Regal Group News
Drum-like membrane resonators are intriguing for precision sensing because their resonance frequencies can be sensitive to a variety of parameters of interest, from mass to thermal radiation. The quest for improved sensitivity in tensioned membranes faces a tradeoff in which a high amplitude of mechanical motion improves signal-to-noise, but too high of a drive (beyond the so-called critical amplitude) introduces nonlinear effects.
In our work published in NanoLetters, we develop an experimentally straightforward method to evade this tradeoff. Using a patterned, trampoline-shaped membrane, we find that dual-mechanical-mode operation can bring these sensors to a thermally-limited frequency stability.Ìý By measuring and correcting for frequency noise arising at high amplitude, we maintain this high stability when operating beyond the linear regime, opening new opportunities for membrane frequency sensing.
Physicists descended on the island of Helgoland this June to celebrate 100 years of quantum mechanics. Our group enjoyed contributing to this the convergence of quantum applications and foundations.
Our work on high optical access cryogenic system for Rydberg atoms has been published in PRX Quantum - see this viewpoint on our studies.
Mechanical resonators featuring large tensile stress have enabled a range of experiments in quantum optomechanics and precision sensing. Many sensing applications require functionalizing tensioned resonators by appending additional mass to them. However, this may dramatically change the resonator mode quality factor, and hence its sensitivity.
In our work published in Physical Review Applied, we study how mode quality factor depends on suspending a mass on a type of membrane resonator known as a trampoline.Ìý Surprisingly, the quality factor becomes independent of the mass in the large-loadÌýregime, for any tensioned resonator, which explains previous related results and will enable new design perspectives.
In our work recently published in Physical Review ResearchÌýwe study Rabi oscillations in a vapor cell environment to understand their coherence in a regime where strong population dynamics are present. With these efforts we take an important step towards applying ideas inÌývector magnetic field measurements using Rabi oscillationsÌýto vapor cells.
Analysis and new designs of low mass SiN mechanical defects in 2D acoustic shieldsÌýfor force sensing --Ìýnow published inÌýPhysical Review Applied.
We are organizing an upcoming workshop on optomechanical architectures for new physics searches through force signatures on scalable arrays of mechanical resonators.ÌýÌýThe workshop is sponsored by anÌýAPS Moore Foundation Fundamental Physics convening awardÌýand co-sponsored by the JILA NSF Physics Frontier Center and JQI.Ìý
ChrisÌýKiehl, a graduate student in the Regal Group,Ìýwon a prize for his poster on quantum sensing and metrology at a conference in Germany this summer.
Microwaves report on the direction of a magnetic field!Ìý Our work on self-calibrated atomic vector magnetometry has been published inÌýPhys. Rev. Lett.Ìý We show that a microwave polarization ellipse can be mapped with atomic transitions, and can serve as a useful three-dimensional reference.Ìý Our next step is to translate this idea to atomic vapor cells to make an atomic vector magnetometer that can calibrate itself at any time.
JILA Fellow Cindy Regal has been named a 2018 Alexander M. Cruickshank Lecturer by the Gordon Research Conferences (GRC). This prestigious title is given worldwide to scientists at the top of their fields in the physical, chemical, and biological sciences.