There is no way a laser can cut through adamantium. Adamantium can only be cut by adamantium, really. The metal has been see numerous times resisting all manners of lasers, beams, explosions, hits, cuts. Plus, it's sad to say, but I wouldn't think that a lightsaber's blade is more powerful than... say... cyclop's ray.
To my opinion, IF a lightsaber could cut adamantium, it would take a long time to go through it, and though it would be practical if one would want to go through a wall or a vault, it would be totally innefective in a fight.
Scarim Coral said:
T I read that in one of the comic Thor Hammer can only dent Captain Shield (which is made of Adamantium) at best.
I agree, but Cap's shield is made of an adamantium-vibranium alloy, which makes it also energy absorbant, which explain why cap didn't get crunched under his unscathed shield.