Spectral and Transmittance Properties of Er3+ Doped Zinc Lithium Lead Calcium Borophosphate Glasses

Zinc lithium lead calcium borophosphate glasses containing Er3+ in (40- x):P2O5:10ZnO:10Li2O:10PbO:10CaO:20B2O3:xEr2O3 (where x=1, 1.5,2 mol %) have been prepared by melt-quenching method. The amorphous nature of the glasses was confirmed by x-ray diffraction studies. Optical absorption, Excitation, fluorescence and Transmittance spectra were recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4, 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability, branching ratio, radiative life time and stimulated emission cross–section of various emission lines have been evaluated. Keywords: ZLLCBP Glasses, Optical Properties, Judd-OfeltTheory, Transmittance Properties.

Influence of Y2O3 Content on Structural, Optical, Spectroscopic, and Laser Properties of Er3+, Yb3+ Co-Doped Phosphate Glasses

The influence of the addition of Y2O3 on the structural, spectroscopic, and laser properties of newly prepared Er, Yb-doped strontium-sodium phosphate glass was investigated. While the addition of Y2O3 has a small influence on the absorption spectra and fluorescence lifetime, it has a strong impact on the emission cross-section and on OH− content. The glasses were used as the active medium for diode-pumped laser emitting at 1556 nm. The increase in Y2O3 content leads to a significant 35% increase in laser slope efficiency up to 10.4%, but at the expense of the substantial reduction of the wavelength tunability from 82 to 54 nm.

Spectroscopic Properties of Alumina Borosilicate Glassesw Alkaline Oxides Doped with Sm2O3 for Display Laser Emission

This research investigates the influence of the concentration of Sm+ 3 ions on the features of a new borosilicate glass system with the composition 50B2O3– 14SiO2- 20Li2O– 15Na2O– 1.0Al2O3-x(Sm2O3), where x = 100, 200, 300, 400, and 500 ppm. The glasses are characterized by XRD, FTIR, UV- Vis- NIR, and photoluminescence spectra. The XRD results proved that all prepared glass has amorphous nature. Moreover, it was found that the value of density, ρ, and refractive index,n, increase with increasing of Sm+ 3 content. Otherwise, the value of molar volume, optical energy gap, and boron-boron distance decrease by increasing sm+ 3 concentration. The structure of glasses studied was investigated by computing \(Internuclear \left({r}_{i}\right)\), Polaron radius \(\left({r}_{p}\right)\), field strength \(\left(F\right)\) and the deconvolution of FTIR spectra. Judd-Ofelt theory applied to clarify the structural changes and nature of the bonds of prepared glasses. Moreover, A spectroscopic quality factor, the branching ratio (βr), and lifetime (τ) are calculated via the parameters of Judd-Ofelt. The color chromaticity of the present glasses evidenced that the emission was in the white-reddish orange region under 402nm excitation depended on the concentration of Sm3+ ions incorporated into the host glasses. From photoluminescence emission, stimulated emission cross-section, and CIE chromaticity leads to these glasses are promising for light-emitting diode (LED) as; laser material in a wide range.

High Power Diode-Pumped Erbium Laser Emitting at Near 1.5 μm

Solid-state lasers emitting in the 1.5–1.6 μm spectral range are very promising for eye-safe laser range finding, ophthalmology, fiber-optic communication systems, and optical location. The aim of this work is the investigation of spectrosposcopic and laser properties of gain medium based on borate crystal for abovementioned lasers.Spectroscopic and laser properties of Er,Yb:YAl3(BO3)4 crystals with different concentrations of dopants were investigated. Polarized absorption and emission cross-section spectra were determined. The ytterbium- erbium energy transfer efficiency was estimated. The maximal energy transfer efficiency up to 97 % was obtained for Er(4 at.%),Yb(11 at.%):YAl3(BO3)4 crystal.The laser operation of heavily doped crystals with erbium concentration up to 4 аt.% (2.2^1020 cm^3) was realized. By using of Er(2 at.%),Yb(11 at.%):YAl3(BO3)4 crystal a maximal continuous- wave (CW) output power of 1.6 W was obtained at 1522 nm with slope efficiency of 32 %. By using of Er(4 at.%),Yb(11 at.%):YAl3(BO3)4 crystal a maximal peak output power up to 2.2 W with slope efficiency of 40 % was realized in quasi-continuous-wave regime of operation. The spatial profile of the output beam was close to TEM00 mode with M2 < 1.2 during all laser experiments.Based on the obtained results, it can be concluded that Er,Yb:YAl3(BO3)4 crystals are promising active media for lasers emitting in the spectral range of 1.5-1.6 pm for the usage in laser rangefinder and laser- induced breakdown spectroscopy systems, and LIDARs.

