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Distinct optical and acoustic phonon temperatures in nm-thick suspended WS2: Direct differentiating via acoustic phonon thermal field invariant
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Award ID(s):
Publication Date:
NSF-PAR ID:
10356264
Journal Name:
Materials Today Physics
Volume:
27
Issue:
C
Page Range or eLocation-ID:
100816
ISSN:
2542-5293
1. The energy damping time in a mechanical resonator is critical to many precision metrology applications, such as timekeeping and force measurements. We present measurements of the phonon lifetime of a microwave-frequency, nanoscale silicon acoustic cavity incorporating a phononic bandgap acoustic shield. Using pulsed laser light to excite a colocalized optical mode of the cavity, we measured the internal acoustic modes with single-phonon sensitivity down to millikelvin temperatures, yielding a phonon lifetime of up to$τph,0≈1.5$seconds (quality factor$Q=5×1010$) and a coherence time of$τcoh,0≈130$microseconds for bandgap-shielded cavities. These acoustically engineered nanoscale structures provide a window into the material origins of quantum noise and have potential applications ranging from tests of various collapse models of quantum mechanics to miniature quantum memory elements in hybrid superconducting quantum circuits.