This is a weird set up but I'm trying to figure out at what angle of deflection a pendulum has based on using a laser point reflecting off an attached mirror. I've worked out the math but I'll need to know the height from the laser origin the beam is deflected at in order to figure out all the relevant angles.
This beam cannot be directly observed, however it is possible to observe after a few seconds so I need a way to 'preserve' the last position of the laser pointer for a few seconds.
Here is my current idea:
Take a glow in the dark paint and shine a UV light on it to 'charge' it and make it glow. Then use a 5mW red laser pointer in order to cause the point where the laser hits to lose it's charge so it looks like a dark dot surrounded by glowing green material.
Is there any alternative ways to doing what I'm trying to do? I know that by using a 405nm blue laser it will instead cause the point to glow so I can just make one specific point glow - but I do not have a blue laser pointer on hand so that's why I'm doing it in reverse with this red one.