the atomic spin wave is $\sim$1.8 ms. A laser-like power threshold is observed and its low threshold is attributed to the long coherence time of the atomic spin wave. The mechanism of the conversion enhancement process is discussed and the conversion efficiency of a single pass of the beams is compared with that of double passes. Finally, a beat signal is observed between the two Stokes fields and its Fourier transform shows that the frequency difference is caused by the AC Stark effect. Precision phase measurement is traditionally restricted by the standard quantum limit. However, this limit is not as fundamental as the Heisenberg limit and can be circumvented by use of nonclassical quantum states and structure modification of the interferometers. Several examples of nonlinear interferometers are proposed and implemented. The wave propagation equations for the nonlinear interferometers are solved. The interference fringes are measured and compared with that of linear interferometers. The first nonlinear interferometer presented is based on second harmonic generation and degenerate parametric down-conversion. The second nonlinear interferometer is composed of two parametric amplifiers. The idea of nonlinear beam splitters is introduced as an analogy to traditional beam splitters. We show that a nonlinear interferometer can be built alternatively by using only one parametric amplifier. Type II phase-matched crystals can be used to increase the amplification factor. An interferometer based on a Raman amplifier is analyzed for its application to sensitive magnetic field measurement.
We report the experimental observation of optical data storage by frequency-selective stimulated spin echoes based on electromagnetically induced transparency in an inhomogeneously broadened rare-earth-doped solid. We find that the spin dephasing time T(2) is almost constant in the range 2-6 K, whereas the optical T(2) shortens rapidly above 4 K. This experiment demonstrates the potential of spin echoes excited by electromagnetically induced transparency for higher-capacity optical data storage at higher temperature.