Dr C Nageswara Raju - Academia.edu (original) (raw)

Papers by Dr C Nageswara Raju

Optics Communications, 2010

Ho 3+ (5 mol %) ions doped Barium Gadolinium Titanate (BaGd2Ti4O12) powder ceramics were synthesi... more Ho 3+ (5 mol %) ions doped Barium Gadolinium Titanate (BaGd2Ti4O12) powder ceramics were synthesized by solid state reaction method. From the X-ray diffraction profiles it is observed that the prepared ceramics were crystallized in the form of orthorhombic structure. Agglomeration and the nanometer particle size were observed from the SEM images of the ceramics. The emission spectrum Ho 3+ : BaGd2Ti4O12 powder ceramics has shown blue emission at 467 nm (5 F3 → 5 I8) with an excitation wavelength 208 nm. Introduction. One of the most important electro ceramics is barium titanate. Barium titanate is a good dielectric material with a high dielectric constant and it is a ferroelectric, piezoelectric and pyroelectric with good nonlinear optical properties. Barium titanate compound is an electrical insulator because of its energy and it has been used for a wide range of scientific and industrial applications such as capacitors, ultrasonic transducers, piezoelectric sensors, Barium titanat...

Materials Today: Proceedings, 2019

Nd 3+ doped BBZPA glasses were prepared by conventional melt quenching method and used to study t... more Nd 3+ doped BBZPA glasses were prepared by conventional melt quenching method and used to study their structural, absorption, emission and decay properties. From XRD, amorphous nature of the undoped glass has been confirmed. The J-O intensity parameters O k (k = 2, 4, 6) and the various radiative parameters were calculated from J-O analysis. From the emission spectra, it is observed that, the laser transition 4 F 3/2 ? 4 I 11/2 at 1059 nm is more intense transition. The decay curves for prepared glasses exhibited single exponential decay. The above results suggest that Nd 3+ doped BBZPA glasses could be suitable for photonic applications. Peer-review under responsibility of the scientific committee of the International Conference on Nano Science & Engineering Application (ICONSEA-2018) Centre for Nano Science and Technology, ICONSEA-2018 Ó 2018 Elsevier Ltd. 2. Experimental procedure 2.1. Glass preparation A series of glass samples doped with different concentrations of Nd 3+ ions were prepared using the chemical composition of

Advances in Geosciences - A 6-Volume Set

Advances in Geosciences - A 6-Volume Set

Materials Today: Proceedings, 2015

Praseodymium (Pr3+) ions doped Barium Gadolinium Titanate (BaGd2Ti4O12) powder ceramics were prep... more Praseodymium (Pr3+) ions doped Barium Gadolinium Titanate (BaGd2Ti4O12) powder ceramics were prepared through high temperature traditional solid state reaction method. The structural, elemental analysis, Photoluminescence and Thermoluminescence properties were studied systematically. From the X- ray diffraction profile, it has been observed that the crystallized powder ceramics is in the form of orthorhombic structure. The average grain size of the prepared powder ceramics were observed in the range of ∼200-300 nm from the SEM images. PL Spectra of Pr3+: BaGd2Ti4O12 ceramics have shown strong red emission at 680 nm with the excitation wave length 450 nm. TL peaks at 351K has been observed in the TL spectrum.

Ferroelectrics Letters Section, 2014

ABSTRACT This article reports on the synthesis, photoluminescence and thermoluminescence properti... more ABSTRACT This article reports on the synthesis, photoluminescence and thermoluminescence properties of samarium and dysprosium ions doped barium gadolinium titanate powder ceramics. The prepared samples were characterized by X- ray diffraction spectrum and it is observed that Sm3+ and Dy3+ ions doped barium gadolinium titanate powder ceramics are orthorhombic structure. From the SEM images of Sm3+ and Dy3+: BaGd2Ti4O12 ceramics, it is observed that the average grain size in the range ∼200-300 nm. The elements present in the composition are confirmed by the EDAX profiles and functional groups have been identified by using Fourier Transform Infrared spectroscopy. Photoluminescence spectra of Sm3+: BaGd2Ti4O12 ceramics have shown strong reddish- orange emission at 598 nm (4G5/2→6H7/2) with an excitation wavelength λexci = 408 nm (6H5/2→4F7/2) and Dy3+: BaGd2Ti4O12 ceramics have shown yellow emission at 587 nm (4F9/2→ 6H13/2) with an excitation wavelength λexci = 427 nm (6H15/2 → 4G11/2). Thermoluminescence (TL) nature of Sm3+ and Dy3+ ions doped BaGd2Ti4O12 ceramics has been observed with gamma ray irradiation.

