Tunable Surface Plasmon Polaritons with Monolithic Schottky Diodes

Abstract

Surface plasmon polaritons (SPPs) provide subwavelength electric field confinement ranging from microwave to the visible. Several approaches have been explored to manipulate SPPs with a typical modulation capability of only a few percent. Here, active control of SPPs using monolithically fabricated Schottky diodes has been first designed and realized, achieving a continuous and significant modulation of transmission, reflection, and absorption. The SPPs propagating on a metal line are attenuated by using split ring resonators (SRRs) with an In-Ga-Zn-O Schottky diode bridging each SRR split gap. The resistance of the diodes can be tuned over a range of a few orders of magnitude with bias voltage, which continuously transforms each SRR to a metallic quasi-loop with subdued resonance. A remarkable modulation of 40% and 19% was demonstrated for the transmission and absorption, respectively, which to the best of our knowledge has not been achieved before. Graphic entry for the Table of Contents (TOC)

Digitally Controlled Tunable Fabric Microwave Filter Based on Organic Electrochemical Transistors

“…Recently, materials such as graphene [28][29][30] and oxide semiconductors. [31] have been newly used to realize the active control of SSPP. In our previous studies, [29,30] we used graphene to control SSPP at microwave frequencies.…”

“…Additionally, the tunable rejection of SSPP within a planar structure was realized by depositing In–Ga–Zn–O diodes. [ 31 ] However, the degree of freedom for modulation was restricted owing to the relatively large size and intrinsic characteristics of the newly applied materials, and frequency‐reconfigurable characteristics were not demonstrated.…”

Multi frequency multi bit amplitude modulation of spoof surface plasmon polaritons by schottky diode bridged interdigital SRRs

“…Typically, SRRs in spoof SPP band-reject devices use parallel gaps 20 , 21 , as illustrated in Fig. 1 a.…”

“…2 b elucidate the rejection bands for spoof SPPs due to the SRR resonances 12 . At the non-resonant frequencies, these two SRRs works as the conventional metallic rectangles to guide spoof SPPs 20 , and share the same cut-off frequency of 62 GHz, which corresponds to the dotted dash lines in Fig. 2 b.…”

“…Ls is the inductance of the coincidence region of SRR and transmission line, R 1 and R 2 are the resistances of the ring, L S1 and L S2 are inductances of the ring and C g1 and C g2 are the capacitances of the interdigital capacitors. R g1 and R g2 are variable attenuation due to the substrate free carries absorption within the SRR gap 20 . The parameters of circuit components in Fig.…”