Dot laser modules occurred malfunction

[xenon4454]

I bought 2 638nm red laser modules. one was 500mw and the other one was 700nm.

Both of them had an issue.I discovered focusing problem from laser modules.

The dot won't be focused, get bigger and bigger as further from laser module.The beam spreads a lot too.

I couldn't solve this problem If I've tried change focusing lens and cleaning lens, laser diode a lot.There was nothing to be changed, how could it be solved for?

 

[WizardG]

No simple lens will focus the high power red diodes (or any of our high power diodes with the exception of the violet BDR-209) to a point. All these high power diodes will focus to a line. The high power red diodes are the worst in this respect..

This can be corrected with special optics. Search for 'cylindrical lens pair' and 'anamorphic prism pair'

 

[xenon4454]

No simple lens will focus the high power red diodes (or any of our high power diodes with the exception of the violet BDR-209) to a point. All these high power diodes will focus to a line. The high power red diodes are the worst in this respect..

This can be corrected with special optics. Search for 'cylindrical lens pair' and 'anamorphic prism pair'

thanks. Now I'd better not to buy high-powered red laser modules.

 

[paul1598419]

That 500 mW one is likely the Mitsubishi ML501P73 and it can be safely driven to get over 1 watt output. They do focus to a line because of the emitter shape, but if that concerns you the special optics WizardG alluded to can mitigate that to some extent. The 700 mW one is likely the Oclaro. I have only had bad luck with these trying to get close to 1 watt outputs. My advice is to stay away from that one.