We report broadband refraction and diffraction experiments in a ferroelectric perovskite, a solid-solution K0.997Ta0.64Nb0.36:Li0.003 (KTN:Li), that demonstrate an index of refraction of n > 26 across the entire visible spectrum . In principle, materials with a broadband giant index of refraction (n > 10) overcome chromatic aberration and shrink the diffraction limit down to the nanoscale, allowing new opportunities for nanoscopic imaging . They also open alternative avenues for the management of light to improve the performance of photovoltaic cells. Recent advances have demonstrated the feasibility of a giant refractive index in metamaterials at microwave and terahertz frequencies [2, 3], but the highest reported broadband index of refraction in the visible is n < 5 .
© 2019 IEEEPDF Article