How "far" has science taken the electromagnetic wave spectrum?

Question

On the long and the short ends?

Thanks

Answer 1

The Navy did some things with VLF (Very Low Frequency) radiation in the 10 to 15 KHz range for submarine communications, and it seems that I remember hearing about a radio-telescope system that could tune down to about that same range as well.
On the high end, there has been a lot of work done with far-UV lasers used in photolithography of microcircuits to increase the line resolution and make smaller microcircuits.
The 'Star Wars' ICBM defense system was to have used an x-ray/gamma-ray laser (pumped with a small fusion bomb ☺) to generate massive amounts of radiation to 'fry' incoming warheads. I suspect that there is still some work being done in that area, but how much or by whom I wouldn't know.

Doug