Figure 2: Optical behaviours of various types of active antenna structures. | Nature Communications

Figure 2: Optical behaviours of various types of active antenna structures.

From: Silicon-based broadband antenna for high responsivity and polarization-insensitive photodetection at telecommunication wavelengths

Figure 2

(a) The presence of the antenna structures are nanoantennas, dot arrays, hole arrays and DTTM arrays. The thickness of the Au film in each structure was 30 nm and the detail dimensions were described. (b) A plane wave having a wavelength of 1,310 nm was propagated above the air-structured metal interface to the Si substrate. All the squares of the electric field amplitudes (|E2|) at distinct depths have been normalized to the highest value of |E2|, which was generated at the surface of the DTTM arrays. Compared with other types of antenna structures, the DTTM arrays provided the strongest optical electric field intensity within its near field. Moreover, the DTTM arrays exhibited high electric field strength in the large volume of the cavity and also around the large area of the air–Au interface. (c) Corresponding simulated absorption spectra of the four types of antenna structures. Among them, the DTTM arrays exhibited the largest absorption in the broadband regime.

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