Phase-Sensitive Pulse Sensor Using 2-D Active Plasmonics on Conformal Substrates

Real-time monitoring of the vital signals using flexible and portable biosensors plays an important role in future human life. However, there is most often a tradeoff between the improvement of the mechanical properties of these sensing chips and their sensitivity. In this study, we proposed 2-D polydimethylsiloxane (PDMS)–Au and silk–Au chips with microhole and microparticle patterns performing in an integrated platform of plasmonic ellipsometry. Under an external sinusoidal signal, we observed the regular dependence of the optical responses and plasmonic resonances on the frequency and not on the current. Using integrated plasmonic-ellipsometry technique and the phenomenon of active plasmonics, PDMS–Au microhole chip has demonstrated that $\Delta $ and $\Psi $ parameters became lesser by increasing the frequency and the resonance wavelength underwent a redshift. However, for silk–Au chip with inverse pattern of microparticle bumps, $\Delta $ and $\Psi $ had augmentation trend with respect to the frequency and the resonance wavelength shifted to shorter wavelengths. By optical and thermal analyses, we have demonstrated that this study can provide new insights into fabricating optically phase and amplitude sensitive biosensors based on conformal substrates with thermo-optical properties that can behave in redshift and blueshift regimes.