Nanomechanical sensors optical

The miniaturization of sensors is permitting the creation of very small nanomechanical sensors at IBM that could create very high sensitivities, e.g. the detection of a few molecules on the surface. Also, at the moment the use of an optical transducer looks promising. Optical sensors based on the physical vibration bands of molecules (e.g. infra-red spectrometers) are not particularly sensitive but combined with new materials the sensitivity can be impressive. For example, a recent report on colour-sensitive dyes based on Lewis acid ase reactions offers considerable promise [8]. Figure 8 shows an electronic nose based on a set of dyes that changes colour when the target analyte is introduced and this is detected using a CCD array chip. The unit has been shown to have ppb sensitivities to certain compounds. 

Mechanical nanosensors possess comparative advantages over optical nanosensors and electromagnetic nanosensors for the measurement of nanoscale mechanical properties [2]. Examples of mechanical nanosensors include CNT-based fluidic shear-stress sensors [3] and the nanomechanical cantilever sensors [4]. 

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