Note: Interference technique for minimally invasive, subnanometer, microsecond measurements of displacements

Area of Science:

• Nanotechnology
• Biophysics
• Optical Physics

Background:

• Single-molecule experiments require high-resolution tracking techniques.
• Mechanical noise and system drift are significant challenges in achieving precise measurements.
• Existing methods often struggle with noise reduction and out-of-plane motion detection.

Purpose of the Study:

• To introduce a novel high-resolution technique for single-molecule experiments.
• To overcome limitations of existing methods in noise reduction and drift subtraction.
• To enable precise in-plane and out-of-plane motion tracking.

Main Methods:

• Differential traveling wave tracking, an interference-based scattering technique.
• Utilizing gold nanoparticles for enhanced scattering intensities.
• Employing differential measurements for in-plane noise and drift subtraction.
• Measuring out-of-plane distances using scattered light intensity under total internal reflectance illumination.

Main Results:

• Achieved a root-mean-square (rms) noise level of 0.10 nm at 10 kHz for in-plane measurements.
• Demonstrated an in-plane noise level of less than 0.5 nm at 600 kHz.
• Successfully implemented a method for simultaneous in-plane and out-of-plane motion tracking.

Conclusions:

• Differential traveling wave tracking offers unprecedented resolution for single-molecule studies.
• The technique effectively mitigates mechanical noise and system drift.
• This advancement has broad implications for various fields requiring precise nanoscale measurements.