Experimental demonstration of an Electromagnetically Induced Virtual Structure toward Quantum Hybrid Interfaces

At a Glance

Metadata	Details
Publication Date	2017-12-13
Journal	arXiv (Cornell University)
Authors	Toshiyuki Tashima, Hiroki Morishita, Norikazu Mizuochi
Analysis	Full AI Review Included

Technical Documentation & Analysis: Electromagnetically Induced Virtual Structure (EIVS) in NV Diamond

This documentation analyzes the research demonstrating the generation of an Electromagnetically Induced Virtual Structure (EIVS) using a single Nitrogen-Vacancy (NV) center in diamond. This work is critical for developing next-generation quantum hybrid interfaces that operate across disparate frequency regimes (microwave and radio-frequency).

Executive Summary

Core Achievement: Successful experimental demonstration of an Electromagnetically Induced Virtual Structure (EIVS), or “dressed state,” using a single NV center in high-purity diamond at ambient (room) temperature.
Hybridization Strategy: The EIVS acts as a host for quantum hybridization between systems operating in vastly different ranges: the electron spin (microwave, ~2.8 GHz) and the ¹⁴N nuclear spin (radio-frequency, few MHz).
Material Basis: The experiment relied on high-quality, Type IIa (111) diamond prepared by precise ¹⁴N ion implantation (30 keV) and high-temperature annealing (750 °C).
Enhanced Coherence: The generated dressed states (EIVS) exhibit significantly improved coherence properties. The dephasing time (T₂) of the EIVS signals was measured to be 2.6 times longer than that of the undressed nuclear hyperfine signals.
Single-Source Multi-Use Potential: This methodology paves the way for complex quantum-information processing by enabling the NV center to serve as a hub linking magnetic materials, nuclear quantum memories (e.g., ¹³C), and superconducting circuits.
Technical Methodology: The EIVS was achieved by simultaneous irradiation of continuous-wave RF pump fields and pulsed MW probe fields, combined via a frequency diplexer delivered via a 10 µm copper wire.

Technical Specifications

Parameter	Value	Unit	Context
Diamond Substrate	Type IIa (111)	N/A	High-Temperature High-Pressure (HTHP) growth
Electron Spin Resonance (MW Probe)	~2.8	GHz	Operational range for electron spin manipulation
Nuclear Spin Resonance (RF Pump)	Few	MHz	Operational range for nuclear spin manipulation
Fixed Pump Frequency Tested	5.3	MHz	Frequency used to demonstrate EIVS generation
Static Magnetic Field (B_0)	~1.5	mT	Field applied along the NV-axis direction
Excitation Laser Wavelength	532	nm	NV center initialization and excitation
Photoluminescence (PL) Range	600 - 700	nm	Detected emission spectrum
Minimum Pump Power for EIVS	> 10	mW	Additional signals (9 dips total) appear above this threshold
Ion Implantation Species	¹⁴N	N/A	Nitrogen source for NV center creation
Ion Implantation Energy	30	keV	Used by commercial service
Post-Implantation Annealing T	750	°C	Required for defect activation and stabilization
Dephasing Time (T_2) Improvement	2.6	Factor	T₂ of EIVS signals compared to undressed hyperfine signals
Single NV Center Purity	~0.1	g⁽²⁾(0)	Second-order correlation measurement

Key Methodologies

The experimental generation of the Electromagnetically Induced Virtual Structure (EIVS) relied on precise material preparation and co-irradiation of high- and low-frequency fields:

Substrate Selection and Preparation: HTHP Type IIa (111) diamond was selected. The (111) orientation is critical for aligning the NV axis relative to the applied magnetic fields (B₀) for optimal spin control.
NV Center Synthesis:
- ¹⁴N ions were implanted at a kinetic energy of 30 keV.
- The substrate temperature during implantation was maintained at 500 °C.
- The sample underwent post-processing annealing at 750 °C for 30 minutes to form and stabilize the NV lattice structure.
Optical Spin Control: Spin initialization (1 µsec pulse) and readout were performed using a 532 nm green laser via a homemade confocal microscope setup.
Electromagnetic Irradiation System:
- MW (~2.8 GHz) and RF (few MHz) fields were generated by separate high-frequency oscillators.
- Fields were combined via a frequency diplexer to ensure simultaneous delivery.
- Irradiation was delivered to the single NV center using a thin copper wire (10 µm diameter) placed near the sample surface.
EIVS Observation: The dressed states were detected through Optically Detected Magnetic Resonance (ODMR) spectra while the RF pump field was continuously applied during both laser initialization and MW probe irradiation (5.5 µsec probe pulse).

