Freshman Engineering Department

Oxy-fluoroborate (OFB) glasses doped with different concentrations of Sm 3 þ ions have been prepared using conventional melt quenching technique and characterised for their lasing potentialities using spectroscopic techniques such as FTIR, optical absorption, emission and emission decay measurements. The FTIR spectrum has been recorded to determine the various functional groups present in the OFB base glass. From the absorption spectra, the bonding parameters (δ) were evaluated to find the bonding nature present between Sm 3 þ ions with its neighbouring ligands. The Judd-Ofelt intensity (J-O) parameters (Ω λ , where λ¼ 2, 4, and 6), measured from the experimental oscillator strengths of the absorption spectral futures, are used to evaluate the radiative parameters for the fluorescent transitions 4 G 5/2 -6 H 5/2 , 4 G 5/2 -6 H 7/2 , 4 G 5/2 -6 H 9/2 and 4 G 5/2 -6 H 11/2 of Sm 3 þ ions in OFB glasses. The asymmetric ratio has been evaluated to understand the local disorder of Sm 3 þ ions in the glass network. The experimental lifetimes (τ exp ) measured from the decay curves are coupled with radiative lifetimes (τ rad ) to measure quantum efficiency (η) of the prepared glasses. The experimental lifetimes (τ exp ) for 4 G 5/2 emission state decrease with increase in Sm 3 þ ion concentration due to energy transfer. In order to elucidate the nature of energy transfer mechanism, the non-exponential decay curves are well fitted to the Inokuti-Hirayama model for S¼6, which indicates that the energy transfer mechanism is of dipole-dipole type. The branching ratio (β R ), stimulated emission cross-section (s se ) and quantum efficiency (η) values measured for the most intense emission transition 4 G 5/2 -6 H 7/2 (598 nm) optimise the concentration of Sm 3 þ ions as 1 mol% to produce bright visible orange lasing emission from these OFB glasses.

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights a b s t r a c t Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of Holmium were prepared by conventional melt quenching technique. The glassy nature of these glasses has been confirmed through the XRD spectral measurements. The FTIR spectra recorded for undoped glass revealed the information related to the functional groups involved in the host glass. Optical absorption, excitation and photoluminescence spectra of these glasses have been recorded at room temperature. The Judd–Ofelt theory has been applied successfully to characterize the absorption spectra of the ZnAlBiB glasses. From this theory various radiative properties such as radiative transition probability (A R), radiative lifetimes (s R), branching ratios (b R) and spectroscopic quality factor (v) for the prominent emission levels 5 F 5 ? 5 I 7 , 5 F 5 ? 5 I 8 and 5 I 7 ? 5 I 8 have been evaluated. The photoluminescence spectra revealed the quenching of luminescence intensity beyond 1.0 mol% of Ho 3+ ion concentration in ZnAlBiB glasses. To investigate the lasing potentiality of 5 F 5 ? 5 I 7 , 5 F 5 ? 5 I 8 and 5 I 7 ? 5 I 8 transitions, the effective band width (Dk p) and the stimulated emission cross-section (r se) were determined. The CIE chromaticity co-ordi-nates were also evaluated from the emission spectra for all the glasses to understand the suitability of these materials for visible red laser emission in principle.

Praseodymium doped Zinc Alumino Bismuth Borate (ZnAlBiB) glasses were prepared by melt quenching technique and characterized by optical absorption and emission studies. The glassy nature of these glasses has been confirmed through XRD spectral measurements. From the absorption spectra, the Judd-Ofelt intensity parameters Ω λ (λ¼ 2, 4 and 6) and other radiative properties like transition probability (A R ), radiative lifetimes (τ R ) and branching ratios (β R ) have been evaluated. Emission spectra were measured for different concentrations of Pr 3+ ions doped glasses by exciting the glasses at 445 nm. The intensity of Pr 3+ emission spectra increases from 0.1 to 1 mol% and beyond 1 mol% concentration quenching is observed. The suitable concentration of Pr 3+ ions in ZnAlBiB glasses to act as a good lasing material at reddish-orange wavelength (604 nm) region has been discussed by measuring the emission cross-sections for the intense emission transition 1 D 2 -3 H 4 . The CIE chromaticity co-ordinates were also evaluated from the emission spectra for all the glasses to understand the suitability of these materials for reddish-orange emission. From the measured emission cross-sections and CIE chromaticity co-ordinates, it was found that 1 mol% of Pr 3+ is aptly suitable for the development of visible reddish-orange lasers.

