Near-infrared imaging via upconversion in Er:CaF crystal with dual wavelength excitation.

We propose a system for imaging 1510 nm near-infrared (NIR) wavelength via upconversion (UC) luminescence in an Er-doped CaF crystal. Er ions are excited from the ground to the excited state levels by an 800-nm pre-excitation wavelength, followed by the promotion of these ions to a higher energy level by the NIR excitation wavelength. Relaxation of these excited ions gives rise to 540 nm UC luminescence in the visible region, enabling the detection of the 1510 nm NIR wavelength.

Metastable atomic-ordered configurations for AlGaN predicted by Monte-Carlo method based on first-principles calculations.

Metastability of AlGaN (= 2-10: integer) with the 1-2 monolayer (ML) in-plane configuration towards the[0001] direction has been demonstrated recently. To theoretically explain the existence of these metastable structures, relatively large calculation cells are needed. However, previous calculations were limited to the use of small calculation cell sizes to estimate the local potential depth (Δ) of ordered AlGaN models.

Ultraviolet-C Photoresponsivity Using Fabricated TiO Thin Films and Transimpedance-Amplifier-Based Test Setup.

We report on fabricated titanium dioxide (TiO) thin films along with a transimpedance amplifier (TIA) test setup as a photoconductivity detector (sensor) in the ultraviolet-C (UV-C) wavelength region, particularly at 260 nm. TiO thin films deposited on high-resistivity undoped silicon-substrate at thicknesses of 100, 500, and 1000 nm exhibited photoresponsivities of 81.6, 55.

The influence of CeF on radiation hardness and luminescence properties of GdO-BO glass scintillator.

The effect of CeF concentration and γ-irradiation on the physical, optical and luminescence properties of GdO-BO-CeF glasses were studied in this work. Before irradiation, the addition of CeF in glass degraded the network connectivity observed from FTIR and possibly created the non-bridging oxygen (NBO) in glass structure. This NBO caused the reduction of Ce/Ce ratio in XANES, the red-shift in transmission spectra and the raise of refractive index with addition of CeF content.

Vacuum ultraviolet photoluminescence of NaMgF:Sm and NaMgF:Sm,Ce: energy levels of the lanthanides in NaMgF:Ln compounds.

The luminescence properties of NaMgF:Sm and NaMgF:Ce,Sm were studied in the vacuum ultraviolet spectral region. Excitation bands corresponding to the charge transfer processes F → Sm, O → Sm, and O → Ce, and the energy transfer processes Ce → Smand O → Sm, were observed. The energies of the Smcharge transfer transitions and the crystal field split Ce45transitions were used to construct a complete host referred binding energy diagram for the series of lanthanide-doped NaMgF:Ln compounds.