Potassium Yttrium Fluoride Research Articles

Close look on cubic Tm:KY3F10 crystal for highly efficient lasing on the 3H4 → 3H5 transition.

We report on Czochralski growth, detailed ground- and excited-state absorption and emission spectroscopy and highly-efficient mid-infrared (∼2.3 µm) laser operation of a cubic potassium yttrium fluoride crystal, Tm:KY3F10. The peak stimulated-emission cross-section for the 3H4 → 3H5 transition is 0.34×10-20 cm2 at 2345 nm with an emission bandwidth exceeding 50 nm. The excited-state absorption spectra for the 3F4 → 3F2,3 and 3F4 → 3H4 transitions are measured and the cross-relaxation is quantified. A continuous-wave 5 at.% Tm:KY3F10 laser generated 0.84 W at 2331-2346 nm by pumping at 773 nm, with a record-high slope efficiency of 47.7% (versus the incident pump power) owing to the efficient action of energy-transfer upconversion leading to a pump quantum efficiency approaching 2. The first Tm:KY3F10 laser with ESA-assisted upconversion pumping (at 1048 nm) is also demonstrated. Due to its broadband emission properties, Tm:KY3F10 is promising for ultrashort pulse generation at ∼2.3-2.4 µm.

Fluorite-type Tm3+:KY3F10: A promising crystal for watt-level lasers at ∼1.9 μm

Tm3+-doped cubic potassium yttrium fluoride, KY3F10, is a promising laser crystal for efficient watt-level lasers at ∼1.9 μm because of the relatively easy crystal growth by the Czochralski method, advantageous thermo-optical properties, high available Tm3+ doping levels and very efficient cross-relaxation mechanism. A compact diode-pumped 8 at.% Tm3+:KY3F10 laser generated 1.85 W at 1891 nm with a slope efficiency of 65.2% and a laser threshold of 450 mW. A negative thermal lens was detected in this crystal owing to the negative dn/dT coefficient (−8.9 × 10−6 K−1). Passive Q-switching of the Tm3+:KY3F10 laser by single-walled carbon nanotube saturable absorber was demonstrated yielding 13.2 μJ/490 ns pulses at a repetition rate of 58 kHz.

Optically stimulated luminescence at room temperature of hydrothermal K2YF5:Pr3+ crystals

AbstractIn this paper optically stimulated luminescence (OSL) properties of Pr3+‐doped double potassium yttrium fluoride (K2YF5) under green light stimulation at room temperature as a function of the doping concentration are reported. Besides, some characteristics concerning the possible application of this composition as a new OSL dosimeter are presented, namely, the dose–response and fading of the OSL signal. The residual thermoluminescence (TL) response of K2YF5:Pr3+ after the OSL experiment has been investigated in order to establish whether the traps responsible for OSL are also involved in the TL process. Spectral analysis of the OSL emission has been carried out to determine the role played by Pr3+ ions in the radiative relaxation process. Finally, the total OSL output of K2YF5:Pr3+ is compared to that of commercial Al2O3:C.

Determination of the trapping parameters of thermoluminescent glow peaks of K 2YF 5:Ce by three points method

The three points analysis method was applied to determine the number of peaks and kinetic parameters. These are the order of kinetics b, the activation energy E (eV), the frequency factor S (s −1) or the pre-exponential factor S″ (s −1) and the relative value of the initial concentration of trapped electrons n 0 (cm −3) associated with the thermoluminescence (TL) glow peaks in double potassium yttrium fluoride (K 2YF 5) doped with cerium ions (Ce 3+) in response to β-irradiation. The three points analysis method indicated that the glow curve of this material is the superposition of five general-order components, which was referred to as P1–P5, in the temperature range between room temperature and 500 °C.

Investigation of the TL response of [formula omitted]: [formula omitted] crystals to X and gamma radiation fields

Double potassium yttrium fluoride crystals doped with optically active rare earth ions have been recently shown to be attractive thermoluminescence (TL) materials for ionizing radiation dosimetry. In this context appropriate studies have been performed to test TL response of K 2 YF 5 crystals doped with Dy 3 + ions to photon radiation fields. Within the framework of this research K 2 YF 5 crystals doped with 0.2, 1.0, 2.0, 5.0 and 10.0 at% Dy 3 + as well as K 2 DyF 5 and undoped K 2 YF 5 crystals have been synthesized under hydrothermal conditions. Polished crystal platelets with thickness of about 1 mm have been irradiated with X and gamma rays in order to study TL sensitivity as well as dose and energy response properties of these compositions in terms of the Dy 3 + concentration. Within this concentration series, K 2 YF 5 crystals doped with 1.0 at% Dy 3 + have been found to have maximum TL response due to a main dosimetric TL peak, which can be deconvoluted in three TL glow peaks centered at 96.4, 104.9 and 130.7 ∘ C , with reasonable linearity behavior over the studied dose range and good reproducibility of dose measurements. The sensitivity increase is observed for previously gamma-sensitized samples and this sensitization process seems also to induce the appearing of the TL glow peak at 130.7 ∘ C . As it has been turned, the linear TL signal coefficient for K 2 Y 0.99 Dy 0.01 F 5 is comparable to that of a CaSO 4 :Mn TL dosemeter, irradiated with a 137Cs gamma radiation source at the same conditions. Photon energy dependence of TL response for K 2 Y 0.99 Dy 0.01 F 5 has been evaluated and it has been found that TL response of this composition to the 41.1 keV X-rays is 30 times higher than that to the 662 keV gamma rays. This fact points out that K 2 YF 5 crystals doped with Dy 3 + have potential as promising materials to be used for low-dose dosimetry in X-rays diagnostic or industrial radiography.

