A sensor for a laser may contain an at least partially transparent plastic with a fluorescent material that receives laser light at one frequency and creates light inside the transparent plastic with a second, different frequency. The light at the second frequency may travel through the plastic to an electronic sensor mounted against the transparent plastic. The sensor may be several feet in length or longer and still detect a single impinging Class I or Class II laser beam. In systems where the position of the laser may be known, a set of linear gain coefficients may be determined to calibrate the electronic sensor, as the signal strength of a received signal may decay with the distance from the electronic sensor to the location where the laser beam impinges the plastic element.