A new solid state material converts visible light into high energy UV light

It is an interesting and novel development. I wonder how photostable the material is with hard uv photons being made inside it. It is impressive to do this at typical sunlight illumination levels.

Usually such frequency doubling requires non-linear materials and insane flux density. eg Doubling the NdYAG from 1066nm to green 533nm.

Frustrated scientists?

NIF has triplers, IR-to-UV, running at megajoules level. Has for decades. Over 80% efficient, AI claims.

The problem with organic triplers is that they may destroy themselves.

At 1.9% conversion efficiency of this thing, it would be far better to use solar panels and UV LEDs.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Trying to solve a particular problem cheaply.

But at very high light intensities. The output of a doubler goes up as the square of the incident light intensity, and the output of a tripler as the cube.

Depending on the power level and the particular chemical structure of the molecule doing the work.

Perhaps. Doing it inside a single complicated molecule means you don't have to put together a complicated mechanical assembly to make it happen.

Yea, I have a litle LED UV flashlight it runs on 3 Eneloop AAA batteries (in series).

And this:

I use a UV flashlight to cure Bondic. It's much better than the tiny LED thing that comes with Bondic.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

I have never used 'Bondic' I repaired a very old mp3 player's battery compartment with hotglue, when it hardens (cools) it stays in form.

I did a 'quick fix' with Tesa white masking tape when my old laptop srews failed to keep it closed after battery replacement, a broken lose in plastic embedded nut,, Thought will repair it later with some 2 componet glue... But after more than a year the tape still holds it together! better than the original screws! Amazing stuff.

The cool thing about Bondic is that it stays liquid until you hit it with the UV, and then it solidifies instantly.

I do worry about it hardening in tight gaps, which is one reason to use a high power UV source and squirt the light in edgewise.

Bondic, hot melt, epoxy, solder all have their uses.

A Manhattan-style prototype works best with epoxy.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

In message snipped-for-privacy@4ax.com, john larkin snipped-for-privacy@glen--canyon.com writes

Is good ole mercury vapour more efficient?

Brian

Probably not. You need to strike an arc in the mercury vapour to generate the UV, and the active bit of the arc gets rather warm.

Mercury vapour lamps have a silica bulb to let the hard UV get through, but the silica bulb also tolerates the high temperatures in the immediate vicinity of the arc. Technically speaking, an arc discharge is differentiated from a glow discharge by the mechanism that generates the electrons that carry the current through vapour that does the emitting.

Both get surfaces pretty warm.

I'm fairly sure that my old benchtop UV eraser used a low pressure mercury glow discharge lamp. The high speed industrial ones were probably arc lamps. John

I've got a very old hand held one that runs off batteries. It's got what looks like a 4" fluorescent tube , without the coating . It was probably used for detecting forged bank notes .

A bit like this ,but not LED

Brian

The UV emission depends largely on the material of the envelope.

Ordinary glass is moderately opaque to UV. Quartz or silica lets the hardest nasty UV through as used in EPROM erasers whilst Wood's glass lets soft UV through just beyond violet.

They were common for detecting fake stamps, banknotes, passports and car documents. If they don't have the right fluorescence then they are not produced using the right paper. I have one still in working condition.

Different minerals fluoresce differently under soft or hard UV.

A more interesting trick which has been developed for agriculture poly tunnels is a nano dot material that is transparent to visible light but downconverts blue to UV photons into red light wavelengths suitable for photosynthesis. Additional yields of 5-10% and less thermal stress in polytunnels has been reported in early trials.