Skip to content
6CCVD Research

Stark echo modulation for quantum memories

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2016-06-02
JournalPhysical review. A/Physical review, A
AuthorsA. Arcangeli, Alban Ferrier, Ph. Goldner
InstitutionsUniversité Paris Sciences et Lettres, Sorbonne Université
Citations27
AnalysisFull AI Review Included

Technical Documentation: Stark Echo Modulation Memory (SEMM) Protocol Analysis

Section titled “Technical Documentation: Stark Echo Modulation Memory (SEMM) Protocol Analysis”

6CCVD Material Science Analysis of arXiv:1602.00441v1

This analysis focuses on the requirements for implementing the Stark Echo Modulation Memory (SEMM) protocol, particularly highlighting the need for high-quality Single Crystal Diamond (SCD) substrates essential for Nitrogen-Vacancy (NV) center quantum memory applications.

Executive Summary

Section titled “Executive Summary”

The Stark Echo Modulation Memory (SEMM) protocol is a critical advancement for low-noise, broadband quantum memories (QM) utilizing solid-state ensembles, including NV centers in diamond.

  • Low-Noise Operation: SEMM successfully suppresses unwanted collective emissions (noise) by inducing linear phase shifts using small electric fields (Stark effect).
  • High Suppression: Experimental investigation in rare earth nuclear spins demonstrated a strong suppression of the intermediate collective emission, achieving a factor of 1.5 x 10-5.
  • High Fidelity: The protocol achieved an average quantum state fidelity of 0.999 during retrieval, confirmed by quantum state tomography.
  • Broadband Capability: SEMM preserves the full inhomogeneous linewidth, enabling large storage bandwidths (demonstrated at ~40 kHz).
  • Material Relevance: The protocol is directly applicable to highly promising solid-state QMs, specifically NV centers in diamond and rare earth doped crystals.
  • 6CCVD Value Proposition: Replication and extension of this research require ultra-low-strain, high-purity Single Crystal Diamond (SCD) substrates, a core specialization of 6CCVD.

Technical Specifications

Section titled “Technical Specifications”

The following hard data points were extracted from the experimental investigation and theoretical proposals for SEMM implementation in various hosts, including NV centers in diamond.

ParameterValueUnitContext
Intermediate Echo Suppression (ÎŒ)1.5 x 10-5FactorObserved in 151EuÂł+:Y₂SiO₅ nuclear spins.
Average Quantum State Fidelity0.999N/ADetermined by quantum state tomography (±X, ±Y, +Z input states).
Operating Temperature3.5KAll experiments conducted.
Memory Bandwidth~40kHzLimited by the length (24 ”s) of the π pulses.
Required Electric Field (E₀)8.2V/cmCalculated for NV centers in diamond (Electron spin, assuming Ts = T₂).
Coherence Lifetime (T₂)1.8msFor NV centers in diamond (Electron spin).
Stark Coefficient (k)17Hz cm/VFor NV centers in diamond (Electron spin).
Stark Field Magnitude (Experimental)±58HzFrequency shift corresponding to ~15 V applied across 1 mm.

Key Methodologies

Section titled “Key Methodologies”

The SEMM protocol was experimentally investigated using rare earth nuclear spins (151Eu³+:Y₂SiO₅) as a proof of concept. The key experimental parameters and steps are summarized below:

  1. Material Selection: 0.1% doped Eu³+:Y₂SiO₅ crystal, exhibiting C₁ symmetry site and C₂h inversion symmetry, crucial for the linear Stark effect.
  2. Transition & Frequency: RF excitations stored and retrieved using the ground state ±1/₂ - ±3/₂ transition of the 151EuÂł+ isotope at 34.58 MHz.
  3. Environmental Conditions: Experiments conducted at 3.5 K with a small static magnetic field of approximately 48 G applied parallel to the D1 crystal dielectric axis to extend the spin coherence lifetime (T₂) to 25 ms.
  4. Electric Field Application: Electric fields were applied parallel to the D1 axis across a 1 mm thick sample using two brass electrodes.
  5. SEMM Sequence: A two-pulse echo sequence (π/2, π pulses) was modified by inserting two Stark pulses (at t₂ and t₅) and a second RF π pulse (at t₆) to achieve noise cancellation and memory retrieval (Echo 2 at t₇).
  6. Stark Pulse Parameters: The Stark pulses were optimized to induce a central phase shift of π/2 (or 1/4 cycle) to cancel the intermediate echo. The applied voltage corresponded to a frequency shift of ±58 Hz.
  7. Detection: Spin echoes were optically detected using Raman heterodyne scattering, utilizing a laser resonant with the EuÂł+ F₀-⁔D₀ transition at 580 nm.

