Leica DMIL Lamp Replacement IR Absorber

[microb]

So I finally got a replacement for the cracked optics window, that with testing proves to be a IR absorber -- not a blocker, absorber.

32mm dia, 2mm thick, slight blue tint, spectrums show reference IR, VIS, and UV in blue; with green being the cracked window and the gray the new. The block machine part is the optics and slide holder that sits above the iris of the lamp pointing down to the invert microscope stage.

Looks like an awesome match. I had to buy a min of ten though.

[MichaelG.]

So I finally got a replacement for the cracked optics window, that with testing proves to be a IR absorber -- not a blocker, absorber.

Great result ... Did you do the analysis, or did your supplier ?

If you did it: Please tell us more !!

MichaelG.

[Hobbyst46]

So I finally got a replacement for the cracked optics window, that with testing proves to be a IR absorber -- not a blocker, absorber.

Great result ... Did you do the analysis, or did your supplier ?

If you did it: Please tell us more !!

MichaelG.

Likewise, I feel puzzled by the spectra. They span from about 150nm to 900nm, scale marks at 50nm. What is the ordinate ? these look like neither transmission spectra nor like absorption spectra.

[microb]

Hi,

I used a USB 2000+ Ocean spectrometer. I set up three LED lights, one for each run. The IR LED is 850nm LED, and as shown does have a varying lobe, like the other LEDs shown. So when looking for a replacement glass window (32x2mm) there are filters listed as IR blockers, but the Leica window was clearly not blocking IR just reducing it. So the term that worked in finding a replacement was an IR absorber.

In the graphs, the blue line represents a light source angled so as to not max-out the sensor.

The green line is the Leica window placed in front of the spectrometer, filtering the light. Light source of course was not moved in anyway as it is a reference.

The grey line is the new replacement IR-absorber window place in front of the spectrometer slit just as was done for the Leica glass window.

The ratio would be the transmission. But I'm just interested in seeing a match.

[MichaelG.]

I used a USB 2000+ Ocean spectrometer. […]

Thanks for that ^^^
It looks worthy of investigation.

MichaelG.
.

Edit: Just found some very helpful notes about it, here:
http://ugastro.berkeley.edu/infrared09/ ... ometer.pdf

[Hobbyst46]

Thanks for the explanation, microb.
The Ocean Optics 2000 spectrophotometer is a cute little instrument, a pleasure to use.
My experience for a good and relatively cheap IR-blocker is a KG5 or KG3 filter from Schott. These are absorption filters. They can be used even with a 100W mercury lamp, although if exposed for a long period they eventually crack.

[microb]

cheap IR-blocker is a KG5 or KG3 filter from Schott. These are absorption filters. They can be used even with a 100W mercury lamp, although if exposed for a long period they eventually crack.

These are KG1 at $6 each bought as a set of ten, which includes shipping divided over the ten.

I couldn't get Schott's website to let me set up an account.

I'd like to by optical glass blocks sometime to lap.