Doped Yttrium Aluminum Borate Research Articles

Determination of the microstructure, energy levels and magnetic dipole transition mechanism for Tm3+doped yttrium aluminum borate

Yttrium aluminum borate (YAB) doped with rare-earth ions are promising materials for infrared lasers and self-frequency summing laser systems.

Optical temperature sensing using a new thermographic phosphor

The luminescence emission of a new thermographic phosphor based on Chromium(III)-doped yttrium aluminum borate (Cr3+:YAB) has a strong temperature dependence, which makes this material well suited for temperature sensing. In this work the luminescence emission decay was investigated in great detail in a broad temperature range, both in time and frequency domain. The results obtained with these two measuring techniques, which are consistent, are used to determine the optimal design parameters for sensor development. The high sensitivity which is thus achievable, together with the high stability of the material, demonstrate that this phosphor is very suitable for the design of a sensitive, low-cost, and robust contactless temperature sensor. Due to the insensitivity of the sensing properties to the immobilization matrix, this material can be easily incorporated in the most appropriate matrix depending on the application.

Fluorescence properties of Sm3+ ions in yttrium aluminum borate phosphors for optical applications

Different concentrations of Sm3+-doped yttrium aluminum borate (YAl3(BO3)4) phosphors were prepared by solid-state reaction method. The phase analysis has been carried out by X-ray diffraction studies. Fluorescence properties were investigated through emission, excitation and decay measurements. Upon 404nm excitation, YAl3(BO3)4:Sm3+ phosphors exhibit their characteristic emission lines at 564nm (4G5/2→6H5/2), 600nm (4G5/2→6H7/2), 646nm (4G5/2→6H9/2) and 707nm (4G5/2→6H11/2). Both emission and excitation spectra show a luminescence quenching beyond 0.01mole concentration of Sm3+ ions due to the energy transfer among the excited Sm3+ ions at higher concentrations. The YAl3(BO3)4:0.01Sm3+ phosphor can be used as a promising material producing intense orange-red emission for various optical applications.

Synthesis and photoluminescence studies on YAl3(BO3)4:Tb3+phosphor

Terbium (Tb 3+ ) doped yttrium aluminium borate phosphors (YAl 3 (BO 3 ) 4 ) with different compositions such as YAl 3 (BO 3 ) 4 :Tb 3+ , Y 1− x Al 3 (BO 3 ) 4 :Tb x 3+ and YAl (3− x ) (BO 3 ) 4 :Tb x 3+ ( x = 1−8 mol.%) were synthesized using modified solid state reaction technique. The synthesized phosphor was studied using powder X-ray diffraction analysis (XRD), photoluminescence spectroscopy (PL), high resolution-scanning electron microscope (HR-SEM). Lattice parameters are calculated for the Tb 3+ doped and substituted YAB phosphors using XRD analysis. The phosphor exhibits green emission at 572 nm with 375 nm of excitation. It is found that the Tb 3+ ions substitution in the sites Y 3+ and Al 3+ ions in Y 1– x Al 3 (BO 3 ) 4 :Tb x 3+ and YAl (3– x ) (BO 3 ) 4 :Tb x 3+ leads to overlapping of energy levels which affects the PL intensity of the phosphor significantly. Thus, phosphor synthesized with the composition YAl 3 (BO 3 ) 4 :Tb 3+ , acquires higher photoluminescence (PL) intensity when compared to Y 1– x Al 3 (BO 3 ) 4 :Tb x 3+ and YAl (3– x ) (BO 3 ) 4 :Tb x 3+ phosphors. Temperature dependent PL property (thermal quenching studies) of YAl 3 (BO 3 ) 4 :Tb 3+ was also performed up to 250 °C. Further, it is found that the PL intensity of the studied phosphor is comparable with commercial green phosphor. HR-SEM analysis demonstrates that the phosphors are grown as nanorods with an average diameter of 50–80 nm and length 250–500 nm.

