Green diode laser modules are a rather new developed technology. As the active material in a laser source defines it's laser color (wavelength), it always requires special materials to create a certain laser source. Several companies strived to develop a green semiconductor laser source for years, and they succeeded to create a stable solution in 2012.
These green laser diode sources at 520nm are used in professional show laser light systems very often now, and the development of those semiconductor laser sources hasn't stopped yet.
The ready-built diode array modules are a good choice as they are very precise plus built in an extremely compact way. Due to industrial manufacturing processes the size could be more and more reduced and the efficiency more and more increased.