1. Jonathan Breeze, Neil Alford, et al [Imperial + UCL] collaboration
Quantum Microwave Technology –MASERs and beyond
Mark Oxborrow
NV diamond
Maser oscillation, continuous, solid-state, room temperature
Jonathan Breeze, Neil Alford, et al
[Imperial + UCL] collaboration

2. “Microwaves”
oven
magnetron
radar

3. Microwaves one the Electromagnetic Spectrum
Maxwell
Hertz
Visible light
Microwaves λ = 10 cm
λ = cm
Factor of 100,000 in wavelength (or frequency)

4. Waves behaving badly …. like particles (“quanta”)

5. Getting Inside Your Head (with MRI, EPR, Endor … )
Philips MRI
Microwaves refresh the parts wot other photons cannot reach.

6. ? Doing “Quantum Optics” ( Quantum Technologies)
Counting/detecting single photons
energy of a photon
Optical wavelengths:
Microwaves: ?
100,000 times less energy per photon
photomultipliers
Difficult!
avalanche photodiodes

7. The Bad News: Thermal Photons
At room temperature, number of microwave photons in an electromagnetic 10 GHz
300
microwave photon

8. The Good News: Spontaneous Emission
Rate of spontaneous emission
Einstein’s A coefficient
(causing shot noise)
extremely low (too small to care about)

9. Cooling to Photonic Ground State (at room temperature)
NV diamond
Microwave wave transition with equivalent Boltzmamn temperature of ~100 mK
3 GHz

10. Look to the Heavens!
Sky Temperature
Frequency

11. Avalanche Photo-detector for Microwave Photons
pentacene:p-terphenyl
Main reference:
“Room-temperature solid-state maser”, M. Oxborrow, J. D. Breeze and N. M. Alford, Nature 488, (2012).

12. Quantum Microwave Technology in a Nutshell:
Every photon’s precious.
Every photon counts.
If you can count microwaves,
in the bank comes large amounts.
picking a pocket or two …