Looking for a source for UVC bandpass filters

[PhotonWrangler]

I'm looking for a vendor that sells UVC (254nm) bandpass filters. I found a couple sources on the "Rainforest" site but I've never heard of them and they're far away with long shipping times.

Any ideas? This is for fluorescing minerals that only respond to shortwave UVC. I have a few UVC LEDs and I want to see how well they work with the visible wavelengths blocked.

 

[adamlau]

Shijiazhuang Tangsinuo Optoelectronic Technology a.k.a tangsinuo on eBay or Etsy. They may not have exactly what you are looking for in stock, but can probably custom what you need as the actual manufacturer and retailer. Be aware that they have a MOQ for custom orders. While not UV-C, I wanted ZWB2 0.5mm (CS) (similar to that on the HDS UV) and the minimum order was around 80 USD. I ordered and received multiple ZWB2 1mm (CS) from them and the quality has been excellent. At the very least, I know who produced it and where to go for questions regarding it.

 

[LEDphile]

Edmund Optics sells optical-grade filters in that range, among many others.

 

[PhotonWrangler]

Thank you Adamlau and LEDphile. I will check these sources out.

 

[electrolyte]

I am not certain that I understand your application so I'll ask. Would long or short pass filters work for you? They might be more efficient with respect to the amount of desirable wavelength passed and to cost.

These things must exist on old-fashioned hand-held (non LED) lights. Would those filters work for you? I asked because I assumed that they'd be cheap on ebay, but I did a search and did not see any.

 

[PhotonWrangler]

I am not certain that I understand your application so I'll ask. Would long or short pass filters work for you? They might be more efficient with respect to the amount of desirable wavelength passed and to cost.

These things must exist on old-fashioned hand-held (non LED) lights. Would those filters work for you? I asked because I assumed that they'd be cheap on ebay, but I did a search and did not see any.

Short-pass filters. I did find a source that worked out. My application is to filter out any visible light from either an LED or germicidal fluorescent source for my fluorescent mineral collecting hobby.

 

[Dave_H]

Short-pass filters. I did find a source that worked out. My application is to filter out any visible light from either an LED or germicidal fluorescent source for my fluorescent mineral collecting hobby.

I can't help with filter specifics, but it is interesting.

Which minerals do you find are activated by short UV (2537A)? I still have old samples around from decades ago, but not much which fluoresces much. My short UV light at the time was ac-only, perhaps could have built and inverter for it, but we were never at old mine sites at night; could have been hazardous to health in the dark.

Dave

 

[PhotonWrangler]

I can't help with filter specifics, but it is interesting.

Which minerals do you find are activated by short UV (2537A)? I still have old samples around from decades ago, but not much which fluoresces much. My short UV light at the time was ac-only, perhaps could have built and inverter for it, but we were never at old mine sites at night; could have been hazardous to health in the dark.

Dave

Franklinite, Willemite and calcite.

 

[Dave_H]

Franklinite, Willemite and calcite.

I scanned some old samples using 254nm old mercury tube light from decades ago which is still working; regrettably not much excitement. It has a visible filter, not sure which type. Minerals collected at the time included feldspar (including Amazonite), quartz (smoky and white, bulk), Apatite in Calcite (white or pink) and a host of others including some Sodalite from famous mine near Bancroft Ont.

Result with 400nm light also did not show anything much.

Dave

 

[PhotonWrangler]

I scanned some old samples using 254nm old mercury tube light from decades ago which is still working; regrettably not much excitement. It has a visible filter, not sure which type. Minerals collected at the time included feldspar (including Amazonite), quartz (smoky and white, bulk), Apatite in Calcite (white or pink) and a host of others including some Sodalite from famous mine near Bancroft Ont.

Result with 400nm light also did not show anything much.

Dave

Huh. Is your mercury lamp still able to fluoresce a postage stamp?

 

[sven_m]

As some last resort, you might try to find and reuse the glass pass filter from a small UV-C discharge tube light (4 Watts).
Pay attention that the pass filter is actually in place (I also saw models without it)

For illustration: once upon time I took a video and a gif-anim of some minerals, comparing 254nm and 365nm. Some minerals even show a short afterglow.

 

[PhotonWrangler]

On a whim I took one of my 365nm lights outside yesterday and looked at some pebbles on the ground. I think I found a little bit of fluorescent sodalite.

 

[Dave_H]

Huh. Is your mercury lamp still able to fluoresce a postage stamp?

The lamp is working OK, just not as intense as it used to be decades ago. Filter aging is likely a factor. Other fluorescent objects light up OK including stamp borders. I have a spare tube somewhere, in case.

I get a bit of weak activity, such as Calcite; just don't have much which fluoresces, may try outside as some larger pieces are there.

Dave

 

[alpg88]

convoy store, zwb3 filter, 255nm.

 

[Dave_H]

I found the box for my old UVS-11 254nm light, with some mineral samples which fluoresce,
Willemite/Calcite from N.J. and others.

Notes say the lamp filter is good for 500 hours. Even over so many years I don't think
it is anywhere close to that, but would the mere passage of time likely cause it to degrade?

Comparing to UVC LED sterilization lamp without visible light filter, the UVS-11 is still
way better even with its intensity down somewhat.

Dave

 

[PhotonWrangler]

I found the box for my old UVS-11 254nm light, with some mineral samples which fluoresce,
Willemite/Calcite from N.J. and others.

Notes say the lamp filter is good for 500 hours. Even over so many years I don't think
it is anywhere close to that, but would the mere passage of time likely cause it to degrade?

Comparing to UVC LED sterilization lamp without visible light filter, the UVS-11 is still
way better even with its intensity down somewhat.

Dave

I don't think those bandpass filters degrade much from the mere passage of time. It's the UVC exposure that causes crazing of the glass.

 

[sven_m]

convoy store, zwb3 filter, 255nm.

Thanks for the fine hint. I then ordered three of them (42x1.8 mm, only size still available).

They have sent UV-A/365nm-pass-filters, instead. I checked with UV-A and UV-C sources and a spectrometer (checking UV-A) and the float glass side of a window (checking UV-C).

I have replied to the store, sending pictures of my tests, that is, reporting "wrong item",
and asking if they currently do have real 254nm-pass-filters in stock.

I'll keep you updated...

 

[sven_m]

And I have then received the correct filters, without any hassle. Thanks Convoy.