TY - JOUR
T1 - Laser Cooling of a Nanomechanical Oscillator to Its Zero-Point Energy
AU - Qiu, Liu
AU - Shomroni, Itay
AU - Seidler, Paul
AU - Kippenberg, Tobias J.
N1 - Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/5/1
Y1 - 2020/5/1
N2 - Optomechanical systems in the well-resolved-sideband regime are ideal for studying a myriad of quantum phenomena with mechanical systems, including backaction-evading measurements, mechanical squeezing, and nonclassical states generation. For these experiments, the mechanical oscillator should be prepared in its ground state, i.e., exhibit negligible residual excess motion compared to its zero-point motion. This can be achieved using the radiation pressure of laser light in the cavity by selectively driving the lower motional sideband, leading to sideband cooling. To date, the preparation of sideband-resolved optical systems to their zero-point energy has eluded laser cooling because of strong optical absorption heating. The alternative method of passive cooling suffers from the same problem, as the requisite milliKelvin environment is incompatible with the strong optical driving needed by many quantum protocols. Here, we employ a highly sideband-resolved silicon optomechanical crystal in a He3 buffer-gas environment at ∼2 K to demonstrate laser sideband cooling to a mean thermal phonon occupancy of 0.09-0.01+0.02 quantum (self-calibrated using motional sideband asymmetry), which is -7.4 dB of the oscillator's zero-point energy and corresponds to 92% ground state probability. Achieving such low occupancy by laser cooling opens the door to a wide range of quantum-optomechanical experiments in the optical domain.
AB - Optomechanical systems in the well-resolved-sideband regime are ideal for studying a myriad of quantum phenomena with mechanical systems, including backaction-evading measurements, mechanical squeezing, and nonclassical states generation. For these experiments, the mechanical oscillator should be prepared in its ground state, i.e., exhibit negligible residual excess motion compared to its zero-point motion. This can be achieved using the radiation pressure of laser light in the cavity by selectively driving the lower motional sideband, leading to sideband cooling. To date, the preparation of sideband-resolved optical systems to their zero-point energy has eluded laser cooling because of strong optical absorption heating. The alternative method of passive cooling suffers from the same problem, as the requisite milliKelvin environment is incompatible with the strong optical driving needed by many quantum protocols. Here, we employ a highly sideband-resolved silicon optomechanical crystal in a He3 buffer-gas environment at ∼2 K to demonstrate laser sideband cooling to a mean thermal phonon occupancy of 0.09-0.01+0.02 quantum (self-calibrated using motional sideband asymmetry), which is -7.4 dB of the oscillator's zero-point energy and corresponds to 92% ground state probability. Achieving such low occupancy by laser cooling opens the door to a wide range of quantum-optomechanical experiments in the optical domain.
UR - http://www.scopus.com/inward/record.url?scp=85084742574&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.124.173601
DO - 10.1103/PhysRevLett.124.173601
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C2 - 32412282
AN - SCOPUS:85084742574
SN - 0031-9007
VL - 124
JO - Physical Review Letters
JF - Physical Review Letters
IS - 17
M1 - 173601
ER -