We study the effective third-order nonlinear susceptibility of a graded metal–dielectric composite film of anisotropic particles with weak nonlinearity by invoking the local field effects within the Maxwell–Garnett theory. We further numerically demonstrate that the film can serve as a novel optical material to produce a broad structure in both the linear and the nonlinear response and an enhan...

The optical properties of thin gold films with thickness varying from 2.5 nm to 30 nm are investigated. Due to the quantum size effect, the optical constants of the thin gold film deviate from the Drudemodel for bulkmaterial as film thickness decreases, especially around 2.5 nm, where the electron energy level becomes discrete. A theory based on the self-consistent solution of the Schrödinger e...

This article provides a novel method of constructing an optical fiber localized surface plasmon resonance (LSPR) biosensor. A gold nanoparticle (NP) assembled film as the sensing layer was built on the polyelectrolyte (PE) multilayer modified sidewall of an unclad optical fiber. By using a trilayer PE structure, we obtained a monodisperse gold NP assembled film. The preparation procedure for th...

We report the ultrafast and large third-order nonlinear optical properties of CdS nanocrystals (NCs) embedded in a polymeric film. The CdS NCs of 2 nm radius are synthesized by an ion-exchange method and highly concentrated in the two layers near the surfaces of the polymeric film. The two-photon absorption coefficient and the optical Kerr coefficient are measured with laser pulses of 250 fs du...

Ternary glasses of Se80Te20-xSnx (x=3 and 9 at.%) are prepared by melt quench technique. Thin films of Se80Te20-xSnx (x=3 and 9 at.%) of different thicknesses in the range of (25 nm -1450 nm) are prepared by the conventional thermal evaporation technique on glass substrate. X-ray diffraction measurements show that both bulk and thin films of Se80Te20-xSnx have amorphous natures. Optical transmi...

Nanometric flat lenses with three-dimensional subwavelength focusing are indispensable in miniaturized optical systems. However, they are fundamentally challenging to achieve because of the difficulties in accurately controlling the optical wavefront by a film with nanometric thickness. Based on the unique and giant refractive index and absorption modulations of the sprayable graphene oxide thi...

Optical control of phase coexistence, previously used as a mechanism for achieving a nonlinearity at planar gallium/glass interfaces, can be exploited as a nonlinear response mechanism in a metallic nanoparticle film. Experimental measurements of the reflective and transmissive nonlinear response of a gallium nanoparticle film, manufactured on the tip of an optical fibre using the light-assiste...

A gradient Si-rich oxide multilayer (GSRO-ML) deposition structure is proposed to achieve super-high density Si quantum dot (QD) thin film formation while preserving QD size controllability for better photovoltaic properties. Our results indicate that the Si QD thin film using a GSRO-ML structure can efficiently increase the QD density and control the QD size. Its optical properties clearly pro...

We report the experimental observation of all-optical modulation of light in a graphene film. The graphene film is scanned across a standing wave formed by two counter-propagating laser beams in a Sagnac interferometer. Through a coherent absorption process the on-axis transmission is modulated with close to 80% efficiency. Furthermore, we observe modulation of the scattered energy by mapping t...

The influence of surface plasmons on the magneto-optic activity in a two-dimensional hexagonal array is addressed. The experiments were performed using hexagonal array of circular holes in a ferromagnetic Ni film. Well pronounced troughs are observed in the optical reflectivity, resulting from the presence of surface plasmons. The surface plasmons are found to strongly enhance the magneto-optic...