An incandescent metasurface for quasimonochromatic polarized mid-wave infrared emission modulated beyond 10 MHz

Incandescent sources such as hot membranes and globars are widely used for mid-infrared spectroscopic applications. The emission properties of these sources can be tailored by means of resonant metasurfaces: control of the spectrum, polarization, and directivity have been reported. For detection or communication applications, fast temperature modulation is desirable but is still a challenge due to thermal inertia. Reducing thermal inertia can be achieved using nanoscale structures at the expense of a low absorption and emission cross-section. Here, we introduce a metasurface that combines nanoscale heaters to ensure fast thermal response and nanophotonic resonances to provide large monochromatic and polarized emissivity. The metasurface is based on platinum and silicon nitride and can sustain high temperatures. We report a peak emissivity of 0.8 and an operation up to 20 MHz, six orders of magnitude faster than commercially available hot membranes.

2.0 μm Ultra Broadband Emission from Tm3+/Ho3+ Co-Doped Gallium Tellurite Glasses for Broadband Light Sources and Tunable Fiber Lasers

A flat 2.0 μm ultra broadband emission with a full width at half maximum (FWHM) of 329 nm is achieved in 1 mol.% Tm2O3 and 0.05 mol.% Ho2O3 co-doped gallium tellurite glasses upon the excitation of an 808 nm laser diode. The influence of Tm3+ and Ho3+ contents on 2.0 μm spectroscopic properties of gallium tellurite glasses is minutely investigated by absorption spectra, emission spectra, and lifetime measurement. In addition, emission cross section and gain coefficient of Ho3+ ions at 2.0 μm are calculated, and the maximum values reach 8.2 × 10−21 cm2 and 1.54 cm−1, respectively. Moreover, forward and backward energy transfer probability between Tm3+ and Ho3+ ions are qualitatively evaluated by the extended spectral overlap method. Large ratio of the forward energy transfer from Tm3+ to Ho3+ to the backward one (19.7) and high forward energy transfer coefficient (6.22 × 1039 cm6/s) are responsible for effective 2.0 μm emission from Ho3+ ions. These results manifest that Tm3+/Ho3+ co-doped gallium tellurite glass is suitable for potential applications of broadband light sources and tunable fiber lasers operating in eye-safe 2.0 µm spectral region.

Temperature-Dependent Stimulated Emission Cross-Section in Nd3+:YLF Crystal

Spectroscopic properties of neodymium-doped yttrium lithium fluoride were measured at different temperatures from 35 K to 350 K in specimens with 1 at% Nd3+ concentration. The absorption spectrum was measured at room temperature from 400 to 900 nm. The decay dynamics of the 4F3/2 multiplet was investigated by measuring the fluorescence lifetime as a function of the sample temperature, and the radiative decay time was derived by extrapolation to 0 K. The stimulated-emission cross-sections of the transitions from the 4F3/2 to the 4I9/2, 4I11/2, and 4I13/2 levels were obtained from the fluorescence spectrum measured at different temperatures, using the Aull–Jenssen technique. The results show consistency with most results previously published at room temperature, extending them over a broader range of temperatures. A semi-empirical formula for the magnitude of the stimulated-emission cross-section as a function of temperature in the 250 K to 350 K temperature range, is presented for the most intense transitions to the 4I11/2 and 4I13/2 levels.

