High bandwidth force estimation for optical tweezers

Hullas Sehgal, Tanuj Aggarwal, Murti V. Salapaka

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


A prevalent mode of optical tweezers involves position clamping that regulates a constant position of a trapped bead. Traditional schemes employ the measured bead position in the open loop or the control signal in the position-clamp mode as an estimate of external force on the trapped bead. This article shows that traditional methods introduce fundamental limitations on bandwidth of the external force estimation. A method is presented that leads to an order of magnitude increase in the bandwidth of the external force estimation. Furthermore, a comprehensive modeling paradigm is introduced that facilitates estimation of forces on the bead.

Original languageEnglish (US)
Article number153114
JournalApplied Physics Letters
Issue number15
StatePublished - 2009

Bibliographical note

Funding Information:
This work was partly supported by NSF Grant Nos. CMMI0814615 and ECCS0814612 to Dr. Murti V. Salapaka.


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