All-Dielectric Silicon Nanoslots forEr3+Photoluminescence Enhancement

Abstract

We study, both experimentally and theoretically, the modification of Er 3+ photoluminescence properties in Si dielectric nanoslots. The ultrathin nanoslot (down to 5-nm thickness), filled with Er in SiO 2 , boosts the electric and magnetic local density of states via coherent near-field interaction. We report an experimental 20-fold enhancement of the radiative decay rate with negligible losses. Moreover, via modifying the geometry of the all-dielectric nanoslot, the outcoupling of the emitted radiation to the far field can be strongly improved, without affecting the strong decay-rate enhancement given by the nanoslot structure. Indeed, for a periodic square array of slotted nanopillars an almost one-order-of-magnitude-higher Er 3+ PL intensity is measured with respect to the unpatterned structures. This has a direct impact on the design of more efficient CMOS-compatible light sources operating at telecom wavelengths.

Active Modulation of Er3+ Emission Lifetime by VO2 Phase‐Change Thin Films

“…On the other hand, a much shorter, temperature-dependent, lifetime is measured on the sample with the VO 2 layer on top ('VO 2 ', red and yellow curves in Figure 2b): ). Moreover, the Er 3þ PL intensity at λ ¼ 1540 nm measured at room temperature (I M PL ) and at high temperature (I R PL ) is significantly modified by the change of the VO 2 refractive index, which affects both the radiative decay rate and the angular distribution of the emission [18,22] (which, on the basis of the CDO model, results more directed toward the sample normal when VO 2 is in its M phase with respect to the R one). Considering the used set-up with a NA of 0.26, a PL intensity contrast (i.e., I M PL =I R PL ) of a factor 2 was measured at λ ¼ 1540 nm, in good agreement with the collection efficiencies ξ M and ξ R calculated with the CDO model, as reported below.…”

“…[9][10][11] Different strategies have been then adopted during the years to overcome such limitations, as the use of metal cluster sensitizers to get broadband enhanced excitation [12][13][14][15] and the engineering of the local density of optical states (LDOS) by coupling with plasmonic or dielectric nanoarrays to enhance the radiative decay rate. [16][17][18][19] Besides this, one of the key issues for the realization of efficient optoelectronic devices for optical communication is the capability to actively modulate their optical response, possibly at ultra-high speed. To this regard, recently the active control of the erbium luminescent emission intensity has been demonstrated by near-field coupling with doped graphene monolayers [20,21] and with a phase-change material (PCM), namely a thin film of vanadium dioxide (VO 2 ).…”

Kerker Condition for Enhancing Emission Rate and Directivity of Single Emitter Coupled to Dielectric Metasurfaces

“…A similar kind of fabrication process is discussed for embedding Er 3+ ions in Si nanoslots. [ 40 ] Further, the work can be extended to structures made using other materials, for example, SiC based metasurface. In such SiC based structures, creating defects centers like vacancy of Si, C, or di‐vacancy is quite possible by ion irradiation.…”

Active Erbium‐Doped Silicon Nanoantenna

“…[24] Therefore, silicon doped with erbium is a very promising material for the fabrication of active dielectric nanoantennas for the NIR wavelength range. The existing fabrication approaches of Sibased NIR nanoantennas are based on the creation of ultrathin layers in the nanoantenna volume such as silicon nanoslots filled with Er in SiO 2 [25] demonstrating 20-fold lifetime shortening in the C-band range or layers of Ge(Si) quantum dots separated by Si spacers [26,27] with tenfold emission enhancement in the Oband. The fabrication of such systems demands a multi-stage process and leads to nontrivial tasks in the case of the fabrication of all-optical chips.…”