Substrate-integrated photonic doping for near-zero-index devices.

Area of Science:

• Electromagnetics and Photonics
• Materials Science

Background:

• Near-zero-index (NZI) media exhibit unique wave phenomena but are limited by bulky, expensive platforms.
• Miniaturization and cost-effectiveness are crucial for practical applications of NZI media.

Purpose of the Study:

• To propose and experimentally validate a novel method for implementing NZI media using substrate-integrated photonic doping.
• To demonstrate the feasibility of NZI media in printed circuit board (PCB) integrated designs for reduced device profiles.
• To explore new applications of this NZI platform in sensing, modulation, and waveguiding.

Main Methods:

• Development of substrate-integrated (SI) photonic doping technique for NZI media realization.
• Experimental validation of NZI supercoupling in straight and curved substrate-integrated waveguides.
• Characterization of position-independent photonic doping, zero-phase advance, and finite group delay properties.
• Design and proposal of three novel NZI devices: dielectric sensor, acousto-microwave modulator, and 'electric fiber'.

Main Results:

• Successful implementation of NZI media within a compact, PCB-integrated design.
• Demonstration of NZI supercoupling and associated unique wave properties in fabricated devices.
• Validation of the position-independent nature of photonic doping.
• Proposed designs for high-sensitivity sensors, efficient modulators, and flexible waveguiding structures.

Conclusions:

• Substrate-integrated photonic doping offers a viable pathway for low-cost, miniaturized NZI media.
• The developed platform enables significant advancements in microwave and terahertz applications.
• This work paves the way for practical realization of NZI-based devices.