6CCVD Solutions & Capabilities

Section titled “6CCVD Solutions & Capabilities”

The SEMM protocol is highly relevant for solid-state quantum memory development, particularly utilizing NV centers in diamond. 6CCVD provides the necessary high-specification MPCVD diamond materials and customization services required to replicate and advance this research.

Applicable Materials for SEMM Implementation

Section titled “Applicable Materials for SEMM Implementation”

To achieve the long coherence times (T₂) and low strain required for high-fidelity quantum memories based on NV centers, researchers must utilize the highest quality Single Crystal Diamond (SCD).

6CCVD MaterialSpecificationApplication Relevance
Optical Grade SCDUltra-low nitrogen content ([N] < 1 ppb), low strain, high T₂.Essential host material for creating high-quality NV centers with long spin coherence lifetimes (T₂).
Custom Doped SCDControlled nitrogen incorporation (e.g., 1-10 ppm) or post-growth implantation.Required for precise density and location control of NV centers, optimizing coupling to microwave resonators.
High-Purity SubstratesSCD substrates up to 10 mm thickness.Provides robust mechanical and thermal stability for cryogenic operation (3.5 K) and electric field application.

Customization Potential for Quantum Memory Devices

Section titled “Customization Potential for Quantum Memory Devices”

The SEMM protocol requires precise control over electric fields and integration with resonators, necessitating custom material engineering. 6CCVD’s in-house capabilities directly support these requirements:

  • Custom Dimensions: We supply SCD plates and wafers in custom sizes and thicknesses (SCD: 0.1 ”m to 500 ”m) to fit specific cavity geometries and resonator designs.
  • Precision Polishing: Achieving low-loss cavity coupling requires exceptional surface quality. 6CCVD guarantees ultra-smooth polishing with Ra < 1 nm for SCD, minimizing scattering losses.
  • Integrated Metalization: The application of electric fields via electrodes (as used in the paper) is critical. 6CCVD offers internal, high-precision metalization services, including:
    • Electrode Deposition: Custom patterning and deposition of metals such as Ti, Pt, Au, or Cu directly onto the diamond surface for reliable electric field application and contact pads.
    • Interface Optimization: Metalization layers can be optimized for integration with superconducting resonators (e.g., Nb or Al, if supplied by the customer) for microwave photon storage.

Engineering Support

Section titled “Engineering Support”

6CCVD’s team of PhD-level material scientists specializes in optimizing MPCVD diamond growth for quantum applications. We offer consultation services to assist researchers in:

  • Material Selection: Determining the optimal SCD grade and thickness to maximize T₂ and minimize strain for specific NV center creation methods.
  • Defect Engineering: Advising on post-growth processing or controlled doping to achieve the desired NV concentration and spatial distribution necessary for efficient cavity coupling and high memory opacity ($d$).
  • Substrate Preparation: Ensuring substrates meet the stringent parallelism and surface finish requirements necessary for uniform electric field application and high-fidelity SEMM operation.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Quantum memories for optical and microwave photons provide key functionalities in quantum processing and communications. Here we propose a protocol well adapted to solid state ensemble based memories coupled to cavities. It is called Stark Echo Modulation Memory (SEMM), and allows large storage bandwidths and low noise. This is achieved in a echo like sequence combined with phase shifts induced by small electric fields through the linear Stark effect. We investigated the protocol for rare earth nuclear spins and found a high suppression of unwanted collective emissions that is compatible with single photon level operation. Broadband storage together with high fidelity for the Stark retrieval process is also demonstrated. SEMM could be used to store optical or microwave photons in ions and/or spins. This includes NV centers in diamond and rare earth doped crystals, which are among the most promising solid-state quantum memories.

Tech Support

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2015 - Handbook on the Physics and Chemistry of Rare Earths

Reads Similar to This

Dissection Method of Solid Rocket Motor Chamber Based on Ultrasonic Vibration Sawing Continuous energy measurement of the electron beam in the storage ring of Diamond Light Source with resonant spin depolarization Li2HgMS4 (M = Si, Ge, Sn) - New Quaternary Diamond-Like Semiconductors for Infrared Laser Frequency Conversion