Christian M. Pluchar, Aman R. Agrawal, Dalziel J. Wilson
{"title":"Quantum-limited optical lever measurement of a torsion oscillator","authors":"Christian M. Pluchar, Aman R. Agrawal, Dalziel J. Wilson","doi":"arxiv-2409.11397","DOIUrl":null,"url":null,"abstract":"The optical lever is a precision displacement sensor with broad applications.\nIn principle, it can track the motion of a mechanical oscillator with added\nnoise at the Standard Quantum Limit (SQL); however, demonstrating this\nperformance requires an oscillator with an exceptionally high torque\nsensitivity, or, equivalently, zero-point angular displacement spectral\ndensity. Here, we describe optical lever measurements on Si$_3$N$_4$\nnanoribbons possessing $Q>3\\times 10^7$ torsion modes with torque sensitivities\nof $10^{-20}\\,\\text{N m}/\\sqrt{\\text{Hz}}$ and zero-point displacement spectral\ndensities of $10^{-10}\\,\\text{rad}/\\sqrt{\\text{Hz}}$. Compensating aberrations\nand leveraging immunity to classical intensity noise, we realize angular\ndisplacement measurements with imprecisions 20 dB below the SQL and demonstrate\nfeedback cooling, using a position modulated laser beam as a torque actuator,\nfrom room temperature to $\\sim5000$ phonons. Our study signals the potential\nfor a new class of torsional quantum optomechanics.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"10 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - PHYS - Quantum Physics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.11397","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The optical lever is a precision displacement sensor with broad applications.
In principle, it can track the motion of a mechanical oscillator with added
noise at the Standard Quantum Limit (SQL); however, demonstrating this
performance requires an oscillator with an exceptionally high torque
sensitivity, or, equivalently, zero-point angular displacement spectral
density. Here, we describe optical lever measurements on Si$_3$N$_4$
nanoribbons possessing $Q>3\times 10^7$ torsion modes with torque sensitivities
of $10^{-20}\,\text{N m}/\sqrt{\text{Hz}}$ and zero-point displacement spectral
densities of $10^{-10}\,\text{rad}/\sqrt{\text{Hz}}$. Compensating aberrations
and leveraging immunity to classical intensity noise, we realize angular
displacement measurements with imprecisions 20 dB below the SQL and demonstrate
feedback cooling, using a position modulated laser beam as a torque actuator,
from room temperature to $\sim5000$ phonons. Our study signals the potential
for a new class of torsional quantum optomechanics.