Tiger in a Cage: Detecting Single Photons at low GHz Frequencies without Refrigerators, Vacuum Chambers or Magnets
Lead Research Organisation:
Imperial College London
Department Name: Materials
Abstract
Optically polarizable "spin" molecules trapped within "cage" molecules will be synthesized and grown as molecular crystals. One such system is phenazine, as the spin-active "guest" molecule, enveloped by a cyclophane ExCage as the "host" molecule. It is conjectured that such molecularly engineered systems can provide the long spin relaxation times exhibited by N@C60 whilst being far easier to synthesize (and crystallize out) at high chemical yields. This conjecture will be tested experimentally, the relaxation times being quantified through transient-EPR measurements. It is further speculated that these systems are capable of generating very high spin polarization densities by dint of the guest molecule's high spatial concentration, far exceeding what can be achieved by "dilute" systems such as pentacene-doped para-terphenyl, which cannot be doped (in the bulk) above 0.1 % without compromising crystallinity. As a "back-up", spin-active charge-transfer crystals, such as phenazine:tetracyanobenzene ("TCNB") will also be grown and assessed.
The most promising molecular systems, in the form of suitably shaped crystals, will then be laminated against piezoelectric chips capable of generating, propagating and detecting surface-acoustic waves (SAWs) in acoustic delay line structures. The chips' substrate material will be a selected "cut" of lithium niobate, the generation and detection of SAWs being provided by an opposing pair of metal interdigital transducers (IDTs) lithographically deposited onto each chip's surface. It is speculated that the coupling between the spin-polarized crystal and the SAW (as it propagates between the two IDTs) will either amplify or attenuate (=cool) the SAW depending on whether the crystal is emissively or absorptively spin-polarised. Immune from the forms of electronic noise that limit the performance of semiconductor-based amplifiers, it is further speculated that, with an emissively spin-polarized crystal, the structure will function as an avalanche photo-multiplier capable of detecting very small numbers of microwave photons at room temperature. Alternatively, with an absorptively polarized crystal, the device should be capable of approaching the quantum ground state (zero photons) of the spin-coupled SAW mode in question.
Devices will be accurately simulated using advanced finite-element simulation software capable of representing coupled piezomechanical-microwave SAW modes. Various combinations of spin-polarizable crystal and SAW mode [e.g. Rayleigh versus Bleustein-Gulyaev] will be explored towards maximizing the spin-phonon coupling whilst avoiding excessive "leakiness" (thus loss) from the SAW mode. Both pulsed and CW operation will be explored.
The most promising molecular systems, in the form of suitably shaped crystals, will then be laminated against piezoelectric chips capable of generating, propagating and detecting surface-acoustic waves (SAWs) in acoustic delay line structures. The chips' substrate material will be a selected "cut" of lithium niobate, the generation and detection of SAWs being provided by an opposing pair of metal interdigital transducers (IDTs) lithographically deposited onto each chip's surface. It is speculated that the coupling between the spin-polarized crystal and the SAW (as it propagates between the two IDTs) will either amplify or attenuate (=cool) the SAW depending on whether the crystal is emissively or absorptively spin-polarised. Immune from the forms of electronic noise that limit the performance of semiconductor-based amplifiers, it is further speculated that, with an emissively spin-polarized crystal, the structure will function as an avalanche photo-multiplier capable of detecting very small numbers of microwave photons at room temperature. Alternatively, with an absorptively polarized crystal, the device should be capable of approaching the quantum ground state (zero photons) of the spin-coupled SAW mode in question.
Devices will be accurately simulated using advanced finite-element simulation software capable of representing coupled piezomechanical-microwave SAW modes. Various combinations of spin-polarizable crystal and SAW mode [e.g. Rayleigh versus Bleustein-Gulyaev] will be explored towards maximizing the spin-phonon coupling whilst avoiding excessive "leakiness" (thus loss) from the SAW mode. Both pulsed and CW operation will be explored.
