Second harmonic generation and sum frequency (SHG SFG) provide effective means to realize coherent light at desired frequencies when lasing is not easily achievable. They have found applications from sensing quantum optics are of particular interest for integrated photonics communication wavelengths. Decreasing the footprints nonlinear components while maintaining their high up-conversion efficiency remains a challenge in miniaturization photonics. Here we explore lithographically defined...

Pure and zinc doped tungsten oxide films were deposited on glass substrates at various wt% of by using the electron beam evaporation method. The scanning microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR double spectrometry techniques used to assess properties pure films. From SEM results, undoped exhibited a rice hull type nanostructure. spider net structure. antibacterial activity Zn-WO3 was studied with Pseudomonas aeruginosa. WO3 are effectively inhibiting bacteria’s growth.

We report on circularly polarized Gaussian beam spin angular momenta that can be inverted upon scattering with quadrupole plasmon modes. The conditions for such conversion are met high-angle collection, dark-field microscopy spherical plasmonic particles. further silvered nanoporous silica microparticles exhibit a strong nonlinearity in their scattering, specifically reverse saturated (RSS), when exposed to high laser power densities the sample of ca. 5 GW/cm2. Handedness by these is only...

We experimentally demonstrate the coexistence of two opposite photo-effects, viz. fast photodarkening (PD) and slow photobleaching (PB) in Ge19As21Se60 thin films, when illuminated with a laser wavelength 671nm, PD appears to begin instantaneously upon light illumination saturates tens seconds. By comparison, PB is slower process that starts only after has saturated. Although we could observe PD/PB even at moderate, one order magnitude lower intensity 0.2 W/cm2, kinetics transformation...

Abstract In this paper, we present interesting results on the quantification of photodarkening (PD), photobleaching (PB) and transient PD (TPD) in a-Ge x As 35−x Se 65 thin films as a function network rigidity. Composition dependent light-induced responses these samples indicate that there exist two parallel competing mechanisms instantaneous arising from part PB Ge network. Raman spectra as-prepared illuminated provide first direct evidence structural changes: an increase AsSe 3/2 pyramidal...

Of late, magnetoelectric multiferroics have gained tremendous importance because they possess coexisting magnetic and ferroelectric phases, with cross-correlation effects between electric degrees of freedom. BiFeO${}_{3}$ stands out as a canonical material in the multiferroics, it exhibits ferroelectricity antiferromagnetism at room temperature. Here, authors demonstrate for first time that linearly polarized ultrafast light pulse leads to simultaneous excitation coherent magnon...

In this article, we employed the nanosecond Z-scan technique to demonstrate nonlinear optical response in Ge30Se55Bi15 thin films after thermal and photoannealing. The intensity dependent open aperture traces reveal that all samples, i.e., as-prepared, thermal, photoannealed films, exhibit reverse saturable absorption. experimental results indicate both photoannealing can be efficiently used enhance absorption coefficient (β) compared as-prepared sample. We further β value of thermally...

Optical properties of metal nanostructures, governed by the so-called localised surface plasmon resonance (LSPR) effects, have invoked intensive investigations in recent times owing to their fundamental nature and potential applications. LSPR scattering from nanostructures is expected show symmetry oscillation mode particle shape. Therefore, information on polarisation crucial for identifying different modes within one distinguish differently shaped particles sample. On contrary, state light...

In this Letter, we demonstrate that femtosecond light-induced interdiffusion of Ag driven by the electrostatic attraction between photo-excited Ag+ ions and negatively charged amorphous layer can act as an efficient single step method for hybrid integration spatially ordered interconnected nanoparticles on surface films. Such self assembled complex structures silver via bottom-up nano-construction a-Se thin film show ultrafast optical response over unusually broad wavelength range be used to...

Abstract In this article, we report the first observation of nanosecond laser induced transient dual absorption bands, one in bandgap (TA 1 ) and another sub-bandgap 2 regions a-Ge 5 As 30 Se 65 thin films. Strikingly, these bands are thermally tunable exhibit a unique contrasting characteristic: magnitude TA decreases while that increases with increasing temperature. Further, decay kinetics is strongly influenced by temperature, which signifies strong temperature dependent exciton...

In this paper, we demonstrate NiCo$_2$O$_4$ (NCO) as an efficient new nonlinear optical material with straightforward potential applications in limiting devices. We obtain absorption coefficient ($\beta$) and refractive index ($n_2$) parallel by performing Z-scan technique, both open closed aperture configurations, respectively. To understand the mechanism responsible for third order nonlinearity NCO, excited sample contrasting laser pulse durations, 7 ns 120 fs, at two different...

