Stiffer optical tweezers through real-time feedback control

Anders E. Wallin (Corresponding Author), Heikki Ojala, Edward Hæggström, Roman Tuma

Research output: Contribution to journalArticleScientificpeer-review


Using real-time re-programmable signal processing we connect acousto-optic steering and back-focal-plane interferometric position detection in optical tweezers to create a fast feedback controlled instrument. When trapping 3𝜇m latex beads in water we find that proportional-gain position-clamping increases the effective lateral trap stiffness ∼13-fold. A theoretical power spectrum for bead fluctuations during position-clamped trapping is derived and agrees with the experimental data. The loop delay, ∼19𝜇s in our experiment, limits the maximum achievable effective trap stiffness.
Original languageEnglish
Pages (from-to)224104
JournalApplied Physics Letters
Issue number22
Publication statusPublished - 2 Jun 2008
MoE publication typeA1 Journal article-refereed


Dive into the research topics of 'Stiffer optical tweezers through real-time feedback control'. Together they form a unique fingerprint.

Cite this