6CCVD Solutions & Capabilities

6CCVD provides the specialized SCD and processing capabilities required to replicate, scale, and extend this pioneering research into quantum hybrid interfaces. Our materials offer the purity and customization necessary for maximizing NV center coherence and yield.

Applicable Materials

To replicate the high-fidelity spin control and enhanced coherence demonstrated by the EIVS, researchers require material with low strain and minimal defect concentrations, exceeding typical HTHP quality.

Required Material Property	6CCVD Recommended Product	Justification for EIVS Research
High Purity & Low Strain	Optical Grade Single Crystal Diamond (SCD)	Our MPCVD SCD offers superior purity (low nitrogen/vacancy background) vital for achieving the T₂ enhancement reported (2.6x increase) and maintaining stable dressed states.
Crystal Orientation	Custom (111) Orientation SCD	The experiment utilized the (111) orientation. 6CCVD provides custom-oriented wafers to maximize the spin polarization and magnetic field alignment for NV-based quantum control.
Spin Coherence Enhancement	Isotopically Purified SCD (e.g., ¹²C > 99.99%)	Although the paper used ¹⁴N as the nuclear spin qubit, extending this work to quantum memory requires coupling to ¹³C nuclear spins. Isotopically pure SCD dramatically increases intrinsic NV coherence (T₂).
Hybrid System Integration	Boron-Doped Diamond (BDD) Wafers	Future hybridization with superconducting circuits (mentioned in the paper) requires conductive materials. 6CCVD BDD plates provide the necessary conductivity and diamond host structure.

Customization Potential

The experimental configuration, particularly the use of a simple copper wire for electromagnetic delivery, highlights the need for integrated, on-chip solutions in scaled quantum devices. 6CCVD offers comprehensive engineering services to advance this integration:

Custom Dimensions and Substrates: We supply large-area SCD and PCD plates up to 125mm, crucial for manufacturing scalable quantum networks and dense NV arrays.
Precision Laser Cutting: Customized shapes and small dimensions can be precisely cut from bulk wafers to fit unique cryostat or microscope configurations.
Custom Metalization: For robust and reproducible on-chip RF/MW delivery systems, 6CCVD offers in-house deposition of thin-film metal stacks. We can engineer specific adhesion layers (Ti, W) and highly conductive contact layers (Au, Pt, Cu, Pd) necessary for optimized high-frequency transmission lines.
- Example: Fabricating coplanar waveguide structures to replace the 10 µm copper wire used in this proof-of-concept.
Advanced Polishing: We guarantee ultra-smooth surfaces, with Ra < 1nm for SCD, ensuring minimal optical loss, which is essential for confocal microscopy (532 nm excitation and 600-700 nm PL collection).

Engineering Support

6CCVD’s in-house PhD material scientists and technical engineers specialize in optimizing diamond properties for solid-state qubits. We can provide direct consultation on:

Material Selection: Guiding researchers in choosing the ideal SCD purity and crystallographic orientation for specific quantum memory or hybrid interface projects.
Post-Processing Protocol: Advising on optimal ion implantation and annealing protocols (like the 750 °C annealing used here) to maximize NV yield and minimize strain damage.
Metalization Design: Collaborating on the design of integrated RF/MW electrodes for efficient spin manipulation in complex quantum systems like the demonstrated EIVS.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. Global shipping is available (DDU default, DDP option).

View Original Abstract

While the manipulation of quantum systems is significantly developed so far, achieving a single-source multi-use system for quantum-information processing and networks is still challenging. A virtual a so-called “dressed state, is a potential host for quantum hybridizations of quantum physical systems with various operational ranges. We present an experimental demonstration of a dressed state generated by two-photon magnetic resonances using a single spin in a single nitrogen-vacancy center in diamond. The two-photon magnetic resonances occur under the application of microwave and radio-frequency fields, with different operational ranges. The experimental results reveal the behavior of two-photon magnetic transitions in a single defect spin in a solid, thus presenting new potential quantum and semi-classical hybrid systems with different operational ranges using superconductivity and spintronics devices.

Tech Support

Original Source

DOI: None