Spectroscopic Properties of Yb³⁺-Doped Silicate Glasses

Linganna, Kadathala,Ju, Seongmin,Kim, Bokhyeon,Han, Won-Taek,Venkatramu, Vemula,Jayasankar, Chalicheemalapalli Kulala De Gruyter 2018 Zeitschrift für physikalische Chemie Vol.232 No.1

<P><B>Abstract</B></P><P>Yb<SUP>3+</SUP>-doped silicate glasses (SiO<SUB>2</SUB>–Nb<SUB>2</SUB>O<SUB>5</SUB>–K<SUB>2</SUB>O–ZnF<SUB>2</SUB>) were prepared by a conventional melt quenching technique and their spectroscopic properties were investigated. The emission cross-section was found to be 0.53×10<SUP>−20</SUP>cm<SUP>2</SUP>at 1006 nm from the reciprocity method described by McCumber from the measured absorption spectrum of 1.0 mol% Yb<SUB>2</SUB>O<SUB>3</SUB>-doped glass. The lifetime (<I>τ</I><SUB>exp</SUB>) and figure of merit (<I>σ<SUB>em</SUB></I>×<I>τ</I><SUB>exp</SUB>) for the<SUP>2</SUP>F<SUB>5/2</SUB>→<SUP>2</SUP>F<SUB>7/2</SUB>transition of 1.0 mol% Yb<SUB>2</SUB>O<SUB>3</SUB>-doped silicate glass, were evaluated to be 0.50 ms and 0.26 cm<SUP>2</SUP>ms, respectively. The other spectroscopic parameters,<I>β</I><SUB>min</SUB>,<I>I</I><SUB>sat</SUB>and<I>I</I><SUB>min</SUB>were found to be 0.17, 29.00 kW/cm<SUP>2</SUP>and 4.90 kW/cm<SUP>2</SUP>, respectively. The results indicate that the present Yb<SUP>3+</SUP>-doped silicate glasses could be useful as laser gain media at 1006 nm.</P>

Optical Absorption and EPR Studies on Gamma-Ray Irradiated RE3+-Doped Fluorophosphate Glasses

Linganna, K.,Ju, S.,Basavapoornima, Ch.,Jayasankar, C. K.,Venkatramu, V.,Kim, C. J.,Han, W.-T. Springer-Verlag 2018 Journal of inorganic and organometallic polymers a Vol.28 No.3

Spectroscopic properties of Er³⁺/Yb³⁺ co-doped fluorophosphate glasses for NIR luminescence and optical temperature sensor applications

Linganna, K.,Agawane, G.L.,In, Jung-Hwan,Park, June,Choi, Ju H. Elsevier 2018 Journal of industrial and engineering chemistry Vol.67 No.-

<P><B>Abstract</B></P> <P>A series of Er<SUP>3+</SUP>/Yb<SUP>3+</SUP> co-doped fluorophosphate glasses with varying YbF<SUB>3</SUB> concentration were prepared by a high temperature melt quenching technique. Absorption and emission cross-sections were determined by using the McCumber theory. The larger emission cross-section (9.86×10<SUP>−21</SUP> cm<SUP>2</SUP>) and longer fluorescence lifetime (12.37ms) were obtained for the <SUP>4</SUP>I<SUB>13/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB> transition of ABS3Er4Yb glass. The sensitivity and temperature of the maximum sensitivity were evaluated by the fluorescence intensity ratio method from the measured upconversion spectra. The results were discussed and compared to the other reported glasses.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Er<SUP>3+</SUP>/Yb<SUP>3+</SUP> co-doped fluorophosphate glasses were prepared and characterized. </LI> <LI> Judd–Ofelt intensity parameters and radiative properties were evaluated from the measured absorption spectra. </LI> <LI> The strong NIR emission observed at 1540nm and its spectroscopic were investigated. </LI> <LI> Temperature dependence upconversion studies were carried out for the thermal sensing behavior of the glasses. </LI> <LI> The sensitivity and temperature of the maximum sensitivity were evaluated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Longer lifetime of Er³⁺/Yb³⁺ co-doped fluorophosphate glasses for optical amplifier applications

