UNLABELLED Due to the localized surface plasmon (LSP) effect induced by Ag nanoparticles inside black silicon, the optical absorption of black silicon is enhanced dramatically in near-infrared range (1,100 to 2,500 nm). The black silicon with Ag nanoparticles shows much higher absorption than black silicon fabricated by chemical etching or reactive ion etching over ultraviolet to near-infrared ...

Near-infrared spectra of HCl highly diluted in liquid Ar show intense absorption in the P-R interbranch region, so-called Q-branch absorption. In spite of its relevance for the shape of the bands, its physical origin has been elusive to date. We employ molecular dynamics simulations to study the influence of some physical effects that could contribute to Q-branch absorption. We check that multi...

By using a simple model of soliton±antisoliton pairs to simulate the quantum lattice ̄uctuations in one-dimensional conjugated polymers, the subgap optical absorption results from the transitions between the lowest unoccupied and the highest occupied levels off the conduction and valence bands, respectively, in the soliton±antisoliton excitations. There is no gap in the absorption induced by th...

We present an isomerism strategy to study the substitution position of perylene diimides on performances aggregation-induced emission (AIE) and two-photon absorption (2PA). Interestingly, enhanced AIE 2PA have been achieved.

The optical absorption of nanoscale thickness semiconductor films on top of light-trapping structures based on optical interference effects combined with spectrum-splitting structures is theoretically investigated. Nearly perfect absorption over a broad spectrum range can be achieved in <100 nm thick films on top of a one-dimensional photonic crystal or metal films. This phenomenon can be attri...

Two commercial photodiodes are tested for two-photon absorption at 520 nm. The results indicate strong linear absorption and negligible two-photon absorption at current power level. Two major types of error associated with autocorrelation measurement based on two-photon induced photocurrent were identified and investigated. Computer simulations show linear absorption can significantly distort t...

We review several experimental methodologies for the determination of nonlinear absorption coefficients of organic chromophores in either solution or thin film form. The goal here is to also be able to identify and quantify the nonlinear absorption process or processes, e.g. the essentially instantaneous two-photon absorption (2PA) or the cumulative excited-state absorption (ESA). These methods...