Advanced Materials Research, 2010

This paper reports on the development and the near infra-red emission(NIR) analysis of Er3+/Yb3+ ... more This paper reports on the development and the near infra-red emission(NIR) analysis of Er3+/Yb3+ and Er3+/ Tm3+ ions doped TeO2 - B2O3 – ZnO - Li2O glasses for tunable laser and optical fiber amplification. From the measured near infra-red emission spectra of Er3+/Yb3+, Er3+/Tm3+: ZLiBT glasses have revealed the prominent near infra-red emission bands at 1532 nm (4I13/2 → 4I15/2), with an excitation wavelength of λexci = 515 nm (Ar+ ion laser). The full width at half-maxima (FWHM) values are also estimated from the measured near infra-red emission spectra of the glasses. Based on spectral results, broad near infra-red emissions should have potential applications in broadly tunable laser sources and broad band optical amplification at low-loss telecommunication windows.

Advanced Materials Research, 2010

This paper reports on the development and spectral results of Eu3+ and Tb3+ ions doped zinc lithi... more This paper reports on the development and spectral results of Eu3+ and Tb3+ ions doped zinc lithium boro tellurite glasses in the following composition: 20TeO2 - (60-x) B2O3 -10 ZnO-10Li2O-x Eu2O3 20TeO2 - (60-x) B2O3 -10 ZnO-10Li2O-x Tb4O7 (where x= 0.125, 0.25, 0.375, 0.5 , 0.625 mol %) The measured emission spectrum of Eu3+ glass have revealed five transitions (5D0→7F0, 7F1, 7F2, 7F3 & 7F4) at 578 nm, 592 nm, 612 nm, 643 nm, 701 nm respectively with λexci=392 nm (7F0→5L6) .In the case of Tb3+ glasses four emission transitions such as (5D4→ 7F6, 7F5,7 F4 & 7F3) that are located at 488 nm, 543 nm, 583 nm and 614nm respectively have been measured with λexci=376 nm. For all these emission bands decay curves have been plotted to evaluate their life times.

Glass Physics and Chemistry, 2012

This paper reports on the preparation and spectral properties of europium (Eu 3+) and terbium (Tb... more This paper reports on the preparation and spectral properties of europium (Eu 3+) and terbium (Tb 3+) ions doped cadmium lead boro tellurite (CLBT) glasses. For reference glasses, physical properties have been evaluated. From the [measurements of X ray diffraction (XRD), glass amorphous nature of these [glasses has been studied. From the emission spectra of Eu 3+ : CLBT glasses, five [transitions (

Journal of Optics, 2014

This article deals with the spectral analysis of Er3+ and Nd3+ ions doped zinc lithium bismuth bo... more This article deals with the spectral analysis of Er3+ and Nd3+ ions doped zinc lithium bismuth borate (ZLiBiB) glasses prepared by melt quenching method. The Vis-NIR absorption spectra of these glasses have been analyzed systematically. Judd-Ofelt intensity parameters Ωλ (λ = 2, 4, 6) have been evaluated and used to compute the radiative properties of emission transitions of Er3+ and Nd3+: ZLiBiB glasses. The NIR emission spectra of Er3+ and Nd3+: ZLiBiB glasses were measured with an Ar+ laser (514.5 nm) as the excitation source. From the NIR emission spectrum of Er3+: ZLiBiB glass a broad emission band centered at 1,538 nm (4I13/2 → 4I15/2) is observed and from Nd3+: ZLiBiB glass, three NIR emission bands at 898, 1,070 and 1,338 nm are observed which are assigned to the transitions (4F3/2 → 4I9/2), (4F3/2 → 4I11/2) and (4F3/2 → 4I13/2) respectively.

