Related papers: Two-photon absorption in silicon using real densit…
Degenerate two-photon indirect absorption in silicon is an important limiting effect on the use of silicon structures for all-optical information processing at telecommunication wavelengths. We perform a full band structure calculation to…
Two-photon absorption is theoretically analyzed within the semiclassical formalism of radiation-matter interaction. We consider an ensemble of inhomogeneously broadened three-level atoms subjected to the action of two counterpropagating…
The optical properties of silicon can be greatly tuned by applying strain and opening new perspectives, particularly in applications where infrared is key. In this work, we use a recent model for the indirect light absorption of silicon and…
We calculate the two-photon absorption in bulk and single layer hexagonal boron nitride (hBN) both by an ab-initio real-time Bethe-Salpeter approach and by a the real-space solution of the excitonic problem in tight-binding formalism. The…
Photons do not carry sufficient momentum to induce indirect optical transitions in semiconducting materials such as silicon, necessitating the assistance of lattice phonons to conserve momentum. Compared to direct bandgap semiconductors,…
We consider theoretically nonlinear effects in a semiconductor quantum well embedded inside a photonic microcavity. Two-photon absorption by a 2p exciton state is considered and investigated; the matrix element of two-photon absorption is…
Multi-photon absorption processes have a nonlinear dependence on the amplitude of the incident optical field i.e. the number of photons. However, multi-photon absorption is generally weak and multi-photon events occur with extremely low…
Basing on recent reliable measurements of the life- and coherence time of Cu$_2$O Rydberg excitons, we present an analytical method which enables to describe the experimental results. The real-density matrix approach (RDMA) is applied to…
The photosensitivity of silicon is inherently very low in the visible electromagnetic spectrum, and it drops rapidly beyond 800 nm in near-infrared wavelengths. Herein, we have experimentally demonstrated a technique utilizing…
We have expressed the nonlinear optical absorption of a semiconductor in terms of its linear spectrum. We determined that the two-photon absorption coefficient in a strong DC-electric field of a direct gap semiconductor can be expressed as…
We theoretically investigate the two-photon absorption spectrum of conventional s-wave superconductors. The calculation is carried out in the local limit at absolute zero. The direct excitation of quasiparticles is excluded under the…
Silicon carbide (SiC) is an indirect-gap semiconductor material widely used in electronic and optoelectronic applications. While experimental measurements of the phonon-assisted absorption coefficient of SiC across its indirect gap have…
We present a simple measurement and analysis technique to determine the fraction of optical loss due to both radiation (scattering) and linear absorption in microphotonic components. The method is generally applicable to optical materials…
We analyze the rate of two-photon absorption in tapered optical fibers with diameters less than the wavelength of the incident light. The rate of two-photon absorption is shown to be enhanced due to the small mode volume of the tapered…
We revisit the calculation of bosonic dark matter absorption via electronic excitations. Working in an effective field theory framework and consistently taking into account in-medium effects, we clarify the relation between dark matter and…
The phonon-assisted interband optical absorption spectrum of silicon is calculated at the quasiparticle level entirely from first principles. We make use of the Wannier interpolation formalism to determine the quasiparticle energies, as…
The possibility of spatially resolving the optical properties of atomically thin materials is especially appealing as they can be modulated at the micro- and nanoscale by reducing their thickness, changing the doping level or applying a…
The nonlinear response of materials, an increasingly important aspect of light-matter interaction, can be challenging to measure in highly absorbing materials. Here, we introduce an interferometric technique that enables a direct…
In this paper, we report on the optical absorption in porous silicon. We model the absorption process assuming that porous silicon is a pseudo 1D material system having a distribution of band gaps. We show that in order to explain the…
In this paper, we analyse the optical absorption in porous silicon . This is the first attempt to explicitly demonstrate that it is not possible to extract the band gap of such low dimensional nanostructures like porous silicon from a Tauc…