Throttling?

[khurrle]

I bought one of the eBay 5mW greenies just to play with and have observed a behavior that I wonder about.

First off I havent ruled out batteries yet so that is a possibility.

When you press the button it comes on amazingly bright and is ever so slightly visible in a well lit room but then almost immediately it seems to throttle and die down to a much less intense brightness. All I had was a box of Ikea batteries so thats all I am using but even with brand new ones it seems to do it.

I will say however that when I swap the back ends of this pointer with one that a friend got at a local frys (with energizer lithiums in it) his does not do this and mine still seems to throttle

Is there a way to fix this or can anyone tell me why it does it?

 

[ElektroFreak]

Sounds like your standard DPSS temperature drift. All DPSS lasers (like your green laser pointer) are sensitive to temperature changes. When you use your laser, it heats up. This heating causes the drop in power you're seeing. Most green laser pointers are not intended for continuous use, so you need to stop and let it cool off to get your power back. Each pointer will behave differently from others, no two are exactly the same.

 

[khurrle]

while I could understand that for a laser that I had been using for a while, this seems to happen in the first 2 seconds of turning it on

is that still the norm?

I dont notice that my 405nm pen does it.

 

[ElektroFreak]

Your 405nm pen isn't DPSS, it's a diode laser which is quite a bit different. Since no two DPSS pointers are alike, the amount of time that it takes for temperature effects to become noticeable will vary considerably from unit to unit. It could be that one pen takes 5 minutes to heat up to the point of power less, while another takes less than 1 minute or even just a couple seconds. With lower quality pens and pointers these temperature effects are generally more obvious and occur in a shorter amount of time.

 

[khurrle]

I see, sorry for the ignorance here, I appreciate the guidance.

 

[ElektroFreak]

No problem at all! Threads like these not only help educate you, but they have the potential to educate anyone who reads them.

 

[BShanahan14rulz]

try putting your friend's energizer lithiums into yours. Make sure they are not rechargeable lithiums, but actually the energizer lithiums that you buy at stores.

 

[khurrle]

Yeah it still dims right away, maybe not quite as much but it still does it.

 

[InfinitusEquitas]

You would be better off with one recheargeable lithium 10440 and once spacer...

Won't eliminate the problem, but will help a bit.

Still, from experience with lots of pens... expect this one to die, sooner rather then later.

Best thing you can do is invest in a quality laser pointer from a good company.

 

[khurrle]

Yeah, I was thinking of ordering one of the really overspec ones from the guy that is selling them on here.

Ill probably contact him today or tomorrow

thanks

 

[Fretwrecker94]

Yeah, I was thinking of ordering one of the really overspec ones from the guy that is selling them on here.

Ill probably contact him today or tomorrow

thanks

Go for it! You won't be disappointed, they are a great deal! I had one (before I sold it) and loved it!

 

[Bluefan]

If a pointer starts showing this behaviour it may not be temperature related, it's not that it's thermal configuration suddenly changes. I have seen greenies that peak after a few hundred milliseconds, that was probably because the thermal lensing increased the cavity stability, heating the laser diode didn't give the same result.

I notice the same behaviour with cheap 5mW red pointers. In that case I suspected the switch to be the problem. If you have access to the driver you could experiment with that.