Optical Tweezers and Optical Manipulation

Third-cycle level | 15.0 credits | Course code: FYP3001
HT 2023
Study period: 2023-10-01 - 2024-06-30
LANGUAGE OF INSTRUCTION: The course is given in English
Application period: 2023-05-21 - 2023-09-16

Course description

An optical trap (or optical tweezers) is generated by focusing a laser beam to a tiny spot. The high intensity in this tiny spot is able to attract and trap small (microscopic) particles present in solution, such as living cells and small colloidal particles. In recent years, optical traps have been more and more widely used in various sub-disciplines within physics and biology. For example, optical tweezers have been employed to measure the small forces (in the range of piconewton down to femtonewton) generated by biomolecules (e.g. the force required to pull a DNA strain), by microorganisms (e.g. the attachment force between a bacterium and a substrate), and by viruses (e.g. the force required to pack the virus DNA into its capsid). Optical tweezers have also been employed to study the properties of matter on microscopic scales and to study statistical physics.

The course will take place over 2023 and the timetable will be flexible. The course will comprise three parts (each 5.0 hp):

(1) Theoretical background on optical manipulation, including the theory of optical trapping in the geometrical optics and dipole-approximation regimes. [January–March: 3 lectures; self-study; take-home problem sets]

(2) Review of application of optical trapping with extensive review of the literature and a focus on applications in colloidal physics, soft matter, statistical physics, and biophysics. [April–June: biweekly group presentations]

(3) Laboratory work consisting of the realization and operation of an optical tweezers setup and the realization of an experiment. Where possible and desirable, the laboratory work can be focused on a project related to the research field of the students. [June–December: lab group work; final report]


The course will be complemented with a 3-5 day workshop in June featuring several international scientists working in optical trapping and related fields.

Requirements and Selection

Entry requirements

Students should have a self-motivated interest in optical trapping and optics.


Priority will be given to students that have the necessary background and can benefit most of this course in their research.

Course syllabus



Department of Physics


Natural Science and Mathematics


physics, optics