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Towards LED-pumped Masers: a new class of room-temperature masers

Lead Research Organisation: NORTHUMBRIA UNIVERSITY
Department Name: Fac of Engineering and Environment

Abstract

"MASERs" (Microwave Amplification by Stimulated Emission of Radiation) are devices that can amplify and detect extremely weak electromagnetic signals. Potential applications include more sensitive variants of electron paramagnetic resonance (EPR) spectroscopy, magnetic resonance body scanners, deep-space telecommunications, read-out schemes for spin-based quantum computers, and embodiments of "quantum optics" at microwave and radio frequencies. Our previous research on masers demonstrates room-temperature operation in pulsed and continuous wave (CW) using solid-state materials and laser/lamp pumping. A key research challenge is to replace the pump laser with a more rugged and low-cost system. in many applications laser sources have been chosen for lack of better. Due to their low brightness, LEDs are not adapted easily to pump masers. However, LED-pumped luminescent concentrators (LED-LC) are perfect for this purpose, especially the powerful rare-earth-based LED-LCs, offering new ways of high brightness technology. LED-LCs are new sources whose brightness fills the gap between the classical incoherent sources and the laser sources.

This proposal focuses on developing LED-pumped masers working at room temperature using luminescent concentrator light technology- such a maser has not been realised to date. These masers will be low-cost, safe, low maintenance and allow simple fabrication. The research will develop the world's first LED-LC pumped masers. A significant asset of LED-pumped LCs is energy scaling and massive collective operation, assuring a long lifetime, stability, and robustness. The LED-based brightness-enhanced light source would also be a profoundly enabling new tool for basic science (understanding luminance, brightness, light concentration, etc) and other bright illumination and excitation applications in scientific, medicine/healthcare (medical endoscopy, dermatology) and industry (RGB projection, 3D inspection).

Because of their complexity in implementation, the masers are used in only a few specialised applications, notably atomic clocks and low-noise amplifiers for radio astronomy and space communications. This new approach and research will enable masers to become more widely available for use and open new application areas such as airport security scanning, quantum computers, medical imaging and potentially in a key role of improving sensors to remote-detect bombs. This work will help the UK become internationally competitive in low-cost room-temperature masers and luminescent concentrator light technology, impacting world-leading groups. In addition, the research will lead to new ideas (i.e., intellectual properties), which will provide economic and societal benefits within a few years in the UK as well as worldwide.
 
Description This award has delivered several important breakthroughs that make next-generation room-temperature maser technology more practical, energy-efficient, and closer to real-world use:

1. A fully LED-pumped room-temperature maser was demonstrated for the first time.
Traditionally, masers required expensive lasers, high magnetic fields, or very low temperatures to operate. This project showed that simple, low-cost LEDs can now pump a maser, greatly reducing complexity, cost, and power consumption. This is a major step toward practical maser devices for sensing, communications, medical imaging, and quantum technologies.
2. New high-brightness luminescent concentrators were developed to dramatically amplify LED light.
The team created improved luminescent concentrator (LC) materials and designs, allowing weak LED light to be concentrated more than tenfold. This makes LEDs bright enough to excite maser gain media effectively, enabling compact and energy-efficient devices.
3. Thermal engineering solutions were created to make high-power LED pumping stable.
The project produced new cooling designs (including high-performance water-cooled heat sinks) that keep LEDs and luminescent crystals within safe operating temperatures. This allows long-term, stable operation-something previous LED-pumped systems could not achieve.
4. New synthetic diamond materials were characterised for NV?-maser applications.
The team performed a multi-technique study of CVD and HPHT diamonds to understand their nitrogen-vacancy content, coherence times, and optical properties. This work identifies which diamond types are most suitable for future room-temperature masers based on NV centres.
5. The first demonstrations of L-band (1-2 GHz) masers driven by LEDs were produced.
This includes:
(i). Feasibility of free-space maser signal transmission
(ii). A milliwatt-level room-temperature L-band maser, an important step toward secure communications and deep-space links