Solid State Sciences, 2013

Abstract Rare earth (Er 3+ and Nd 3+ ) ions doped cadmium lithium boro tellurite (CLiBT) glasses ... more Abstract Rare earth (Er 3+ and Nd 3+ ) ions doped cadmium lithium boro tellurite (CLiBT) glasses were prepared by melt quenching method. The vis–NIR absorption spectra of these glasses have been analyzed systematically. Judd–Ofelt intensity parameters Ω λ ( λ = 2, 4, 6) have been evaluated and used to compute the radiative properties of emission transitions of Er 3+ and Nd 3+ : CLiBT glasses. From the NIR emission spectra of Er 3+ : CLiBT glasses a broad emission band centered at 1538 nm ( 4 I 13/2 → 4 I 15/2 ) is observed and from Nd 3+ : CLiBT glasses, three NIR emission bands at 898 nm ( 4 F 3/2 → 4 I 9/2 ), 1070 nm ( 4 F 3/2 → 4 I 11/2 ) and 1338 nm ( 4 F 3/2 → 4 I 13/2 ) are observed with an excitation wavelength λ exci = 514.5 nm (Ar + Laser). The FWHM and stimulated emission cross-section values are calculated for Er 3+ and Nd 3+ : CLiBT glasses. FWHM × σ e P values are also calculated for Er 3+ : CLiBT glasses.

Radiation Effects and Defects in Solids, 2011

Page 1. Radiation Effects & Defects in Solids iFirst, 2011, 1–10 Optical analysis of Sm 3+ an... more Page 1. Radiation Effects & Defects in Solids iFirst, 2011, 1–10 Optical analysis of Sm 3+ and Dy 3+ ion-doped cadmium lead boro tellurite glasses P. Giridhar, S. Sailaja, M. Bhushana Reddy, K. Vemasevana Raju, C. Nageswara Raju and B. Sudhakar Reddy* ...

Physica B: Condensed Matter, 2012

5mol% of Pr3+ and Tm3+ ions activated calcium gadolinium tungstate (Ca2Gd2W3O14) phosphors were s... more 5mol% of Pr3+ and Tm3+ ions activated calcium gadolinium tungstate (Ca2Gd2W3O14) phosphors were synthesized by traditional solid state reaction method. Crystalline phase structure was identified from the X-ray diffraction (XRD) profiles. From the scanning electron microscopy (SEM) images, we have observed the agglomeration of the particles, and average grain size is around 40–300nm. Using the energy dispersive X-ray analysis (EDAX) and Fourier transform infrared (FTIR) spectra, identified the elements and functional groups present in the prepared phosphors. The emission spectrum of Pr3+: Ca2Gd2W3O14 powder phosphors have shown an intense red emission at 615nm with the excitation wavelength λexci=450nm and thus these red color emitting powder phosphors are used as one of the components in the preparation of WLEDs. The excitation spectrum of Tm3+: Ca2Gd2W3O14 powder phosphor has shown a ligand to metal charge transfer (W–O) band (LMCT) within the WO42− group. Emission spectrum of Tm3+: Ca2Gd2W3O14 phosphors have shown blue emissions at 453nm (1D2→3F4).

Luminescence, 2012

This article reports on the optical properties of 0.5% mol of Sm 3+ , Dy 3+ ion-doped B 2 O 3-TeO... more This article reports on the optical properties of 0.5% mol of Sm 3+ , Dy 3+ ion-doped B 2 O 3-TeO 2-Li 2 O-AlF 3 (LiAlFBT) glasses. The glass samples were characterized by optical absorption and emission spectra. Judd-Ofelt theory was applied to analyze the optical absorption spectra and calculate the intensity parameters and radiative properties of the emission transitions. The emission spectra of Sm 3+ and Dy 3+ :LiAlFBT glasses showed a bright reddish-orange emission at 598 nm (4 G 5/2 ! 6 H 7/2) and an intense yellow emission at 574 nm (4 F 9/2 ! 6 H 13/2), respectively. Full width at half maximum (FWHM), stimulated emission cross section, gain bandwidth and optical gain values were also calculated to extend the applications of the Sm 3+ and Dy 3+ :LiAlFBT glasses.

