I work with a Sum-Frequency Generation (SFG) Femtosecond Laser Setup, and it is extremely necessary to keep accurate records of experimental conditions such as current, power, polarization, etc. I have a B.S. in Chemistry, and transitioning from chemistry to physical chemistry (laser spectroscopy) has been difficult, but not impossible. I had to read a ton of manuals and re-teach myself the basics of optics.
I find myself spending hours in the laser room doing experiments because I didn't know what to do and had to do the experiment by trial and error (basically playing with mirrors, beam splitters, periscopes, delay stages, etc) until I was satisfied).
Keep maticulous records, including temperature and humidity of the room, because laser spectroscopy is sensitive to such conditions. I only ask my advisor for help when I have exhausted all efforts on my part. Advisors like to see you solve problems on your own.
Have fun.