Average power of green lasers - Question

[IgorT]

Many of you here have lasers from Nova, with peak and average power in the signature.

I have a question about the average power rating..
Is that the mathematical average of the power readings, or is it the power, at which the laser stays most of the time, and doesn't drop below it?


I have a 150mW from CNI (should be the same as Nova X150), that peaks at 172-174mW, but drops to 130 in only 30-40 seconds.. Is this normal? The mathematical average is still 150, but i kind of epected the power to remain above 150mW. Should i return it or were my expectations wrong?


Are there any power vs. time plots posted here?

 

[Switch]

It's the mathematical average of the power readings.If it peaks over the average, it'll drop under the average too. It would probably be more stable with better cooling, but that's a disadvantage of the small size of pen lasers. :-/

 

[IgorT]

Thanks!

That makes me feel a lot better. I was worried there is something wrong with mine.. Yeah, they would benefit a lot from better cooling and current regulation. Unfortunatelly, i don't want to dissasemble this one just yet. At least not till the warranty expires. I only just got it yesturday, and i'm already obsessed with modification possibilities..

 

[electron]

You also need to take into account the ambient temperature, it does make a difference; if the ambient temperature is say 90f, you'll get less power out of your laser than say 74f.

 

[IgorT]

Well, i've seen green lasers behave in a variety of different ways.

I had some, that would start high and slowly drop below the rated power, as they would heat up, and others of the same type, that would start below the rated power, and slowly climb above it with heat. I had to increase the heatsinking in the first and reduce it in the second one, to get both to behave perfectly.

I also tried cooling them below ambient temperature, and some became more powerfull, while others of the same type lost all power at that same temperature.

These crystals can be very unpredictable, even if they are from a quality manufacturer.

 

[CompWiz]

My green works better the colder it is,
if i leave it in my pocket it gets warm and will dim sightly after about 500ms.

If its cold(like after its been sitting in my basement for awhile at around 58F)
it can make certain black plastics smoke! (with a lens ofcorse )