Luminescence, 2011

This article reports on the optical properties of Er 3+ ions doped CdO-Bi 2 O 3-B 2 O 3 (CdBiB) g... more This article reports on the optical properties of Er 3+ ions doped CdO-Bi 2 O 3-B 2 O 3 (CdBiB) glasses. The materials were characterized by optical absorption and emission spectra. By using Judd-Ofelt theory, the intensity parameters Ω l (l = 2, 4, 6) and also oscillatory strengths were calculated from the absorption spectra. The results were used to compute the radiative properties of Er 3+ :CdBiB glasses. The concentration quenching and energy transfer from Yb 3+-Er 3+ were explained. The stimulated emission cross-section, full width at half maximum (FWHM) and FWHM Â σ E p values are also calculated for all the Er 3+ :CdBiB glasses.

Luminescence, 2011

Rare earth ions (Eu 3+ or Tb 3+)-activated Ca 3 Ga 2 Si 3 O 12 (CaGaSi) phosphors were synthesize... more Rare earth ions (Eu 3+ or Tb 3+)-activated Ca 3 Ga 2 Si 3 O 12 (CaGaSi) phosphors were synthesized by using a sol-gel method. Photoluminescence spectra of Eu 3+ : CaGaSi phosphors exhibited five emission bands at 578, 592, 612, 652 and 701 nm, which were assigned to the transitions (5 D 0 → 7 F 0 , 7 F 1, 7 F 2 , 7 F 3 and 7 F 4), respectively, with an excitation wavelength of λ exci = 392 nm. Among these, the transition 5 D 0 → 7 F 2 (612 nm) displayed bright red emission. In the case of Tb 3+ : CaGaSi phosphors, four emission bands were observed at 488 (5 D 4 → 7 F 6), 543 (5 D 4 → 7 F 5), 584 (5 D 4 → 7 F 4) and 614 nm (5 D 4 → 7 F 3) from the measurement of PL spectra with λ exci = 376 nm. Among these, the transition 5 D 4 → 7 F 5 at 543 nm displayed bright green emission. The structure and morphology of the phosphors were studied from the measurements of X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX) results.

Journal of Nanoscience and Nanotechnology, 2012

Rare-earth (Sm3+ or Dy3+) ions doped cadmium lithium boro tellurite glasses have been prepared by... more Rare-earth (Sm3+ or Dy3+) ions doped cadmium lithium boro tellurite glasses have been prepared by melt quenching method for their spectral studies. From X-ray diffraction (XRD) patterns the glass amorphous nature has been confirmed. Vis-NIR absorption, excitation and emission spectra of these glasses have been analyzed systematically and also rare earth ion concentration is optimised Sm3+: CLiBT glasses have shown strong orange-reddish emission at 598 nm (4G5/2-->6H7/2) with an excitation wavelength lambda(exci) = 401 nm and Dy3+: CLiBT glasses have shown strong yellow emission at 574 nm (6F9/2-->6H13/2) with lambda(exci) = 451 nm.

Journal of Molecular Structure, 2013

h i g h l i g h t s " Various concentrations of Sm 3+ :CdBiB glasses have been prepared. " The em... more h i g h l i g h t s " Various concentrations of Sm 3+ :CdBiB glasses have been prepared. " The emission spectra of Sm 3+ :CdBiB glasses have shown reddish-orange emission. " By using the J-O theory, the radiative properties have been studied and computed. " The nature of luminescence decay curves of 4 G 5/2 level of Sm 3+ :CdBiB glasses have been reported. " Based on the spectral properties, it is concluded that 1.0 mol% of Sm 3+ :CdBiB glass is potential for laser applications.

