205 Raining, raining, raining every day at five o'clock on the dot. Switch it off.  Plasmons are collective electron oscillations usually excited at metal surfaces by a light source. Doped graphene layers have also shown the similar surface plasmon effects to that of metallic thin films. Through the engineering of metallic substrates or nanoparticles (e.g., gold, silver and copper) with graphene, the plasmonic properties of the hybrid structures could be tuned for improving the optoelectronic device performances. Since you added quite a few layers on your copper coils, you should try this as well. Multiple layers will tune up your coils to a specific range. Then, you shall find out what they are connected to, if you are still not aware of what you are doing. When the plasmons are resonant at the graphene/metal surface level, a strong electric field is induced which enhances the generation of SPIN-SPYRS.  Metals are only transparent to light with higher frequency than the metal's plasma frequency.  Ne 10 el23 cm−3.  which is ultraviolet.