This paper offers recent successful examples for the application of nanosecond (ns) as well as picosecond (ps) and femtosecond (fs) laser pulses to media of gaseous, liquid or solid nature via non-linear interactions as a review, the laser ignition and dental ultra-short pulse interaction being parts of the authors' own work. Plasma-initiated ignition of combustible gas mixtures represents a potential alternative way for long-lasting operation of gas engines with rather clean exhaust. Ultra-short pulses are useful for materials processing including dental hard tissue. Using miniaturized scanners of different types yields perfect cavity sizes without collateral damage at ablation rates coming close to mechanical drills in dentistry. (c) 2005 Elsevier B.V All rights reserved.