Raman scattering enhancement in porous silicon microcavity

Abstract

We have measured an enhancement factor of Raman signal up to 30 times using a Fabry-Pérot structure made of porous silicon (PS) layers of different porosity. The obtained enhancement was due to the coupling of the laser radiation and Stokes photons of porous silicon with the microcavity mode at the optimal laser beam incidence and scattering angles. Our results provide a way to increase the sensitivity of Raman spectroscopy for studying the species inside porous silicon which can considerably influence the properties of this material and hence of PS based devices.

Enhanced-Raman scattering from silicon nanoparticle substrates

“…The latter brings SERS into the forefront with single-molecule spectroscopy [3,4]. SERS is concerned with the molecular vibration of surface species, while there is still another less-known Raman enhancement effect which is chiefly concerned with the lattice vibration of the bulk substrate itself, such as semiconducting or insulating materials [5][6][7][8][9][10][11][12][13][14][15]. This enhancement is mostly due to the coupling of the laser radiation and Stokes photons with microcavities [6][7][8][9][13][14][15].…”

Enhanced Raman scattering by self-assembled silica spherical microparticles

“…1 Extensive studies, therefore, have been conducted in order to improve the sensitivity of Raman scattering for the last two decades. [2][3][4][5][6][7][8][9][10][11][12][13][14] Several mechanisms related to physics, chemistry, and optics can be used to achieve this goal, such as electromagnetic and chemical mechanisms for surface-enhanced Raman scattering ͑SERS͒, [2][3][4][5] interference mechanism for interferenceenhanced Raman scattering ͑IERS͒, 6,7 angle-dependent reflection for total internal reflection Raman spectroscopy ͑TIRRS͒, 8 resonance effect from microstructures or subwavelength particles for resonance Raman scattering ͑RRS͒, 9,10 near-field optics for high-resolution near-field Raman microscopy ͑NORM͒, 11 and the localized evanescent electric field and surface plasmon polariton for tip-enhanced Raman spectroscopy ͑TERS͒. [12][13][14][15] Metal particles, e.g., Ag and Au, or substrates with roughness as sample carriers are the best candidates for the realization of SERS due to the high enhancement factor ͑10 4 -10 14 ͒; however, they are irreproducible and unpredictable.…”

Second- and third-harmonic generation in birefringent photonic crystals and microcavities based on anisotropic porous silicon

“…One of the convenient materials for making one-dimensional PBG structures is porous silicon (PS) allowing easily controllable variations of optical thickness and refractive index of a particular layer. 9 Proper layers periodicity and sharp internal interfaces can be achieved resulting in bright effects such as narrow strong photoluminiscence, 10 manyfold enhanced Raman scattering 11 …”