Together, these outcomes establish a new, low-cost technological route for compact, efficient maser systems that can be used outside specialised laboratories.
Exploitation Route 1. Quantum sensing & timing: Deploy LED-pumped, low-noise maser front-ends for portable magnetometers, atomic-clock references, and low-phase-noise microwave sources.
2. Medical imaging & diagnostics: Use high-brightness LED-LC sources as compact, robust illuminators; explore maser-based ultra-low-noise receivers for MRI and spectroscopy.
3. Communications (including deep-space): Translate L-band maser prototypes into low-power, long-range links and secure or resilient RF systems.
4. Materials & device R&D: Apply the NV-diamond characterisation dataset and thermal/packaging designs to accelerate maser devices and bright solid-state light sources in other labs.
5. Industrial photonics: Re-use the luminescent concentrator designs (and extraction/taper strategies) in laser pumping, metrology, and high-intensity illumination products.
Sectors Aerospace

Defence and Marine

Digital/Communication/Information Technologies (including Software)

Education

Electronics

Energy

Healthcare

Manufacturing

including Industrial Biotechology

Pharmaceuticals and Medical Biotechnology

Security and Diplomacy

Transport

 
Description They have been used to: 1. inform and inspire school and college pupils through talks and hands-on workshops; 2. support NUSTEM in creating a new outreach programme and primary-school activity; 3. raise public awareness via media coverage; 4. influence early industrial discussions on low-noise communications and sensing; 5. guide new research directions around LED-LC maser architectures.
First Year Of Impact 2025
Sector Aerospace, Defence and Marine,Creative Economy,Digital/Communication/Information Technologies (including Software),Education,Electronics,Energy,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology,Security and Diplomacy,Transport
Impact Types Cultural

Societal

Economic

Policy & public services

 
Description Exploring Solar-Pumped MASERs Through Optical Concentrator Trials ( Internal Funding:Seedcorn Funding)
Amount £16,271 (GBP)
Funding ID Project 1203446 
Organisation Northumbria University 
Sector Academic/University
Country United Kingdom
Start 11/2025 
End 06/2026
 
Description Grant Award via the Northern Accelerator, Connecting Capability Fund (NA-SPF 57)
Amount £30,000 (GBP)
Funding ID Grant Award via the Northern Accelerator, Connecting Capability Fund (NA-SPF 57). Northern Accelerator is funded as part of the In-TUNE project, a collaboration comprising Durham, Newcastle and Northumbria universities and Centre for Process Innovation. 
Organisation United Kingdom Research and Innovation 
Sector Public
Country United Kingdom
Start 09/2024 
End 03/2025
 
Description MASER-Link: A Reconfigurable MASER-Based Microwave Communications Platform for Resilient Satellite Ground Links_EPSRC_NESCA IAA
Amount £64,635 (GBP)
Funding ID Project 1189228: MASER-Link: A Reconfigurable MASER-Based Microwave Communications Platform For Resilient Satellite Ground Links. This is part of STREAM 1: North East Space Communications Accelerator (NESCA), Project Reference: EP/Z536301/1 
Organisation United Kingdom Research and Innovation 
Sector Public
Country United Kingdom
Start 02/2026 
End 06/2027
 
Title LED-Pumped MASER Experimental Setup 
Description A novel LED-pumped MASER experimental setup, replacing conventional high-powered laser excitation with a low-cost, scalable LED-based system. The setup integrates a luminescent concentrator, optical pumping, and microwave resonator, making MASER research more energy-efficient, accessible, and scalable. 
Type Of Material Improvements to research infrastructure 
Year Produced 2024 
Provided To Others? Yes  
Impact This setup enhances research infrastructure by enabling new investigations into room-temperature MASERs, improving experimental efficiency, and accelerating applications in quantum sensing, secure communications, and microwave signal amplification. 
URL https://www.nature.com/articles/s44172-025-00455-w
 
