Emission properties of high-Q silicon nitride photonic crystal heterostructure cavities

Abstract

We report on the fabrication and optical characterization of photonic crystal (PC) double-heterostructure cavities made from silicon nitride (SiN). The intrinsic luminescence of the SiN membranes was used as an internal light source in the visible wavelength range (600–700nm) to study the quality factor and polarization properties of the cavity modes. Quality factors of up to 3400 were found experimentally, which represents the highest value reported so far in low-index PCs. These results highlight the role of SiN as a promising material system for PC devices in the visible.

Photonic Crystal and Plasmonic Silicon-Based Light Sources

“…Due to the low index of refraction of the SRN layer (n = 2.1), it is more challenging to achieve high Qs in silicon nitride than in Si. We designed and fabricated cavities for this material with modest Q-factors [22], and since then others have achieved Qs as high as 3400 [23]. It is important to point out that for PC design, using SRN is more advantageous than the Si-NCs in SiO 2 matrix because it has a higher refractive index.…”

Silicon Nitride Photonic Crystal Free-Standing Membranes: A Flexible Platform for Visible Spectral Range Devices

“…At visible wavelengths, these phenomena have been observed by means of several optically confined systems [28,29], but 2D-PhCs represent the most promising structures, since they give the best control on the optical properties of the resonators. To date, PhC cavities for visible spectral range are based on various geometries [6,11,21] and on higher-order modes of the widely studied H1 defect [30] (sketched in Fig. 1(a), inset).…”

“…Another appealing material is Silicon Nitride (Si 3 N 4 ), which answers to most of the above-mentioned requirements. Indeed, stoichiometric silicon nitride is transparent in the visible spectral range with a refractive index n ∼ 1.9 (@ λ = 600nm), it can be grown on Si with low-cost and widely diffused growth facilities such as Plasma Enhanced Several Si 3 N 4 2D-PhC cavities have been already proposed in past years [6,20,21], showing a maximum experimental quality factor (Q) of ∼ 5000 in the case of a double heterostructure nanocavity [21]. Moreover, recent advances in the development of nanobeam cavities have led to extremely high quality factors also in the visible range, with a maximum Q of ∼ 55000 [22][23][24].…”

Optical sensing with Anderson-localised light

“…Their quality factors, evaluated as the central wavelength divided by the full width half maximum of the spectral peak, show a distribution ranging from one to ten thousand 10 . It is worth noting that such disorder-induced optical cavities show quality factors that exceed those of engineered two-dimensional silicon nitride photonic crystal cavities confining light at comparable wavelenghts [14][15][16] . Compared to engineered photonic crystal cavities, the formation of a large number of high-quality optical cavities within the same device is particularly suitable for optical sensing, since many optical resonances can be monitored simultaneously.…”