What happens if a light source would slowly decrease the wavelength from visible to nonvisible light?

Question

Ie if we had a light that could emit light from purple to UV. Do we see an instant change from purple to nothing or does it slowly fade out?

In: Physics

Answer 1

here you can see a video of a green laser pointed at low temperature, when it’s very cold it becomes IR light, as it heats up it become more and more green

[https://youtu.be/9tOcUyakk0Q?t=204](https://www.youtube.com/watch?v=9tOcUyakk0Q)