Optical Coherence Storage in Spin States (With 6 Figures)

We introduce new figures of merit (FOM's) for resonant optical materials used in recording, storage, and processing of optically encoded information using coherent optical transients. The goal is to account for maximum coherence storage time as well as for efficiency of the light matter interaction quantified using the ratio between the rate of dephasing and the rate of spontaneous radiative decay. Highest FOM values are achieved when the dephasing rate approaches the fundamental limit set by spontaneous emission under the condition that the total transition oscillator strength is concentrated between a single pair of energy levels. In this case, the information (both classical and quantum) can be transferred from the radiation field to the storage medium and back at the fastest possible rate, while the loss of optically prepared coherence is minimized. We analyze FOM's of some of the most promising rare-earth-doped crystals at cryogenic temperatures and show that the homogeneous line width may approach the radiative limit in some cases even when the peak cross section remains below the fundamental limit.We introduce new figures of merit (FOM's) for resonant optical materials used in recording, storage, and processing of optically encoded information using coherent optical transients. The goal is to account for maximum coherence storage time as well as for efficiency of the light matter interaction quantified using the ratio between the rate of dephasing and the rate of spontaneous radiative decay. Highest FOM values are achieved when the dephasing rate approaches the fundamental limit set by spontaneous emission under the condition that the total transition oscillator strength is concentrated between a single pair of energy levels. In this case, the information (both classical and quantum) can be transferred from the radiation field to the storage medium and back at the fastest possible rate, while the loss of optically prepared coherence is minimized. We analyze FOM's of some of the most promising rare-earth-doped crystals at cryogenic temperatures and show that the homogeneous line width may approach the radiative limit in some cases even when the peak cross section remains below the fundamental limit.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEJan 20, 20106 citations

Slow decoherence and the radiative decay limit in rare-earth-doped crystals for coherent optical storage

Alexander Rebane, Charles W. Thiel, R. K. Mohan +1 more

We analyze the material requirements for recording, storage, and processing of optically encoded information using coherent optical transients in resonant solids. We introduce new figures of merit (FOM’s) that explicitly account for the ratio between the rate of the decoherence and the rate of the spontaneous radiative decay. Highest FOM values are achieved when the decoherence rate approaches the fundamental limit set by spontaneous emission under the condition that the total transition oscillator strength is concentrated between a single pair of energy levels. We analyze FOM’s of some of the most promising rare-earth-doped crystals at cryogenic temperatures.We analyze the material requirements for recording, storage, and processing of optically encoded information using coherent optical transients in resonant solids. We introduce new figures of merit (FOM’s) that explicitly account for the ratio between the rate of the decoherence and the rate of the spontaneous radiative decay. Highest FOM values are achieved when the decoherence rate approaches the fundamental limit set by spontaneous emission under the condition that the total transition oscillator strength is concentrated between a single pair of energy levels. We analyze FOM’s of some of the most promising rare-earth-doped crystals at cryogenic temperatures.

Bulletin of the Russian Academy of Sciences PhysicsJul 1, 20109 citations

Spin-Coherent States

Monique Combescure, Didier Robert

Theoretical and mathematical physicsJan 1, 20124 citations

Faithful Solid State Optical Memory with Dynamically Decoupled Spin Wave Storage

Marko Lovrić, Dieter Suter, Alban Ferrier +1 more

We report a high fidelity optical memory in which dynamical decoupling is used to extend the storage time. This is demonstrated in a rare-earth doped crystal in which optical coherences were transferred to nuclear spin coherences and then protected against environmental noise by dynamical decoupling, leading to storage times of up to 4.2 ms. An interference experiment shows that relative phases of input pulses are preserved through the whole storage and retrieval process with a visibility ≈1, demonstrating the usefulness of dynamical decoupling for extending the storage time of quantum memories. We also show that dynamical decoupling sequences insensitive to initial spin coherence increase retrieval efficiency.We report a high fidelity optical memory in which dynamical decoupling is used to extend the storage time. This is demonstrated in a rare-earth doped crystal in which optical coherences were transferred to nuclear spin coherences and then protected against environmental noise by dynamical decoupling, leading to storage times of up to 4.2 ms. An interference experiment shows that relative phases of input pulses are preserved through the whole storage and retrieval process with a visibility ≈1, demonstrating the usefulness of dynamical decoupling for extending the storage time of quantum memories. We also show that dynamical decoupling sequences insensitive to initial spin coherence increase retrieval efficiency.

arXiv:1302.3358Physical Review LettersJul 11, 201347 citations

On-Demand Coherent Mapping of Telecom Optical States onto Erbium Hyperfine Spins

Zongfeng Li, Mahdi Hosseini

Optical quantum memories operating directly at telecom wavelengths are a key enabling technology for long-distance quantum networks, yet on-demand storage onto long-lived ground-state spins in this spectral region has remained elusive due to the challenge of coherently transferring optical excitations to hyperfine spin states. Here we demonstrate spin-wave storage in $^{167}$ Er $^{3+}$ :Y $_2$ SiO $_5$ at 0.8 K and 1.1 T, establishing the core operational primitive required for on-demand telecom quantum memories. Using classical optical control pulses, we coherently transfer collective optical excitations to erbium hyperfine states with transfer efficiency exceeding 12%, enabling on-demand retrieval. We measure a hyperfine population lifetime of 25 s and demonstrate spin-wave storage for up to 25 $μ$ s. By identifying hyperfine inhomogeneous broadening as the dominant present limitation, our measurements define a clear pathway toward second-scale storage through improved spectral tailoring and dynamical decoupling. The results highlight the application of erbium-based solid-state memories for scalable fiber-compatible quantum repeater architectures.Optical quantum memories operating directly at telecom wavelengths are a key enabling technology for long-distance quantum networks, yet on-demand storage onto long-lived ground-state spins in this spectral region has remained elusive due to the challenge of coherently transferring optical excitations to hyperfine spin states. Here we demonstrate spin-wave storage in $^{167}$Er$^{3+}$:Y$_2$SiO$_5$ at 0.8 K and 1.1 T, establishing the core operational primitive required for on-demand telecom quantum memories. Using classical optical control pulses, we coherently transfer collective optical excitations to erbium hyperfine states with transfer efficiency exceeding 12%, enabling on-demand retrieval. We measure a hyperfine population lifetime of 25 s and demonstrate spin-wave storage for up to 25 $μ$s. By identifying hyperfine inhomogeneous broadening as the dominant present limitation, our measurements define a clear pathway toward second-scale storage through improved spectral tailoring and dynamical decoupling. The results highlight the application of erbium-based solid-state memories for scalable fiber-compatible quantum repeater architectures.

quant-pharXiv:2606.15009Jun 16, 20261 citation

^{167}

^{3+}

_2

SiO

_5

at 0.8 K and 1.1 T, establishing the core operational primitive required for on-demand telecom quantum memories. Using classical optical control pulses, we coherently transfer collective optical excitations to erbium hyperfine states with transfer efficiency exceeding 12%, enabling on-demand retrieval. We measure a hyperfine population lifetime of 25 s and demonstrate spin-wave storage for up to 25

μ

s. By identifying hyperfine inhomogeneous broadening as the dominant present limitation, our measurements define a clear pathway toward second-scale storage through improved spectral tailoring and dynamical decoupling. The results highlight the application of erbium-based solid-state memories for scalable fiber-compatible quantum repeater architectures.