Skip to content

Overview

Theo Murphy meeting organised by Dr Shannon Nicley, Dr Gavin Morley and Professor Ken Haenen.

A discussion on the recent progress of diamond growth and engineering for the creation and optimisation of colour centres, toward the integration of diamond based qubits in quantum systems.

The schedule of talks is available below.

Poster session

There will be an in person poster session on Monday 10 October at the meeting venue which will be available to view for the duration of the meeting. If you would like to apply to present a poster please submit your proposed title, abstract (not more than 200 words and in third person), author list, name of the proposed presenter and institution to the Scientific Programmes team no later than Friday 30 September 2022. Please include the text 'Poster abstract submission' in the email subject line. Please note that places are limited and posters are selected at the scientific organisers' discretion.

Attending this event

This meeting is intended for researchers in relevant fields and is a residential meeting.

  • Free to attend - participants are responsible for booking their own accommodation
  • Meals will be available to book on Eventbrite when registering to attend the meeting
  • Limited places, advance registration essential
  • This is an in-person meeting only

Enquiries: contact the Scientific Programmes team

Image credit: Shannon Nicley

Organisers

Schedule


Chair

09:00-09:30
Exploring the tin vacancy centre in diamond: charge states, spins and photons

Abstract

For many applications in the field of quantum information processing stationary qubits are required, providing long-lived spin coherence and suitable level schemes for coherent control and efficient optical read out. In addition, transferring the spin information to indistinguishable single photons is necessary e.g. to distribute entanglement in quantum networks. 
Colour centres in diamond, more specifically the group-IV-vacancy centres, have emerged as promising candidates among solid state qubits. They exhibit favourable properties such as individually addressable spins with long coherence times and bright emission of single, close to transform limited photons. Recent experiments have shown that the negatively charged tin-vacancy centre (SnV) combines long spin coherence times at conveniently achievable cryogenic temperatures (>1K) with truly lifetime-limited transition linewidths down to 20 MHz. We explore the charge transition cycle upon resonant excitation which leads to shelving in the dark SnV(2-) state and devise a method for charge state stabilization by illumination with a second light field. The charge-stabilized SnV(-) centre exhibits exceptional spectral stability with very small spectral diffusion (4 MHz on a homogenous linewidth of 25 MHz over 1 hour) and promising spin dephasing time (5 µs, measured via coherent population trapping). We discuss prospects of coherent spin manipulation and generation of indistinguishable single photons.

Speakers

09:30-09:45
09:45-10:15

Abstract

Abstract will be available soon

Speakers

10:15-10:30
Discussion
10:30-11:00
Coffee break
11:00-11:30

Abstract

Abstract will be available soon

Speakers

11:30-11:45
Discussion
11:45-12:15

Abstract

Abstract will be available soon

Speakers

12:15-12:30
Discussion
12:30-13:35
Lunch break

Chair

13:35-14:05

Abstract

Abstract will be available soon

Speakers

14:05-14:20
Discussion
14:20-14:50
Exploring and exploiting diamond surface band bending

Abstract

The real world applications of diamond quantum sensors require optically active defects to be increasingly located within nanometres of the diamond surface, where their quantum properties such as coherence time, charge state stability and spectral width can suffer significant degradation. I will detail our efforts to explore the origins of these surface noise and band-bending effects, through a novel combination of surface spectroscopy and defect-based electromagnetic measurements. I will then present our efforts to engineer and exploit these phenomena to enhance the sensitivity of near-surface NV systems for biological systems.

Speakers

14:50-15:05
Discussion
15:05-15:30
Tea break
15:30-16:00
Laser writing and ion implantation of colour centres for quantum technologies

Abstract

The Nitrogen Vacancy centre in its negatively charged state (NV) became the most established quantum emitter for the development of proof-of-concept quantum devices, in particular in the field of quantum sensing. The performance of NV-based quantum sensors strictly depends on the concentration of colour centres in the sensing ensemble, making it fundamental the possibility to control such concentration. An emerging technique for the formation of NV ensembles on demand is femtosecond laser writing, in which static exposures allow the formation of vacancies and a consequent annealing permits the formation of NVs thanks to the nitrogen pre-existing in diamond. In this work, we will discuss how laser writing can be used to achieve high concentration of NVs in diamond, aligned to laser written photonics for enhanced interaction. In addition, we will introduce a hybrid method of shallow ion implantation of quantum emitters into laser written photonics for novel quantum sensing devices.

Speakers

16:00-16:15
Discussion
16:15-16:45
Identification and deterministic creation of next-generation quantum bits in synthetic diamond

Abstract

The development of a truly scalable quantum information processing (QIP) platform, so far, has been impeded by a lack of qubits with long coherence times and high-quality optical interfaces. Crystal defects in diamond, specifically the nitrogen vacancy (NV) and group-IV vacancy (SiV, GeV, SnV) centers have emerged as leading qubit candidates but face several challenges such as poor optical quality and susceptibility to spectral diffusion (NV), a requirement for dilution refrigeration to reach sufficiently long spin decoherence (SiV), low controllability (GeV, SnV), or a lack of deterministic creation (SiV, SnV, GeV).

