https://doi.org/10.1140/epjp/s13360-020-00843-5
Review
Optical tweezers: theory and practice
1
Department of Physics, Università degli di Studi di Napoli “Federico II” Complesso Universitario Monte S. Angelo, Via Cintia, 80126, Naples, Italy
2
Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT, London, UK
3
CNR-IPCF, Istituto Processi Chimico-Fisici, V.le F. Stagno D’Alcontres 37, 98158, Messina, Italy
4
Department of Physics, University of Gothenburg, 41296, Gothenburg, Sweden
Received:
1
July
2020
Accepted:
6
October
2020
Published online:
7
December
2020
The possibility for the manipulation of many different samples using only the light from a laser beam opened the way to a variety of experiments. The technique, known as Optical Tweezers, is nowadays employed in a multitude of applications demonstrating its relevance. Since the pioneering work of Arthur Ashkin, where he used a single strongly focused laser beam, ever more complex experimental set-ups are required in order to perform novel and challenging experiments. Here we provide a comprehensive review of the theoretical background and experimental techniques. We start by giving an overview of the theory of optical forces: first, we consider optical forces in approximated regimes when the particles are much larger (ray optics) or much smaller (dipole approximation) than the light wavelength; then, we discuss the full electromagnetic theory of optical forces with a focus on T-matrix methods. Then, we describe the important aspect of Brownian motion in optical traps and its implementation in optical tweezers simulations. Finally, we provide a general description of typical experimental setups of optical tweezers and calibration techniques with particular emphasis on holographic optical tweezers.
We would like to dedicate this paper to the memory of Arthur Ashkin (1922–2020).
© The Author(s) 2020
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