Nanocomposites based on transparent polymer matrices containing nanoparticles (NPs) of noble metals are modern-day materials that can be specially designed for photonics, linear and nonlinear optics, laser physics and sensing applications. We present the improved photosensitive nanocomposites doped with Au and Ag NPs allowing fabrication of high effective submicrometer dimensional diffraction structures using holographic method. A general approach for the fabrication of holographic structures using a two-component mixture of the monomers of different reactivity was developed. Two different methods, ex situ and in situ, were studied to introduce Au and Ag NPs in the polymer matrix. The diffusion model of the grating formation upon holographic exposure as well as the process of Ag NP synthesis in a polymer matrix is considered. The influence of the NP size on the polymerization process, material dynamic range and nonlinear properties were investigated. The mechanisms and characteristics of the nanocomposite nonlinear optical response are discussed.

In this paper, we report the synthesis and characterization of unconventional nanocomposites made of bimetallic nanoparticles dispersed in a liquid crystal glass. Core-shell bimetallic nanoparticles (Ag/Au or Au/Ag) and Ag-Au bimetallic nanoalloys are synthesized using cadmium alkanoate glass-forming liquid crystals as nanoreactors. Optical spectra of the produced glassy nanocomposites exhibit a distinctive absorption peak due to a surface plasmon resonance. In addition, these unusual materials demonstrate a strong nonlinear–optical response probed by means of the Z-scan technique. The use of near-infrared (1064 nm) and visible (532 nm) nanosecond laser pulses reveal a variety of nonlinear–optical mechanisms that depend on the composition of the studied nanocomposites. Our results indicate that metal alkanoate-based glass-forming ionic liquid crystals with embedded plasmonic nanoparticles are promising, yet they are overlooked photonic nanomaterials suitable for optical and nonlinear-optical applications.

The unique properties of nanomaterials along with their suitability for photonics applications can be explored by dispersing nanodopants in a transparent glass matrix. As a rule, the creation of glass nanocomposites involves the synthesis of nanoparticles followed by their dispersion in a glass host. This laborious two-step process can be simplified if glass-forming liquid crystals are used as a nanoreactor and host matrix. In this paper, we discuss the successful realization of this approach using mesogenic metal alkanoates for the fabrication of unconventional glass nanocomposites containing metal and/or bimetallic nanoparticles. More specifically, metal (gold and silver) and bimetallic (silver-gold) nanoparticles are synthesized in the liquid crystal phase of a glass-forming cadmium octanoate. Upon cooling, cadmium octanoate samples containing the synthesized nanoparticles easily vitrify, resulting in the formation of glass nanocomposites. The produced glass nanocomposites exhibit a relatively strong (10⁻⁸–10⁻⁷ esu) nonlinear-optical response tested by means of a Z-scan technique and utilizing visible (532 nm) and near-infrared (1064 nm) nanosecond laser pulses. The evaluated values of the effective nonlinear absorption coefficients and nonlinear refractive indices of the studied samples depend on their composition and on the intensity of laser beams, thus revealing the presence of several nonlinear-optical mechanisms acting simultaneously. Potential applications of the designed glass nanocomposites are also discussed.

The article presents results of the parameters of optical cubic nonlinearity (OCN) of thin amorphous Cu2O films under 532 and 1064 nm pulsed laser excitation. The films were synthesized on SiO2 (silica) substrates by reactive pulsed laser deposition technique at 293 or 800 K under a different oxygen pressure of 1, 3, or 5 Pa. The bandgap of the films was determined from the absorption spectra. The films synthesized under 1 and 3 Pa oxygen pressure at 293 K demonstrated at 1064 nm positive OCN, whereas the films obtained at 293 K, 5 Pa, and 800 K, 1 Pa demonstrated negative OCN. The largest nonlinear refractive index of n2 = + 1.35 × 10−6 cm2/W was obtained for the film synthesized at 293 K, 1 Pa. Under 532 nm excitation, the films also revealed positive or negative OCN, depending on the synthesis parameters, with the absolute value of |n2| on the order of 10−7 cm2/W. The largest |n2| = 5.16 × 10−7 cm2/W was obtained for the 293 K, 3 Pa film. Depending on the manufacturing conditions, the films exhibited saturated absorption or reversed saturated absorption.

Nonlinear optical properties of thin polycrystalline PdO films are investigated using the Z-scan technique and a 800 nm 180 fs laser, whose wavelength is significantly longer than the absorption edge at 500 nm. Cubic nonlinear susceptibility Re χ⁽³⁾ = +1.1 × 10⁻⁶ esu (n₂ = 5.6 × 10⁻⁹ cm²/W) and nonlinear absorption coefficient β ≈ 5 × 10⁻⁵ cm/W are determined. The positive sign of Re χ⁽³⁾ implies intraband carrier (predominantly holes) relaxation dynamics and the optical Kerr effect as underlying mechanisms. Relaxation time of refractive nonlinearity is estimated in the picosecond range. Linear absorption spectra in the interval of 1.5–6 eV, compared with the literature data, suggest that microcrystals in our films are predominantly oriented with the С axis orthogonal to the film.