A TLD reader system has a laser diode that heats a thermoluminescent material causing a hemispherical photon emission that is collected by a ball lens. A filter ensures the ball lens receives and collects a predetermined transmittance value of the photons emitted within a predetermined range of wavelength. The ball lens sends the collected photons via a fiber-optic connection to a detection module. An infrared sensor senses the temperature and monitors the heating profile of the thermoluminescent material. A computer-controlled feedback loop maintains a constant output power from the laser diode.