RPL laser "dual beam" issue = wasted power demo

Aseras · Oct 24, 2007

Re: RPL laser "dual beam" issue = wasted power dem

Double beam is normal for dpss lasers. It depends on the cavity setup, you can waste it or block it. it's just a fact with using crystal's that you get extra beams. It's up to the manufacture to filter or block them for undesired operation. it's not economically feasible to recombine the beam output, the optics would be too large and too expensive.

example on sams site:

The ndyv04 produces mostly 1064 but also 532 ( and a handful of other trace lines )

LarryQ · Oct 24, 2007

Re: RPL laser "dual beam" issue = wasted power dem

Ok...

So is there a basic formula to predict the percentage of the secondary beam?

I mean, due to the crystal/lens matrix, (Nice graphic by the way!!) I see where some of the beam is going to become a by product...

Given that losses in the crystal chamber are at best unpredictable, is there a way to predict the secondary beam's Power level?

Say, given a 1 watt input from a 808 Pump diode...What would the best guestimate be of both beam power levels as individuals??

Or more to what most of us laser heads want to know.... If I measure the Primary beam at say 200 Mw, how much is being "Lost" from the secondary beam leaving at such an angle?

If this extra energy is indeed captured and blocked inside the head ..this would seem to be a Huge thermal problem to deal with.

Amazing the things that can be learned here on LPF!!!

LarryQ

Milos · Oct 24, 2007

Re: RPL laser "dual beam" issue = wasted power dem

Thanks for the input Aseras.
It still holds a lot of practical questions though!
Here are some of mine:

It depends on the cavity setup

Why would you choose such design? why not avoid it and preserve energy?

you can waste it or block

What do you mean by "waste it", and how can you just "block" half of the output ??. Isn't 100% of that 2nd beam becoming heat inside laser body?! Again, that alone sounds crazy to me.

it's just a fact with using crystal's that you get extra beams. It's up to the manufacture to filter or block them for undesired operation

Are you saying that ALL DPSS lasers have some sort of "second beam? And if its up to manufacturer, how else do they block them besides putting something in front that absorbs possibly extra 300mW+ of green?

I'm sorry I'm dissecting your post, but I cant hold questions in on this. All this is telling me that all dpss pointers actually produce as much as double of their rated "front" output power. Only problem is getting it all together into one beam. And its too difficult to join so one simply gets blocked and absorbed heat.

Great new stuff though, I'm kind of sad to hear about the wasted energy , but happy that there is a whole new story behind the process.

Rhith · Oct 24, 2007

Re: RPL laser "dual beam" issue = wasted power dem

This was grabbed from the BFG website.
"Lasers with a single dot are called TEM00 which stands for Transverse Electromagnetic Mode. Mode jumping to TEM01 or TEM02 will cause 2 or 3 dots respectively. Some lasers are manufactured specifically to be 2 dots. Primarily high-powered greens exceeding 200mW, or many blue lasers. This is normal though."

So it might be something that is needed? Interesting thing to ponder. We need to Jack over here to let us know what's going on.

Aseras · Oct 24, 2007

Re: RPL laser "dual beam" issue = wasted power dem

"it depends"

That's the answer to everything.

A good quality crystal setup with the right reflective and antireflective coatings in the right places is what makes the cavity. If you coat the cavity optics to block early 532 you loose some power and generate more heat in the crystal set. So they let the beams pass and block or divert them elsewhere and let the heat build up there rather than in the crystals or in the coatings. heat reduces the efficiency and too much heat will break down the coatings and the crystal and it'll burn. it's better to dump it somewhere else where it won't be a problem.

No matter how good the coating are there will always be some leftover that will get reflected or blocked simply because the light has to pass over 5-10 surfaces to exit. some stuff is just gonna bounce around.

it is in all dpss laser no matter what, the major differences are how it's dealt with.

These are still tem00 lasers. it's not tem01 or tem02. it's not blocking one part of a temo01 beam. some lasers are temo01 for a wider fat beam for visibility.

Kenom · Oct 24, 2007

Re: RPL laser "dual beam" issue = wasted power dem

Aseras said:
"it depends"

That's the answer to everything.

A good quality crystal setup with the right reflective and antireflective coatings in the right places is what makes the cavity. If you coat the cavity optics to block early 532 you loose some power and generate more heat in the crystal set. So they let the beams pass and block or divert them elsewhere and let the heat build up there rather than in the crystals or in the coatings. heat reduces the efficiency and too much heat will break down the coatings and the crystal and it'll burn. it's better to dump it somewhere else where it won't be a problem.