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of neodymium are prepared by using the melt quenching technique to study their physical, absorption and luminescence properties to understand the lasing potentialities of these glasses. From the absorption spectra various spectroscopic parameters and Judd-Ofelt (JO) parameters are evaluated. These JO parameters are used to calculate the transition probability (A), radiative lifetime (τ R ), and branching ratios (β R ) for most of the fluorescent levels of Nd 3+ . The emission spectra recorded for these glasses gives three prominent transitions 4 F 3/2 -4 I 9/2 , 4 F 3/2 -4 I 11/2 and 4 F 3/2 -4 I 13/2 for which effective band widths (Δλ P ) and stimulated emission cross-sections (s se ) are evaluated. Branching ratios and stimulated emission crosssections measured for all these glasses show that the 4 F 3/2 -4 I 11/2 transition under investigation has the potential for laser applications. The intensity of Nd 3+ emission spectra increases with increasing concentrations of Nd 3+ up to 1 mol% and beyond 1 mol% the concentration quenching is observed. The high stimulated emission cross-section and branching ratios from the present glasses suggests their potential for infrared lasers. From the absorption and emission spectral studies it was found that, 1 mol% of Nd 3+ ion concentration is optimum for Zinc Alumino Bismuth Borate glasses to generate a strong laser emission at 1060 nm.

Good optical quality Dy 3 þ doped Zinc Alumino Bismuth Borate (ZnAlBiB) glasses were prepared by the conventional melt quenching technique and characterized by optical absorption and luminescence studies. The glassy nature of these materials has been confirmed through XRD measurements. From the absorption spectra, the three phenomenological JO parameters O l (l¼ 2,4 and 6) have been determined from the absorption spectral intensities by using the JO theory. Luminescence spectra were measured for different concentrations of Dy 3 þ ions doped glasses by exciting the glasses at 387 nm. The intensity of Dy 3 þ emission spectra increases from 0.5 mol% to 1 mol % and beyond 1 mol % the concentration quenching is observed. The suitable concentration of Dy 3 þ ions for ZnAlBiB glassy material to act as good lasing material has been discussed by measuring the branching ratios and emission cross-sections for two strong emission transitions such as 4 F 9/2 -6 H 15/2 and 4 F 9/2 -6 H 13/2 observed in visible region. By exciting these glassy materials at various excitation wavelengths in n-UV region, the CIE chromaticity coordinates were evaluated for the two sharp emissions observed in blue ( 4 F 9/2 -6 H 15/2 ) and yellow ( 4 F 9/2 -6 H 13/2 ) regions to understand the suitability of these materials for white light generation.

Zinc Alumino Bismuth borate (ZnAlBiB) optical glasses of different compositions doped with 1 mol% of Dy 3+ ions were prepared by the conventional melt quenching technique and investigated by the XRD, optical absorption, photoluminescence and decay curve analysis. The glassy nature of ZnAlBiB host has been confirmed through XRD measurements. From the absorption spectral measurements, the three phenomenological intensity parameters Ω λ (λ ¼2,4 and 6) have been determined from the Judd–Ofelt (J–O) theory. By using JO intensity parameters, several radiative properties such as transition probability (A R), branching ratio (β R) and radiative lifetimes (τ R) have been determined. The room temperature photoluminescence spectra of Dy 3+ ions doped ZnAlBiB glasses gave two relatively intense emission bands 4 F 9/2-6 H 15/2 (blue), 4 F 9/2-6 H 13/2 (yellow) along with one faint band. The higher values of branching ratios and stimulated emission cross-sections for the 4 F 9/2-6 H 13/2 transition suggest the utility of these glasses as potential laser materials. The decay curves have been recorded for all the ZnAlBiB glasses to measure the quantum efficiency of these glasses by measuring the experimental lifetime (τ exp). The radiative properties and CIE chromaticity coordinates have been evaluated from the emission spectra to understand the feasibility of these glasses for optoelectronic devices.

