抄録
A review of the present status of research on the generation of coherent VUV andsoft X-ray radiation is presented. In the last 15 years many techniques have been developed by utilizing third-and higher-order nonlinear processes to generate coherent radiation in the spectral region below 200 nm. The shortest wavelength of the coherent radiation generated so far is 14.6 nm, which is the 17th harmonic of an intense picosecond Kr F laser (248 nm) output, and the continuousliy tunable coherent radiation has been successfully generated down to about 70 nm. Further development of the nonlinear frequency conversion technique may extend the spectral region of useful coherent radiation to the XUV and X-ray.
