Abstract
Recently reported metamaterial analogues of plasmon-induced transparency are very promising in designing novel optical components, such as slow-light devices and optical switches. However, most of the previous works mainly focus on manipulating the PIT effects using planar structures in the free space under normal incidence, where the resonances are mostly induced by the incident electric fields. Here, we present a PIT analogue in a waveguide system in the terahertz regime by inserting coupled split-ring resonator pairs into a tapered parallel plate waveguide. Different from the free-space cases, the incident magnetic fields can also play an important role here. By carefully arranging the relative orientations of the coupled split-ring resonators in each pair, giant modulation of the PIT effect is observed. This straightforward approach may enable novel devices for integrated terahertz devices.
Highlights
Induced transparency (EIT) is a quantum interference effect that occurs in three-level atomic systems, which renders an initially opaque medium to transparency under the pumping of a coupling laser [1], [2]
In terms of its functionalities, the tapered parallel plate waveguide (TPPWG) can be divided into three parts: i) an input cylindrical tapered horn with R = 203 mm to convert the free-space THz beam to a waveguide mode; ii) the central parallel plate waveguide with a length of lc = 20 mm to support the desired THz waveguide mode, which is the place where the waveguide mode interacts with the metamaterials; and iii) an output cylindrical horn that is mirror symmetric to the input one to convert the waveguide mode to the free-space THz beam
The plasmon-induced transparency (PIT) effect only occurs when the mirror symmetry of the SRRP is broken, whose strength is determined by the coupling effect strength between the two split-ring resonator (SRR)
Summary
Induced transparency (EIT) is a quantum interference effect that occurs in three-level (ground, excited, and metastable states) atomic systems, which renders an initially opaque medium to transparency under the pumping of a coupling laser [1], [2]. Plasmonic metamaterials composed of periodic subwavelength metallic structures have been intensively studied, which can mimic the quantum EIT effect in a classical way [7]–[9]. In such a metamaterial system, all the non-resonant states behave as the ground state, The associate editor coordinating the review of this manuscript and approving it for publication was Santi C.
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