Quantifying experimental errors in measuring colloidal interaction potentials with optical tweezers

Area of Science:

• Colloid and Interface Science
• Optical Physics
• Nanotechnology

Background:

• Accurate measurement of inter-particle potentials is crucial for understanding colloidal systems.
• Existing optical tweezers (OT) methods are affected by unquantified experimental errors.
• Previous studies acknowledged but did not thoroughly examine individual error effects.

Purpose of the Study:

• To develop and validate a systematic framework for modeling and quantifying experimental errors in OT-based potential measurements.
• To decouple and independently control key error sources: z-motion, dynamic, and static errors.
• To enhance the precision and reliability of interaction potential measurements using optical tweezers.

Main Methods:

• Development of a theoretical framework to model z-motion, dynamic, and static errors.
• Controlled experiments to validate the error modeling framework.
• Systematic tuning of experimental parameters to decouple and quantify individual error sources.

Main Results:

• Demonstrated that the three key experimental errors can be independently controlled and accounted for.
• Developed a method to reduce measurement ambiguities and improve accuracy compared to theoretical models.
• Successfully applied the correction method to extract physically meaningful depletion attraction potentials.

Conclusions:

• The presented framework offers a robust methodology for enhancing the accuracy of OT-based potential measurements.
• This approach significantly improves the study of colloidal interactions by providing more reliable data.
• Enables more accurate comparisons between experimental results and theoretical predictions.