Anete Berzina

Materials with high nonlinear optical (NLO) efficiency have attracted a lot of attention in the development of integrated photonics. In the literature, we see many variations of parameters for third- and fifth-order NLO effect measurement methods, raising the question of how to accurately distinguish third-order NLO effects. Here, we study nonlinear refraction (NLR) and two-photon absorption (2PA) of anisole, chloroform, carbon disulfide (CS ₂ ), and toluene in 400–1100 nm range using the Z-scan method. Anisole, toluene, and CS ₂ show 2PA and a combination of third- and fifth-order NLO properties in 400–575 nm range at 500 kHz pulse repetition frequency. Frequency-dependent fifth-order NLR indicates thermal effect influence, and polarization-resolved measurements allow to perform more fundamental analysis.

This study presents a novel silver nanoparticle ink formulation designed for inkjet printing applications using terpineol as an eco-friendly solvent and butylamine as a stabilizer to ensure stability, high conductivity, and compatibility with inkjet technology. Silver nanoparticles were synthesized using a modified one-pot method in the presence of highly effective stabilizers and surface modifiers such as oleic acid and oleylamine, resulting in uniform particles of less than 10 nm in size, which were then dispersed in a mixture of terpineol and butylamine. The resulting ink demonstrated exceptional stability over 85 days, maintaining optimal rheological properties for inkjet printing. The ink exhibited a perfect jetting performance. We were able to obtain silver conductive patterns reaching 81% of bulk silver conductivity. These results highlight the ink’s promise for scalable, sustainable manufacturing, combining environmental advantages with high-performance functionality.

We characterize the nonlinear optical properties of indium–tin oxide (ITO) quantum dots (QDs) in the IR range using the Z-scan method. We present results of three-photon absorption (3PA), third harmonic generation (3HG), and Kerr-effect-induced nonlinear refraction in ITO QDs. Z-scan measurements were carried out for the QDs solution, while 3HG was demonstrated using QD thin films. The Kerr-induced nonlinear refractive index was analyzed along the 800–950 nm range showing an increase in this parameter from −6.7 × 10⁻¹⁸ to −1.5 × 10⁻¹⁷ m² W⁻¹. At longer wavelengths (1000–1100 nm), the higher-order effects started to contribute to a nonlinear refractive index. The 3PA coefficient at 950 nm was measured to be 1.42 × 10⁻²⁵ m³/W². We discuss the peculiarities in the wavelength-dependent variation of the coefficient of nonlinear absorption responsible for 3PA in the range of 800–1150 nm. Third harmonic generation was analyzed in the 1200–1550 nm spectral range. The absolute value of 3HG conversion efficiency in the 150 nm thick film at the wavelength of laser radiation (1350 nm) was estimated to be ~10^–5.