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses at different compositions doped with 1 mol% of Sm 3 þ ions were prepared by using the melt quenching technique and investigated by XRD, optical absorption, emission and decay curve analysis to understand the visible luminescence of these glasses. From the absorption spectra the JO parameters are evaluated and are used to calculate the radiative properties such as transition probability, radiative lifetime, branching ratio and absorption cross-sections for various fluorescent levels of Sm 3 þ ions. The emission spectra of Sm 3 þ ions doped ZnAlBiB glasses show two intense emission bands 4 G 5/2-6 H 7/2 (orange) and 4 G 5/2-6 H 9/2 (red) for which the stimulated emission cross-section and branching ratios are evaluated to understand the potentiality of these materials as visible lasers. The decay profiles for the 4 G 5/2 fluorescent level of Sm 3 þ doped ZnAlBiB glasses have been recorded to measure the quantum efficiency (η) of these glasses. The strong visible emissions, large stimulated emission cross-sections, high branching ratios and good quantum efficiencies observed for the present ZnAlBiB glasses suggest the suitability of these glasses as laser and photonic devices operating in visible region.

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of Eu 3 þ ions have been prepared by rapid melt quenching technique and characterized for their luminescence behavior through various spectroscopic techniques such as absorption, excitation, emission, decay profiles and confocal image measurements at room temperature. From the measured absorption spectra, the bonding parameters (δ) were evaluated to find the nature of bonding between Eu 3 þ ions with its surrounding ligands in these ZnAlBiB glasses. The emission spectra of Eu 3 þ ions in ZnAlBiB glasses excited at 410 nm (CW laser) show the characteristic of Eu 3 þ ions with more intense visible red emission corresponding to 5 D 0 -7 F 2 transition. This intense visible red emission is further confirmed by the confocal luminescence images recorded for all the ZnAlBiB glasses. Judd-Ofelt (J-O) parameters estimated from the emission spectral information are used to estimate the important radiative properties such as transition probability (A R ), branching ratios (β R ) and emission-cross sections for the prominent emission levels. The large stimulated emission cross-sections and branching ratios observed for ZnAlBiB glasses suggest the utility of these glasses in visible red region of the electromagnetic spectrum. The CIE chromaticity coordinates evaluated from the emission spectra and the confocal images recorded for all the ZnAlBiB glasses also indicates that, these glasses at higher concentration of Eu 3 þ ions are aptly suitable for intense red emission at 613 nm corresponding to 5 D 0 -7 F 2 transition.

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with terbium (Tb 3 þ) ions with a chemical composition 20ZnO–10Al 2 O 3 –(10 À x)Bi 2 O 3 –60B 2 O 3 À xTb 2 O 3 (x ¼ 0.1, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mol%) were prepared by a conventional melt quenching method and studied their optical absorption, photoluminescence and decay spectral properties. The Judd–Ofelt (J–O) parameters evaluated from the experimental oscillator strengths were used to measure the radiative properties for the prominent luminescent transitions of Tb 3 þ ions such as 5 D 4-7 F 6 , 7 F 5 , 7 F 4 and 7 F 3. The effect of Tb 3 þ ion concentration on the luminescence process observed in the visible region was discussed in detail. The emission spectra recorded for all the ZnAlBiB glasses doped with Tb 3 þ ions, show an intense peak in green region at 542 nm. The stimulated emission cross-section, branching ratios and quantum efficiency values evaluated for green emission (5 D 4-7 F 5) suggests the utility of these glasses for green luminescence applications. It was found that, within the concentration range investigated, 2.5 mol% of Tb 3 þ doped ZnAlBiB glass is most suitable for green luminescence applications at 542 nm in principle.

