445nm laser diode Nichia NDB7875

So much time without new lasers... I had to stop this! Just received Nichia NDB7875 - 445nm laser diode with nominal power of 1.6W:


Through the window one can see laser itself and static discharge protection device (it looks like small cube):


Let's go straight to the microscope. I was ordering this laser before, but that time I've noticed strange crack on crystal and returned laser back to the seller. This time "crack" is exactly the same - so apparently it supposed to look this way


Let's see how it works. I should warn readers that observing Class 4 laser emission via microscope is dangerous - I only did it via digital camera.
Minimal possible power, current is below 1mA:


~50mA, lasing threshold is still far away, it works in "LED mode":


~180mA, just before lasing threshold:


After adding 5mA - lasing starts, we can see interference patterns across the screen:


As laser diode heats up - lasing threshold gets higher and eventually lasing becomes unstable and stops. This camera has progressive scan - so we can see bands with lasing and in LED mode: