**3.4 Study IV**

In the recent study, 'Fano resonances' were observed in purely mechanical systems constituted by an array of nano and microcantilever resonators [39]. An array of micro/nano-scale cantilevers were used for mass sensing. A fabricated prototype and the output response is shown in **Figure 9**. Nanoscale cantilevers (thickness of 100 *nm*) fabricated of silicon nitrate were excited with piezoelectric disk shaker. A laser optical based detection was performed with sub-picometer resolution. Cantilevers here are directly connected to the bulk silicon without any suspended overhang at the base. As a consequence, each cantilever resonance is said to be identified by the main resonance curve (Lorentzian curve). No other resonant peak (entangled states due to coupling) are observed in the output response. Instead, due to an interference between the tails of the Lorentzian curve and the resonance peaks of the other cantilevers in an array, it was said that fano-peaks appeared at the corresponding resonant frequencies of the other cantilevers in an array (**Figure 9(b)**). Increased sensitivity (i.e. being able to measure smallest change in mass, *Δm* of up to 5 *pg*, *Δm m/Q*) of fano-resonances was attributed to their exhibited relatively higher quality factor, *Q* (10 than the main resonance

#### **Figure 9.**

*Fabricated prototype (a) and (b) vibration spectra of one cantilever in an array. Up to 9 cantilevers, not shown here were used in this work to propose a single and fast measurement scheme for cantilever arrays using Fanoresonance analysis [39]. Reprinted from [39] with the permission of Springer Nature under creative commons licenses.*

peak). A negative shift in the resonant frequencies of all the 'Fano-resonances' was observed as the results of parallel mass loading on all the cantilevers in an array. Therefore, a single, fast measurement scheme (parallelization) was proposed to characterize the frequency response of one cantilever in an array. Several configurations of micro/nano scale cantilever arrays were fabricated and experimental results were given along with the theory model.
