High-Order Harmonic Generation

A brief overview of high‐order harmonic generation is given. Special emphasis is made on the use of this technique as a source of coherent radiation in the extreme ultraviolet. The experimental techniques as well as some characteristics of the generated radiation are presented. In particular, the wavelength range that can be covered and the number of photons per pulse that can be generated will be discussed and compared with other sources of radiation in this wavelength range. Finally some applications of radiation generated as high order harmonics will be briefly mentioned.