Lead Tungsten Tellurite (LTT) glasses doped with different concentrations of Nd 3+ ions were prepared by using the melt quenching technique to study the absorption, emission and decay spectral profiles with an aim to understand the lasing potentialities of these glasses. From the absorption spectra, the Judd–Ofelt (J–O) parameters are evaluated and in turn used to calculate the transition probability (A R), total transition probability (A T), radiative lifetime (s R) and branching ratios (b R) for prominent emission levels of Nd 3+. The emission spectra recorded for LTT glasses gives three emission transitions 4 F 3/2 ? 4 I 9/2 , 4 F 3/2 ? 4 I 11/2 and 4 F 3/2 ? 4 I 13/2 for which effective band widths (Dk P) and stimulated emission cross-sections (r se) are evaluated. Branching ratios (b R) measured for all the LTT glasses show that 4 F 3/2 ? 4 I 11/2 transition is quite suitable for lasing applications. The intensity of emission spectra increases with increase in the concentrations of Nd 3+ up to 1.0 mol% and beyond concentration quenching is observed. Relatively higher emission cross-sections and branching ratios observed for the present LTT glasses over the reported glasses suggests the feasibility of using LTT glasses for infrared laser applications. From the absorption, emission and decay spectral measurements, it was found that 1.0 mol% of Nd 3+ ion concentration is aptly suitable for LTT glasses to give a strong NIR laser emission at 1062 nm.

Er 3 þ doped Zinc Alumino Bismuth Borate (ZnAlBiB) glasses with composition 20ZnOþ 10Al 2 O 3 þ (10À x)Bi 2 O 3 þ60B 2 O 3 þ xEr 2 O 3 (where x¼ 0.1, 0.5, 1.0 and 2.0 mol%) were prepared by using a melt quenching technique to study their luminescence efficiency in different regions of electromagnetic spectrum using absorption, emission , up-conversion and time resolved photoluminescence spectral studies at room temperature. The Judd– Ofelt (JO) parameters evaluated by applying JO theory to the absorption spectra of Er 3 þ doped ZnAlBiB glasses were used to calculate the radiative properties such as transition probability (A R), Branching ratios (β R), radiative lifetimes (τ R), stimulated emission cross-section (se σ), gain band width (se P σ λ × Δ) and optical gain (R se σ τ ×) parameters for the prominent luminescent levels of Er 3 þ. Visible and near infra-red (NIR) emission spectra have been recorded by exciting the glass samples at 486 nm and 980 nm respectively. Quantum efficiency (η) values for the prepared glasses were evaluated from the decay curves recorded for the NIR transition 4 I 13/2-4 I 15/2. The up-conversion luminescence shown by these glasses were recorded and analysed to understand utility of these glasses as up-conversion lasers by exciting them with 980 nm laser diode. The visible, up-conversion and NIR luminescence studies indicate that Er 3 þ ions doped ZnAlBiB glasses are aptly suitable for solid state lasers and optical amplifiers.

Lead Tungsten Tellurite (LTT) glasses doped with different concentrations of Ho 3 þ ions have been synthesized using the melt quenching method and characterized to understand their visible emission characteristic features using optical absorption and photoluminescence spectral studies. The Judd–Ofelt (JO) parameters measured from the absorption spectral features were used to evaluate radiative properties such as transition probability (A R), branching ratio (β R) and radiative lifetimes (τ R) for the prominent fluorescent levels of Ho 3 þ ions in LTT glasses. The photoluminescence spectra recorded for all the Ho 3 þ doped LTT glasses at an excitation wavelength 452 nm gives three prominent emission transitions 5 F 4-5 I 8 , 5 F 5-5 I 8 and 5 F 4-5 I 7 , of which 5 F 4-5 I 8 observed in visible green region (546 nm) is relatively more intense than the other two transitions. The intensity of 5 F 4-5 I 8 emission transition in these glasses increases up to 1 mol% of Ho 3 þ ions and beyond concentration quenching is observed. Branching ratios (β R) and emission cross-sections (s se) were evaluated for the intense emission transition 5 F 4-5 I 8 in these glasses to understand the luminescence efficiency in visible green region (546 nm). The CIE chromaticity coordinates were also evaluated in order to understand the suitability of these glasses for visible lumi-nescence. From the measured emission cross-sections and CIE coordinates, it was found that 1 mol% of Ho 3 þ ions in LTT glasses are most suitable for visible green luminescence in principle.

