New synthesis techniques for highly concentrated colloidal C60 suspensions were developed. The nonlinear absorption and nonlinear scattering behavior of colloidal C60 suspensions and benchmark materials (carbon black suspension and C60 solution) were studied with an apparatus that simultaneously measured the total scattered and transmitted energy, inferring absorbance. These experimental results were compared to simple thermodynamic and reverse saturable absorption models, as well as a hybridized model proposed for the nonlinear optical behavior of C60 colloids. All samples followed an attenuation pattern in the nonlinear scattering regime that was fit by a single extinction coefficient, indicating that the energy in excess of that required to reach the sublimation threshold does not significantly affect the size of the induced scattering centers. C60 colloids evidenced strong quenching of the first excited singlet band, leading to weak intersystem-crossing to the triplet manifold. The degree of quenching was morphology dependent. Tighter crystalline packing led to stronger quenching. Samples with higher triplet quantum yield evidenced less efficient heating of the particles. Consequently, for otherwise similar C60 colloids, stronger nonlinear absorption response was found to diminish the nonlinear scattering response. Large, crystalline C60 colloids had a stronger nonlinear optical response than benchmarks.

Time-resolved imagery is presented showing the changes that occur in the focal volume of dilute liquid–particle suspensions following the arrival of single, Q-switched, frequency-doubled, Nd:YAG laser pulses. Data are presented for a carbon particle suspension consisting of used (carbonized) 10W-15 motor oil and for a suspension of the inorganic metallic cluster molecule Mo2Ag4S8[PPh3]4. The images in conjunction with the accompanying limiting data show that the reduction in transmission, observed as the input pulse energy is increased, results from scattering from bubbles augmented by plasma absorption. The imaging technique involves converting a portion of the laser pulse to probe pulses that are then delayed through varying lengths of optical fiber. The focal volume is probed perpendicular to the incident beam at various times from 12 ns to 2.9 μs after the arrival of the pulse in the test cell. Light emitted from the cell as a result of incandescence or a hot plasma is also imaged. Nonlinear loss, time-resolved pump–probe and picosecond limiting experiments, performed at the University of Central Florida’s Center for Research in Electro-Optics and Lasers (CREOL), are described in the companion paper in this issue entitled “Nonlinear optical properties of the inorganic metal cluster Mo2Ag4S8[PPh3]4.”

Magnified imagery of the focal volume within a nonlinear material, following the arrival of a high power laser pulse, provides insights on the response of the material. Emitted and scattered light images are presented along with time-resolved shadowgraphs (obtained through a pump-probe scheme) showing the response from various limiting materials in both liquid and solid hosts. The different types of images taken together make it possible to determine what occurs and where it occurs within the limiting material. Often unsuspected phenomena are found to be important. Conclusions from the data and the general utility of the technique are discussed.

Time-resolved imagery is presented showing the changes that occur in the focal volume of dilute liquid/particle suspensions following the arrival of single, Q-switched, frequency-doubled, Nd:YAG laser pulses. Limiting data and corresponding imagery at 21, 84, 244, 790, and 2900 nanoseconds following the laser pulse are presented for a carbon particle suspension consisting of used (carbonized) 1OW-15 motor oil and for a suspension of the inorganic metallic cluster molecule Mo2Ag4S8 [PPh3]4. The images in conjunction with the accompanying limiting data show that the reduction in transmission, observed as the input pulse energy is increased, results from scattering from bubbles augmented by plasma absorption.

Time-resolved imagery is presented showing the changes that occur in the focal volume of nonlinear liquids and suspensions as well as neat solvents, following the arrival of single Q-switched doubled Nd:YAG laser pulses. The images show that increasing input pulse energy results in partial beam deflection in silicon naphthalocyanine, scattering and absorption centers in suspensions, and plasma, shockwaves and bubbles following the breakdown of neat solvents. The technique involves converting a portion of the laser pulse to probe pulses which are then delayed through varying lengths of optical fiber. The focal volume is probed perpendicular to the incident beam at various times from 12 ns to 2.9 microseconds after the arrival of the pulse in the test cell. Several unsuspected phenomena have been found. A discussion of the type of information which may be gleaned from this data as well as several key findings are given.