Evanescent-field-coupled guided-mode sensor based on a waveguide grating

Abstract

A guided-mode (GM) sensor with a dielectric waveguide grating formed on a thin reflective film using Kretschmann configuration is proposed. Numerical results based on a finite-element method approach indicate a significant resolution improvement due to the excitation of a GM supported by the waveguide grating-sensing media system. The applicability of the waveguide theory to the design of waveguide gratings is validated by a comparison to the exact electromagnetic theory. Strong localization of an electromagnetic field in the sensing media within the grating with intensity enhancement up to two orders of magnitude is demonstrated. The sensor has potential for biological sensing and imaging applications.

Phase-change Fano resonator for active modulation of thermal emission

“…In this formula, n eff is directly proportional to the grating filling factor (or grating width). 42 Therefore, the resonance wavelength depends on the grating width, as seen for the broadband design in Fig. 1(b).…”

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“…where P is periodicity, m is the diffraction order, and n eff is the effective refractive index of the SPP mode. In the other side, the n eff is directly proportional to grating filling factor (or grating width) [16]. This can be seen in Fig.…”

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