National Institute for Laser Plasma and Radiation Physics

Missing Citation [...].

Laser-induced autofluorescence (LIAF) spectroscopy is a label-free optical technique sensitive to biochemical and structural tissue properties. Its application in upper aerodigestive tract malignancies is in its early stages. This study evaluates the feasibility of a matrix scan-based LIAF approach for examining differences between normal and malignant tissues. An exploratory case series involving three patients with oropharyngeal malignancies was conducted. Tissue sections from normal and tumor regions were analyzed using LIAF spectroscopy, including intensity and lifetime measurements, implemented through a matrix scanning protocol with fixed excitation, detection sensitivity, and sample thickness. Complementary Fourier-transform infrared (FTIR) spectroscopy was used to qualitatively assess biochemical variations, and spectroscopic findings were correlated with histopathological evaluation. Within individual cases, consistent differences in autofluorescence spectral and lifetime characteristics were observed between benign and malignant tissue regions. FTIR analysis revealed concurrent biochemical variations that qualitatively supported the autofluorescence observations. This exploratory study demonstrates the potential of combining LIAF matrix scan with FTIR spectroscopy to investigate tissue-specific spectral variations in upper aerodigestive tract lesions. The findings are preliminary and motivate further investigation using larger patient groups and clinically relevant acquisition conditions.

This study explores a novel photodynamic therapy approach using scintillating nanoparticles activated by laser-driven ionizing radiation. The method enables deep-tissue treatment with ultra-high dose rates, offering potential advances in targeted cancer therapy and FLASH radiobiology.

Memristors have emerged as a promising technology for next-generation memory and neuromorphic computing. Anodization offers an attractive alternative fabrication method with a wide range of tunable parameters and easy production setups.

Yb 3+ doped phosphate glass and composites containing Yb 2 Si 2 O 7 , LiNbO 3 :Yb 3+ , and CaWO 4 :Yb 3+ crystals embedded in phosphate glass were irradiated with a 3.5 MeV proton beam to investigate the impact of the radiation treatment on the Yb 3+ spectroscopic properties. While the structure of the Yb 3+ doped glass remained almost unaffected by the proton exposure, the irradiation was found to lead to structural changes in the composites, including defect formation and partial dissolution of the crystals with variations in the local environment of the Yb 3+ ions. Micro-Raman spectroscopy revealed structural modifications induced by irradiation, including radiation-induced crystallization within the glass phase of the composite, as well as changes in the Raman spectra of the embedded crystals. Despite these microscopic changes, no visible alterations in transparency nor coloration were observed, demonstrating the composites' resistance to 3.5 MeV proton beam. The radioluminescence spectra were measured in-situ and changes in the spectroscopic properties were observed from all samples, with Yb 3+ doped glass exhibiting the highest sensitivity with accumulated dose, followed by the composites prepared with CaWO 4 :Yb 3+ and Yb 2 Si 2 O 7 . These results highlight the impact of proton irradiation on the structural and spectroscopic properties of Yb 3+ doped crystals embedded in phosphate glass, demonstrating their potential for real-time radiation dosimetry.

Titanium dioxide is attractive for energy storage due to its abundance, stability, non-toxicity, low cost, and favorable electronic/optical properties. Colossal permittivity (CP) in co-doped TiO2 is mainly linked to defect structures rather than intrinsic bulk behavior. This work studies the dielectric properties of TiO2 co-doped with niobium and magnesium, synthesized by solid-state reaction. Grain size effects were examined by varying ball milling parameters of (½Mg½Nb)0.05Ti0.95O2 and then were correlated with structure, morphology, and dielectric response. X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), and impedance spectroscopy (IS) (40 Hz–106 Hz, 150–370 K) were employed for structural, morphological, and electrical characterization. XRD confirmed the rutile phase. For co-doped samples, larger grains yielded higher dielectric constants, reaching high permittivity (ε′ = 429, T = 300 K, f = 10 kHz at 500 rpm for 2 h). Lower loss tangent (tan δ = 0.11, T = 300 K, f = 10 kHz at 200 rpm for 2 h) is linked to Mg segregation at grain boundaries. The most conductive sample showed the highest dielectric constant, suggesting an IBLC polarization mechanism driven by grain boundary effects. XPS confirmed Nb and Mg incorporation, with Ti4+ dominant and minor Ti3+ from oxygen vacancies and surface hydroxylation/defects.

This paper presents the synthesis and characterization of Ge nanoparticles in Si3 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$N_{4}$</tex> dielectric <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(GeNPs: \text{Si}_{3} N_{4})$</tex> deposited on silicon substrates by magnetron co-sputtering, followed by rapid thermal annealing at 700° C and 800° C. The films exhibit self-powered photodetection behavior, with photocurrent values significantly increasing with a factor of 160 under illumination, especially at 200 K measurement temperatures. Spectral response measurements reveal cut-off wavelengths extending into the short-wave infrared (SWIR) region, influenced by both the annealing temperature and the measurement conditions. Hightemperature annealing promotes Ge diffusion, leading to reduced Ge clustering and defect passivation, which increase transparency in the IR range and shift the cutoff absorption edge toward shorter wavelengths. These results highlight the potential of Ge-NPs: <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Si}_{3} ~\mathrm{N}_{4}$</tex> nanocomposite films for efficient, low-power optoelectronic applications operating in the SWIR domain.