Predictions of the absorption of focused finite amplitude waves based on weak shock theory have been tested experimentally. The characteristics of this absorption are qualitatively different from those associated with small signal losses. Under appropriate conditions, the absorption of finite amplitude ultrasound is determined largely by source amplitude, field geometry, and the nonlinear prope...

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...

The nonlinear optical properties and the role of the surface-plasmon resonance (SPR) on optical limiting (OL) properties of Ag–Cu nanoclusters co-doped in SiO2 matrix prepared using the sol-gel technique with a Cu/Ag molar ratio of 1, 2 and 3, respectively, are presented. The studies were made using the second harmonic of high-power nanosecond and picosecond Nd:YAG lasers. These films show a se...

The effects of coherence of quantum transitions and the interference of resonant nonlinear optical processes on the spectra of absorption, amplification, and nonlinear-optical generation are considered. The most favorable conditions are discussed for the inversionless amplification, resonant refraction in the absence of absorption and for resonant enhancement of nonlinear-optical generation at ...

In the context of nonlinear scattering, a continuous wave incident onto a nonlinear discrete molecular chain of coupled oscillators can be partially absorbed as a result of a 3-wave resonant interaction that couples two HF-waves of frequencies close to the edge of the Brillouin zone. Hence both nonlinearity and discreteness are necessary for generating this new absorption process which manisfes...

Organic compounds containing conjugated carbon chains have been extensively investigated due to their interesting properties including nonlinear optical response. Polyynes are a group of compounds where the conjugation can be modified by appropriate selection of end-groups, enabling "control" and improvement of nonlinear effects. In this work, we investigate three newly synthesized aryl end-cap...

There has been much interest in the development of two-photon absorbing materials and many efforts to understand the nonlinear absorption properties of these dyes but this area is still not well understood. A computational model has been developed in our lab to understand the nanosecond nonlinear absorption properties that incorporate all of the measured one-photon photophysical parameters of a...