Polycrystalline diamond circular resonant diaphragms with low onset of nonlinear response

In this paper, we report the results of an initial study to characterize the resonance behavior of ultra-thin, large area, circular polycrystalline diamond diaphragms as a potential structural material for resonant sensors. The resonant response of the diaphragms fabricated on Si substrates was measured for excitation frequencies from the low kHz to 1 MHz. Due to the large aspect ratio, a high Young´s modulus and high quality factors, resonances enter the nonlinear Duffing regime at very low drive voltages. This nonlinear behavior is known for its use in parametric excitation, allowing for interesting applications in many areas, including quantum optics and plasma physics. Higher resonance mode center frequencies were found to deviate from expected frequencies when compared to membrane theory due to the large aspect ratio and high Young´s modulus-to-stress ratio.