Optical Tweezers are considered one of the most suitable techniques for biological tasks, however the lack of automation make this technology less accessible. We present here a new 3D force sensing method with high bandwidth (up to 10Khz) which can allow implementing complex robotic approaches. Proposed technique uses high speed image tracking with nano-metric resolution in 3 directions. Its capabilities are demonstrated in a teleoperated 3D manipulation scenario with a haptic user interface, where naive users performed direct in vitro haptic exploration of isolated Red Blood Cells inside a Petri dish.

The optical trap is a powerful non-contact approach for manipulating micron sized objects. Teleoperation of optical tweezers can be performed by coupling with a haptic interface, which allows an efficient robotic device to control positions and get force feedback. This provides users direct and intuitive microscopic interactions. The major difficulty in order for haptic devices to generate a reliable tactile sensation lies in its high frequency requirement of more than 1 kHz. This paper presents a fast force feedback teleoperation system for optical tweezers that attains this high frequency. The used force sensor is a novel event-based camera that transmits output as a continuous stream of asynchronous temporal events thus enabling high speed event-based visual processing. This new sensor is compared to a conventional frame based one to show advantages of our setup. A complex task of exploiting three dimensional target surface is performed demonstrating the robustness and efficiency of the presented method. This is the first time microspheres are used to touch targets of arbitrary form and color, which may interest broad-reaching biological and physical applications.

Laser induced convection flows is a new and promising method to achieve better manipulation of mesoscale objects (above 1 mum and below 500 mum) in a liquid medium. The temperature gradient created by laser absorption generates natural and thermocapillary (or Marangoni) convection flows. These flows are used to perform the manipulation itself. In this paper, we demonstrate for the first time that large and heavy particles can be dragged using the Marangoni convection flows. Experiments based on these phenomena show that fast and accurate underwater micromanipulation of particles up to 280 mum is possible using only a convergent 1480 nm laser beam.