Crystalline Silicon White Light Sources Driven by Optical Resonances

Abstract

Silicon (Si) is generally considered as a poor photon emitter, and various scenarios have been proposed to improve the photon emission efficiency of Si. Here, we report the observation of a burst of the hot electron luminescence from Si nanoparticles with diameters of 150–250 nm, which is triggered by the exponential increase of the carrier density at high temperatures. We show that the stable white light emission above the threshold can be realized by resonantly exciting either the mirror-image-induced magnetic dipole resonance of a Si nanoparticle placed on a thin silver film or the surface lattice resonance of a regular array of Si nanopillars with femtosecond laser pulses of only a few picojoules, where significant enhancements in two- and three-photon-induced absorption can be achieved. Our findings indicate the possibility of realizing all-Si-based nanolasers with manipulated emission wavelength, which can be easily incorporated into future integrated optical circuits.

Efficient White Light Emission from Ga/Ga2O3 Hybrid Nanoparticles

“…Here, we characterized the quantum efficiency of a single NP by exploiting the nonlinear dependence of the multiphoton-induced absorption on the excitation irradiance. [27,28] The experimental setup used to measure the quantum efficiencies of the Ga and Ga/Ga 2 O 3 NPs is schematically shown in Note S1, Supporting Information. The key to measuring the multiphoton-induced absorption is that the reflected laser light can be detected in the PL spectra (Figures 1a and 3a), although a stop-band filter with a transmissivity of ≈4 × 10 −6 was used.…”

“…There have been several attempts to develop an efficient nanoscale emitter by enhancing either the excitation electric field [22][23][24][25] or the emission electric field. [15] For semiconductor emitters, efficient white light emission has been achieved in silicon (Si) [26][27][28] and gallium arsenide (GaAs) [22] NPs by resonantly exciting their Mie resonances, especially the magnetic dipole (MD) resonance. For metal emitters, white light emission has been observed in Ga NPs [23] and Au hotspots [24,25] by exciting their SPRs.…”

Highly efficient nonlinear optical emission from a subwavelength crystalline silicon cuboid mediated by supercavity mode

“…As a result, the significantly enhanced Auger recombination process in combination with the accelerated radiative recombination processes mediated by the electric and magnetic quadrupole resonances increase the quantum efficiency by several orders of magnitude 18 . When the injected carrier density exceeds a critical value, it is expected that the radiative recombination rate will become proportional to the carrier density, resulting in a further enhancement in the quantum efficiency 21 , 22 . On the other hand, the high temperature in the Si nanoparticle resulting from the thermalization of hot carriers may induce the intrinsic excitation of carriers.…”

“…On the other hand, the high temperature in the Si nanoparticle resulting from the thermalization of hot carriers may induce the intrinsic excitation of carriers. In this case, high-density electrons can be generated at the bottom of the conduction band (Δ point), continuously supplying hot electrons for the interband radiative recombination mediated by phonons 22 . Therefore, how to generate dense electron-hole plasma in a Si nanoparticle has become the key point to produce highly efficient hot electron luminescence.…”

“…Previously, the enhanced the two-photon-induced absorption (TPA) achieved at the MD resonance of a Si nanoparticle and the mirror-image-induced MD of a particle-on-film system have been exploited to inject high-density carriers into the Si nanoparticle 18 , 21 , 22 . However, the quality (Q) factors of such optical modes (~10) are not large enough to fully exploit the TPA of the Si nanoparticle induced by femtosecond laser pulses of ~100 fs, which possesses a linewidth of ~10 nm in the near infrared spectral range (i.e., ~800 nm).…”