Description Collaboration with Crytur on engineered luminescent materials for LED-pumped maser development 
Organisation Crytur
Country Czech Republic 
Sector Private 
PI Contribution My research team and I contribute the following: Leading the scientific development of LED-pumped luminescent concentrators (LED-LC) and their integration with room-temperature masers. Conducting optical modelling, material characterisation, design and construction of maser prototypes (pentacene and diamond-based systems). Providing experimental facilities at Northumbria University, including state-of-the-art maser/laser laboratories, optical and microwave characterisation equipment, and expertise in maser/laser design. Managing the overall EPSRC New Investigator Award project, supervising PDRA and PhD researchers, and coordinating research activities across academic and industrial partners.
Collaborator Contribution Crytur's contributions include: Supplying engineered luminescent crystals and a range of YAG-based dopants including (Lu,Y,Gd)3Al5O12:Ce³?. Providing consultancy and cooperation in all phases of the project, including materials engineering, crystal growth, coatings, and optimisation of luminescent materials. Offering in-kind support valued at £15,000, covering materials, specialist staff time, and access to R&D facilities. Supporting the spectral-flexibility development of luminescent components for LED-pumped maser systems.
Impact Development of engineered luminescent materials suitable for high-brightness LED-LC pumping. Integration of Crytur-engineered crystals into LED-pumped maser prototypes (pentacene and diamond). Enhanced spectral-flexibility and brightness optimisation for maser gain media. Joint progress toward the world's first LED-pumped room-temperature maser, supporting advances in quantum sensing, high-brightness photonics, and low-cost excitation technologies. Contribution to a multi-disciplinary research programme spanning materials science, photonics, quantum technologies, and optical engineering.
Start Year 2023
 
Description Element Six Collaboration on Diamond MASER 
Organisation De Beers Group
Department Element Six
Country Luxembourg 
Sector Private 
PI Contribution Our research team at Northumbria University ( PI: Dr Juna Sathian, PhD student for Pentacene MASER: Sophia Long, PhD student for Diamond MASER: Weronika Korgul and Postdoc on this project Priyanka Choubey) is utilising the CVD and HTHP diamond samples provided by Element Six (via MTA) for: 1) Characterisation of Diamond Samples: -Conducting optical and electronic characterisation of Element Six's diamonds to assess their suitability for maser applications. -Performing Electron Paramagnetic Resonance (EPR), Optically Detected Magnetic Resonance (ODMR), fluorescence, and UV-Vis spectroscopy to study NV centre properties. 2) Demonstration of Laser-Pumped MASER -Using laser-excited NV-centres in diamond to demonstrate room-temperature maser operation. -Investigating resonator designs and spin dynamics for enhanced maser performance. 3) Development of LED-Pumped MASER -Exploring LED-pumped luminescent concentrator (LC) technology as a cost-effective alternative to lasers for maser excitation. -Optimising light coupling, brightness enhancement, and thermal management for continuous maser operation. This collaboration is instrumental in advancing low-cost, scalable maser technology, with potential applications in quantum sensing, medical imaging, and secure communications.
Collaborator Contribution The University of Warwick, through Prof. Gavin Morley's Diamond Research Group, is providing specialist characterisation support of NV-diamond samples, essential for maser development. This includes Electron Paramagnetic Resonance (EPR), Optically Detected Magnetic Resonance (ODMR), and low-temperature spectroscopy to evaluate NV centre spin properties, coherence times, and charge state dynamics. These measurements are critical for determining the suitability of the diamond samples for maser, ensuring optimal performance in LED-pumped maser applications. At Imperial College London, Prof. Neil Alford's group provides access to maser experimental facilities, enabling direct validation of room-temperature maser operation. Their contribution includes microwave cavity testing, spin manipulation techniques, and performance benchmarking, utilising their established expertise in solid-state maser technology. This collaboration ensures the experimental verification and refinement of maser performance parameters, accelerating the transition from research to practical application.
Impact The collaboration with Element Six has significantly contributed to WP3: LED-pumped diamond maser, focusing on the characterisation and demonstration of CVD and HTHP diamond samples for room-temperature maser applications. This partnership has been instrumental in advancing the understanding of NV centre properties, improving maser performance, and optimising system design for practical applications. Under the research led by PhD student Weronika Korgul, UV-Vis spectroscopy confirmed the NV and NV? absorption peaks, validating their suitability for maser excitation. Raman spectroscopy assessed diamond purity, structural integrity, and nitrogen-vacancy concentration, showing that lower NV concentrations enhance maser stability. Additionally, Optically Detected Magnetic Resonance (ODMR) was successfully conducted at room temperature, confirming the presence of maser-conducive spin defects and informing the ideal excitation wavelengths for masing. Using LightTools Illumination Software, the diamond pump system was simulated to evaluate irradiance output and optical coupling. A comparison between pentacene and NV-diamond systems revealed that diamond provides a highly concentrated irradiance output, supporting its use in high-brightness maser applications. These findings help optimise light absorption efficiency for maser operation. This collaboration is multi-disciplinary, integrating expertise from quantum physics and optics for NV-diamond spin characterisation, materials science and engineering for diamond quality assessment, optoelectronics and photonics for maser excitation system development, and computational modelling for maser cavity simulations and light distribution optimisation. By combining expertise across these fields, the collaboration with Element Six has accelerated breakthroughs in room-temperature maser technology, laying the groundwork for future advancements in quantum sensing, secure communications, and precision measurement systems.
Start Year 2023
 
