Now showing items 1-20 of 29

    • Active matter alters the growth dynamics of coffee rings 

      Andaç, Tuğba; Weigmann, Pascal; Velu, Sabareesh K. P.; Pinçe, Erçağ; Volpe, G.; Volpe, Giovanni; Callegar, Agnese (Royal Society of Chemistry, 2019)
      How particles are deposited at the edge of evaporating droplets, i.e. the coffee ring effect, plays a crucial role in phenomena as diverse as thin-film deposition, self-assembly, and biofilm formation. Recently, microorganisms ...
    • Active matter alters the growth dynamics of coffee rings 

      Callegari, Agnese; Andaç, Tuğba; Weigmann, Pascal; Velu, Sabareesh K. P.; Pinçe, Erçağ; Volpe, G.; Volpe, Giovanni (OSA, 2018)
      We show that bacterial mobility starts playing a major role in determining the growth dynamics of the edge of drying droplets, as the droplet evaporation rate slows down.
    • Brownian gyrator: an experimental realization 

      Soni, Jalpa; Argun, A.; Dabelow, L.; Bo, S.; Eichhorn, R.; Pesce, G.; Volpe, Giovanni (OSA, 2017)
      We present an experimental realization of a minimal heat engine in the form of a single Brownian particle, performing gyrating motion by systematic torque generation due to dissipation from two different heat baths in a ...
    • Clustering of Janus particles in an optical potential driven by hydrodynamic fluxes 

      Mousavi, S. Masoumeh; Kasianiuk, Iryna; Kasyanyuk, Denis; Velu, Sabareesh K. P.; Callegari, Agnese; Biancofiore, Luca; Volpe, Giovanni (Royal Society of Chemistry, 2019-06)
      Self-organisation is driven by the interactions between the individual components of a system mediated by the environment, and is one of the most important strategies used by many biological systems to develop complex and ...
    • Controlling active brownian particles in complex settings 

      Velu, Sabareesh K. P.; Pinçe, Erçağ; Callegari, Agnese; Elahi, Parviz; Gigan, S.; Volpe, Giovanni; Volpe, G. (OSA, 2017)
      We show active Brownian particles (passive Brownian particles in a bacterial bath) switches between two long-term behaviors, i.e. gathering and dispersal of individuals, in response to the statistical properties of the ...
    • Controlling the dynamics of colloidal particles by critical Casimir forces 

      Magazzu, A.; Callegari, Agnese; Staforelli, J. P.; Gambassi, A.; Dietrich, S.; Volpe, Giovanni (Royal Society of Chemistry, 2019-01)
      Critical Casimir forces can play an important role for applications in nano-science and nano-technology, owing to their piconewton strength, nanometric action range, fine tunability as a function of temperature, and exquisite ...
    • Engineering particle trajectories in microfluidic flows using speckle light fields 

      Volpe, G.; Volpe, Giovanni; Gigan, S. (SPIE, 2014)
      Optical tweezers have been widely used in physics, chemistry and biology to manipulate and trap microscopic and nanoscopic objects. Current optical trapping techniques rely on carefully engineered setups to manipulate ...
    • Erratum: controlling the dynamics of colloidal particles by critical Casimir forces (Soft Matter (2019) 15 (2152-2162) DOI: 10.1039/C8SM01376D) 

      Magazzu, A.; Callegari, Agnese; Staforelli, J. P.; Gambassi, A.; Dietrich, S.; Volpe, Giovanni (Royal Society of Chemistry, 2020)
      Correction for ‘Controlling the dynamics of colloidal particles by critical Casimir forces’ by Alessandro Magazzù et al., Soft Matter, 2019, 15, 2152–2162, DOI: 10.1039/C8SM01376D. The authors regret an error in the grant ...
    • Experimental investigation of critical Casimir forces in binary liquid mixtures by blinking optical tweezers 

      Magazzu, Alessandro; Schmidt, F.; Callegari, Agnese; Gambassi, A.; Dietrich, S.; Volpe, Giovanni (OSA, 2017)
      We investigate, for the first time and by blinking optical tweezers, the effects of critical Casimir forces (CCFs) on the free dynamics of a pair of spherical colloidal particles, immersed in binary liquid mixtures upon ...
    • Generation of cylindrical vector beams with few-mode fibers excited by Laguerre–Gaussian beams 

