> > Hi Philippe,
>
> I haven't tried taking photographs at these wavelengths, but I've had lots
> of experience with pulsed UV lasers and low-level UV and VUV (vacuum UV --
> below 200 nm) photometry/spectroscopy. For UV, you need fused silica
> optics. Much more expensive than BK-7 or BAK-4 glass. The highest
quality
> cultured quartz will get you down to as low as 150 nm, with transmission
> dropping like a rock much below that. Good fused silica can typically get
> you to 180 without much trouble. Anti-reflection coatings for these
optics
> are usually magnesium fluoride or calcium fluoride. Remember that below
200
> nm, absorption by oxygen starts to be a significant issue.
Any lead where to talk and ask for these "toys" I know they are expensive...
make a 15mm 3,5 feel like a lunch in a cafeteria. 250-300nm is my goal,
200nm just a dream ...
> Regarding your other questions.... A Newtonian telescope, when used as a
> prime-focus lens, would fit the bill as a mirror lens with no refracting
> elements.
What kind of mirror should be used for UV purpose ?
> Somebody on the list gave a reference for a couple of web sites
> for pinhole lens photography and pinhole camera construction. Can't
> remember the URLs, but I remember that the pinhole diameter for a 50 mm
lens
> -- for visual wavelengths (ca. 500 nm) -- is on the order of 0.25 mm. I
> believe the corresponding focal length at UV wavelength should be on the
> order of about half that value, or perhaps 25 mm. I think chromatic
> aberration may be more of an issue for pinhole lenses in the UV than is
the
> case in the visible region.
I was thinking to filter UV before the pinhole, then maybe just one
correcting lense, I don't really care about distortion at the moment ;-P
> I'm curious about what you might use as a film
> for UV, since the typical gelatin emulsion is going to absorb very
strongly
> below 300. Perhaps you could image directly onto a scintillation screen
> (e.g. a glass plate with a thin layer of fluorescent dye, or bleached
white
> card stock -- which sometimes has fluorescent dye), then photograph that
> image onto a standard emulsion? Sounds like fun anyway. Good luck!
I have access to 10"x15" UV sensitive Positive and negative film, I also can
sensitise copper and quartz =) Electronic design has some pluses... I was
just trying to combine the 2 together...
For the waffer they start to experiment on EUV ... like you said I don't
want to go under 200nm as Oxygen start to steal it for itself.
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