Effect of BaF2 Variation on Spectroscopic Properties of Tm3+ Doped Gallium Tellurite Glasses for Efficient 2.0 μm Laser

The effects of substitution of BaF2 for BaO on physical properties and 1. 8 μm emission have been systematically investigated to improve spectroscopic properties in Tm3+ doped gallium tellurite glasses for efficient 2.0 μm fiber laser. It is found that refractive index and density gradually decrease with increasing BaF2 content from 0 to 9 mol.%, due to the generation of more non-bridging oxygens. Furthermore, OH− absorption coefficient (αOH) reduces monotonically from 3.4 to 2.2 cm−1 and thus emission intensity near 1.8 μm in gallium tellurite glass with 9 mol.% BaF2 is 1.6 times as large as that without BaF2 while the lifetime becomes 1.7 times as long as the one without BaF2. Relative energy transfer mechanism is proposed. The maximum emission cross section and gain coefficient at around 1.8 μm of gallium tellurite glass containing 9 mol.% BaF2 are 8.8 × 10−21 cm2 and 3.3 cm−1, respectively. These results indicate that Tm3+ doped gallium tellurite glasses containing BaF2 appear to be an excellent host material for efficient 2.0 μm fiber laser development.

Fabrication, microstructures, and optical properties of Yb:Lu2O3 laser ceramics from co-precipitated nano-powders

The Yb:Lu2O3 precursor made up of spherical particles was synthesized through the co-precipitation method in the water/ethanol solvent. The 5 at% Yb:Lu2O3 powder is in the cubic phase after calcination at 1100 °C for 4 h. The powder also consists of spherical nanoparticles with the average particle and grain sizes of 96 and 49 nm, respectively. The average grain size of the pre-sintered ceramic sample is 526 nm and that of the sample by hot isostatic pressing grows to 612 nm. The 1.0 mm-thick sample has an in-line transmittance of 81.6% (theoretical value of 82.2%) at 1100 nm. The largest absorption cross-section at 976 nm is 0.96×10−20 cm2 with the emission cross-section at 1033 nm of 0.92×10−20 cm2 and the gain cross sections are calculated with the smallest population inversion parameter β of 0.059. The highest slope efficiency of 68.7% with the optical efficiency of 65.1% is obtained at 1033.3 nm in quasi-continuous wave (QCW) pumping. In the case of continuous wave (CW) pumping, the highest slope efficiency is 61.0% with the optical efficiency of 54.1%. The obtained laser performance indicates that Yb:Lu2O3 ceramics have excellent resistance to thermal load stresses, which shows great potential in high-power solid-state laser applications.

Emission cross sections for energetic O+(4S,2D,2P)–N2 collisions

Measurements of emission cross sections for the [Formula: see text] collision system with the incident beam of 1–10 keV [Formula: see text] in the ground [Formula: see text]) and metastable [Formula: see text] and [Formula: see text] states are reported. The emission cross section induced by incident ions in the metastable state [Formula: see text] is much larger than that for the ground [Formula: see text] state. The emission cross section of [Formula: see text] ion for [Formula: see text], [Formula: see text], and [Formula: see text] bands system is measured and the ratio of intensities for these bands is established as [Formula: see text] It is shown that the cross sections for the [Formula: see text] ions emissions in the dissociative charge exchange processes increase with the increase of the incident ion energy. The energy dependence of the emission cross section of the band [Formula: see text] [Formula: see text] nm of the first-negative band system of the [Formula: see text] and degree of linear polarization of emission in [Formula: see text] collision are measured for the first time. An influence of an admixture of the ion metastable state on a degree of linear polarization is revealed. The mechanism of the processes realized during collisions of ground and metastable oxygen ions on molecular nitrogen have been established. It is demonstrated that for [Formula: see text] collision system the degree of linear polarization by metastable [Formula: see text] ions is less compared to those that are in the ground [Formula: see text] state and the sign of emission of degree of linear polarization of excited molecular ions does not change.