>>12949214there are several:
1) use a different lasing medium;
2) use optical parametric amplification (for freely tunable wavelength within some range);
3) use high harmonic generation (discrete wavelengths - lambda/2, lambda/3, etc).
The problem with 1 is that gain mediums with good qualities can be hard to come by (especially for UV range - excimer lasers are pretty much unique in that respect).
The problem with 2 is that the tuning range is limited and conversion efficiency changes within the range.
The problem with 3 is that conversion efficiency for high harmonics (harmonic number beyond 4) is very low - can be just several % for 5th harmonic.
>t. laser engineer 
