While most computer art imagery some level renders an image on pixels or pixel like things (i.e. half-tone dots), there are other ways to do this. Laser light shows from the late 90s were essentially just expensive vector graphics hardware like the classic video games "Asteroids" and "Battlezone". The laser itself is always on and a particular location becomes brighter by the laser spending more time in that location, and it becomes darker by avoiding a location all together or passing through it quickly.
This image is just a mathematical plot showing three functions. The photograph is rendered using three "virtual" lasers (i.e. the functions) that each sweep a sine waves across the image from left to right at a constant rate and amplitude. When the source image needs more of a particular color, the frequency of the sine wave is increased, which in turn increases the energy of the image and the brightness rendered. For darker regions, the frequency of the sine wave is decreased.
As with a computer monitor, the eye fuses these sine waves together giving the illusion of a dense 2d image when in fact it is still just sine waves. This is most noticeable in the dark regions of the image, for example the top right corner or the eyes.