Linganna, K.,Agawane, G.L.,Choi, Ju H. Elsevier 2017 Journal of non-crystalline solids Vol.471 No.-

<P><B>Abstract</B></P> <P>Er<SUP>3+</SUP>/Yb<SUP>3+</SUP> co-doped fluorophosphate glasses with the molar composition of Mg(PO<SUB>3</SUB>)<SUB>2</SUB>-(50-x)BaF<SUB>2</SUB>-CaF<SUB>2</SUB>:3ErF<SUB>3</SUB>/xYbF<SUB>3</SUB>, where x=3, 4, 5, 6, 7, 8 and 9mol%, were prepared by a conventional melt quenching technique and studied their spectroscopic properties for fiber amplifier applications. The strong emission band at 1.53μm corresponding to <SUP>4</SUP>I<SUB>13/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB> transition of Er<SUP>3+</SUP> ion was observed for all the studied glasses and found the optimized Er/Yb concentration of 3:4. The emission cross-section of 1.53μm emission band was calculated to be of the order of 2.60×10<SUP>−20</SUP> cm<SUP>2</SUP> by using the McCumber theory. The effective bandwidth was found to be of the order of 84 nm. To the best of our knowledge, for the first time, longer excited state lifetime (t=~15ms) for the <SUP>4</SUP>I<SUB>13/2</SUB> level of Er<SUP>3+</SUP> ion was noticed for the optimized Er<SUP>3+</SUP>/Yb<SUP>3+</SUP> co-doped fluorophosphate glasses. Those results were compared to the other host matrices and found that the investigated fluorophosphate glasses are promising and attractive as gain media for laser and fiber amplifier applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We successfully prepared and characterized Er/Yb co-doped fluorophosphate glasses. </LI> <LI> The spectroscopic properties were evaluated for the prepared glasses. </LI> <LI> The effective bandwidth for the <SUP>4</SUP>I<SUB>13/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB> transition was found to be ~84nm. </LI> <LI> The emission cross-section was found to be 2.58×10<SUP>−20</SUP> cm<SUP>2</SUP> (Er:Yb=3:4). </LI> <LI> The longer lifetime for <SUP>4</SUP>I<SUB>13/2</SUB> level was found to be 16.58ms (Er:Yb=3:4). </LI> </UL> </P>

1.53 μm luminescence properties of Er³⁺-doped K-Sr-Al phosphate glasses

Linganna, K.,Rathaiah, M.,Vijaya, N.,Basavapoornima, Ch.,Jayasankar, C.K.,Ju, S.,Han, W.T.,Venkatramu, V. Ceramurgica ; Elsevier Science Ltd 2015 CERAMICS INTERNATIONAL Vol.41 No.4

<P>Trivalent erbium (Er3+)-doped K-Sr-Al phosphate glasses were prepared and studied their spectroscopic properties as a function of Er2O3 concentration. Judd-Ofelt analysis has been carried out for 1.0 mol% Er2O3-doped phosphate glass and in turn radiative properties have been evaluated for the excited levels of Er3+ ion. The radiative lifetime for the (4)t(13/2) level was found to be higher for the present glass when compared to other Er3+-doped glasses. The Er3+-doped glasses exhibit intense near infrared emission at 1.53 mu m corresponds to I-4(13/2)-> I-4(15/2) transition as well as green emission at 546 nm corresponding to S-4(3/2)-> I-4(15/2) under 980 nm and 488 nm excitations, respectively. The emission cross-section spectrum for 1.0 mol% of Er2O3-doped glass has been evaluated using McCumber theory. The gain cross-section has been evaluated as a function of population inversion, which revealed that the lasing action would be achieved at 1.53 mu m for a population inversion about 40%. Decay curves for the I-4(13/2) level were measured and lifetimes have been determined for the studied glasses. The results indicate that the present glasses could be useful for laser as well as optical amplifiers at 1.53 mu m. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.</P>

