A compact low-loss 2-to-4 plasmonic decoder based on suspended graphene for surface plasmon polariton transmission

This work introduces a novel design for a high-performance plasmonic 2-to-4 decoder. The proposed structure utilizes suspended graphene and a silicon dioxide ridge to create a low-loss channel with 60 nm in width and 10 nm in height. By achieving a high concentration field in the channel, the lateral field leakage is minimized, resulting in a transmission loss of only 0.268 dB/μm. Leveraging this designed channel, a subwavelength structure is proposed to decode optical information from two inputs into four output ports. The device exhibits a contrast ratio of 37.11 dB and a cross talk of −37.13 dB, all within a compact area of 1.08 μm2. A comparison with other studies confirms that this research presents a significant improvement in the characteristics of the plasmonic decoder.