19 replies to this topic

[Andrea B.]

Last Update: 06 March 2015 17:30 GMT: Changed title and added a chart.

Just a few notes-to-self about glass. Thought I'd go ahead and post them in case you want an approximate transmission range.

Newport: http://www.newport.c...33/content.aspx
Sinclari: http://www.sinclairm...s/optical3.html
Edmund: OPTICAL GLASS SPECIFICATIONS

Fused silica: lenses, optics, high temp apps.

Silica, SiO₂.

Hard, very low thermal expansion, resists high temps.

Transmits approximately between 195 - 2100nm

Soda-lime: windows, containers/glassware

Silica + sodium oxide + lime + magnesia.

Easily formed, high thermal expansion, poorly resistant to heat.

Container glass has more Al/Ca and less Na/Mg.

Transmits approximately between 350 - 2000nm

Borosilicate: cookware, chemical reagents, mirrors.

Silica + boric oxide + soda + alumina.

Fairly hard, low thermal expansion, Pyrex.

Transmits approx between 380 - 2100nm.

(Is this range for borosilicate B7?)

From John Dowdy: Borosilicate transmits quite a bit lower than 380nm, 50% transmission can be <320nm depending on the thickness and grade.

Calcium fluoride: lenses, laser optics.

Fluorite, CaF₂.

Non-birefringent, high thermal expansion, don't use in hot environment.

Low index of refraction, anti-reflection coatings not needed.

Transmits approximately between 170 - 8000 nm.

Magnesium fluoride: lenses, windows, laser polarizers.

MgF₂.

Birefringent, useful in fluorine environments, moderate thermal expansion.

Low index of refraction, anti-reflection coatings not needed.

Transmits approximately between 150 - 6500 nm.

Zinc selenide: thermal imaging, medical IR imaging.

ZnSe.

Soft, scratchable, resistant to thermal shock.

High index of refraction, needs anti-reflection coating.

Transmits approximately between 600 - 16000 nm.

Sapphire

Transmits approximately between 100 - 600 nm ?

Lead-oxide: crystal glassware and decorative ware.

Silica + lead oxide + potassium oxide + soda + zinc oxide + alumina.

Dense, elastic, high refractive index, cannot stand high heat.

Alumino-silicate: fiberglass, in plastics.

Silica + alumina + lime + magnesia + barium oxide + boric oxide.

Oxide: fiber optics.

Silica + germanium oxide.

Very clear.

From Enrico Savazzi: Germanium (admittedly, not a glass but a metalloid) was used in the past to make IR lenses. Better alternatives are used today, since Germanium is sensitive to surface degradation. It transmits well between 6.5 and 13 micrometers (not nm), but has several narrow transmission windows also at shorter wavelengths.

Here's a nice chart from Edmund Optics: Link to Original Page
(More charts in posts below.)

[JCDowdy]

Borosilicate transmits quite a bit lower than 380nm, 50% transmission can be <320nm depending on the thickness and grade.

see also: OPTICAL GLASS SPECIFICATIONS

Edited by JCDowdy, 12 February 2015 - 17:03.

[enricosavazzi]

Germanium (admittedly, not a glass but a metalloid) was used in the past to make IR lenses. Better alternatives are used today, since Germanium is sensitive to surface degradation. It transmits well between 6.5 and 13 micrometers (not nm), but has several narrow transmission windows also at shorter wavelengths.

[Andrea B.]

Thanks, gentlemen !

The borosilicate trans chart shown was for B7 I think. I will add a note.

And also a note about the Germanium. Twice I've written Geranium !!

[JCDowdy]

I have a thermoelectrically cooled Germanium detector for an IR spectroradiometer.

I also have a Geranium detector with optional cool crumb sweeper.

[Shane]

Quote

Sapphire Transmits approximately between 100 - 600 nm ?

Depends on impurity levels and impurity type.

[Reed F. Curry]

We also have some good UV transmission with Schott WG225, WG280, etc. which are clear filter glasses. See http://www.schott.co...rt_2013_eng.pdf



And the Schott B270 has excellent UV transmission

Edited by Reed F. Curry, 14 February 2015 - 21:52.

[Reed F. Curry]

I have been using a number of different clear glass types on my new filter. Fused Quartz is available in different transmission capabilities, as is fused silica.

Schott sells a fused silica as Lithosil in differing grades.




see https://www.thorlabs...ata%20Sheet.pdf

Here is a good comparison graphic


Below are the curves for GE fused quartz. The GE 124 is a defacto industry standard for optical windows.

