They explain that in the article. Light barely gets absorbed in water, which is why you can see several meters deep in water. Only the absorbed part can turn into heat.
They measured an effect that partly evaporates water more efficiently than the heat influx can. The theory mentioned in the article is, that light directly knocks out water molecules at the water/air surface boundary.
The measured effect was the most effective with light of a green wavelength
They explain that in the article. Light barely gets absorbed in water, which is why you can see several meters deep in water. Only the absorbed part can turn into heat.
They measured an effect that partly evaporates water more efficiently than the heat influx can. The theory mentioned in the article is, that light directly knocks out water molecules at the water/air surface boundary. The measured effect was the most effective with light of a green wavelength