An international team of researchers has demonstrated a new concept for the generation of intense extreme-ultraviolet (XUV) radiation by high-harmonic generation (HHG). Its advantage lies in the fact that its footprint is much smaller than currently existing intense XUV lasers. The new scheme is straightforward and could be implemented in many laboratories worldwide, which may boost the research field of ultrafast XUV science.
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“(2) The generated XUV beam is large and has a large divergence, and can therefore be focused to a small spot size.”
What? Large diverging laser outputs focus to a smaller point? Never heard of this before. At least for diodes, I thought it was a function of the wavelength and emitter size alone, other than the optics used.
I think it might be a bit of poor wording. But a larger input beam diameter will allow a tighter spot at the same focal length. Beam expanders have been used in co2 lasers.
I’ve been so clueless about this aspect, I just use beam expanders to lower the divergence of a collimated beam, but have seen lots of beam expanders on ebay for cutting, I never understood.
If I get time at some point I’ll go over why with you.