Methods for evaluating performance a diode laser are provided. In embodiments, methods include receiving a laser beam profile of a diode laser, determining first, second and third laser beam widths at first, second and third laser intensities, respectively, for the laser beam profile, computing a first ratio between the second and third laser beam widths, computing a second ratio between the first and second laser beam widths, evaluating laser performance based on the first and second ratios, and outputting a determination regarding the suitability of the laser for use in a flow cytometry setting. Devices for practicing the subject methods are also provided, and include first and second stages configured to receive a diode laser and beam profiler, respectively. Aspects of the invention further include flow cytometers incorporating a diode laser that has been evaluated by the subject method.