Levenberg-Marquardt Validation of Multiple Fano Resonances in Plasmonic Cavity for Adrenal/Breast Cancer Detection

A technique of slanting MIM plasmonic waveguide-based cavity is numerically studied and implemented. Initially, the proposed rectangular cavity is proficient for generating five Breit-Wigner and six Fano resonances. The polygonal cavity is designed out of rectangular cavity by slanting one of its edge that reshaped the Breit-Wigner resonances into Fano profile with remaining resonances unaffected. The polygonal cavity obtains total eleven Fano resonances by coupling with an inclined split waveguide. The influence of slanting on reshaping of resonances is studied with orthogonality of modes and overlap integration has been calculated. The Fano resonances in the transmittance spectrum are individually validated with Fano profile formula and the corresponding Fano shape parameter are computed. The validation is done with the help of Levenberg-Marquardt algorithm and the goodness of fits are calculated. The best performance parameters of Fano resonances are expressed as operating wavelength ${\bm{\lambda }}\ = \ 450 - 1800\ {\text{nm}}$ , sensitivity $( {\bm{S}} )\ = \ 1643\ {\text{nm}}/{\rm{RIU}}$ , full-width, half maxima $( {{\bm{FWHM}}} )\ = \ 0.76\ {\text{nm}}$ , quality factor ( ${\bm{Q}})\ = \ 743.77$ and figure of merit $( {{\bm{FOM}}} )\ = \ 738.69\ {\rm{RIU}}^{ - 1}$ . The proposed device is further studied for the detection of certain cancer types including Adrenal cancer, Breast Type1 cancer and Breast Type2 cancer. The maximum sensitivity in case of detection of all the three cancer types yielded out to be ${\bm{S}}\ = \ 1642.857\ {\text{nm}}/{\rm{RIU}}$ . The other sensing performance parameter called figure of merit is calculated to be ${\bm{FOM}}\ = \ 610.90\ {\rm{RI}}{{{\rm{U}}}^{ - 1}}$ for Adrenal and Breast Type 1 and ${\bm{FOM}}\ = \ 671.99\ {\rm{RI}}{{{\rm{U}}}^{ - 1}}$ for Breast Type 2 cancers.