      Volpe, Giovanni; Petrov, D. (Elsevier, 2004-07-01)
      We propose a novel method to efficiently produce light beams with radial, azimuthal, and hybrid polarization, through a few-mode fiber excited by a Laguerre–Gaussian beam. With different input polarization we can selectively ...
    • Influence of noise on force measurements 

      Volpe, Giovanni; Helden, L.; Brettschneider, T.; Wehr, J.; Bechinger, C. (The American Physical Society, 2010-04)
      We demonstrate how the ineluctable presence of thermal noise alters the measurement of forces acting on microscopic and nanoscopic objects. We quantify this effect exemplarily for a Brownian particle near a wall subjected ...
    • Intracavity optical trapping of microscopic particles in a ring-cavity fiber laser 

      Kalantarifard, Fatemeh; Elahi, Parviz; Makey, Ghaith; İlday, F. Ömer; Volpe, Giovanni; Maragò, O. M. (Nature Publishing Group, 2019-06)
      Standard optical tweezers rely on optical forces arising when a focused laser beam interacts with a microscopic particle: scattering forces, pushing the particle along the beam direction, and gradient forces, attracting ...
    • Intracavity optical trapping with ytterbium doped fiber 

      Laser, R.; Sayed, R.; Kalantarifard, Fatemeh; Elahi P.; İlday, F. Ömer; Volpe, Giovanni; Marago O.M. (SPIE, 2013)
      We propose a novel approach for trapping micron-sized particles and living cells based on optical feedback. This approach can be implemented at low numerical aperture (NA=0.5, 20X) and long working distance. In this ...
    • Microscopic engine powered by critical demixing 

      Schmidt, F.; Magazzu, Alessandro; Callegari, Agnese; Biancofiore, Luca; Cichos, F.; Volpe, Giovanni (OSA, 2017)
      We propose a new type of engine that is powered by the local, reversible demixing of a critical binary liquid. A microscopic particle is optically trapped and performs revolutions due to the emergence of diffusiophoresis.
    • Microswimmers in patterned environments 

      Volpe, Giovanni; Buttinoni, I.; Vogt, D.; Kümmerer, H.- J.; Bechinger, C. (The Royal Society of Chemistry, 2011-07-14)
      Tiny self-propelled swimmers capable of autonomous navigation through complex environments provide appealing opportunities for localization, pick-up and delivery of microscopic and nanoscopic objects. Inspired by motile ...
    • Non-Boltzmann stationary distributions and non-equilibrium relations in active baths 

      Argun, A.; Moradi, A. R.; Pinçe, E.; Bağcı, Gökhan Barış; Imparato, A.; Volpe, Giovanni (Optical Society of America, 2017)
      The presence of active noise generated by motile bacteria results in the violation of Boltzmann distribution. Therefore, non-equilibrium relations become invalid active baths. Yet these relations can be recovered by ...
    • Nonadditivity of critical Casimir forces 

      Callegari, Agnese; Paladugu, Sathyanarayana; Tuna, Yazgan; Barth, Lukas; Dietrich, S.; Gambassi, A.; Volpe, Giovanni (OSA, 2017)
      We provide the first experimental evidence of nonadditivity for critical Casimir forces: the force that two colloidal particles exert together on a third one differs from the sum of the forces they exert separately.
    • Novel perspectives for the application of total internal reflection microscopy 

      Volpe, Giovanni; Brettschneider, T.; Helden, L.; Bechinger, C. (Optical Society of America, 2009-12)
      Total Internal Reflection Microscopy (TIRM) is a sensitive non-invasive technique to measure the interaction potentials between a colloidal particle and a wall with femtonewton resolution. The equilibrium distribution of ...
    • Numerical simulation of Brownian particles in optical force fields 

      Volpe, G.; Volpe, Giovanni (SPIE, 2013)
      Optical forces can affect the motion of a Brownian particle. For example, optical tweezers use optical forces to trap a particle at a desirable position. Using more complex force fields it is possible to generate more ...