For lasers in fiction, see also the ray gun.
Before stimulated emission was discovered, novelists used to describe machines that we can identify as "lasers".
A laser-like device was described in Alexey Tolstoy's sci-fi novel The Hyperboloid of Engineer Garin in 1927.
Mikhail Bulgakov exaggerated the biological effect (laser bio stimulation) of intensive red light in his sci-fi novel Fatal Eggs (1925), without any reasonable description of the source of this red light. (In that novel, the red light first appears occasionally from the illuminating system of an advanced microscope; then the protagonist Prof. Persikov arranges the special set-up for generation of the red light.)