2 green dots then they join

[caleb]

why does my laser have two green dots at first then they join to make a powerful one.

 

[daguin]

why does my laser have two green dots at first then they join to make a powerful one.

It's starting in TEM01 and changing to TEM00 as it warms up. How long does it take to change to TEM00? Does it stay there?

Peace,
dave

 

[Murudai]

Yup, classic mode hopping

What laser is it?

 

[diachi]

Your laser is mode hopping, it could be due to problems with the diode or crystals, or it could just be a temperature issue, if you tell us what laser it is we will have a better idea.

Diachi

 

[IgorT]

It's bad crystals or bad alignment... But it would be much worse, if it started as one spot and then split into two, after warming up..

If it was an expensive laser and has a warranty, you should still replace it. Even if it's a DX laser, you can just open a ticket, attach a photo of the two spots, and they will replace it for you. Unfortunatelly, you never know if the next one will be better with DX. :

Some of their lower powered ones are good, but the higher powered ones can be bad with five out of six!

 

[Petrovski]

Sounds exactly like the way my eBayser behaves.

 

[GooeyGus]

I would say two dots joining into one is not an issue at all, as long a it doesn't split back up. Many of these crystals don't like being cold and can go tem01 for a split second at startup before they join. I've used a few high quality lasers (nova/cni) that would be tem01 for about 1/20th of a second at start-up, then shift to tem00 and be fine way past the suggested duty cycle. Even with optimal alignment things like this can happen. Like I said, as long as it doesn't shift back over to tem01, its no big deal.

 

[110100100]

I have a p.o.s dragonlasers viper 95mw i got pretty cheap from a co-worker, it's beam splits near 2mins run time. Think it's just a temp issue since it's just a pen or is it just a crap diode?

 

[styropyro]

I have a p.o.s dragonlasers viper 95mw i got pretty cheap from a co-worker, it's beam splits near 2mins run time. Think it's just a temp issue since it's just a pen or is it just a crap diode?

It's probably just a heat issue, you aren't supposed to keep one of those on for two minutes straight. Can it burn at all when it isn't mode hopping?

 

[Abray]

My Galileo even did this. I couldn't tell when it was focused, but When I ripped it apart, and the divergence was slightly worse, it was obvious that it was starting up at TEM01 then shifting to TEM00. Just one question...further down the line of dissection, it made a half circle on one side, a line down the middle, and then another half circle on the other side. What mode is that? Almost 3 dots side by side, but a little flattened.

 

[110100100]

[quote author=110100100 link=1215328612/0#7 date=1215740227]I have a p.o.s dragonlasers viper 95mw i got pretty cheap from a co-worker, it's beam splits near 2mins run time.  Think it's just a temp issue since it's just a pen or is it just a crap diode?

It's probably just a heat issue, you aren't supposed to keep one of those on for two minutes straight. Can it burn at all when it isn't mode hopping?[/quote]

yeah, not great but it still burns before mode hopping.

 

[diachi]

Abray, it could be near TEM[sub]11[/sub] what one is it most like on this diagram ?

 

[Ace82]

With green lasers, mode hopping should hardly exist. 473 is another story, as the crystals are much more sensitive to heat. I'd be willing to bet that your laser is under powered in general. I'd bet that the crystals are slightly out of alignment. Once it warms up, it probably has as much power as it is supposed to at cold, thus the peak power output is most likely 10-20mW less then it should be.

 

[caleb]

its 5mw, off ebay (probably from DX). im sure its just temperature now becuase it takes way longer outside. i only find it a problem now as it is winter.