Role of monovalent co-dopants on the PL emission properties of YAl3(BO3)4:Ce3+ phosphor

The cerium (Ce3+) doped yttrium aluminium borate (YAB) phosphor was synthesized by modified solid state reaction. The phosphor's phase purity and its emission properties were studied using powder X-ray diffraction pattern and photoluminescence spectroscopy. The synthesized YAB had rhomobohedral crystal structure. The phosphor had two different excitation and emission spectra. By 325 nm excitation, the phosphor had emission at 373 nm and with 363 nm excitation; the phosphor gave violet-blue emission at 418 nm. The UV emission of the phosphor originated due to Ce3+ ions at the yttrium site and violet-blue emission owing to Ce3+ ions at non-regular sites viz., Al3+ and interstitial sites. The emission intensity of the phosphor was enhanced when monovalent ions (K+, Na+, and F−) were added as co-dopants. The crucial role of ionic radii of monovalent co-dopants on the emission enhancement of the YAB:Ce3+ phosphor was reported. Thermogravimetric study showed that the YAB possessed high thermal stability at up to 900 °C.

Self-frequency-doubling of ultrafast laser inscribed neodymium doped yttrium aluminum borate waveguides

Buried channel optical waveguides, supporting orthogonal polarizations, have been fabricated in a neodymium doped yttrium aluminum borate nonlinear laser crystal by ultrafast laser inscription following the so-called “double line” approach. Confocal fluorescence and second harmonic imaging experiments have revealed that the original fluorescence and nonlinear properties have been not deteriorated by the waveguide inscription procedure. Preliminary laser experiments have shown the ability of the fabricated structures for green laser light generation under 808 nm optical pumping by self-frequency-doubling of the 1.06 μm laser line of neodymium ions.

Preparation and Characterization of Chromium(III)-Activated Yttrium Aluminum Borate: A New Thermographic Phosphor for Optical Sensing and Imaging at Ambient Temperatures.

A new thermographic phosphor based on chromium(III)-doped yttrium aluminum borate (YAB) is obtained as single crystals by high temperature flux growth and as a microcrystalline powder via solution combustion synthesis. The phosphor is excitable both in the blue (λmax 422 nm) and in the red part of the spectrum (λmax 600 nm) and shows bright NIR emission. The brightness of the phosphor is comparable to that of a well-known lamp phosphor Mn(IV)-doped magnesium fluorogermanate. At ambient temperatures, the Cr(III)-doped YAB shows high temperature dependence of the luminescence decay time, which approaches 1% per deg. The material shows no decrease in luminescence intensity at higher temperatures. The new phosphor is particularly promising for applications in temperature-compensated optical chemosensors (including those based on NIR-emitting indicators) and in pressure-sensitive paints.

Red light-excitable dual lifetime referenced optical pH sensors with intrinsic temperature compensation

Red light-excitable pH sensing materials are manufactured which rely on the use of a fluorescent seminaphthorhodafluor indicator and a luminescent inorganic phosphor as a reference. The phosphors, chromium(III)-activated lanthanide aluminium borates, benefit from chemical and photochemical robustness and are not affected by oxygen. Particularly, a dual lifetime referenced sensing material relies on Cr(III)-activated gadolinium aluminium borate which has low temperature dependence of the decay time. The second material is based on highly temperature-sensitive Cr(III)-doped yttrium aluminium borate and enables dual sensing of pH and temperature. Here, the phosphor simultaneously acts as a temperature probe and as a reference for the pH indicator. The adverse effects of temperature on the properties of the pH indicator are compensated for. The dynamic range of the sensors is optimized by varying the ratio of the components which makes the materials suitable for physiological measurements and for marine applications. The rather poor chemical and photochemical stability of the pH indicator at room temperature should be considered if prolonged measurements are performed.

19.4: Luminescence Characteristics of YAl3B4O12: Tb3+ Phosphor for PDP Application