Description Imperial College London (ICL) - Maser & LED-Pumped Maser Research Collaboration 
Organisation Imperial College London
Country United Kingdom 
Sector Academic/University 
PI Contribution Developing LED-pumped luminescent concentrator (LED-LC) architectures for maser excitation. Providing modelling, optical design, and maser prototype development. Integrating LED-LC technologies with maser gain media previously developed in collaboration with ICL.
Collaborator Contribution In-kind contribution £15k of investigator time for maser-related collaboration, meetings, and scientific input. £20k in access to specialist equipment for maser characterisation and materials testing. Providing deep expertise in room-temperature maser physics and prior maser prototypes (including Nature-published systems).
Impact Joint development of LED-pumped maser architectures. Knowledge exchange on room-temperature diamond masers. Cross-institutional training for PDRA and PhD researchers. Strong multi-disciplinary impact: materials science, quantum technology, photonics, electrical engineering. PUBLICATIONS 1. L-Band Milliwatt Room-Temperature Solid-State Maser 2026 Materials Advances (submitted; Manuscript ID: MA-ART-03-2026-000332) Authors: S. Long, M. Attwood, J. Chan, P. Choubey, H. Torun, J. Sathian 2. Thermal Performance of LED-pumped Ce:YAG Luminescent Concentrators based high-radiance sources 2026 Optica Manuscript (submitted) Authors: P.S. Choubey, J. Sathian 3. Feasibility of Free-Space Transmission using L-Band Maser Signals in Organic Gain Media 2025 arXiv preprint arXiv:2511.09059 Authors: S. Long, P. Choubey, M. Attwood, J. Chang, H. Torun, J. Sathian 4. L-Band Milliwatt Room-Temperature Solid-State Maser 2025 arXiv preprint arXiv:2511.09056 Authors: S. Long, M. Attwood, J. Chang, P. Choubey, H. Torun, J. Sathian 5. LED-pumped room-temperature solid-state maser 2025 Communications Engineering 4 (1), 122 Authors: S. Long, L. Lopez, B. Ford, F. Balembois, R. Montis, W. Ng, D.M. Arroo, ... 6. Room-temperature microwave MASERs with LED pumping: a step towards practical realization 2024 Quantum Sensing, Imaging, and Precision Metrology II (PC129121Q) Authors: J. Sathian, S. Long, L. Lopez, B. Ford, F. Balembois, W. Ng, D.M. Arroo, ...
Start Year 2023
 