Nevertheless, past detailed studies of these systems now enable a more targeted search for new defects in diamond with optimized properties for QIP applications. We here report on one of these candidates, the nickel vacancy (NiV) defect in diamond, and present first fluorescence spectroscopic measurements, demonstrating the NiV’s favorable optical properties. Through magneto-optical studies and group-theoretical modelling we confirm the center’s electronic properties and show first results hinting towards favorable spin properties. Finally, we will discuss the possibility of deterministic fabrication of NiVs via multiphoton laser writing in combination with growth of bespoke CVD material to further enable a future scalable QIP platform based on NiV defects in diamond.

Speakers

16:45-17:00
Discussion
17:00-18:00
Poster session

Chair

09:00-09:30
Improved NV diamond for laser threshold magnetometry

Abstract

How can magnetic field sensing with nitrogen-vacancy (NV) centres become more sensitive? By using NV diamond as a laser medium theoretical shot-noise-limited sensitivities could be improved by several orders of magnitude. However, this requires exceptional NV diamond material: a high density of NV- centres, a high NV- / NV0 ratio, good conversion efficiencies from substitutional nitrogen to NV centres, long coherence times as well as low optical absorption and low birefringence. 
In this talk we show multiple material studies including CVD growth, irradiation and new characterisation methods to improve NV diamond. We also show our recent progress in stimulated emission read-out of NV centres, including milliWatt-Signals, the first magnetic-field-dependent laser signal, a new NV ensemble contrast record and a one-order-of-magnitude advantage over fluorescence readout. This experimental demonstration of laser threshold magnetometry indicates the great potential of NV laser systems for improving quantum sensing

Speakers

09:30-09:45
Discussion
09:45-10:15

Abstract

Abstract will be available soon

Speakers

10:15-10:30
Discussion
10:30-11:00
Coffee break
11:00-11:30
Diamond crystal growth for quantum sensing applications

Abstract

Formation and control of electron spin of negatively charged nitrogen vacancy centre (NV−) in diamond is attracting much attention for next-generation quantum devices. For sensing applications, a relatively large amount of NV− centre is required to increase sensitivity. Typically, [NV−] of 0.1−3ppm is desired to detect weak magnetic fields. The coherence time of the electron spin T2 and T2* is another important factor for increasing sensitivity, and this value has been reported to be inversely proportional to the density of nitrogen concentration. 
Considering these facts, we have optimized diamond growth condition for both chemical-vapor deposition (CVD) and high-pressure/high-temperature (HPHT) methods. In order to prolong T2 values, we applied 12C isotopic enrichment and improved a crystalline quality of diamond. For obtaining higher [NV−], first we improved controllability of nitrogen concentration in the doping range of 0.1−50ppm. Then, NV− centre is created in diamond crystals through electron beam irradiation and subsequent vacuum annealing. It is also important to elucidate the creation of point defects other than the NV− centre during NV− centre formation processes and to understand their effect on T2, that is, on magnetic sensitivity. We performed electron paramagnetic resonance and photoluminescence measurements from this point of view. In this presentation, I will talk about recent activity on diamond growth in NIMS for quantum sensing applications.

Speakers

11:30-11:45
Discussion
11:45-12:15
Current status and prospects of solid-state quantum sensors for quantum-LEAP

Abstract

Solid-state quantum sensors using diamond and SiC are expected to have various applications due to their principle possibilities such as wide field dynamic range, operating temperature range, and high special resolution down to the atomic level. In the MEXT Q-LEAP Quantum Solid-state Flagship Project, five companies, five academia, and two national research institutes have teamed up to develop a solid-state quantum sensor from basic technologies such as materials and quantum protocols to sensor modules and application prototypes. 
In this talk, I would like to introduce the latest research topics of Q-LEAP, such as high precision simultaneous measurement of current and temperature in EV batteries, high resolution magnetocardiographic imaging of rats, probing into living cells by tip-type NV sensor. In addition, expectations for a future "quantum leap" society based on quantum solid-state sensor technology will be discussed.
This work was supported by MEXT Quantum Leap Flagship Program (MEXT Q-LEAP) Grant Number JPMXS0118067395.

Speakers

12:15-12:30
Discussion
12:30-13:35
Lunch break

Chair

13:35-14:05
Diamond spin qubits: Quantum computing and quantum simulations

Abstract

Synthetic diamond has recently emerged as a candidate material for a range of quantum-based applications including: secure quantum communication, quantum information processing and quantum sensing. In such applications, the synthetic diamond acts as a host for impurities or defects, acting like a solid-state atom trap. The quantum states of these impurities, such as the Nitrogen-Vacancy (NV) and Silicon-Vacancy (SiV) defects, can be individually manipulated.  In this presentation we will show how single colour centres can be created with a few nanometres accuracy and coherent dipole-dipole coupling was employed to generate their entanglement. We will discuss further development of the field of   quantum simulation with coupled nuclear spin qubits in isotopically engineered diamond.

Speakers

14:05-14:20
Discussion
14:20-14:50

Abstract

Abstract will be available soon

Speakers

14:50-15:05
Discussion
15:05-15:30
Tea break
15:30-16:00

Abstract

Abstract will be available soon

Speakers

16:00-16:15
Discussion
16:15-16:45
Panel discussion

Speakers