People |
ORCID iD |
Mark Oxborrow (Principal Investigator) | |
Max Attwood (Researcher) |
Publications
Arroo D
(2021)
Perspective on room-temperature solid-state masers
in Applied Physics Letters
Attwood M
(2023)
N-heteroacenes as an organic gain medium for room temperature masers
Attwood M
(2023)
N-heteroacenes as an organic gain medium for room temperature masers
Attwood M
(2023)
N-Heteroacenes as an Organic Gain Medium for Room-Temperature Masers.
in Chemistry of materials : a publication of the American Chemical Society
Attwood M
(2021)
Asymmetric N -heteroacene tetracene analogues as potential n-type semiconductors
in Journal of Materials Chemistry C
Ng W
(2024)
"Maser-in-a-shoebox": A portable plug-and-play maser device at room temperature and zero magnetic field
in Applied Physics Letters
Ng W
(2021)
Quasi-continuous cooling of a microwave mode on a benchtop using hyperpolarized NV- diamond
in Applied Physics Letters
Ng W
(2021)
Exploring the Triplet Spin Dynamics of the Charge-Transfer Co-crystal Phenazine/1,2,4,5-Tetracyanobenzene for Potential Use in Organic Maser Gain Media
in The Journal of Physical Chemistry C
Ng W
(2023)
Move Aside Pentacene: Diazapentacene-Doped para-Terphenyl, a Zero-Field Room-Temperature Maser with Strong Coupling for Cavity Quantum Electrodynamics.
in Advanced materials (Deerfield Beach, Fla.)
Wu H
(2022)
Enhanced quantum sensing with room-temperature solid-state masers.
in Science advances
Description | Invention of a method of removing thermal noise from a microwave cavity |
Exploitation Route | Licensing of patent applied for. |
Sectors | Aerospace, Defence and Marine,Electronics,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology |
URL | https://imperial.tech/our-technologies/a-noise-reduction-protocol-for-epr-nmr-and-quantum-sensing/? |
Description | Innovate UK Project No: 10005893 Magnetic induction heating method for stun and dispatch of slaughter weight broilers |
Organisation | Royal Veterinary College (RVC) |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We are supplying design consultancy and development work on high power microwave resonators for use in agriculture. The dielectric resonators developed in this collaboration are almost identical to those required for detecting single microwave photons except are operated at vastly higher power levels of hundreds/thousands of watts. |
Collaborator Contribution | None. It is a case of technology transfer from academia to industry. |
Impact | Early days. The project only started in on December 1st 2021. |
Start Year | 2021 |
Description | RF magnetic induction pest controller for cabbage stem flea beetle control - commercial prototype |
Organisation | Harper Adams University |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | The application area here is the killing of certain pests, e.g. cabbage stem flea beetle, which is currently devastating the UK's oil-seed rape crops, without using chemical insecticides and/or resorting to genetic modifications (GM). This application might seem light years away from low-noise microwave amplification with masers but the skills and know-how needed to design an efficient, effective maser are exactly the same as those that are needed to design high-power dielectric resonators working at hundreds of watts (or even kilowatts) for pest control. Hence the technology transfer from "masers" to "insect/grub zappers". I am now collaborating with a Cornwall-based consortium (labs located at ESAM, near St. Austell) to develop demonstrators and prototypes or the technology: resonators that lethally expose insects to intense magnetic fields at GHz frequencies that leave the leaves, flowers and grains of plants unscathed. Contributions (work packages in the project): (a) RF consultancy towards defining novel design of developed microwave resonator for killing crop-destroying pests. (b) Metrology: development of novel probe (based on a temperature-sensitive liquid crystal) to measure strength of the high-frequency magnetic fields used. |
Collaborator Contribution | None. Technology/know-how transfer from academia to industry. |
Impact | Novel design of microwave resonator for killing agricultural pests without the need for insecticides or GM. Novel design of magnetic field probe at microwave frequencies. |
Start Year | 2021 |
Title | Reduction of thermal noise in microwave cavity |
Description | Reduction of thermal noise in microwave cavity |
IP Reference | 2212465.5 |
Protection | Patent / Patent application |
Year Protection Granted | 2022 |
Licensed | No |
Impact | Pending |