Description Institut d'Optique Graduate School (Université Paris-Saclay) - LED-LC Laser & Maser Joint Development Collaboration 
Organisation Laboratoire Charles Fabry
Country France 
Sector Academic/University 
PI Contribution LED-LC system development, modelling, and integration with maser prototypes. Participation in Royal Society International Exchange Grant work. Providing maser design, materials testing, and optical characterisation
Collaborator Contribution Offering £30k (equivalent) in access to powerful LED-LC concentrator equipment. Shared expertise in LED-LC pumped laser technology. Joint investigation of the first LED-pumped masers.
Impact Joint development of LED-LC pumped laser systems. Preparatory work for the first LED-pumped maser. Cross-disciplinary impact: optics, lasers, masers, quantum devices. Publications: 1. LED-pumped room-temperature solid-state maser 2025 Communications Engineering 4 (1), 122 Authors: S. Long, L. Lopez, B. Ford, F. Balembois, R. Montis, W. Ng, D.M. Arroo, J. Sathian 2. Exploring light-emitting diode pumped luminescent concentrators in solid-state laser applications 2024 Methods and Applications in Fluorescence 12 (3), 032001 Authors: H.C.S. Perera, B. Ford, G. Das, F. Balembois, J. Sathian 3. Room-temperature microwave MASERs with LED pumping: a step towards practical realization 2024 Quantum Sensing, Imaging, and Precision Metrology II (PC129121Q) Authors: J. Sathian, S. Long, L. Lopez, B. Ford, F. Balembois, W. Ng, D.M. Arroo, ... 4. Luminescent Concentrators for Next Generation Microwave Photonics 2023 The European Conference on Lasers and Electro-Optics (ci_8_5) Authors: J. Sathian, L. Lopez, S. Long, B. Ford, H. Torun, F. Balembois
Start Year 2023
 
Description University of Warwick - Diamond NV Maser Characterisation Collaboration 
Organisation University of Warwick
Country United Kingdom 
Sector Academic/University 
PI Contribution Providing LED-LC systems for optically pumping NV-centre diamonds for maser studies. Conducting joint experiments and modelling on NV-centre maser performance. Supplying luminescent concentrator technology to Warwick for combined tests.
Collaborator Contribution Providing access to EPR and ODMR facilities for diamond characterisation (NV concentration, lifetimes, relaxation times). Offering £5k of in-kind investigator time and £10k of equipment access. Supplying diamond physics expertise related to NV defects and maser gain media.
Impact Joint EPR/ODMR studies of NV-centre samples. Identification of optimal NV-centre diamonds for masers. Multi-disciplinary impact: materials, quantum physics, photonics, microwave engineering. PUBLICATIONS Multi-technique characterisation of synthetic diamond samples for NV?-based room-temperature maser applications (in submission / preparation) 2026 AIP Publishing (manuscript in preparation) Authors: W. Korgul, P.S. Choubey, D. Tiwari, B. Breeze, G.W. Morley, J. Sathian
Start Year 2023
 
Title A Light Source 
Description There is provided a light source arranged to output light at a first wavelength. The light source comprises a luminescent concentrator having a slab-shaped geometry. The luminescent concentrator comprises: an input port arranged to receive light and define a first area; an output port arranged to transmit light and define a second area which is smaller than the first area; and surfaces arranged to direct light inside the luminescent concentrator to the output port. The luminescent concentrator further comprises lumophores arranged to receive light at a second wavelength and emit light at the first wavelength; and a pump light supply coupled to the input port and arranged to illuminate the input port with light at the second wavelength. 
IP Reference US2017329065 
Protection Patent / Patent application
Year Protection Granted 2017
Licensed No
 