Spectroscopic properties of Er3+/Yb3+ co-doped fluorophosphate glasses for NIR luminescence and optical temperature sensor applications

K. Linganna,G.L. Agawane,인정환,박준,최주현 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.67 No.-

A series of Er3+/Yb3+ co-doped fluorophosphate glasses with varying YbF3 concentration were prepared by a high temperature melt quenching technique. Absorption and emission cross-sections were determined by using the McCumber theory. The larger emission cross-section (9.86 × 10−21 cm2) and longer fluorescence lifetime (12.37 ms) were obtained for the 4I13/2 → 4I15/2 transition of ABS3Er4Yb glass. The sensitivity and temperature of the maximum sensitivity were evaluated by the fluorescence intensity ratio method from the measured upconversion spectra. The results were discussed and compared to the other reported glasses.

UV Photoluminescence of Alumino-Germano-Silicate Glass Optical Fiber Incorporated with Gd₂O₃ Nano-Particles Upon Illumination of Xenon-Lamp

Ju, Seongmin,Linganna, Kadathala,Kim, Bok Hyeon,Boo, Seongjae,An, Yong Ho,Han, Won-Taek American Scientific Publishers 2018 Journal of Nanoscience and Nanotechnology Vol.18 No.3

<P>Alumino-germano-silicate glass optical fiber incorporated with Gd2O3 nano-particles (NPs) was developed by using the modified chemical vapor deposition and the drawing process. The formation of spherical Gd2O3 NPs in the fiber core with average diameter of 10.8 nm was confirmed by the TEM. The distinct absorption peaks in the fiber preform appearing in the UV region at 205, 247, 253, 274, and 312 nm were due to the incorporated Gd2O3 NPs via reorganization of the seven 4f electrons into various multiplets of Gd ions. In the case of the optical fiber obtained by drawing of the preform at high temperature about 2150 degrees C, absorption peaks due to Gd2O3 NPs were found to appear at 383 and 455 nm, which were red-shifted from 274 and 312 nm of the preform, respectively, and it may be due to increase in the size of Gd2O3 NPs after the drawing process. To investigate the photoluminescence (PL) property for UV sensor applications, the PL of the fiber was obtained by illumination of the Xenon-lamp. A PL band appeared in the wavelength band from 370 nm to 450 nm, centering at about 400 nm, which can be attributed to the presence of Gd2O3 NPs embedded in the fiber core. It was also found that the PL intensity at 400 nm showed linear dependence with the excitation power from 0 to 400 W.</P>

Spectroscopic and pump power dependent upconversion studies of Er³⁺-doped lead phosphate glasses for photonic applications

Basavapoornima, Ch.,Linganna, K.,Kesavulu, C.R.,Ju, S.,Kim, B.H.,Han, W.-T.,Jayasankar, C.K. Elsevier 2017 Journal of alloys and compounds Vol.699 No.-

