Paper
3 March 2015 Optical trapping with superfocused high-M2 laser diode beam
G. S. Sokolovskii, V. V. Dudelev, Vasileia Melissinaki, S. N. Losev, Ksenya K. Soboleva, A. G. Deryagin, V. I. Kuchinskii, M. Farsari, W. Sibbett, E. U Rafailov
Author Affiliations +
Abstract
Many applications of high-power laser diodes demand tight focusing. This is often not possible due to the multimode nature of semiconductor laser radiation possessing beam propagation parameter M2 values in double-digits. We propose a method of ‘interference’ superfocusing of high-M2 diode laser beams with a technique developed for the generation of Bessel beams based on the employment of an axicon fabricated on the tip of a 100 μm diameter optical fiber with high-precision direct laser writing. Using axicons with apex angle 1400 and rounded tip area as small as ~10 μm diameter, we demonstrate 2-4 μm diameter focused laser ‘needle’ beams with approximately 20 μm propagation length generated from multimode diode laser with beam propagation parameter M2=18 and emission wavelength of 960 nm. This is a few-fold reduction compared to the minimal focal spot size of ~11 μm that could be achieved if focused by an ‘ideal’ lens of unity numerical aperture. The same technique using a 1600 axicon allowed us to demonstrate few-μm-wide laser ‘needle’ beams with nearly 100 μm propagation length with which to demonstrate optical trapping of 5-6 μm rat blood red cells in a water-heparin solution. Our results indicate the good potential of superfocused diode laser beams for applications relating to optical trapping and manipulation of microscopic objects including living biological objects with aspirations towards subsequent novel lab-on-chip configurations.
© (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
G. S. Sokolovskii, V. V. Dudelev, Vasileia Melissinaki, S. N. Losev, Ksenya K. Soboleva, A. G. Deryagin, V. I. Kuchinskii, M. Farsari, W. Sibbett, and E. U Rafailov "Optical trapping with superfocused high-M2 laser diode beam", Proc. SPIE 9343, Laser Resonators, Microresonators, and Beam Control XVII, 93430Q (3 March 2015); https://doi.org/10.1117/12.2078957
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Cited by 1 scholarly publication.
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KEYWORDS
Semiconductor lasers

Axicons

Optical tweezers

Laser beam propagation

Bessel beams

Wave propagation

Blood

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