Batch fabrication of flowable colorimetric pressure sensing particles via surface micromachining

The batch fabrication and test of artificial optical resonator slab-type micro particles (14 μm diameter, 0.7 μm gap) is presented as a means to map absolute pressure within microscopic environments. The pressure-sensing particles consist of a semi-transparent elastic polysilicon shell enclosing a reference vacuum cavity. The optical resonance frequency and the corresponding external pressure can hence be interrogated optically via reflectivity measurements. We demonstrate the measurement of internal pressures between 0-20 psi within microfluidic environments.