Applications of the three points analysis method for obtaining the trap parameters and the separation of thermoluminescence glow curve into its components

Here, we apply a recently developed technique to separate a composite thermoluminescence (TL) glow curve into its individual components and to evaluate the trap parameters of the individual TL glow peaks. These parameters include the order of kinetics b, the activation energy E (eV) and the frequency factor S (s−1) or the pre-exponential factor S″ (s−1). Recently, a general equation was developed to estimate the order of kinetics b. The characteristic point of this equation is that any set of three data points in a TL glow curve can yield b. Using this characteristic, an improved procedure was suggested to separate a composite glow curve, which includes several overlapping peaks, into its individual components and to obtain the trap parameters of the individual glow peaks. The method was applied here to analyze and determine the trap parameters of the TL glow curve of the promising TL dosimetric material, double potassium yttrium fluoride (K2YF5) doped with praseodymium ions (Pr3+), in response to γ-irradiation.

Ionic transport and battery characterization studies of barium-doped potassium yttrium fluoride

Pure and barium fluoride doped potassium yttrium fluoride materials were synthesized using the solid state reaction method and were characterized by X-ray diffraction, transference number and transient ionic current measurements. In all the samples the conductivity was found to be mainly ionic while the electronic conductivity was found to be small. Solid state batteries were fabricated in the configuration K/electrolyte/( I 2 + C + electrolyte) with KYF 4 and KYF 4: BaF 2 as the solid electrolytes. Their discharge characteristics were studied for a load of 100 K Ω at 313 K. Open circuit voltage (OCV) and short circuit current (SCC) of the cells range from 2.38 to 2.82 V and 650 to 2340 μA, respectively. Various cell parameters were evaluated.

Multisite nature and efficient lasing at 1041 and 1302 nm in Nd3+ doped potassium yttrium fluoride

Lasing of Nd3+ ions in different crystallographic sites of KYF4 has been demonstrated to occur at different wavelengths. Low threshold, high efficiency lasing performance at 1041 and 1302 nm were achieved under selective pumping conditions. The stimulated emission cross section at 1041.2 nm was estimated to be 2.6×10−19 cm2 and the radiative lifetime was found to be 600 μs.

Thermally stimulated depolarization current studies in sodium- and barium-doped potassium yttrium fluoride

The results of thermally stimulated depolarization current (TSDC) and electrical conductivity studies of potassium yttrium fluoride (KYF4) compound doped with sodium and barium are presented. The TSDCs were measured as a function of the polarizing temperature and polarizing field strengths at a constant heating rate of 0.09 K s−1. The conductivity studies were carried out in the temperature range 370–835 K with different dopant concentrations. The variation of the conductivity with the doping concentration was found to be non-linear. The relaxation parameters and the activation energies were evaluated. The origin of the TSDC peak in KYF4:Na was attributed to space charge polarization. However, in the case of KYF4:Ba, in addition to space charge polarization, there is also a small contribution from the dipolar mechanism.

Complex admittance study of potassium yttrium fluoride

Abstract The complex admittance of pure and 0.5 mol% sodium doped potassium yttrium fluoride polycrystalline pellets, between two inert blocking electrodes, was studied from 300 to 950 K in the frequency range 50–100 kHz. In most cases the admittance plot exhibited a depressed circular arc in the low frequency region and a straight line in the high frequency region. The bulk conductivity σ, the dielectric constant e′ and the loss angle tan δ were determined from the admittance plots. The high values of e′ observed at high temperatures were attributed to space charge polarization effects. The a.c. conductivity was found to increase with increasing frequency.

Electrical conduction of potassium yttrium fluoride thin films

Electrical conduction of potassium yttrium fluoride thin films

Thermally stimulated discharge currents in potassium yttrium fluoride

Thermally stimulated discharge currents of potassium yttrium fluoride pellets have been studied as a function of polarizing temperature and polarizing field strength at a constant heating rate of 0.09 K s −1. The activation energies, relaxation parameters and charge were evaluated. The origin of the thermally stimulated discharge current (TSDC) peak was attributed to the space charge process.

Ionic conductivity of doped potassium yttrium fluoride

Crystal Research and TechnologyVolume 25, Issue 11 p. K278-K282 Short Note Ionic conductivity of doped potassium yttrium fluoride Md. Shareefuddin, Md. Shareefuddin Department of Physics, Osmania University, Hyderabad - 500 007, IndiaSearch for more papers by this authorU. V. Subba Rao, U. V. Subba Rao Department of Physics, Osmania University, Hyderabad - 500 007, IndiaSearch for more papers by this authorK. Narasimha Reddy, K. Narasimha Reddy Department of Physics, Osmania University, Hyderabad - 500 007, IndiaSearch for more papers by this authorDr. M. Narasimha Chary, Dr. M. Narasimha Chary Department of Physics, Osmania University, Hyderabad - 500 007, IndiaSearch for more papers by this author Md. Shareefuddin, Md. Shareefuddin Department of Physics, Osmania University, Hyderabad - 500 007, IndiaSearch for more papers by this authorU. V. Subba Rao, U. V. Subba Rao Department of Physics, Osmania University, Hyderabad - 500 007, IndiaSearch for more papers by this authorK. Narasimha Reddy, K. Narasimha Reddy Department of Physics, Osmania University, Hyderabad - 500 007, IndiaSearch for more papers by this authorDr. M. Narasimha Chary, Dr. M. Narasimha Chary Department of Physics, Osmania University, Hyderabad - 500 007, IndiaSearch for more papers by this author First published: November 1990 https://doi.org/10.1002/crat.2170251131Citations: 6AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume25, Issue11November 1990Pages K278-K282 RelatedInformation