• م.د محمود محمد اسماعيل
  • Mahmoud Mohammed Ismail
  • تدريسي : قسم تقنيات البصريات
  • Teaching : Department of Optical Technologies
  • دكتوراه فيزياء الجوامد والليزر
  • Physics of solid state lasers
  • mahmoud@esraa.edu.iq
  • mah_m1985@yahoo.com
  • Google Scholar
  • ORCId
  • Research Gate
  • scopus
  • 336

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    البحوث

    البحوث

    2026 Ceramics international
    Samarium -doped Borate glasses were synthesized utilizing the melt quenching technique in order to investigate their lasing and lighting capabilities. The optical and spectroscopic properties of the synthesized glass were analyzed utilizing photoluminescence excitation (PLE), photoluminescence (PL), and time-resolved photoluminescence (TRPL) methods. The Judd-Ofelt (JO) model were employed to determine the radiative properties, including branching ratios (βR), radiative transition probability (A), radiative lifetime (τR) and stimulated emission cross-section (σe) for the 4G5/2 → 6H5/2, 6H7/2, and 6H9/2 transitions of Sm3+ ions of the prepared samples. The discerned pattern in the Judd-Ofelt parameters across all samples is Ω2 > Ω4 > Ω6. The PLE showed that the samples can be efficiently excited at a wavelength of 487 nm corresponding to the 6H5/2 → 4I11/2 electronic transition of Sm3+. The photoluminescence spectrum features three asymmetric bands cantered at approximately 561 nm, 598 nm, and 646 nm and the emission intensity increases nearly linearly with the Sm3+ concentration, indicating a uniform distribution of Sm3+ ions throughout the glass matrix. The quantum efficiency (Ƞ) is approximately 36 % for Sm3+ ion concentration below 1 mol% and reduces to 26 % for the sample doped with 2 mol% of Sm3+. The lifetime measurements show nearly constant lifetime 0f (1.1 ms) below 2 mol% of Sm3+ suggesting a negligible physical clustering for Sm3+ below 2 mol%. Our samples demonstrated a higher optical gain (55.2 x10−25 cm2s−1) compared to other reported glasses. The CIE coordinates, essential emission wavelengths, color correlated temperature (CCT), and color purity values of the prepared glasses are displayed and tabulated to study the lighting capacities of the prepared samples. It was found that by increasing Sm3+ content, the color purity increased and CIE coordinate directed from cold white to pale orange. Based on obtained results, our glass system exhibits a moderate potential for lasing around 598 nm, 646 nm and white lighting applications. © 2026 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

    2026 Ceramics international
    The development of single-phase white-emitting phosphors activated by near-ultraviolet light, can effectively solve the other strategies’ problems for producing white light such as color reabsorption, high Correlated Color Temperature(CCT), and low color rendering index. A single-phase white-emitting glass Ce3+-(B2O3-PbO-BaO-CdO) was created using the conventional melt quenching technique for usage in white light emitting diodes (W-LEDs). The optical and spectroscopic characteristics of the synthesized glass were examined using the photoluminescence (PL) and time-resolved photoluminescence (TRPL) techniques. According to the results, the samples were effectively activated using UV light leading them to release an asymmetric broadband light emission with five overlapped peaks at wavelengths of 427 nm, 466 nm, 513 nm, 564 nm, and 627 nm. The emitted spectra contain all white light components, including blue, green, and red. In comparison to other glasses, our glasses exhibited extended lifetimes (7191.5 ns), indicating a more stable 5d energy level. All the samples exhibit a low degree of color purity, as they emit a full spectrum of white light. The B1Ce sample demonstrates the lowest color purity (8.54%), with chromaticity coordinates closely aligned to the white D55 standard (0.32,0.32), and the correlated color temperature was 6,335 K, signifying daylight conditions. According to the current study, Ce3+-(B2O3-PbO-BaO-CdO) glass seems like a good option for near-UV chip-based W-LED applications.

    2025 Optical Materials

    2025 Ceramics international

    2025 Ceramics international

    2024 Optical Materials

    2023 Journal of Luminescence
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    2024