8 research outputs found
A Step-by-step Guide to the Realisation of Advanced Optical Tweezers
Since the pioneering work of Arthur Ashkin, optical tweezers have become an
indispensable tool for contactless manipulation of micro- and nanoparticles.
Nowadays optical tweezers are employed in a myriad of applications
demonstrating the importance of these tools. While the basic principle of
optical tweezers is the use of a strongly focused laser beam to trap and
manipulate particles, ever more complex experimental set-ups are required in
order to perform novel and challenging experiments. With this article, we
provide a detailed step- by-step guide for the construction of advanced optical
manipulation systems. First, we explain how to build a single-beam optical
tweezers on a home-made microscope and how to calibrate it. Improving on this
design, we realize a holographic optical tweezers, which can manipulate
independently multiple particles and generate more sophisticated wavefronts
such as Laguerre-Gaussian beams. Finally, we explain how to implement a speckle
optical tweezers, which permit one to employ random speckle light fields for
deterministic optical manipulation.Comment: 29 pages, 7 figure
The transverse breathing mode of an elongated Bose-Einstein condensate
We study experimentally the transverse monopole mode of an elongated rubidium
condensate. Due to the scaling invariance of the non-linear Schr\"odinger
(Gross-Pitaevski) equation, the oscillation is monochromatic and sinusoidal at
short times, even under strong excitation. For ultra-low temperatures, the
quality factor can exceed 2000, where and
are the mode angular frequency and damping rate. This value is much
larger than any previously reported for other eigenmodes of a condensate. We
also present the temperature variation of and .Comment: 4 pages, 4 figures, submitted to PR
Superfluid to solid crossover in a rotating Bose-Einstein condensed gas
The properties of a rotating Bose-Einstein condensate confined in a prolate
cylindrically symmetric trap are explored both analytically and numerically. As
the rotation frequency increases, an ever greater number of vortices are
energetically favored. Though the cloud anisotropy and moment of inertia
approach those of a classical fluid at high frequencies, the observed vortex
density is consistently lower than the solid-body estimate. Furthermore, the
vortices are found to arrange themselves in highly regular triangular arrays,
with little distortion even near the condensate surface. These results are
shown to be a direct consequence of the inhomogeneous confining potential.Comment: 4+e pages, 5 embedded figures, revte
Roadmap for Optical Tweezers 2023
Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects ranging from atoms to space light sails. Since the pioneering work by Arthur Ashkin in the 1970s, optical tweezers have evolved into sophisticated instruments and have been employed in a broad range of applications in life sciences, physics, and engineering. These include accurate force and torque measurement at the femtonewton level, microrheology of complex fluids, single micro- and nanoparticle spectroscopy, single-cell analysis, and statistical-physics experiments. This roadmap provides insights into current investigations involving optical forces and optical tweezers from their theoretical foundations to designs and setups. It also offers perspectives for applications to a wide range of research fields, from biophysics to space exploration
A Raman Study of MMP2 and MnSOD, Two Pathology Biomarkers
International audienceMatrix Metalloproteinases (MMPs) are cell-secreted soluble and membranetethered enzymes that degrade extracellular matrix (ECM) proteins. These proteases play a key role in diverse physiological and pathological processes, including embryonic development, wound repair, inflammatory diseases and cancer [1]. On the other hand, Superoxide Dismutases (SODs) are metalloenzymes that defend biological systems against oxidative damage mediated by the superoxide anion [2]. The vibrational spectra of MMPs and SODs can provide crucial information about conformational changes induced by external factors, e.g. the interaction with metal ions, drugs, others proteins or peptides. On the other side, Raman spectroscopy can be used as a tool for non-invasive and non-ambiguous spectral detection of these proteins at very low concentration (10-8-10-12 M), with potential applications in early diseases diagnosis [3]. At present, there is still insufficient knowledge on the Raman spectral fingerprints of these proteins. Here we present a complete Raman analysis of MMP2 and MnSOD using multiwavelength-excitation at 514, 633, and 785 nm
Roadmap for Optical Tweezers 2023
Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects ranging from atoms to space light sails. Since the pioneering work by Arthur Ashkin in the 1970s, optical tweezers have evolved into sophisticated instruments and have been employed in a broad range of applications in life sciences, physics, and engineering. These include accurate force and torque measurement at the femtonewton level, microrheology of complex fluids, single micro- and nanoparticle spectroscopy, single-cell analysis, and statistical-physics experiments. This roadmap provides insights into current investigations involving optical forces and optical tweezers from their theoretical foundations to designs and setups. It also offers perspectives for applications to a wide range of research fields, from biophysics to space exploration.ISSN:2515-764