Repair of a mode hopping greenie.

[Uranium]

This is what i have to work with. What could cause a laser to mode hop, yet still lase at the rated power? I want to know if repair is possible before i break the glue.

 

[RA_pierce]

If it is still lasing at the rated power i would leave it alone.
What make is this laser and what is the rated power?

It may not be worth the trouble.
Mode-switching caused by the lasing material. In higher power DPSS it is more common and harder to avoid.

 

[kcorbhv]

from wl site

A mode shift may occur under extreme temperatures. If your laser unit is too hot or too cold, the beam may appear unstable and shift modes causing a secondary dot to appear. A mode shift may occur during the first several seconds of using your laser unit. Please note that as your laser “warms up” and returns to room temperature, the beam will return to normal mode, TEM00. The normal operating temperature of all Wicked Laser products is 10ºC ~ 40ºC. Using your laser unit beyond these parameters will damage your laser beyond repair.

 

[Trevor]

This is what i have to work with. What could cause a laser to mode hop, yet still lase at the rated power? I want to know if repair is possible before i break the glue.

The crystals are probably just ever so slightly out of alignment - it lases fine, but the effects from heating and cooling of the crystal are way more pronounced.

To fix this, you'd either need to ship it back or open the module and try to fix the alignment. In both scenarios, you'll probably have to fork out enough cash to replace the laser... :yabbem:

-Trevor

 

[BKarim]

all pointers are made xith factory glued crystals. so you can't fix alignement (assuming they are mis-aligned)

 

[Trevor]

all pointers are made xith factory glued crystals. so you can't fix alignement (assuming they are mis-aligned)

• The laser was fine.
• He dropped it a bunch.
• Pump diode is fine, optics are not causing the patterns.
• Crystals still lase.

Leads me to believe the crystals were knocked out of alignment, which logically means they can be realigned...

-Trevor

 

[Uranium]

I've decided not to screw with it. I don't want to make the problem worse.

 

[RA_pierce]

I've decided not to screw with it. I don't want to make the problem worse.

Good choice.
If it is any consolation, my PGL does not stay in TEM00, but it does output above and beyond the rated power.
I don't consider it a defect. It's "the nature of the beast" if you will.