TY - JOUR
T1 - Bench-Top Cooling of a Microwave Mode Using an Optically Pumped Spin Refrigerator
AU - Wu, Hao
AU - Mirkhanov, Shamil
AU - Ng, Wern
AU - Oxborrow, Mark
N1 - Publisher Copyright:
© 2021 American Physical Society.
PY - 2021/7/30
Y1 - 2021/7/30
N2 - We experimentally demonstrate the temporary removal of thermal photons from a microwave mode at 1.45 GHz through its interaction with the spin-polarized triplet states of photo-excited pentacene molecules doped within a p-terphenyl crystal at room temperature. The crystal functions electromagnetically as a narrowband cryogenic load, removing photons from the otherwise room-temperature mode via stimulated absorption. The noise temperature of the microwave mode dropped to 50-32+18 K (as directly inferred by noise-power measurements), while the metal walls of the cavity enclosing the mode remained at room temperature. Simulations based on the same system's behavior as a maser (which could be characterized more accurately) indicate the possibility of the mode's temperature sinking to ∼10 K (corresponding to ∼140 microwave photons). These observations, when combined with engineering improvements to deepen the cooling, identify the system as a narrowband yet extremely convenient platform - free of cryogenics, vacuum chambers, and strong magnets - for realizing low-noise detectors, quantum memory, and quantum-enhanced machines (such as heat engines) based on strong spin-photon coupling and entanglement at microwave frequencies.
AB - We experimentally demonstrate the temporary removal of thermal photons from a microwave mode at 1.45 GHz through its interaction with the spin-polarized triplet states of photo-excited pentacene molecules doped within a p-terphenyl crystal at room temperature. The crystal functions electromagnetically as a narrowband cryogenic load, removing photons from the otherwise room-temperature mode via stimulated absorption. The noise temperature of the microwave mode dropped to 50-32+18 K (as directly inferred by noise-power measurements), while the metal walls of the cavity enclosing the mode remained at room temperature. Simulations based on the same system's behavior as a maser (which could be characterized more accurately) indicate the possibility of the mode's temperature sinking to ∼10 K (corresponding to ∼140 microwave photons). These observations, when combined with engineering improvements to deepen the cooling, identify the system as a narrowband yet extremely convenient platform - free of cryogenics, vacuum chambers, and strong magnets - for realizing low-noise detectors, quantum memory, and quantum-enhanced machines (such as heat engines) based on strong spin-photon coupling and entanglement at microwave frequencies.
UR - http://www.scopus.com/inward/record.url?scp=85112595828&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.127.053604
DO - 10.1103/PhysRevLett.127.053604
M3 - Article
C2 - 34397251
AN - SCOPUS:85112595828
SN - 0031-9007
VL - 127
JO - Physical Review Letters
JF - Physical Review Letters
IS - 5
M1 - 053604
ER -