565nm DPSS labby

[diachi]

It does "look" like a cheap 532nm laser. I agree with that. I doubt it is using a small 808nm diode for the pump. I would also like to know what they are using, but from what I can see, I can only guess at how they are doing it here.

We were talking about that earlier on Discord, ~808nm is likely, but it's possible that the pump isn't 808nm too. We need someone with a spectrometer that goes to ~1µm to look at one of these and give us an idea of what's happening.

What's going on with that crystal, from what I've seen they are all at an oblique angle to what we normally see, is it possible a common KTP crystal is being used for direct doubling when put at some strange angle? I know, that's one hell of a stretch, but why am I seeing the crystals off the normal axis?

Maybe I missed something but I didn't see anything in the pictures that indicated the orientation of the pump diode in relation to the xtal(s)?

More info about pump diode:

It’s voltage is 1,5V and current 1A

So, most likely IR at around ~1W. 1.5V puts it low for 808nm, but it could be running at a lower current than rated for that specific diode.

 

[Alaskan]

Sure looks like one side of that crystal is raised to me.

 

[Encap]

Well, I have done work with Dr.Laser before and after looking at his spectrometer printout and seeing the collimated dot, I believe they are lasers. Mine is supposed to ship out tomorrow. Will you take my word that it is a laser if I post a review? Or will you still say it isn't possible and I can't tell a laser from an LED?

Will be interesting to know your findings.

Don't have any trouble believing it is a laser.
Was just tending to believe/find plausible the manufacturer's saying it was otherwise being that 565nm and 575nm LEDs are dirt cheap and commonly available.

Could be a large size version of the cheapo mass produced small 532nm modules used in $2 pens, with whatever pump diode and crystal(s), that there is really little if any market for as lasers and is more suited to low cost "holiday lights"/image projectors

A cheap low quality item however it would be nice to know precisely what component technologies are employed if it is a laser-----pump diode, crystal or crystals, leakage at what wavelength, lens or the component parts and performance of whatever technique they are using.

 

[ZRaffleticket]

I find it odd they're being sold as holiday lights being just a bare module that they are...

@Alaskan - I think the one side looks raised from the camera not being shot 100% straight down the barrel, I needed a little angle to it to to show extra detail. That was the best pic of about 150. I couldn't remove the interior lens in the module because the Chinese love their glue.

 

[Alaskan]

From the beam shots and mRad report, no way this is an LED.

 

[ZRaffleticket]

This just in, divergence is now at 0.822 mRad. I've broken the glue holding the lens in place and since moved the lens into a better focus. Now this has better divergence than the best my 589 can offer.

 

[Alaskan]

Outstanding, your unit came from the China seller, correct?

 

[ZRaffleticket]

No - mine came from the Australian listing. The Alibaba heads look different from what was posted in the other thread

 

[steve001]

This just in, divergence is now at 0.822 mRad. I've broken the glue holding the lens in place and since moved the lens into a better focus. Now this has better divergence than the best my 589 can offer.

If there's room place a longer focal lenght pcx lens.

 

[paul1598419]

Can't wait to get my hands on mine. Too many unanswered questions. I was thinking the output collimator might be tweaked to improve divergence, but still waiting on mine to arrive. I am wondering also if the pump diode in these are under driven if output power might be increased using the driver's current adjustment.

 

[Benm]

This is a very curious thing!

Frequency doubling requires a very narrow wavelength, normally only produced by crystal lasers (as in your typical 532 nm, but also 473 and such). Diode lasers usually have a relatively broad output spectrum making it hard to impossible to do frequency doubling with their light.

So i wonder what they are doing here... To get to 565 nm you would need to start with 1130 nm when doubling, for 575 it would be 1150 nm.

Diodes with that output wavelength exist and aren't that rare or difficult to produce, but i doubt they could be easily frequency doubled - certainly not at this price point.

The only way to find out would probably be to take a spectrum all the way down to 1200 nm or so, and find either the output of a 1150nm-ish diode, or that of a (likely 808 nm) pump diode and solid state laser in the 1150nm range.

I have my doubts though... you can get laser diodes around 1064 nm, but good luck trying to produce any green light with those and a ktp crystal.

 

[paul1598419]

It is difficult, but not impossible. Diachi linked a 488nm laser done this way by Lazeerer. That was from 2013 IIRC.

Yes, it was a Melles Griot direct diode 976nm duobled to 488nm. Here's the link: https://laserpointerforums.com/f40/488nm-direct-double-mg-lab-laser-system-85658.html.

 

[hakzaw1]

looked for 'buy' link at that low price--all I find is $30 PLUS $49 TO SHIP?:cryyy:

:thanks:

 

[paul1598419]

Do you have a PL account? MagicL520 opened a thread there offering the 575nm lasers for $65.00 total.....including shipping. You might try sending him a PM.

 

[hakzaw1]

TY Paul
:thanks:

 

[Alaskan]

Maybe I missed something but I didn't see anything in the pictures that indicated the orientation of the pump diode in relation to the xtal(s)?

You must not be looking at the same photo I was looking at, never mind, I ordered one and will see for myself.

Edit:

Adding photo

The way I see it, the camera angle is such that the shape of the crystal is LESS exaggerated at that angle, not more, but maybe it's just a light artifact making the cube look that way.