• Ultraviolet Photography
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Arc lighter in UV

UV Camera
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#1 JMC

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Posted 05 August 2020 - 11:29

Browsing ebay the other day I came across something called an Arc lighter. This generates an air plasma between its electrodes as an alternative to a traditional fluid based lighter. As it didn't cost much I thought I'd get one and see what the emission spectra was like.

Here's the lighter, without and with being lit.

Attached Image: 20200804_122945.jpg

Attached Image: 20200804_123013.jpg

When I put my cosine correcter terminated optical fiber close to it (very close, about 5mm) I just about managed to get the irradiance spectra;

Attached Image: Arc lighter irradiance.jpg

Very similar to what I'd expect for an air plasma which was good to see, but really not very bright.

Also took some pictures of it in UV, using the ACS converted Nikon d810 (similar response to Baader U), and Rayfact 105mm UV lens. Whitebalanced in Darktable, and cropped from originals. Couple of different exposures.

Longer exposure (ISO1000, 6s, f16).
Attached Image: DSC_8615 cropped.jpg

Short exposure (ISO1000, 1/2s f16)
Attached Image: DSC_8618 cropped.jpg

Obviously with the longer exposure the emission over saturates and goes white, but you can see it illuminating the lighter a bit. At the shorter exposure, the 2 back electrodes are behaving differently to the other 2. I can just about see a hint of yellow in the bulk of the plasma, which make sense given the large emission peak in the 340nm region.

Overall not the brightest little UV source (I wont be replacing my Xenon flashes any time soon), but an interesting little device. Part of me wonders whether it shocks like a taser, but I currently have no plans for putting my fingers on the electrodes to try it.....
Jonathan M. Crowther

http://jmcscientificconsulting.com

#2 Cadmium

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Posted 05 August 2020 - 11:31

Jonathan, Very interesting! Thanks. :smile:

#3 UlfW

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Posted 05 August 2020 - 11:50

I wonder how much EMC-noise emission it have.
Ulf Wilhelmson
Curious and trying to see the invisible.

#4 Stefano

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Posted 05 August 2020 - 11:51

That's an interesting spectrum. A peak every 20 nm.

#5 colinbm

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Posted 05 August 2020 - 12:09

I wonder what volts & amps are involved here ?

#6 Stefano

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Posted 05 August 2020 - 13:10

View Postcolinbm, on 05 August 2020 - 12:09, said:

I wonder what volts & amps are involved here ?
Maybe 20-30 kV (assuming a 1 cm gap) and probably a lot of current for a short period of time. The average current is probably very low.

#7 JMC

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Posted 05 August 2020 - 14:58

A quick search led me to this spectra;

Attached Image: Emission-spectrum-of-DBD-plasma-operating-in-air-under-atmospheric-pressure.jpg

From here - https://www.research...of_Biomaterials

Peaks look to be a pretty good match.
Jonathan M. Crowther

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#8 Stefano

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Posted 05 August 2020 - 15:04

Yes, it looks pretty similar.

#9 OlDoinyo

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Posted 05 August 2020 - 15:24

I have long wanted to try lightning photography at night in UV. This could at least be considered a proof of concept--there would indeed be UV to record.

#10 Andy Perrin

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Posted 05 August 2020 - 18:47

Well that is very cool, both as a device concept and the measured spectrum you made.

#11 dabateman

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Posted 05 August 2020 - 22:28

View PostOlDoinyo, on 05 August 2020 - 15:24, said:

I have long wanted to try lightning photography at night in UV. This could at least be considered a proof of concept--there would indeed be UV to record.

I think a 365nm led flashlight would be much brighter, safer and more ideal than a literal torch for lighting.

Jonathan,
Very cool. This could help in building a vaporized iodine lamp that I have always wanted. That way I can get a 207nm line.
I might consider something like this.

#12 colinbm

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Posted 05 August 2020 - 23:14

I wonder if a Plasma Cutting Torch has the same spectrum ?

Posted Image

#13 colinbm

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Posted 06 August 2020 - 12:12

Using your microwave oven to make blue violet plasma....Don't tell Mum
https://www.youtube....h?v=l0u8Vtf2GoQ