Is there any way to combine electromagnetic radiation from a broad spectrum into a narrow spectrum?

Question

The ideea is to bring a photon of any frequency to the frequency needed to ionise the desired material with minimal heat losses. The photons with high energy dissipate the excess energy as heat after ionisation, the photons with low energy dissipate heat without ionisation. Can somehow two sides of the spectrum be combined to form the middle?

In: 1

Answer 1

I’m inclined to say no to this. Unless the excess heat from the high energy photons poses an issue, it would be best to just lose that extra energy. Otherwise, flourescence could be used to release photons at the right wavelength. But this method would at best just transfer the excess energy to the flourescent material instead of to the area around the ionisation target.

I think the most you could do to improve efficiency would be to use photon upconversion on the low energy photons. This would allow you to use multiple low energy photons to emit a single higher energy photon. Again, this would involve a net loss in energy out vs energy in, but it’s an improvement in terms of total number of usable photons for ionisation.