Optics Communications, 2010

Ho 3+ (5 mol %) ions doped Barium Gadolinium Titanate (BaGd2Ti4O12) powder ceramics were synthesi... more Ho 3+ (5 mol %) ions doped Barium Gadolinium Titanate (BaGd2Ti4O12) powder ceramics were synthesized by solid state reaction method. From the X-ray diffraction profiles it is observed that the prepared ceramics were crystallized in the form of orthorhombic structure. Agglomeration and the nanometer particle size were observed from the SEM images of the ceramics. The emission spectrum Ho 3+ : BaGd2Ti4O12 powder ceramics has shown blue emission at 467 nm (5 F3 → 5 I8) with an excitation wavelength 208 nm. Introduction. One of the most important electro ceramics is barium titanate. Barium titanate is a good dielectric material with a high dielectric constant and it is a ferroelectric, piezoelectric and pyroelectric with good nonlinear optical properties. Barium titanate compound is an electrical insulator because of its energy and it has been used for a wide range of scientific and industrial applications such as capacitors, ultrasonic transducers, piezoelectric sensors, Barium titanat...

Materials Today: Proceedings, 2019

Nd 3+ doped BBZPA glasses were prepared by conventional melt quenching method and used to study t... more Nd 3+ doped BBZPA glasses were prepared by conventional melt quenching method and used to study their structural, absorption, emission and decay properties. From XRD, amorphous nature of the undoped glass has been confirmed. The J-O intensity parameters O k (k = 2, 4, 6) and the various radiative parameters were calculated from J-O analysis. From the emission spectra, it is observed that, the laser transition 4 F 3/2 ? 4 I 11/2 at 1059 nm is more intense transition. The decay curves for prepared glasses exhibited single exponential decay. The above results suggest that Nd 3+ doped BBZPA glasses could be suitable for photonic applications. Peer-review under responsibility of the scientific committee of the International Conference on Nano Science & Engineering Application (ICONSEA-2018) Centre for Nano Science and Technology, ICONSEA-2018 Ó 2018 Elsevier Ltd. 2. Experimental procedure 2.1. Glass preparation A series of glass samples doped with different concentrations of Nd 3+ ions were prepared using the chemical composition of

Advances in Geosciences - A 6-Volume Set

Advances in Geosciences - A 6-Volume Set

Materials Today: Proceedings, 2015

Praseodymium (Pr3+) ions doped Barium Gadolinium Titanate (BaGd2Ti4O12) powder ceramics were prep... more Praseodymium (Pr3+) ions doped Barium Gadolinium Titanate (BaGd2Ti4O12) powder ceramics were prepared through high temperature traditional solid state reaction method. The structural, elemental analysis, Photoluminescence and Thermoluminescence properties were studied systematically. From the X- ray diffraction profile, it has been observed that the crystallized powder ceramics is in the form of orthorhombic structure. The average grain size of the prepared powder ceramics were observed in the range of ∼200-300 nm from the SEM images. PL Spectra of Pr3+: BaGd2Ti4O12 ceramics have shown strong red emission at 680 nm with the excitation wave length 450 nm. TL peaks at 351K has been observed in the TL spectrum.

Ferroelectrics Letters Section, 2014

ABSTRACT This article reports on the synthesis, photoluminescence and thermoluminescence properti... more ABSTRACT This article reports on the synthesis, photoluminescence and thermoluminescence properties of samarium and dysprosium ions doped barium gadolinium titanate powder ceramics. The prepared samples were characterized by X- ray diffraction spectrum and it is observed that Sm3+ and Dy3+ ions doped barium gadolinium titanate powder ceramics are orthorhombic structure. From the SEM images of Sm3+ and Dy3+: BaGd2Ti4O12 ceramics, it is observed that the average grain size in the range ∼200-300 nm. The elements present in the composition are confirmed by the EDAX profiles and functional groups have been identified by using Fourier Transform Infrared spectroscopy. Photoluminescence spectra of Sm3+: BaGd2Ti4O12 ceramics have shown strong reddish- orange emission at 598 nm (4G5/2→6H7/2) with an excitation wavelength λexci = 408 nm (6H5/2→4F7/2) and Dy3+: BaGd2Ti4O12 ceramics have shown yellow emission at 587 nm (4F9/2→ 6H13/2) with an excitation wavelength λexci = 427 nm (6H15/2 → 4G11/2). Thermoluminescence (TL) nature of Sm3+ and Dy3+ ions doped BaGd2Ti4O12 ceramics has been observed with gamma ray irradiation.