<P><B>Abstract</B></P> <P>Er<SUP>3+</SUP>-doped lead phosphate glasses (PKAPbNEr) were prepared by a melt quenching technique and their spectroscopic properties were investigated for 1.54 μm fiber amplifier applications. Judd-Ofelt (JO) analysis was carried out from the absorption spectra of 1.0 mol% Er<SUB>2</SUB>O<SUB>3</SUB>-doped glass and the derived JO parameters were found to be Ω<SUB>2</SUB> = 4.7, Ω<SUB>4</SUB> = 0.7 and Ω<SUB>6</SUB> = 1.2 (×10<SUP>−20</SUP> cm<SUP>2</SUP>). The transition probabilities, branching ratios and radiative lifetimes for several excited states of Er<SUP>3+</SUP> were predicted using JO parameters and refractive index. The stimulated emission-cross section of the green emission (<SUP>4</SUP>S<SUB>3/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB>) has been determined to be 3.31 × 10<SUP>−21</SUP> cm<SUP>2</SUP>. Absorption cross-section (σ<SUB>abs</SUB>(λ)), emission cross-section (σ<SUB>emi</SUB>(λ)) and gain bandwidth (FWHM × σ<SUB>emi</SUB>(λ)) of <SUP>4</SUP>I<SUB>13/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB> transition at 1.54 μm were deduced from the McCumber theory and found to be 4.97 × 10<SUP>−21</SUP>, 6.63 × 10<SUP>−21</SUP> and 267 × 10<SUP>−28</SUP> (cm<SUP>2</SUP>), respectively. The decay curves exhibit single exponential nature and the lifetimes were determined to be 4.50, 4.57, 2.61, 2.06, 1.48 and 1.04 ms for 0.05, 0.1, 0.5, 1.0, 2.0 and 4.0 mol %, respectively, for Er<SUB>2</SUB>O<SUB>3</SUB>-doped lead phosphate glasses. The results confirm that the present Er<SUP>3+</SUP>-doped lead phosphate glasses could be considered as promising candidates as gain media for photonic applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spectroscopic properties of Er<SUP>3+</SUP>-doped lead phosphate glasses were studied. </LI> <LI> Efficient upconversion luminescence was observed under 980 nm excitation. </LI> <LI> The emission cross-section for the <SUP>4</SUP>S<SUB>3/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB> level is 3.31 × 10<SUP>−21</SUP> cm<SUP>2</SUP>. </LI> <LI> The lifetimes for <SUP>2</SUP>H<SUB>11/2</SUB>, <SUP>4</SUP>S<SUB>3/2</SUB> and <SUP>4</SUP>F<SUB>9/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB> levels were found to be similar. </LI> <LI> The results confirm that these glasses are suitable for photonic applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Structural and spectroscopic properties of γ-ray irradiated Er³⁺-doped lead phosphate glasses

Maheswari, T.,Basavapoornima, Ch.,Linganna, K.,Ju, S.,Han, W.-T.,Jayasankar, C.K. Elsevier 2018 Journal of luminescence Vol.203 No.-

<P><B>Abstract</B></P> <P>Structural and spectroscopic properties of varying concentrations of Er<SUP>3+</SUP> ion in P<SUB>2</SUB>O<SUB>5</SUB>- PbO-K<SUB>2</SUB>O-Al<SUB>2</SUB>O<SUB>3</SUB>-Na<SUB>2</SUB>O (PPbKANEr) glasses were studied before and after consecutive γ-ray irradiation. FTIR spectra of all the contemplated glasses confirm the presence of characteristic vibrational bands mainly because of phosphate groups. The optical absorption spectra of Er<SUB>2</SUB>O<SUB>3</SUB>-doped glasses are more stable and do not exhibit any variations after γ-ray irradiation particularly when Er<SUP>3+</SUP> ions are present in higher concentrations. Judd-Ofelt (JO) analysis was carried out for γ-ray irradiated glasses and the resultant three phenomenological intensity parameters were found to be Ω<SUB>2</SUB> = 1.98, Ω<SUB>4</SUB> = 0.78 and Ω<SUB>6</SUB> = 1.24 (×10<SUP>–20</SUP> cm<SUP>2</SUP>). A bright emission corresponding to <SUP>4</SUP>S<SUB>3/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB> transition in the green region was observed with the excitation of 379 nm. Broad luminescence peak at 1535 nm (<SUP>4</SUP>I<SUB>13/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB>) are observed in the region of 1400–1700 nm with the excitation of 980 nm. The important spectroscopic properties such as absorption (σ<SUB>abs</SUB>(λ)) and emission cross-sections (σ<SUB>emi</SUB>(λ)), gain band width (FWHM × σ<SUB>emi</SUB>(λ)) for <SUP>4</SUP>I<SUB>13/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB> transition at 1.53 µm were assessed for γ-ray irradiated PPbKANEr1.0 glass and the values found to be 6.73 × 10<SUP>–21</SUP> cm<SUP>2</SUP>, 7.33 × 10<SUP>–21</SUP> cm<SUP>2</SUP> and 264 × 10<SUP>–28</SUP> (cm<SUP>3</SUP>), respectively. The decay curves for the <SUP>4</SUP>I<SUB>13/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB> transition of the γ-ray irradiated PPbKANEr glasses exhibit exponential nature and the lifetimes found to be decreased (3.72–0.62 ms) with the increasing Er<SUB>2</SUB>O<SUB>3</SUB> concentration (0.05–4.0 mol%). The upconversion luminescence spectra exhibit two emissions at 525 nm (<SUP>2</SUP>H<SUB>11/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB>) and 543 nm (<SUP>4</SUP>S<SUB>3/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB>) in the green region along with a fairly feeble red emission at around 650 nm (<SUP>4</SUP>F<SUB>9/2</SUB> → <SUP>4</SUP>I<SUB>15/2</SUB>).</P> <P><B>Graphical abstract</B></P> <P>Comparison of the fluorescence decay of the <SUP>4</SUP>S<SUB>3/2</SUB> level for γ-ray irradiated leadphosphate glass doped with 1.0 mol% of Er<SUB>2</SUB>O<SUB>3</SUB>.</P> <P>[DISPLAY OMISSION]</P>

