laminar flow
Laminar flow will exist only if the airfoil is smooth. If a small spec of dirt or bug is stuck near the leading edge it will trip the laminar flow. Nobody has figured a way to avoid bug impacts as far as I know, so laminar flow is not really found in actual operations(sailplanes can benefit from laminar flow lower drag, but only if the pilot cleans the wing before flight and flies through the lower atmosphere without striking many bugs. Each bug leaves an expanding wake.
Also the airfoil profile must be designed for laminar flow and I dont think helicopter airfoils are designed for laminar flow.
And the airfoil must be carefully sanded to provide a smooth flow.(no waves in the surface more than .003" in two inches)
If you can feel any imperfection with your hand, it will not support laminar flow.
I would forget about laminar flow. The studies mentioned were probably made with smooth airfoils in a laboratory.
Turbulent separation is something to think about however, and vortex generators are normally employed to prevent the reverse flow of turbulent separation and the high drag and loss of lift.
Another idea would be something 3M company was working on years ago. They invented something called "riblet skin" (I think) a plastic skin with micro grooves that reduced drag similar to the shark skin zeeoo mentioned.
But it could be big problem if the tape starts to disbond in flight, think about that before you modify a blade. I applied some duct tape once to the tip of my airplane prop to experiment with balance. Then I flew it. The tape came off part way and made a buzzing noise and I could barely climb. Little things can have a big effect.
slowrotor