Sm 3þ ions doped Alkaline-Earth Boro Tellurite (AEBT) glasses were prepared by using conventional melt quenching technique and characterized using the spectroscopic techniques such as FT-IR, optical absorption , emission and decay spectral measurements to understand their utility in optoelectronic devices. From absorption spectra, the bonding parameters, nephelauxetic ratios were determined to know the nature of bonding between Sm 3þ ions and its surrounding ligands. From the measured oscillator strengths, the Judd-Ofelt (J-O) intensity parameters were evaluated and in turn used to estimate various radiative parameters for the fluorescent levels of Sm 3þ ions in AEBT glasses. The PL spectra of Sm 3þ ions exhibit three emission bands corresponding to the transitions 4 G 5/2 / 6 H 5/2 , 6 H 7/2 and 6 H 9/2 in the visible region for which the emission cross-sections and branching ratios were evaluated. The decay spectral profiles measured for 4 G 5/2 / 6 H 7/2 transition showed single exponential for lower concentration and non-exponential for higher concentration of doped rare earth ion in the as prepared glasses. Conversion of decay spectral profiles from single to non-exponential have been analyzed using InokutieHirayama (I eH) model to understand the energy transfer mechanism involved in the decay process. CIE Chromaticity coordinates were measured using emission spectral data to identify the exact region of emission from the as-prepared glasses. From the evaluated radiative parameters, emission cross-sections and quantum efficiencies, it was observed that AEBT glass with 1 mol% of Sm 3þ ions is more suitable for designing optoelectronic devices.

Zinc Alumino Bismuth borate (ZnAlBiB) optical glasses of different compositions doped with 1 mol% of Dy 3+ ions were prepared by the conventional melt quenching technique and investigated by the XRD, optical absorption, photoluminescence and decay curve analysis. The glassy nature of ZnAlBiB host has been confirmed through XRD measurements. From the absorption spectral measurements, the three phenomenological intensity parameters Ω λ (λ ¼2,4 and 6) have been determined from the Judd-Ofelt (J-O) theory. By using JO intensity parameters, several radiative properties such as transition probability (A R), branching ratio (β R) and radiative lifetimes (τ R) have been determined. The room temperature photoluminescence spectra of Dy 3+ ions doped ZnAlBiB glasses gave two relatively intense emission bands 4 F 9/2-6 H 15/2 (blue), 4 F 9/2-6 H 13/2 (yellow) along with one faint band. The higher values of branching ratios and stimulated emission cross-sections for the 4 F 9/2-6 H 13/2 transition suggest the utility of these glasses as potential laser materials. The decay curves have been recorded for all the ZnAlBiB glasses to measure the quantum efficiency of these glasses by measuring the experimental lifetime (τ exp). The radiative properties and CIE chromaticity coordinates have been evaluated from the emission spectra to understand the feasibility of these glasses for optoelectronic devices.

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of Holmium were prepared by conventional melt quenching technique. The glassy nature of these glasses has been confirmed through the XRD spectral measurements. The FTIR spectra recorded for undoped glass revealed the information related to the functional groups involved in the host glass. Optical absorption, excitation and photoluminescence spectra of these glasses have been recorded at room temperature. The Judd-Ofelt theory has been applied successfully to characterize the absorption spectra of the ZnAlBiB glasses. From this theory various radiative properties such as radiative transition probability (A R ), radiative lifetimes (s R ), branching ratios (b R ) and spectroscopic quality factor (v) for the prominent emission levels 5 F 5 ? 5 I 7 , 5 F 5 ? 5 I 8 and 5 I 7 ? 5 I 8 have been evaluated. The photoluminescence spectra revealed the quenching of luminescence intensity beyond 1.0 mol% of Ho 3+ ion concentration in ZnAlBiB glasses. To investigate the lasing potentiality of 5 F 5 ? 5 I 7 , 5 F 5 ? 5 I 8 and 5 I 7 ? 5 I 8 transitions, the effective band width (Dk p ) and the stimulated emission cross-section (r se ) were determined. The CIE chromaticity co-ordinates were also evaluated from the emission spectra for all the glasses to understand the suitability of these materials for visible red laser emission in principle.

h i g h l i g h t s ZnAlBiB glasses were prepared by conventional melt quenching technique. Emission data coupled with JO analysis were used to measure radiative properties. Quantum efficiency of ZnAlBiB glasses were measured from decay curves.