valeg96 - 24-4-2023 at 06:24
Hello everyone. I decided to invest some of my free time to measure the emission wavelength of a selection of ultraviolet lamps. I believe this will
be an interesting reference thread for anyone wanting to try photochemistry or working with luminescent substances, or simply with TLCs.
I decided to record these spectra as only very, very few companies provide the emission spectra of their lamps, and recording such spectra can be
extremely hard if you don't have a fluorimeter. More lights will be added in the future, if you have some specific tubes you want to be checked out we
could arrange a custom measure (I'm based in France).
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Generic 9W UVA Fluorescent tube, commonly sold for nail gel curing. (generic Amazon reference)
The emission max is 365±5nm, followed by 405, 436, 536, 576, 579, 738br
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Generic 5W Wood's lamp, of the kind sold for banknotes. (generic Aliexpress reference)
The emission max is 354±20 nm, followed by emission in the NIR at 731, 811, 842
Comparing these two tubes shows why these UVA lamps are usually referred to as BL (Blue Light, lamp for nails) and BL-B (Blue Light-Black, Wood's
lamp). A classic wood lamp is not as visible to the human eye and contains way less light in the green-yellow region.
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Here is the spectra of two commercial UV LED torches that I find are excellent, affordable and powerful, measured both with the glass filter they come
with, and without. (Amazon for TATTU U1 and Amazon for TATTU U1s)
The emission is at 367±7 nm for U1s and 383±2 nm for U1.
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These are two UV LED lamps by ThorLabs, which probably range in the 500-700 eur each (generic ThorLabs reference).
The emission is fairly sharp, with only a ±5 nm half width. There is NIR emission, though.
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This is an UVA lamp found in TLC lamps.
The emission is similar to the UVA lamp for nail curing, but the presence of a blue filter blocks most of the visible emission.
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This is an UVC lamp found in TLC lamps.
The emission is most intense at 507 nm, with peaks at 252, 312, 365, 405, 436, 546, 578 and 625 nm. The filter
present in the lamp mostly absorbs the light at the wavelegths in italics. The absence of this filter is likely why UVC lamps commonly found for water
or surface sterilization are very poor at revealing TLCs, as they are too rich is visible and UVA radiation.