Pierre Verlot
ENS Paris Sacaly (LUMIN)
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Measuring the vibrations of very small mechanical systems
Nanomechanical systems have been thriving for almost 30 years. These devices consist of mechanical resonators, with dimensions below the micrometer range. The interest for nanomechanical resonators stems from both their integrability, and unique sensitivity as versatile transducers, owing to their very low mass.
The question of measuring the vibrations of nanomechanical resonators is essential, both as an elementary requirement for their operability, but also as a topic for itself: Indeed, their extreme sensitivity applies to the dynamical effects induced by the measurement, also known as ‘backaction’, which may strongly affect both their transduction behaviour and sensitivity potential.
We will present our latest efforts to addressing the detection of very (very) small nanomechanical devices. In particular, we will discuss two radically opposed regimes of measurement: On the one hand, we will see how electromechanical coupling to focused electron beams enables the sensitive detection of devices as small as carbon nanotube resonators, and how the associated, strongly dissipative measurement backaction can become an asset for achieving highly resolved thermal imaging of nanomechanical systems. On the other hand, we will address the question of the efficiency of dispersive optomechanical coupling at the nanoscale. By deploying a Fisher information-based approach, we will see that current nano-optomechanical detection schemes may benefit from sensitivity enhancements of several orders of magnitude, by properly shaping both input and output of the measurement.