Advanced Materials Research, 2010

This paper reports on the development and the near infra-red emission(NIR) analysis of Er3+/Yb3+ ... more This paper reports on the development and the near infra-red emission(NIR) analysis of Er3+/Yb3+ and Er3+/ Tm3+ ions doped TeO2 - B2O3 – ZnO - Li2O glasses for tunable laser and optical fiber amplification. From the measured near infra-red emission spectra of Er3+/Yb3+, Er3+/Tm3+: ZLiBT glasses have revealed the prominent near infra-red emission bands at 1532 nm (4I13/2 → 4I15/2), with an excitation wavelength of λexci = 515 nm (Ar+ ion laser). The full width at half-maxima (FWHM) values are also estimated from the measured near infra-red emission spectra of the glasses. Based on spectral results, broad near infra-red emissions should have potential applications in broadly tunable laser sources and broad band optical amplification at low-loss telecommunication windows.

Advanced Materials Research, 2010

This paper reports on the development and spectral results of Eu3+ and Tb3+ ions doped zinc lithi... more This paper reports on the development and spectral results of Eu3+ and Tb3+ ions doped zinc lithium boro tellurite glasses in the following composition: 20TeO2 - (60-x) B2O3 -10 ZnO-10Li2O-x Eu2O3 20TeO2 - (60-x) B2O3 -10 ZnO-10Li2O-x Tb4O7 (where x= 0.125, 0.25, 0.375, 0.5 , 0.625 mol %) The measured emission spectrum of Eu3+ glass have revealed five transitions (5D0→7F0, 7F1, 7F2, 7F3 & 7F4) at 578 nm, 592 nm, 612 nm, 643 nm, 701 nm respectively with λexci=392 nm (7F0→5L6) .In the case of Tb3+ glasses four emission transitions such as (5D4→ 7F6, 7F5,7 F4 & 7F3) that are located at 488 nm, 543 nm, 583 nm and 614nm respectively have been measured with λexci=376 nm. For all these emission bands decay curves have been plotted to evaluate their life times.

Glass Physics and Chemistry, 2012

This paper reports on the preparation and spectral properties of europium (Eu 3+) and terbium (Tb... more This paper reports on the preparation and spectral properties of europium (Eu 3+) and terbium (Tb 3+) ions doped cadmium lead boro tellurite (CLBT) glasses. For reference glasses, physical properties have been evaluated. From the [measurements of X ray diffraction (XRD), glass amorphous nature of these [glasses has been studied. From the emission spectra of Eu 3+ : CLBT glasses, five [transitions (

Journal of Optics, 2014

This article deals with the spectral analysis of Er3+ and Nd3+ ions doped zinc lithium bismuth bo... more This article deals with the spectral analysis of Er3+ and Nd3+ ions doped zinc lithium bismuth borate (ZLiBiB) glasses prepared by melt quenching method. The Vis-NIR absorption spectra of these glasses have been analyzed systematically. Judd-Ofelt intensity parameters Ωλ (λ = 2, 4, 6) have been evaluated and used to compute the radiative properties of emission transitions of Er3+ and Nd3+: ZLiBiB glasses. The NIR emission spectra of Er3+ and Nd3+: ZLiBiB glasses were measured with an Ar+ laser (514.5 nm) as the excitation source. From the NIR emission spectrum of Er3+: ZLiBiB glass a broad emission band centered at 1,538 nm (4I13/2 → 4I15/2) is observed and from Nd3+: ZLiBiB glass, three NIR emission bands at 898, 1,070 and 1,338 nm are observed which are assigned to the transitions (4F3/2 → 4I9/2), (4F3/2 → 4I11/2) and (4F3/2 → 4I13/2) respectively.

