Surface plasmon induced spot and line formation at interfaces of ITO coated LiNbO3 slabs and gigantic nonlinearity

Abstract

Remarkable spots and lines were clearly observed at the two interfaces of indium-tin-oxide coated Z-cut Fe-doped lithium noibate plates under illumination by milliwatt continuous-wave laser light; this occurred because of the visible surface plasmons (SPs) supported by the promising non-metal plasmonic system. The intriguing observations are here explained via the SP-strengthened nonlinear effect, through consideration of the electrostatic field (which is comparable to the atomic field) and its large gradient; this hints at a promising, highly sensitive plasmonic system. The gigantic nonlinear effect discussed in this paper should be ubiquitously existed in many oxide ferroelectric/semiconductor combinations and is promising for visible plasmonic applications.

Photonic Characterisation of Indium Tin Oxide as a Function of Deposition Conditions

“…For example, ITO has been shown to exhibit an extremely large ultrafast nonlinearity at the ENZ point [ 58 ], providing an optically induced enhancement to changes in the refractive index. Moreover, surface plasmons have been observed on ITO-coated structures, producing a strong nonlinearity and a large refractive index change within a half-wavelength range [ 59 ]. Hence, the linear photonic characterisation of TCO dispersion trends and ENZ behaviour we detail here provide a fundamental basis for also exploring nonlinear optical responses of TCOs.…”