In this article, we studied intensity dependent third order nonlinear optical response in ternary As40Sb7Se53 and As40Sb10Se50 chalcogenide glasses by employing nanosecond Z-scan technique. At low intensity, observed saturable absorption which makes a remarkable transition to reverse at higher intensities. On the other hand, when Sb concentration increased As40Sb10Se50, disappears sample exhibits only two-photon absorption. Experimental results further indicate that strong our samples can be...

Ge-rich ternary chalcogenide glasses (ChGs) exhibit photobleaching (PB) when illuminated with bandgap light. This effect originates from the combined effects of intrinsic structural changes and photo-oxidation. In a sharp contradiction to previous observations, in this Letter, we demonstrate, for first time, that Ge(25)As(10)Se(65) ChG thin films photodarkening (PD) at 20 K PB 300 420 after having been continuously ∼3 hours. The temporal evolution PD/PB shows distinct characteristics...

In this Letter, we report the first observation of dramatic decrease in nanosecond (ns) pulsed laser-induced transient absorption (TA) a-Ge(x)As(35-x)Se₆₅ thin films by tuning amorphous network from floppy to rigid. Our results provide direct experimental evidence a self-trapped exciton mechanism, where trapping excitons occurs through bond rearrangements. Taken together, rigid with more constraints than degrees freedom are unable undergo any such rearrangements and weaker TA. However, also...

In this article, we demonstrate the combined effect of photodoping and photoinduced-surface deposition in a bilayer chalcogenide glass (ChG) Ag as an alternative method to optically synthesize nanoparticles (AgNP) on surface ChG. our experiment, AgNP formation occurs through two distinct stages: first stage, is transported As2S3 layer Ag+ ions, second stage ions are photo-deposited AgNP. The ex situ x-ray photoelectron spectroscopy measurements AFM observations show photoinduced mass transport

Amorphous chalcogenide glasses are intrinsically metastable, highly photosensitive, and therefore exhibit numerous light-induced effects upon bandgap sub-bandgap illumination. Depending on the pulse duration of excitation laser, ChGs a series spanning over femtosecond to seconds time domain. For continuous wave (CW) illumination, dominantly metastable in terms photodarkening (PD) photobleaching (PB) that take place via homopolar heteropolar bond conversion. On other hand, under nanosecond...

In this Letter, we report for the first time, to best of our knowledge, continuous-wave laser background illumination (BGI) as a simple and yet useful tool tune nanosecond transient absorption (TA) in a-Ge25As10Se65 thin films. experiments, observed remarkable blueshift TA function BGI intensity. Strikingly, relaxations background-illuminated samples are much faster than as-prepared samples. This observation provides new insights into bond-breaking mechanism. Further, decay time constants...

Metal nanoparticle-semiconductor interfaces are sites of complex light-matter interactions, in particular, the exciton-plasmon coupling which plays a key role optical response such heterostructures. There exists pathway photoinduced charge transfer from semiconductor to metal, can be used controllably vary driving forces at interface that leads tunable optoelectronic properties. In this letter, we report observation dramatic suppression plasmonic as well excitonic absorption a-Ge24Se76/gold...

Temporal and spectral behaviors of plasmons determine their ability to enhance the characteristics metamaterials tailored a wide range applications, including electric-field enhancement, hot-electron injection, sensing, as well polarization angular momentum manipulation. We report dark-field (DF) polarimetry experiment on single particles with incident circularly polarized light in which gold nanoparticles scatter opposite handedness at visible wavelengths. Remarkably, for silvered...

Nanosecond near resonant excitation in As50S50 thin films leads to strong nonlinear optical response, i.e. absorption coefficient up 4 x 106 cm/GW and refractive index of 8.5 cm2/GW, both which is the strongest ever reported amorphous semiconductors. We propose a five-level energy model explain such effect indicates that process reverse saturable nature, mediated by excited state from triplet-triplet transition. On other hand, observation negative reveals occurrence self-defocusing effect....

Little is known about the role of network rigidity in light-induced structural rearrangements glasses due to a lack supporting experiments and theories. In this article, we demonstrate for first time ultrafast manifested as induced absorption (IA) over broad spectral range a-GexAs35-xSe65 thin films above mean-field percolation transition, quantified by mean coordination number ⟨r⟩ = 2.40. The IA spectrum arising from self-trapped excitons softening glass that strikingly reveals two...