Optical tweezers and manipulation of PMMA beads in various conditions (EN)

Kotsifaki, DG (EN)

Serafetinides, AA (EN)

Makropoulou, M (EN)

Laser optical trapping and micromanipulation of microparticles or cells and subcellular structures have gained remarkable interest in biomedical research and applications. Several laser sources are employed for the combination of a laser scalpel with an optical tweezers device, under microscopic control. However, although the principles and the mechanisms of pulsed laser ablation have been well described for macroscopic interventions, the microbeam operation, under microscopic guidance, necessitates further experiments and investigations. We present experimental results of controlled micro-ablation of PMMA beads of 3-8 μm diameters, trapped by laser tweezers in various media e.g. solutes of different index of refraction. An optical tweezers system, based on a continuous wave He-Ne laser emitting at 632.8 nm, was tested on beads and, despite the low power of the He-Ne laser, the optical trap was stable. Another optical system, based on a cw Nd:YAG laser emitting at 1.06 μm, was tested on microspheres too. Successful beads ablation was carried out by irradiation with multiple, or even a single nitrogen laser pulse of 7 ns pulse duration at a wavelength of 337 nm. The ablative perforation of the microspheres was estimated by controlling the laser fluence. Moreover, shape deformations of PMMA microspheres were observed. The experimentally obtained results are theoretically explained via the spatial intensity distribution based on Mie light scattering theory. Furthermore, the appearance of laser ablation holes in the back side of microspheres is explained by the ablation triggered shock waves propagation. The role of the stretching forces action is also discussed. Additionally, we report experimental results on measuring the optical trap force of PMMA beads. A powerful optical tweezers system based on a continuous wave Nd:YAG laser was used in order to estimate the trapping efficiency for several beads diameter. © 2009 SPIE-OSA. (EN)

conferenceItem (EN)

Light scattering theory (EN)

Micro beams (EN)

Shape deformation (EN)

Nitrogen laser (EN)

Biomedical research (EN)

Laser fluences (EN)

Laser sources (EN)

Neodymium (EN)

Optical tweezers (EN)

Micro-particles (EN)

Refractive index (EN)

He:Ne laser (EN)

Pulse durations (EN)

Spatial intensity distribution (EN)

Microspheres (EN)

Laser tweezers (EN)

Neon (EN)

Lasers (EN)

Low Power (EN)

Optical trapping and micromanipulation (EN)

Trapping efficiencies (EN)

Micro-ablation (EN)

System-based (EN)

Microscopic control (EN)

Neodymium lasers (EN)

Nd:YAG laser (EN)

Continuous Wave (EN)

CW Nd:YAG laser (EN)

Pulsed laser applications (EN)

Refraction (EN)

He-Ne lasers (EN)

Optical systems (EN)

Pulsed laser deposition (EN)

Laser ablation (EN)

Helium (EN)

Nitrogen (EN)

Microoptics (EN)

ND : YAG lasers (EN)

Pulsed laser ablation (EN)

Optical instruments (EN)

Laser scalpel (EN)

Subcellular structure (EN)

Laser tissue interaction (EN)

Optical trap (EN)

Stretching force (EN)

PMMA microspheres (EN)

Index of refraction (EN)

Εθνικό Μετσόβιο Πολυτεχνείο

Ψηφιακό Αποθετήριο της Κεντρικής Βιβλιοθήκης του ΕΜΠ | Dspace@NTUA

Κεντρική Βιβλιοθήκη Ε.Μ.Π.

Ιδρυματικό Αποθετήριο

Δημοσιεύσεις μελών Δ.Ε.Π. σε συνέδρια

Progress in Biomedical Optics and Imaging - Proceedings of SPIE (EN)

2009 (EN)

http://hdl.handle.net/123456789/35834

16057422 (EN)

7373 (EN)

10.1117/12.831895 (EN)