altA line of green laser diode modules available from BEA Lasers (Elk Grove Village, IL) is suitable for spectroscopy, particle measurement, medical tissue analysis, interferometry, holography, robotic control, and flow visualization. The Model 2501 is a fixed-focus CW diode pumped laser diode module with a beam divergence of <1.2 mrad. The laser housing measures 11 mm in diameter and 37.39-mm long. The front of the module includes threads so additional optics can be added. The Model 2503 is a fixed-focus CW diode pumped laser diode module with a beam divergence of <0.8 mrad. The laser housing measures 12 mm in diameter and 47.4-mm long. Both modules require 3 Vdc with operating current of approximately 300 mA.