Noise suppression methods in picometer heterodyne displacement interferometer

Yanqi Zhang, Felipe Guzman

Research output: Chapter in Book/Report/Conference proceedingConference contribution


High sensitivity displacement interferometer has wide applications in gravitational wave detection area, performing as crucial part in test mass dynamics measurement and seismic motion monitoring for low-noise observatory operation. With advances in heterodyne laser interferometry, sensitivities at levels of sub-nm/šHz over sub-Hz frequencies can be achieved. However, the breakthrough towards picometer level still needs various techniques in noise characterization and suppression. In this article, a compact heterodyne laser interferometer design as well as benchtop prototype system is presented. Common noise sources and their effects are investigated, including laser frequency noise, non-linear OPD noise, thermo-elastic noise, as well as readout noise from phasemeters and photoreceivers to determine the sensitivity limits in our system. Furthermore, each individual noise source is characterized with dedicated instruments and the coupling coefficients are determined respectively. By subtracting the individual noise contributions, the interferometer sensitivity reaches a sensitivity at the picometer level above 100 mHz frequency. We will present our progress and current results.

Original languageEnglish (US)
Title of host publicationApplied Optical Metrology IV
EditorsErik Novak, James D. Trolinger, Christopher C. Wilcox
ISBN (Electronic)9781510644724
StatePublished - 2021
EventApplied Optical Metrology IV 2021 - San Diego, United States
Duration: Aug 1 2021Aug 5 2021

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceApplied Optical Metrology IV 2021
Country/TerritoryUnited States
CitySan Diego


  • Displacement Measuring Interferometry (DMI)
  • Heterodyne interferometer
  • Inertial sensing
  • Noise suppression

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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