Burning, I am not impressed...

... with using lasers to pop balloons, burn through tape..., it's a neat trick. If one wants to burn stuff using light's energy this is the way to do it. Use a very large Fresnel lens. With such a large lens one can make lava, vaporize or melt metal... . This is the way to burn stuff.
https://www.youtube.com/watch?v=svAPyyUJUCo