Hello, my team and I are building an underwater ROV for a competition. We are thinking of using lasers for measuring the distance of what we have to measure. Has anyone ever had an experience with doing this method and how did you do it? Also will you have trouble with refraction with the laser underwater, and if so which color laser would refract the least? Thanks to any responses.
Refraction between air and water is not a big issue. You can calculate how to align the lasers. In the water the laser will travel straight as it does in air. If you have turbulances in the water, air bubbles and stuff like that it will interfere with the light propagation.
For the wavelength blue is least absorbed in water. You can google the wavelength dependent absorption coefficients. It depends on the penetration depth you want to achieve. Most probably intensity differences between low and far distances will be most challanging.
I hope that helps you a little bit
Daniel