Laser-Scan refers to the method of both burning a barcode into a prisoner's skin and reading the same barcode. This was used for identification purposes for prisoners in Skynet work camps, which makes them analogous to the markings given to prisoners in many historic and modern prisons and prison camps (e.g. Ukrainian prisons, Nazi concentration camps, US internment camps, etc.).
Kyle Reese shows his barcode brand to Sarah Connor in The Terminator during the parking garage scene. Derek Reese and Allison Young are both shown receiving their barcode brands in Terminator: The Sarah Connor Chronicles.
In the real world, devices capable of both burning and reading barcodes (or optical media) use two different lasers. The scanning laser requires very little power (5mW), while the burning laser (usually of the same type) can use as much as 400mW of power (which, itself, is not very high as compared to a typical audio circuit, for example). The types of lasers used vary from device to device, but are usually semiconductor based, as opposed to gem or gas-based.