[lost cat]

How about lanthinum and thorium doped glass? Anyone try those for UV?

[Shane]

More than likely they will fluoresce to UV.

[Alex H]

Here is a catalog of modern glass from LZOS factory in Russia: http://lzos.ru/content/view/77/29/ And although the list is in Russian language, the leftmost column list current glass type names which themselves are links to spec sheets in English. These spec. sheets, among other things, provide internal transmission for 10mm and 25mm thickness for all glass types. Not all spec. sheets have detailed transmission data for 300-400nm range. Note also that the table lists equivalent (not identical) glass types for Schott (Шотт), Corning (Корнинг Франс), Hoya (Хойя) and Ohara (Охара).

[lost cat]

Alex H, on 24 December 2015 - 18:01, said:

Here is a catalog of modern glass from LZOS factory in Russia: http://lzos.ru/content/view/77/29/ And although the list is in Russian language, the leftmost column list current glass type names which themselves are links to spec sheets in English. These spec. sheets, among other things, provide internal transmission for 10mm and 25mm thickness for all glass types. Not all spec. sheets have detailed transmission data for 300-400nm range. Note also that the table lists equivalent (not identical) glass types for Schott (Шотт), Corning (Корнинг Франс), Hoya (Хойя) and Ohara (Охара).

Thank you for the link

At the top of the page is an English language button. Here is a link to the same table in English:

http://lzos.ru/en/in...task=view&id=54

[Andrea B.]

Now what is Ohara glass? I think I don't recall hearing about that?

[lost cat]

Shane, on 24 December 2015 - 16:30, said:

More than likely they will fluoresce to UV.

For 10mm sections of glass:

KF6 undoped crown has 50% cutoff at ~315nm

LK5 fluor doped crown 50% cutoff at ~337nm.
LK6 fluor doped crown 50% cutoff at ~325nm.
LK7 fluor doped crown 50% cutoff at ~315nm.

K8 borosilicate crown 50% cutoff at ~320nm.

CTK7 lanthanum doped crown 50% cutoff at ~337nm.
CTK9 tantalum doped crown, 50% cutoff at ~355nm.
CTK19 tantalum doped crown, 50% cutoff at ~342nm.

It appears lanthinum and tantalum doped glass can work but are not as good as other glass types. Of course that would depend on whether the doped lenses can be designed to compensate for the reduced transmission and perhaps may have other benefits to outweigh the drawbacks.

Too bad many of the data sheets don't extend into the UV.

Edited by lost cat, 24 December 2015 - 20:13.

[Shane]

The glass may still transmit into the UV but that doesn't preclude it from also fluorescing.

[lost cat]

Shane, on 24 December 2015 - 20:12, said:

The glass may still transmit into the UV but that doesn't preclude it from also fluorescing.

Well any photon that makes it to the other side of the glass with the same energy as it entered is a photon not impressed for luminescence.

But you are correct, transmission efficiency is but one part of the answer. Quantum yields and wavelengths would be the others.

And if the fluorescence is low enough rear mounting a filter might be enough to eliminate it.

Edited by lost cat, 24 December 2015 - 23:19.

[Shane]

Quote

And if the fluorescence is low enough rear mounting a filter might be enough to eliminate it.

Assuming that all fluorescence is occurring in the visible.

[Alex H]

lost cat, on 24 December 2015 - 19:11, said:

Thank you for the link

At the top of the page is an English language button. Here is a link to the same table in English:

http://lzos.ru/en/in...task=view&id=54

Thanks. I was not paying attention to English language button, since I speak Russian.

Unfortunately, these data sheets have limited use. The only publication of lens optical diagrams (from former USSR) that also includes glass types that I was able to find is an old GOI lens catalogue by Lishnevskaya.

[lost cat]

Alex H, on 25 December 2015 - 04:56, said:

Thanks. I was not paying attention to English language button, since I speak Russian.

Unfortunately, these data sheets have limited use. The only publication of lens optical diagrams (from former USSR) that also includes glass types that I was able to find is an old GOI lens catalogue by Lishnevskaya.

I wouldn't say that exactly. The data shows doped crown glasses don't transmit UV as well as undoped. My next question would be whether lanthinum doped elements might allow for a design that would compensate for the lower UV T.

[lost cat]

Shane, on 24 December 2015 - 23:39, said:

Assuming that all fluorescence is occurring in the visible.

True, any fluorescence in the pass zone of the filter would be problematic.