Thermo-mechanical studies on Er³⁺-doped fluorophosphate glasses for near infrared lasers

Agawane, G.L.,Linganna, K.,In, Jung-Hwan,Park, June,Choi, Ju H. Elsevier 2017 Ceramics international Vol.43 No.14

<P><B>Abstract</B></P> <P>Thermal, mechanical and thermo-mechanical properties of Mg(PO<SUB>3</SUB>)<SUB>2</SUB>-BaF<SUB>2</SUB>-CaF<SUB>2</SUB>-ErF<SUB>3</SUB> fluorophosphate (FP) glasses with varying Mg(PO<SUB>3</SUB>)<SUB>2</SUB> and ErF<SUB>3</SUB> molar ratios have been investigated. The simultaneous thermal analysis revealed that the <I>T</I> <SUB>g</SUB>, <I>T</I> <SUB>x</SUB>, <I>T</I> <SUB>p</SUB> and Δ<I>T</I> increased constantly with increasing Mg(PO<SUB>3</SUB>)<SUB>2</SUB> and ErF<SUB>3</SUB> content and that favorable large values of Δ<I>T</I> (>100°C) were obtained at higher Mg(PO<SUB>3</SUB>)<SUB>2</SUB> and ErF<SUB>3</SUB> content. The thermo-mechanical analysis showed that the <I>T</I> <SUB>g</SUB> and <I>T</I> <SUB>s</SUB> increased constantly and coefficient of thermal expansion decreased from 16.5×10<SUP>−6</SUP> K<SUP>−1</SUP> to 11.2<SUP>×1</SUP>0<SUP>−6</SUP> K<SUP>−1</SUP> with an increase in Mg(PO<SUB>3</SUB>)<SUB>2</SUB> and ErF<SUB>3</SUB> content. The Knoop hardness (<I>H</I> <SUB>K</SUB>) increased constantly from 381kgf/mm<SUP>2</SUP> to 480kgf/mm<SUP>2</SUP> with increased Mg(PO<SUB>3</SUB>)<SUB>2</SUB> and ErF<SUB>3</SUB> content, which indicates strengthening of the glass network with increased –PO bonds. The <I>H</I> <SUB>K</SUB> measurement at different applied loads and indentation times was carried out and from this study, it was found that an appropriate incorporation of cations into the FP glasses and the optimum rare earth concentration could considerably increase the thermal and mechanical strength of the glass. The studied glass compositions showed beneficial thermal properties and outstanding mechanical strength and can be applied for fiber drawing.</P>