AbstractPhotoluminescence(PL) characteristics under vacuum ultraviolet(VUV) region of Tb3+ doped yttrium aluminium borate phosphor were investigated for Plasma Display panel(PDP) application. The single‐phase green emitting Y1−xTbxAl3B4O12(YAB: Tb3+) powder phosphors were prepared with various Tb3+ ion concentration. As a result, the intensity around 147nm of excitation spectrum in YAB: Tb3+ decrease slightly with increase of Tb3+ ion concentration due to concentration quenching behavior, but on the contrary, the intensity of 172nm increase with increase of Tb3+ ion concentration due to attributing the 4f8 → 4f7 5d1 transition of Tb3+ [1]. However in the result of gas discharge chamber test which has the same gas mixture as real PDP, relative PL luminance of YAB: Tb3+ increase with increase of Tb3+ ion concentration due to effect of increasing absorption at 172nm. Besides, YAB: Tb3+ with high Tb3+ ion concentration (x=0.7) has higher VUV luminance saturation property than low Tb3+ ion concentration (x=0.4) since high Tb3+ ion concentration phosphor has more activators than lower one which can react with VUV photon in unit volume.

Microscopic studies on imperfections in selected YAB single crystals

AbstractThe as‐grown surface and inner structures of undoped and Nd3+‐, Cr3+‐, V3+‐, Ce3+‐, Er3+ and Yb3+ – and (Er3+ + Yb3+) – doped yttrium aluminum borate (YAB) single crystals grown from (K2Mo3O10 + B2O3) flux by spontaneous crystallization or top seeded solution growth (TSSG) technique, were investigated using optical and scanning electron microscopic and analytic chemical methods. Fine and rough growth hillocks of dislocational origin, growth layers, traces of inner planar defects and foreign phase crystalline debris were found and analyzed on the as‐grown faces of crystals. Irregular grains and regular block structures and foreign phase inclusions were observed and studied in the interior of the crystals. The chemical compositions measured by energy dispersive X‐ray spectrometry on perfect and imperfect micro regions are compared with those obtained by flame atomic absorption spectrometry on bulk crystals. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

High resolution FT absorption study of holmium doped yttrium aluminum borate single crystals

AbstractHigh resolution FT spectroscopy has been applied to investigate a YAB: Ho3+ (1 mol%) single crystal, grown by the top‐seeded flux method, in the wave number 4000–25000 cm–1 and temperature 9–300 K ranges, respectively. The complex Ho3+ (4f10) non‐Kramers ion transitions from the ground 5I8 to the excited 5I7, 5I6, 5I5, 5I4, 5F5, 5S2, 5F4, 5F3, 5F2, 3K8, 5F1 + 5G6, and 5G5 manifolds were analyzed. The low‐temperature high resolution spectra of the investigated manifolds show for many electronic transitions hyperfine structures related to the Ho3+ nuclear magnetic moment. The experimental data are fitted by a single ion Hamiltonian and the crystal field parameters are obtained. The results are compared with those previously published for other rare earths in the same matrix. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Optical properties of Dy3+ doped yttrium–aluminium borate

A Dy3+ doped yttrium–aluminium borate (Dy:YAB) crystal has been optically characterized. Therefractive indices at seven different wavelengths, ranging from the visible to the nearinfrared (IR), have been measured and the Sellmeier curves have been calculated. Thepolarized optical absorption spectra have been obtained at room temperature, and theJudd–Ofelt parameters have been calculated. The lifetime of the upper laser level4F9/2 has beenestimated and compared with the experimental value. Evidence of high luminescence quantum efficiencyof the 4F9/2 state in YAB is provided by measured lifetimes.

Self-frequency-sum mixing in Nd doped nonlinear crystals for laser generation in the three fundamental colours: The NYAB case

When combined with a suitable nonlinear crystal host, several coincidences occurring in Nd 3+ ions allow for simultaneous generation of laser radiation in the three fundamental colours; red, green and blue (RGB) in the same solid state laser crystal. We show experimentally this possibility in neodymium doped yttrium aluminium borate (NYAB) Nd 3+:YAl 3(BO 3) 4, although the same achievement is very likely to be possible in other nonlinear crystals containing Nd 3+ laser active ions.

Xenon flash lamp pumped self-frequency doubling NYAB pulsed laser

Neodymium doped yttrium aluminum borate (NYAB) crystals with sizes up to 45mm have been grown successfully. NYAB rod of φ4 × 12mm was pumped by xenon flash lamp, and several mJ of 0.53μm green laser output was obtained. The oscillation threshold, the pulse duration, the laser beam polarization, and the laser beam divergence were measured to be 78mJ, 100ns, 90% and 2mrad, respectively.