Solid State Sciences, 2013

Abstract Rare earth (Er 3+ and Nd 3+ ) ions doped cadmium lithium boro tellurite (CLiBT) glasses ... more Abstract Rare earth (Er 3+ and Nd 3+ ) ions doped cadmium lithium boro tellurite (CLiBT) glasses were prepared by melt quenching method. The vis–NIR absorption spectra of these glasses have been analyzed systematically. Judd–Ofelt intensity parameters Ω λ ( λ = 2, 4, 6) have been evaluated and used to compute the radiative properties of emission transitions of Er 3+ and Nd 3+ : CLiBT glasses. From the NIR emission spectra of Er 3+ : CLiBT glasses a broad emission band centered at 1538 nm ( 4 I 13/2 → 4 I 15/2 ) is observed and from Nd 3+ : CLiBT glasses, three NIR emission bands at 898 nm ( 4 F 3/2 → 4 I 9/2 ), 1070 nm ( 4 F 3/2 → 4 I 11/2 ) and 1338 nm ( 4 F 3/2 → 4 I 13/2 ) are observed with an excitation wavelength λ exci = 514.5 nm (Ar + Laser). The FWHM and stimulated emission cross-section values are calculated for Er 3+ and Nd 3+ : CLiBT glasses. FWHM × σ e P values are also calculated for Er 3+ : CLiBT glasses.

Radiation Effects and Defects in Solids, 2011

Page 1. Radiation Effects & Defects in Solids iFirst, 2011, 1–10 Optical analysis of Sm 3+ an... more Page 1. Radiation Effects & Defects in Solids iFirst, 2011, 1–10 Optical analysis of Sm 3+ and Dy 3+ ion-doped cadmium lead boro tellurite glasses P. Giridhar, S. Sailaja, M. Bhushana Reddy, K. Vemasevana Raju, C. Nageswara Raju and B. Sudhakar Reddy* ...

Physica B: Condensed Matter, 2012

5mol% of Pr3+ and Tm3+ ions activated calcium gadolinium tungstate (Ca2Gd2W3O14) phosphors were s... more 5mol% of Pr3+ and Tm3+ ions activated calcium gadolinium tungstate (Ca2Gd2W3O14) phosphors were synthesized by traditional solid state reaction method. Crystalline phase structure was identified from the X-ray diffraction (XRD) profiles. From the scanning electron microscopy (SEM) images, we have observed the agglomeration of the particles, and average grain size is around 40–300nm. Using the energy dispersive X-ray analysis (EDAX) and Fourier transform infrared (FTIR) spectra, identified the elements and functional groups present in the prepared phosphors. The emission spectrum of Pr3+: Ca2Gd2W3O14 powder phosphors have shown an intense red emission at 615nm with the excitation wavelength λexci=450nm and thus these red color emitting powder phosphors are used as one of the components in the preparation of WLEDs. The excitation spectrum of Tm3+: Ca2Gd2W3O14 powder phosphor has shown a ligand to metal charge transfer (W–O) band (LMCT) within the WO42− group. Emission spectrum of Tm3+: Ca2Gd2W3O14 phosphors have shown blue emissions at 453nm (1D2→3F4).

Luminescence, 2012

This article reports on the optical properties of 0.5% mol of Sm 3+ , Dy 3+ ion-doped B 2 O 3-TeO... more This article reports on the optical properties of 0.5% mol of Sm 3+ , Dy 3+ ion-doped B 2 O 3-TeO 2-Li 2 O-AlF 3 (LiAlFBT) glasses. The glass samples were characterized by optical absorption and emission spectra. Judd-Ofelt theory was applied to analyze the optical absorption spectra and calculate the intensity parameters and radiative properties of the emission transitions. The emission spectra of Sm 3+ and Dy 3+ :LiAlFBT glasses showed a bright reddish-orange emission at 598 nm (4 G 5/2 ! 6 H 7/2) and an intense yellow emission at 574 nm (4 F 9/2 ! 6 H 13/2), respectively. Full width at half maximum (FWHM), stimulated emission cross section, gain bandwidth and optical gain values were also calculated to extend the applications of the Sm 3+ and Dy 3+ :LiAlFBT glasses.

