Absolute position total internal reflection microscopy with an optical tweezer

Lulu Liu, Alexander Woolf, Alejandro W. Rodriguez, Federico Capasso

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


A noninvasive, in situ calibration method for total internal reflection microscopy (TIRM) based on optical tweezing is presented, which greatly expands the capabilities of this technique. We show that by making only simple modifications to the basic TIRM sensing setup and procedure, a probe particle's absolute position relative to a dielectric interface may be known with better than 10 nm precision out to a distance greater than 1 μm from the surface. This represents an approximate 10x improvement in error and 3x improvement in measurement range over conventional TIRM methods. The technique's advantage is in the direct measurement of the probe particle's scattering intensity vs. height profile in situ, rather than relying on assumptions, inexact system analogs, or detailed knowledge of system parameters for calibration. To demonstrate the improved versatility of the TIRM method in terms of tunability, precision, and range, we show our results for the hindered near-wall diffusion coefficient for a spherical dielectric particle.

Original languageEnglish (US)
Pages (from-to)E5609-E5615
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number52
StatePublished - Dec 30 2014

All Science Journal Classification (ASJC) codes

  • General


  • Calibration
  • Optical tweezer
  • Particle tracking
  • TIRM


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