The 520nm laser is not like traditional 532nm green laser. The 520nm laser is also green, it’s another green laser, the 520nm green is light than 532nm green, therefore it’s grass green or light green laser.
520nm laser diode is the key components for 520nm laser pointers or modules. Osram is one of the 520nm laser diodes manufacturers.
Osram PL520B, 520nm, 80mW Single Mode Green Laser Diode from laserdiodesource .
rpmclasers RWLD-520S 520nm Laser Diode.
aerodiode 520 nm laser diode – CW & Pulsed – Standard (Fabry-Perot) technology.
integratedoptics 520 nm Laser (Diode; MM Fiber).
Here are some sellers for 520nm laser modules,
520nm 5mw Green Laser Module Diode 515nm Laser Beam Dot Lazer Glass Lens Module from Amazon.