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A novel hydroxyethylammonium maleate single crystal was grown by slow evaporation solution method for the first time. The structure of the title compound is determined by single crystal X-ray diffraction. The linear optical properties were studied using ultraviolet-visible and photoluminescence spectroscopy. The third-order nonlinear optical property of title compound was studied by Z-scan technique to determine its nonlinear absorption and nonlinear refraction. Thermal property was studied by thermogravimetry, differential thermal analysis and differential scanning calorimetric analyses. The mechanical stability of the material was studied by Vickers microhardness tester. Further, etching study was done to examine the defects in the crystal. [ABSTRACT FROM AUTHOR]

Ultrafast excited state dynamics of dinaphthoporphycenes were investigated using femtosecond and picosecond degenerate pump-probe techniques at 600 nm and 800 nm, respectively. Femtosecond pump-probe data indicated photo-induced absorption at 600 nm resulting from two-photon/single photon excitation, whereas picosecond pump-probe data demonstrated photo-bleaching which was a consequence of three-photon absorption. The fastest lifetimes (100-120 fs) observed are attributed to the intramolecular vibrational relaxation, the slower ones (1-3 ps) to internal conversion, and the slowest components (7-10 ps) to non-radiative decay back to ground state. Z-scan studies in the 560-600 nm range were also carried out. [ABSTRACT FROM AUTHOR]

• Impact of heat treatment on NLO features of Nd 2 O 3 doped borate glasses embedded with Ag NPs has been investigated. • NLO features were studied in near infra-red region under ultrafast regime. • The origin of enhancement of NLO features has been highlighted. • The nonlinear results reveal the investigated glasses are beneficial for optical limiting devices. Nd3+ ions containing borate glasses embedded with silver (Ag) nanoparticles (NPs) were prepared by melting and quenching process. Thermal treatment at 450 °C for different holding durations has been performed to tune the size of the NPs embedded in the glass. The influence of growth of NPs on nonlinear optical (NLO) and optical limiting (OL) properties of glasses has been evaluated in the near–infrared spectral provenience under femtosecond pulse regime. The NLO and OL attributes evaluated using Z–scan configuration disclose the enhanced trend of two–photon absorption and nonlinear refraction coefficients and a decrease behaviour of OL threshold with the augment of thermal holding time. This enhancement in NLO coefficients and OL performance with thermal annealing duration is ascribed to the enhancement of the local field with the size of the NPs. The outcomes acknowledge the Nd3+ ions bearing borate glasses embedded with bigger Ag NPs are preferable for nanophotonic applications and optoelectronic functionalities. [ABSTRACT FROM AUTHOR]

• Efficacy of Sm 2 O 3 on nonlinear optical properties of borate-based glass has been studied in nanosecond and femtosecond regimes. • The nonlinear optical properties are enhanced with addition of Sm 2 O 3 to Li 2 O in the composition of the glass. • The nonlinear optical features are stronger under nanosecond pulse regime than those achieved at femtosecond regime. • The results indicate the lithium zinc borate glass bearing 5 mol% of Sm 2 O 3 is useful for the nonlinear photonic functionalities. Influence of samarium trioxide on nonlinear optical (NLO) traits such as NLO absorption and refraction attributes of lithium zinc borate glasses has been investigated respectively using the open– and closed–aperture Z–scan techniques in visible and near–infrared spectral regions under nanosecond and femtosecond pulse regimes. The open–aperture Z–scan observations identified reverse saturable absorption and the mechanism responsible was two–photon absorption. The closed–aperture Z–scan depicted positive nonlinear refraction caused by the effect of self–focusing. There was an improvement in the NLO features with the increased samarium tri–oxide quantity in the composition thanks to non–bridging oxygens formation and the high polarizability of samarium ions. The NLO coefficients were more robust under nanosecond pulse excitation than those obtained under femtosecond excitation, attributed to the influence of excited state absorption and the two-photon absorption and thermal effects arising from longer pulse duration. [ABSTRACT FROM AUTHOR]

• Efficaccy of heat treatment on optical nonlinear features has been investigated. • Nonlinear optical features have been ascertained using femtosecond laser pulses. • The intensity–dependent nonlinear optical features were evaluated. • The results disclosed that the glasses are advantageous for nonlinear photonic functionalities depending on the input intensity. We present results from our experimental measurements on the effect of annealing and intensity–dependent femtosecond (MHz) third–order nonlinear optical (NLO) attributes of gold nanoparticles (NPs) embedded sodium borate glass specimens. A melt–quench procedure was used to fabricate the gold nanoparticle–loaded sodium antimony containing borate glasses, which were then subjected to different schedules of thermal treatment at 500 °C. The highest saturation intensity and nonlinear refraction magnitude were observed for the 7–hour annealed glass specimen (i.e., for NBAu–7 glass). Thus, on the NBAu–7 glass, intensity–sensitive NLO measurements were performed. The saturable absorption behavior that was detected at lower peak intensities switched to reverse saturable absorption during the exposure of NBAu–7 glass with high fluence laser pulses. While the sign of the nonlinear refraction remained unchanged, the magnitude increased. The methodology examined in this work may enable the fabrication of borate–based glasses loaded with gold NPs with high saturation intensities and robust nonlinear refractive index magnitudes to be used in optical switching operations. The results of the current study support that the NBAu–7 glass is advantageous for optical switching functions when exposed to low–energy laser pulses. In contrast, the same glass benefits optical limiting functions when exposed to high–fluence laser pulses. [ABSTRACT FROM AUTHOR]

