Robin, Good suggestion, which I must have forgotten.
The problem with it for now could be practicality. Semiconductor lasers operating at 3.40 eV are not available, but UV LEDs are getting close. However, it would seem that you would need coherency, so we may be a year or more away from affordable UV semiconductor lasers (unless you know of a source). Pundits have been predicting UV lasers from GaN and AlGaN for a long time but AFAIK only excimers costing $$$ are available now for getting to 3.4 eV. Last time I checked eBay (last week) you could buy blue/violet lasers at about 400 nm, and Nichia has LEDs at 365 nm "peak", meaning don't count on it ... so they are getting there. These things show up on eBay before they appear in a catalogue. Nichia and Cree are the leaders. I wonder (assuming Bass is correct about sequential coupling) if there is anything "special" about an octave of coherent waves at 3.4 eV - in terms of coupling better - than say compared to 10 waves at 2.72 eV ? Obviously the fewer the better, but would an octave have a special resonance for coupling, as in music? -----Original Message----- From: [email protected] Hi, >In fact 15 × 1.81 eV = 27.15 eV, in good agreement with Mills 1991 value of 27.2 eV Which is why I suggested in some time back in private correspondence that they try a harmonic of 680 nm. Perhaps 2 or 3 times shorter wavelength. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/Project.html