Luminescence, 2011

This article reports on the optical properties of Er 3+ ions doped CdO-Bi 2 O 3-B 2 O 3 (CdBiB) g... more This article reports on the optical properties of Er 3+ ions doped CdO-Bi 2 O 3-B 2 O 3 (CdBiB) glasses. The materials were characterized by optical absorption and emission spectra. By using Judd-Ofelt theory, the intensity parameters Ω l (l = 2, 4, 6) and also oscillatory strengths were calculated from the absorption spectra. The results were used to compute the radiative properties of Er 3+ :CdBiB glasses. The concentration quenching and energy transfer from Yb 3+-Er 3+ were explained. The stimulated emission cross-section, full width at half maximum (FWHM) and FWHM Â σ E p values are also calculated for all the Er 3+ :CdBiB glasses.

Luminescence, 2011

Rare earth ions (Eu 3+ or Tb 3+)-activated Ca 3 Ga 2 Si 3 O 12 (CaGaSi) phosphors were synthesize... more Rare earth ions (Eu 3+ or Tb 3+)-activated Ca 3 Ga 2 Si 3 O 12 (CaGaSi) phosphors were synthesized by using a sol-gel method. Photoluminescence spectra of Eu 3+ : CaGaSi phosphors exhibited five emission bands at 578, 592, 612, 652 and 701 nm, which were assigned to the transitions (5 D 0 → 7 F 0 , 7 F 1, 7 F 2 , 7 F 3 and 7 F 4), respectively, with an excitation wavelength of λ exci = 392 nm. Among these, the transition 5 D 0 → 7 F 2 (612 nm) displayed bright red emission. In the case of Tb 3+ : CaGaSi phosphors, four emission bands were observed at 488 (5 D 4 → 7 F 6), 543 (5 D 4 → 7 F 5), 584 (5 D 4 → 7 F 4) and 614 nm (5 D 4 → 7 F 3) from the measurement of PL spectra with λ exci = 376 nm. Among these, the transition 5 D 4 → 7 F 5 at 543 nm displayed bright green emission. The structure and morphology of the phosphors were studied from the measurements of X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX) results.

Journal of Nanoscience and Nanotechnology, 2012

Rare-earth (Sm3+ or Dy3+) ions doped cadmium lithium boro tellurite glasses have been prepared by... more Rare-earth (Sm3+ or Dy3+) ions doped cadmium lithium boro tellurite glasses have been prepared by melt quenching method for their spectral studies. From X-ray diffraction (XRD) patterns the glass amorphous nature has been confirmed. Vis-NIR absorption, excitation and emission spectra of these glasses have been analyzed systematically and also rare earth ion concentration is optimised Sm3+: CLiBT glasses have shown strong orange-reddish emission at 598 nm (4G5/2-->6H7/2) with an excitation wavelength lambda(exci) = 401 nm and Dy3+: CLiBT glasses have shown strong yellow emission at 574 nm (6F9/2-->6H13/2) with lambda(exci) = 451 nm.

Journal of Molecular Structure, 2013

h i g h l i g h t s " Various concentrations of Sm 3+ :CdBiB glasses have been prepared. " The em... more h i g h l i g h t s " Various concentrations of Sm 3+ :CdBiB glasses have been prepared. " The emission spectra of Sm 3+ :CdBiB glasses have shown reddish-orange emission. " By using the J-O theory, the radiative properties have been studied and computed. " The nature of luminescence decay curves of 4 G 5/2 level of Sm 3+ :CdBiB glasses have been reported. " Based on the spectral properties, it is concluded that 1.0 mol% of Sm 3+ :CdBiB glass is potential for laser applications.