• Eu3+ doped borate based glass embedded with gold nanoparticles were prepared by melt quenching process. • Efficacy of annealing schedule on nonlinear optical properties of glass was studied. • The nonlinear optical properties were assessed by Z-scan technique in near-infrared region in ultrafast regime. • The study instantiate the AU nanoparticles embedded borate glass annealed for 30 h at 450 °C is beneficial for nonlinear photonic, optoelectronic, and optical power limiting applications. In this work, the Eu 2 O 3 doped B 2 O 3 glass specimen embedded with gold nanoparticles (NPs) was designed by the process of melt-quenching and subjected for thermal treatment to understanding the efficacy of thermal dependency on the optical and nonlinear optical (NLO) characteristics. Linear optical studies have revealed a decrease trend in the energy band gap as the function of annealing duration, indicating the increase of non-bridging oxygen concentration in the glass host. The NLO properties were assessed in near-infrared region utilizing 150 fs laser pulses delivered at the rate of 80 MHz. The aperture free Z-scan measurements exhibited an increased nonlinear absorption coefficient with annealing duration. Further, the closed aperture Z-scan data depicted an increase trend in the positive nonlinear refraction with annealing duration and eventually reduced at the greater duration of annealing. The optical limiting studies demonstrated similar behaviour to the nonlinear absorption characteristics of studied glass samples. These results are related to the local field stimulated by surface plasmons of gold NPs near the Eu3+ ions during the exposure of glass to high fluence laser beam. Our results indicate that B 2 O 3 glasses embedded with Au NPs heat-treated for 30 h at 450 °C are good candidates for nonlinear photonic, optoelectronic, and optical power limiting applications in photonics. [ABSTRACT FROM AUTHOR]

• The glasses activated with Eu 2 O 3 and silver nanoparticles have been prepared by melt-quenching process. • Microscopic studies confirmed the formation of uniformly distributed spherical silver NPs. • The annealing process has been followed to tune the optical nonlinearities of glasses. • The α 2 grows with heat treatment durations up to 40 hrs, beyond which the α 2 deteriorated. • The study revealed, the glass heat treated at 40 hrs could be advantageous in fabricating power optical limiters. Achieving strong optical nonlinearities in vitreous nanocomposites is imperative for the advancement of futuristic telecommunication and photonic technologies. In this regard the borate materials (vitreous) are deemed to be important and currently available commercial hosts. In the current work, we demonstrate the tuning of the third-order nonlinear optical (NLO) attributes of borate-based glass samples doped with metal nanoparticles (NPs) and rare earth ions through annealing process. The NLO attributes, such as nonlinear optical absorption and refraction have been analysed by the sensitive Z-scan approach in the open and closed aperture configurations, respectively. The NLO features were examined in the near-infrared spectral region using ultrafast laser pulses fired at a high repetition rate from a Ti: sapphire laser oscillator. The open aperture data unveiled the existence of two-photon absorption whilst closed aperture indicated the occurrence of self-focusing nonlinear refraction. The NLO coefficients improved with heat treatment duration but the nonlinear absorption coefficient reduced at longer heat treatment schedules. The enhancement in the NLO coefficients is ascribed to the local field enriched by metallic silver NPs in the proximity of the rare earth ions when high-energy laser pulses irradiate the hosts. The results suggest the glasses routed with rare earth ions and metallic silver NPs annealed for 40 hrs at 450 °C are beneficial for optical communication and nonlinear photonic device applications, including optical limiting functionalities. [ABSTRACT FROM AUTHOR]

Efficacy of tri‒valent samarium ions concentration on the optical and third‒order nonlinear optical (NLO) properties of multicomponent cadmium alkali borate‒based glasses prepared by standard melting‒quenching method has been investigated in this work. The optical properties of cadmium alkali borate glass activated by rare-earth oxide (i.e., Sm 2 O 3) were carried out by using UV–Visible absorption spectroscopy at room temperature. Optical absorption peaks were obtained around 402 nm, 1076 nm, and 1078 nm wavelength. The Fourier transform infrared spectroscopy results revealed the existence of distinct borate units, in the structure of glasses used in the investigation. Z‒scan experiments in the near‒infrared (NIR) spectral regions utilizing the femtosecond (fs) laser pulses were used in order to evaluate the NLO parameters. The two‒photon absorption coefficient and the index of nonlinear refraction values improved significantly for 2 mol% of Sm 2 O 3. This endorses 2 mol% of Sm 2 O 3 encompassed glasses are beneficial for constructing the NLO devices assigned to perform in the NIR region. • Effect of Sm 2 O 3 on third‒order nonlinear optical properties of multicomponent borate‒based glass was studied. • CA Z‒scan patterns exhibited positive nonlinear refraction manifested to self‒focusing effect. • OA Z‒scan patterns confirms existence of RSA manifested to TPA. • Multicomponent borate‒based glass containing 2 mol % of Sm 2 O 3 exhibited large TPA and χ(3). [ABSTRACT FROM AUTHOR]

• Organic nonlinear optical Triphenylamine single crystal has been grown from Bridgman – Stockbarger method. • The excellent optical transmittance of TPA single crystal has been observed in the near infrared region (82%). • Thermal stability of TPA single crystal has been observed upto 140 °C. Optically transparent Triphenylamine (TPA) single crystal has been grown by Bridgman-Stockbarger method. Phase confirmation of TPA crystal was investigated using SXRD and PXRD analyses. Hirshfeld Surface was performed on TPA. The chemical bonding structure of TPA has been obtained from the FTIR spectral study. Optical transmittance properties of the grown crystal were obtained from the UV–Visible NIR spectrum analysis. Thermal properties of the TPA single crystal were identified using TG-DTA analyser. Q-switched Nd:YAG laser (λ = 1064 nm) has been used for the LDT measurement. Second harmonic generation of organic TPA crystal was analysed by Kurtz- Perry powder technique. [ABSTRACT FROM AUTHOR]