“After Sunset” was created by artist Andy Gikling in Adobe Illustrator and exported into a laser control system called LasX. On deviantART, Gikling explains:

 

“The substrate is actually a cut of wood composite with a finish of standard chalkboard paint…. The piece is about 1 meter wide. The file was exported directly from Illustrator as a PDF and loaded into LasX’s Lightguide v5 Laser Control Software. The real-time beam control was performed by LasX’s Proton laser controller – the beam’s position is updated 100K times per second by the Proton controller. This control platform is able to consume all the PDF layer data and can work with layers containing grey-scale images as well as vectors/paths. The source PDF file contains over 70K vertices to define the vectors and the Lightguide v5 CAD engine loads it easily…
 
In the first part of the video the laser is ‘raster’ processing. Raster processing is the laser equivalent of the old school ink-jet printer style of paper printing. Here the beam is sent left and right across the material at a speed of 20 meters per second at a vertical repeat spacing of one pass per pixel in the image. The grey level in the image is mapped to the laser’s power output on the fly. This is how the chalkboard yields different levels of grey – we’re damaging the paint with just the right amount a power to get the effect…
 
The second part of the video shows the software ‘vector’ processing the piece. In this mode the laser beam follows the vectors defined in the PDF file. The geometry is perfectly aligned with the raster part of the image. A beam speed of 6 meters per second was shown. During this process the laser is outputting nearly 1500 watts of power. This causes the cuts to go through the paint and into the wood behind it – leaving an orange and brown color. The reason the vectors follow such a strange order across the piece is because a simple “proximity sort” was performed in the Lightguide v5 software before processing. [source]