Cathodoluminescence and selective emission of Er3+ in oxides

Abstract

Abstract-The dependence of the Er 3+ cathodoluminescence and selective emission on the power of the YAG:Er 3+ and Er 2 O 3 excitation by an electron beam is spectroscopically studied for applications in high-intensity radiation sources of the visible and near-IR spectral ranges. PACS numbers: 78.60. Hk, 44.40.+a, 07.57.Kp, 78.30 and the cross relaxation [4][5][6]. A relatively high SE integral intensity in the visible and near-IR spectral ranges has been realized upon the laser thermal excitation of Er 2 O 3 at a wavelength of 10.6 µm [6]. The resonant optical pumping of the active media activated with rare-earth ions causes an increase in the laser efficiency for the visible and near-IR spectral ranges [7][8][9][10][11][12]. This accounts for the interest in the development of the thermophoto-lasers (TPLs) [6,13,14] whose laser elements are pumped by the thermally non-equilibrium SE [15]. The electron-beam excited SE of the rare-earth oxides can be another variant of the optical pumping.(ii) In this work, we experimentally study the dependence of the emission spectra and intensity of YAG:Er and Er 2 O 3 polycrystalline samples are synthesized using the melting of powders irradiated with a CO 2 laser at a radiation power of about 100 W and a wavelength of 10.6 µm on a substrate made of single-crystal silicon. The dispersed oxides are produced using the crushing and grinding of the single-crystalline and polycrystalline powders in a mortar.The electron-beam excited emission spectra of the oxides I(λ) ~ n(λ)/∆λ (n(λ) is the number of photons in the spectral interval ∆λ) are measured using an FSD-6 diffraction spectrometer with a fiber-optic input directed at a certain angle relative to the electron-irradiated oxide target. The measurements are performed in the sensitivity spectral range (300-900 nm) of a semiconductor detector array with the resolution ∆λ = 10 nm. The normal scan duration is 40 ms, and the number of scans is about 10. Using computer processing, we perform the correction of the measured emission spectra with regard to the spectral sensitivity of the array, the smoothing of the noisy spectra, and the intensity normalization needed for the curve plotting. Integralspectral intensity I Σ , which is proportional to the total number of photons in the sensitivity spectral range, is calculated for the spectral series measured at the given experimental configuration [6].(iii) The typical dependences of the normalized emission spectra I n (λ) = I(λ)/I max (λ) of the YAG:Er 3+ single crystal, crystalline powder, and polycrystal and the Er 2 O 3 powder on the electron-beam excitation power P = iU are presented in Fig. 1. Table 1 shows the discharge-tube voltages U and currents i. On the plots, the spectrum numbers correspond to the column numbers in the first row and the terms of the electronic states involved in the radiative transitions to the ground state are denoted in accordance with the