Title First Demonstration of Free-Space MASER Signal Transmission Using LED-Pumped L-Band Maser 
Description This output represents the first demonstration of free-space transmission of a MASER signal, enabled by the LED-pumped L-band maser architecture developed in this project. The technique shows that maser emission can propagate over distance without waveguides, using compact, energy-efficient LED pumping combined with engineered organic gain media. It introduces a new method for low-noise, room-temperature microwave signal generation and transmission, significantly reducing the complexity and cost traditionally associated with maser systems. 
Type Of Technology New/Improved Technique/Technology 
Year Produced 2025 
Impact This technique opens a new technological route for long-distance, low-noise microwave communication using solid-state masers. It has potential applications in secure communications, deep-space links, quantum-enhanced sensing, and low-noise RF front-end electronics. The demonstration has generated interest from academic and industrial partners exploring compact maser systems, and it strengthens the UK's capability in next-generation quantum and communication technologies. 
URL https://arxiv.org/abs/2511.09059
 
Title Stability-Optimised High-Power LED-LC Pump Module for Long-Term Maser Operation 
Description This technical output is a stability-tested, high-power LED-Ce:YAG luminescent concentrator (LC) pump module, developed to provide long-term, thermally stable optical pumping for room-temperature masers, including NV-diamond devices. The product is based on a combined experimental and modelling study using a 50 W GaN multi-die LED array coupled to a Ce:YAG LC, with custom water-cooled copper heatsinks, IR thermography, RTD sensing, and steady-state thermal simulations. The work establishes the thermal-stability envelope, identifies safe operating regimes, and defines duty-cycle strategies that maintain near-ambient temperatures even at >100 W peak pump power. This module provides the first comprehensive stability and reliability study of LED-LC pumping suitable for extended maser operation, including future diamond masers where continuous thermal management is critical. 
Type Of Technology New/Improved Technique/Technology 
Year Produced 2026 
Impact This stability-verified LED-LC pump architecture directly enables long-duration, repeatable operation of LED-pumped masers, overcoming a major barrier to scalability. The operating guidelines and thermal-management solutions support reliable performance for diamond maser development, secure communications prototypes, and future low-noise quantum RF sources. The approach also provides transferrable thermal-engineering methodologies for medical imaging illumination, industrial high-brightness LED systems, and solid-state laser/maser pump modules, increasing UK capability in robust photonic hardware. 
 
Title World's First LED-Pumped MASER 
Description The LED-pumped MASER is the first demonstration of microwave amplification using an LED-excited gain medium with a luminescent concentrator, eliminating the need for expensive and high-powered laser excitation. This advance enables MASERs to be more compact, energy-efficient, and scalable, unlocking new applications in quantum sensing, secure communications, and medical imaging. 
Type Of Technology New/Improved Technique/Technology 
Year Produced 2024 
Impact This breakthrough solves a 60-year-old challenge of operating MASERs at room temperature with low-cost optical pumping, making them commercially viable for quantum technologies, deep-space communications, and precision magnetometry. The LED-pumped MASER concept has already led to new research directions in solid-state MASER physics and has the potential for widespread adoption in sensing and microwave signal processing. 
URL https://www.nature.com/articles/s44172-025-00455-w
 
Description NUSTEM (Northumbria University STEM) Primary school workshops 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact The NUSTEM team has been developing a primary school workshop titled "Challenges in Long-Distance Communication", designed to increase awareness of how various technologies, including MASERs, can help overcome communication challenges on Earth and in space. A pilot session was conducted in early December with Year 5 pupils from Kenton Bar School in Newcastle.

Over the next few months, the workshop will be refined, and by summer 2025, up to five local primary schools will visit Northumbria University to participate. From September 2025, the workshop will also be available for delivery in local schools, and it will be offered again as part of the summer university visit program for primary schools in 2026.
Year(s) Of Engagement Activity 2024,2025