Victor Roberts wrote:
[snip]
It does not radiate as a blackbody because the CRI is listed
as "up to 88." However, the SPD is right on their data
sheet:
Fascinating SPD. Shows two sharp "dips", looking almost like absorption
bands, around 450 and 360nm. It would certainly make an interesting
specimen for spectroanalysis!
Might they be absorption in the fiber or a lens/reflector arrangement?
I just now got around to taking a look.
I notice narrow dips at 410 and 451 nm. I consider this typical of
indium. I have seen metal halide lamps with indium emission bands
broadened and self-reversed, and also broadened to unrecognizability while
the absorption features remain narrow enough to recognize.
I have seen that in some extra-blue HID headlight lamps - indium's blue
and violet emission bands broadened, mainly redward, through most of the
visible spectrum!
I don't recognize that roughly 520 nm bump as anything.
I recognize what I think are the 546 nm mercury line and the 590-596 nm
sodium feature - minor narrow bumps. I am guessing that the 436 nm
mercury line is not showing up due to the indium being optically thick in
the regions of the discharge that can produce this mercury wavelength.
The little 671 nm bump makes me think there is a small amount of
lithium.
As for that almost-770-nm bump: Makes me think potassium. But I don't
know why one would add potassium - a potassium compound maybe present as a
contaminant of the indium compound or of something else?
One thing notable: The CIE x and y chromaticity coordinates according
to the PDF. That data sounds to me greenish compared to an 8500K
blackbody.
- Don Klipstein (
[email protected])
