Spontaneous Beam Diversion?

[FRITZ HID]

I'm not very versed in the diode lasers but know enough to get thru my day however....

i have an eBay "200mW" pointer, DPSS Green and when i 1st got it, it seemed fairly stable however after a couple of months use (on and off, bursts not more than 45-60s) it started to behave oddly... after running for 5-10 sec (on new batts) the beam suddenly splits into 2 beams. one sharp, one slightly off & about 0.5 deg from the main beam.
i KNOW this laser has no IR filter.
it has never been dropped or shocked.
what would cause this? thermal damage of some type?
is there a fix?
TIA
-Fritz

 

[Encap]

Mode hopping? Switching from TEM 00 to a different mode?

See: https://en.wikipedia.org/wiki/Transverse_mode

Any of the output look like any of the below configurations?

 

[FRITZ HID]

no... close to 01 but not centered/divided like that... more like main beam weakens and a 2nd, weaker beam shoots off at a degree or 2 off the main axis.

 

[RedCowboy]

The glue that holds the crystal in place can get hot and the crystal can shift causing mode hop, it's easy to see on a wall with the output lens removed.

Typically not worth fixing, try a direct 520 such as an Osram PL-520

 

[FRITZ HID]

yep, seems to be the KTP.
took it apart and when i applied a chipchiller to the KTP mount the beam realigned. Wasn't an expensive laser so not going to stress about it. Maybe someday i'll find a use for the IR diode.

Tnx guys.