O-like 100mW green laser module TTL modulation focus problem

Hi, I recently bought the O-like 100mW green laser module TTL modulation and I have a focus related question. I managed to unscrew the cap and I got to a threaded disc that holds the focusing lens. If I twist it i can adjust the divergence. The problem is that I can reduce the size of the dot up to a certain point then it gets big again. The smallest dot I can make is quite large at around 40 meters. What can I do? Are there any additional focusing optics I can use?

The only way to achieve better divergence than what you have is to add a beam expander.