No matter how good the coating are there will always be some leftover that will get reflected or blocked simply because the light has to pass over 5-10 surfaces to exit. some stuff is just gonna bounce around.

it is in all dpss laser no matter what, the major differences are how it's dealt with.

These are still tem00 lasers. it's not tem01 or tem02. it's not blocking one part of a temo01 beam. some lasers are temo01 for a wider fat beam for visibility.

So you will see a complete removal of this problem once they develop a Green laser diode. Since it's not going through all the crystals and optics it doesn't need to go through so many surfaces. Excellent. Very educational aseras. appreciate it.

Milos · Oct 24, 2007

Re: RPL laser "dual beam" issue = wasted power dem

I see.
Thanks a lot for explanation Aseras. It sounds like a lot better choice to absorb heat somewhere outside cavity.
I guess RPL would be most efficient if second beam was let out "loose" and not blocked anywhere inside the body.

I hope to see in the future RPL "Dual Beam" model that sends this second beam out of the front of the laser as an option. It could be simply directed with mirrors and extra collimating lens so it fires out the front side by side with the primary beam. And if you want only one beam, you could block it in with a little door.

Wouldn't be very useful, but it would look cool as hell ;D ;D

sambo5472 · Oct 25, 2007

Re: RPL laser "dual beam" issue = wasted power dem

Very interesting thread, i'll be keeping an eye on this, learning lot's off new things

7histology · Oct 25, 2007

Re: RPL laser "dual beam" issue = wasted power dem

Yes, very interesting thread. Aseras is educational as usual. What progress if any is there in developing a green diode?

Aseras · Oct 25, 2007

Re: RPL laser "dual beam" issue = wasted power dem

green diodes exist just very $$$. By this time next year we should have some good ones.

rubberband · Oct 25, 2007

Re: RPL laser "dual beam" issue = wasted power dem

ok so does this problem also pertain to the aries series lasers from laserglow?

Aseras · Oct 25, 2007

Re: RPL laser "dual beam" issue = wasted power dem

So in the interest of science ( and the fact that my GF is out of town for the week and isn't nagging/needing me ) I've torn apart my rpl completley to show you all where and why this happens. I also took my little rpl 260 to over 500mw tinkering with it last night too.

Let me just add this, it's a BITCH to align this laser, it's very picky and the ktp rod is so long it's a pain to get it happy and back to tem00. I did greatly increase the power while scarificing some beam quality ( the divergance sucks now and theres some scatter thansk to the dual beam interference, but up close the beam waist has been made so small it always visible even in sunlight, and it'll draw on wood ( and my arm, hand... the wall )and burn it as fast as you can wave it )

I'm going to do a writeup and some pictures and videos.

RobTheVIP · Oct 25, 2007

Re: RPL laser "dual beam" issue = wasted power dem

Aseras said:
So in the interest of science ( and the fact that my GF is out of town for the week and isn't nagging/needing me ) I've torn apart my rpl completley to show you all where and why this happens. I also took my little rpl 260 to over 500mw tinkering with it last night too.

Let me just add this, it's a BITCH to align this laser, it's very picky and the ktp rod is so long it's a pain to get it happy and back to tem00. I did greatly increase the power while scarificing some beam quality ( the divergance sucks now and theres some scatter thansk to the dual beam interference, but up close the beam waist has been made so small it always visible even in sunlight, and it'll draw on wood ( and my arm, hand... the wall )and burn it as fast as you can wave it )

I'm going to do a writeup and some pictures and videos.

Gazoo · Oct 25, 2007

Re: RPL laser "dual beam" issue = wasted power dem

Wow...I can't wait for the media and write up. Very interesting..

Milos · Oct 26, 2007

Re: RPL laser "dual beam" issue = wasted power dem

I agree! This is like my favorite thread eva!!

Big thanks to all who contributed.

DoughDTD · Oct 31, 2007

Re: RPL laser "dual beam" issue = wasted power dem

bump...still hopin to get a response from jack about this

RPL laser "dual beam" issue = wasted power demo

Aseras

0

LarryQ

0

Milos

0

Rhith

0

Aseras

0

Kenom

0

Milos

0

sambo5472

0

7histology

0

Aseras

0

rubberband

0

Aseras

0

RobTheVIP

0

Gazoo

0

Milos

0

DoughDTD

0

Online statistics

Forum statistics

Share this page