Optically active Er3+ ions in SiO2 codoped with Si nanoclusters

Abstract

Optical properties of directly excited erbium ͑Er 3+ ͒ ions have been studied in silicon rich silicon oxide materials codoped with Er 3+ . The spectral dependence of the direct excitation cross section ͑ dir ͒ of the Er 3+ atomic 4 I 15/2 → 4 I 11/2 transition ͑around 0.98 m͒ has been measured by time resolved -photoluminescence measurements. We have determined that dir is 9.0Ϯ 1.5 ϫ 10 −21 cm 2 at 983 nm, at least twice larger than the value determined on a stoichiometric SiO 2 matrix. This result, in combination with a measurement of the population of excited Er 3+ as a function of the pumping flux, has allowed quantifying accurately the amount of optically active Er 3+ . This concentration is, in the best of the cases, 26% of the total Er population measured by secondary ion mass spectrometry, which means that only this percentage could provide optical gain in an eventual optical amplifier based on this material.

Si nanoparticle–Er3+ coupling through contact in as-deposited nanostructured films

“…The value of f Exc is as high as 53% for the SE film and 23% for the ES film, which are among the largest ever reported 4 This proves the high efficiency of the excitation process in our as-deposited films. Of further note is the fact that there is a large increase in f Exc , by a factor 53%, which occurs when the order of the dopant deposition is changed.…”

“…1 This limitation arises because codoping is usually performed by mixing the Si and Er components such that there is no control over their local relative position and thus their separation. [2][3][4] This limits the percentage of Er 3+ ions that are optically excited, usually to values of a few percent; and only recently has a value of 23% been achieved. 4 This is still far below the excitation fraction of 50% that is considered to be necessary to achieve gain, as has been proposed by recent reports, which suggest different routes to improve the excitation by achieving a longer excitation energy-transfer distance, 5 by using alternative excitation routes such as Si-related luminescent centers, 6,7 or by Er-doping of amorphous silicon-rich oxides.…”

Limit to the erbium ions emission in silicon-rich oxide films by erbium ion clustering

“…There is consensus in the literature that the principal reason obstructing the optical gain achievement in this material is a low fraction of sensitized erbium ions [7][8][9][10]. Recently, we have demonstrated that this is followed by the loss of light emission capability of Er 3+ when embedded in SRO material [11]. While the main fraction of embedded erbium ions does not participate in the process of light emission, absorption properties of non-emitting ions remain unaltered [12].…”

Energy transfer mechanism and Auger effect in Er3+ coupled silicon nanoparticle samples

“…These samples are particularly interesting since they show the highest to date fraction of Er ions coupled to Si-np ͑ϳ52%͒, 13 which produces an internal gain in waveguide samples of about 1 dB/cm. 14 In this study, we have demonstrated that the physics behind the transfer mechanism does not depend on the Si-np nature; in particular, we have verified that Auger back transfer processes are negligible in crystalline Si-nc samples, confirming the previous results obtained in amorphous Si-np.…”