Time‐resolved investigations of erbium ions in ZBLAN‐based glasses and glass ceramics

Abstract

The lifetimes of the excited levels of Er3+ in ZBLAN-based glasses and glass ceramics were investigated by using time resolved spectroscopy. Upon direct excitation most of the radiative lifetimes of the excited levels do not show a dependency on the Er3+ doping level. However, for increasing Er3+ concentrations the lifetime of the thermally coupled (4S3/2+2H11/2) levels decreases significantly. For Er3+ doped glass ceramics containing BaCl2 nanocrystals the radiative lifetimes of the Er3+ levels change. For the (4S3/2+2H11/2) levels a fast component corresponding to the Er3+ doped glass and an additional slow component of a few hundred s was found

New energy-transfer upconversion process in Er^3+:ZBLAN mid-infrared fiber lasers

“…The branching ratio of the 4 S 3/2 / 2 H 11/2 → 4 F 9/2 is small ( β 54 = 0.25) [12] which further reduces the effect of this term. The intrinsic lifetime of the 4 S 3/2 / 2 H 11/2 levels, τ 5 , depends on the Er 3+ concentration and varies between 560 µs at very low doping concentrations to ∼ 15 µs at very high ones (9 mol.%) [16]. This decrease in lifetime is due to increases in the rate of ET processes such as the W 50 .…”

Influence of BaCl2 Nanocrystal Size on the Optical Properties of Nd3+ in Fluorozirconate Glass

“…As shown previously, , a uniform growth of hexagonal BaCl 2 nanocrystals inside such glasses can be induced by thermal treatment if additional chloride is introduced at the expense of fluoride. BaCl 2 in hexagonal symmetry has a maximal phonon energy of about 220 cm –1 which makes MPR even less probable, ,, and hence, under the influence of BaCl 2 , RE ions favor radiative decays. ,, However, until now only speculations were possible if the strong effects of BaCl 2 nanocrystals on the optical properties of Nd 3+ ions in these materials are related to the location of the RE ions at the interface between nanocrystals and the glass matrix or even their possible inclusion into the nanocrystals. , In addition, it is not clear whether the physical reason for the huge lifetime increase found for several transitions is solely the change in the phonon spectra or if the nanocrystals directly affect the radiative transition probabilities. It is the goal of this work to gather reliable information on these questions.…”

Highly Efficient and Broadband Upconversion of NIR Sunlight with Neodymium‐Doped Glass Ceramics

“…ZBLAN (ZrF4‐BaF2‐LaF3‐AlF3‐NaF)‐based glasses and glass ceramics are suitable hosts for efficient rare‐earth (RE) emission and photoluminescence upconversion. The ubiquitous REs erbium and neodymium are efficient emitters when embedded into ZBLAN . A possible application of RE‐based upconversion in photovoltaics is to make NIR photons at energies below the silicon bandgap available for electrical power generation in Si‐based solar cells .…”