Technical Details

The AFM head

The instrumental platform is composed by two independent Atomic Force Microscope heads mounted on the same baseplate. Each head is based on the Tuning Force concept: a tiny tungsten tip is glued on one of the prongs of a quartz oscillator modelled as a tuning fork. This is the typical oscillator used in quartz watches. As the tip advances toward the sample, it feels the interaction potential changing the tune characteristics of the fork. The variations of the tune are used to monitor the distance tip/sample and to describe the morphology of the sample. More details on the physics at the basis of tuning fork microscopes can be found here (thesis of MS Rodrigues).

Figure 1: The instrumental platform is based on two separated AFM heads and a sample nanopositioner

Haptics

Haptics consists in returning to the operator of a sensing device a feeling of the detected parameter by converting the value of the parameter in force, and feedbacking it to his hands.

Figure 2

Touching, manipulating and feeling nano-objects with two AFM tips consists on demultiplying the movement of the joysticks in the hands of the operator by six order of magnitude and giving back on the same joystick the force (gradient) measured by the tuning force multiplied by eight orders of magnitudes. This equals to move the joystick of one millimeter for having the tip moving one nanometer and rendering a force of one nanoNewton with 100 milliNewton, about ten grams.

TGR

The high fidelity, high repetition rate implementation of this demultiplication/amplification process is performed by the ERGOS TGR haptic electronic controller which basic characteristics are 3 kHz sampling rate and 10 Newton maximum rendering. More details on the Hergos haptic device can be found here (who???)