Characterization of a large core photonic crystal fiber made of lead–bismuth–gallium oxide glass for broadband infrared transmission

We report on characterization of a large solid core, photonic crystal fiber dedicated to broadband transmission range from visible to mid-infrared. We have fabricated a multi-mode photonic crystal fiber, made of a heavy metal-oxide glass based on the $\hbox {PbO}{-}\hbox {Bi}_{2}\hbox {O}_{3}{-}\hbox {Ga}_{2}\hbox {O}_{3}$ system, modified with $\hbox {SiO}_{2}$ and CdO, synthesized in-house, which shows good transmission up to $4.5\,\upmu \hbox {m}$ , as well as good rheological properties that permit multiple thermal processing steps without crystallization. The core of the fiber is created by replacement of central 60 tubes with solid rods. The photonic cladding is composed of 8 rings of air holes with a filling factor of 0.42. Simulation results shows that the fiber can be used for broadband transmission in the range of 430–3,000 nm. Calculated effective mode area of the fiber is $295\,\upmu \hbox {m}^{2}$ . We have measured attenuation of the fiber in the range 800–1,700 nm and its sensitivity to bending losses. Attenuation ranges from 1 to 4 dB/m in the considered range and bending losses are below 0.7 dB.     

UV-violet emission properties of 2F(2)5/2 energy level of Nd3+ ions in ZBLAN glass

In this work the short-wavelength emission properties are investigated for the highest observed 4f metastable energy level ²F(2)_5/2 of Nd³⁺ ions in fluorozirconate ZBLAN glass. Various dopant concentrations, ambient temperatures and excitation conditions have been considered throughout the study. Distinct spectral features were observed under pulsed and cw excitation at 514 nm. In particular, pulsed pumping enabled recording of ²F(2)_5/2 emission spectra, not observable under CW excitation, as well as the level’s fluorescence decay dynamics and its evolution with temperature and dopant concentration. According to the best of the authors’ knowledge, neither the fluorescence lifetime of ²F(2)_5/2 of Nd³⁺ in ZBLAN, nor its concentration dependent evolution were reported before.     

Biological Effects of Cold Atmospheric Pressure Plasma on Skin Cancer

Plasma Chemistry and Plasma Processing - Cold atmospheric pressure plasmas (CAPPs) increasingly attracted scientific attention in the field of medicine, especially oncology. Because of the surface...     

Application of Oil-in-Water Nanoemulsion Carrying Size-Defined Gold Nanoparticles Synthesized by Non-thermal Plasma for the Human Breast Cancer Cell Lines Migration and Apoptosis

Plasma Chemistry and Plasma Processing - In this work, the gold nanoparticles (AuNPs) were synthesized using pulse-modulated radio-frequency atmospheric pressure glow discharge (pm-rf-APGD). By...     

Photoinduced electron transfer across a molecular wall: coumarin dyes as donors and methyl viologen and TiO2 as acceptors

Coumarins C-153, C-480, and C-1 formed 1:2 (guest:host) complexes with a water-soluble cavitand having eight carboxylic acid groups (OA) in aqueous borate buffer solution. The complexes were photoexcited in the presence of electron acceptors (methyl viologen, MV(2+), or TiO(2)) to probe the possibility of electron transfer between a donor and an acceptor physically separated by a molecular wall. In solution at basic pH, the dication MV(2+) was associated to the exterior of the complex C-153@OA(2), as suggested by diffusion constants (~1.2 × 10(-6) cm(2)/s) determined by DOSY NMR. The fluorescence of C-153@OA(2) was quenched in the presence of increasing amounts of MV(2+) and Stern-Volmer plots of I(o)/I and τ(o)/τ vs [MV(2+)] indicated that the quenching was static. As per FT-IR-ATR spectra, the capsule C-153@OA(2) was bound to TiO(2) nanoparticle films. Selective excitation (λ(exc) = 420) of the above bound complex resulted in fluorescence quenching. When adsorbed on insulating ZrO(2) nanoparticle films, excitation of the complex resulted in a broad fluorescence spectrum centered at 500 nm and consistent with C-153 being within the lipophilic capsule interior. Consistent with the above results, colloidal TiO(2) quenched the emission while colloidal ZrO(2) did not.     

Mid-infrared supercontinuum generation in soft-glass suspended core photonic crystal fiber

Supercontinuum from 800 to 2,600 nm has been obtained in a soft glass suspended-core photonic crystal fiber. The fiber has been fabricated using an in-house synthesized, lead-bismuth-galate oxide glass (PBG-08), which has a transmission window from 500 nm to 4,500 nm. Dispersion characteristic has been designed to enable efficient pumping in the anomalous regime, using typical telecommunication wavelengths and influence of discrepancy between design and physical dispersion profile of fiber is discussed. An optical parametric amplifier system seeded with a Ti:Sapphire oscillator has been used as a light source (70 fs pulses with 100 kHz repetition rate). Supercontinuum bandwidth on the mid-infrared side is limited by OH $^-$ absorption of the glass and presence of second zero-dispersion wavelength in the spectral area of interest. Flatness the spectrum remains under 7 dB from roughly 1,800 nm to about 2,500 nm.     

Initial state-resolved excited state absorption spectroscopy of ZBLAN:Ho<Superscript>3+</Superscript> glass

Phase-sensitive and frequency-resolved detection techniques are used for the initial state-resolved excited state absorption (ESA) measurements in ZBLAN:Ho³⁺ glass. Both experimental techniques were applied simultaneously in a broad spectral range (550–1750 nm) for the first time. Estimated results are compared and discussed in detail. A simple kinetic model, used for qualitative considerations, is presented and successfully compared with the experimental data. The measured spectra will be useful for identifying new up-conversion excitation channels in the considered system, where ESA transitions originating from several excited levels are observed.     

Thermodynamic and structural properties of binary mixtures of some glycols with 2-butoxyethanol at T = (293.15, 298.15 and 303.15) K

Densities and relative permittivities at T = (293.15, 298.15, and 303.15) K in the binary mixtures of 2-butoxyethanol with ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol have been measured as a function of composition. From the experimental data excess molar volumes and deviations in relative permittivity have been calculated over the entire composition range. Both excess molar volumes and relative permittivity deviations have been correlated using Redlich–Kister type polynomial equation by the method of least-squares for the estimation of the binary coefficients and the standard errors. The experimental and calculated quantities were used to analyze the mixing behaviour of the components.