Room-temperature emission at telecom wavelengths from silicon photonic crystal nanocavities

Abstract

Strongly enhanced light emission at wavelengths between 1.3 and 1.6 μm is reported at room temperature in silicon photonic crystal (PhC) nanocavities with optimized out-coupling efficiency. Sharp peaks corresponding to the resonant modes of PhC nanocavities dominate the broad sub-bandgap emission from optically active defects in the crystalline Si membrane. We measure a 300-fold enhancement of the emission from the PhC nanocavity due to a combination of far-field enhancement and the Purcell effect. The cavity enhanced emission has a very weak temperature dependence, namely less than a factor of 2 reduction between 10 K and room temperature, which makes this approach suitable for the realization of efficient light sources as well as providing a quick and easy tool for the broadband optical characterization of silicon-on-insulator nanostructures.

Hydrogen induced optically-active defects in silicon photonic nanocavities

“…Measurements performed at low temperatures (data not shown) show an overall increase of both cavity modes and background. Moreover, similarly to what reported in references [23,24,31], the background PL shows a stronger suppression with increasing temperature than the PL of cavity modes, and therefore the peak-to-background ratio monotonically increases with increasing temperature. This is a consequence of the Purcell effect, as demonstrated in ref [31].…”

“…The filtered light was then fed into a grating spectrometer with an InGaAs detector. Further details on the characterization methods can be found elsewhere [23,24].…”

“…The cavity modes shift towards higher wavelengths by increasing the lattice constant and their intensities approximately follow the shape of the background sub-bandgap emission. The strong PL enhancement shown by the nanocavities (about a factor 300 in the best case) is explained by the concurring effect of two mechanisms: (i) the enhancement of the extraction efficiency due to the coupling of the Si PhC slab to radiative modes, (ii) and the Purcell effect acting on the emitting centers coupled to the cavity modes [23]. Measurements performed at low temperatures (data not shown) show an overall increase of both cavity modes and background.…”

Hybrid photonic crystal lasers

“…Silicon Photonics is one of the most promising technologies for cost-effective fabrication of photonic components and integrated circuits, however, there are some major challenges in terms of device performance. The development of efficient light emission from silicon has been the subject of a large body of research [1][2][3] but still remains elusive. The practical solution is the heterogeneous integration of III-V component on the silicon based photonic integrated circuits by means of direct wafer bonding [4], or the hybrid integration of III-Vs by means of flip-chip bonding [5].…”

Control of Q-factor in nanobeam cavities on substrate

“…Optical cavities showing high quality factors are essential building blocks for many applications such as nonlinear optics [1], refractive index sensing [2], enhanced emission [3] and filters [4] to mention a few. In twodimensional photonic crystals (2D-PhCs), light confinement is achieved by taking advantage of both photonic bandgaps (in the plane) and total internal reflection (perpendicular direction), respectively.…”