Melles Griot 561nm Lab laser

[ultimatekaiser]

Update: think it might just be a slight alignment issue. Was experimenting with orientations today, and got TEM00 @ 8.1mW out of it after laying it on its right side! Other orientations yielded weirdness and less power @ TEM01. Maybe it got a bit bashed up in shipping afterall. There's no rattling so whatever is loose it's not by much and gradual. Things are looking better!

Edit: up to 8.81 mW from leaving it running

 

[ultimatekaiser]

HUGE UPDATE!

Fantastic news to report. I have successfully realigned this head back up to full power! turns out the block holding the pickoff lens was loose and not fastened down properly, possibly from multiple thermal cycles, or laziness at the lab. the crystal mount TEC was also very slightly 'un-snug' so I adjusted it a bit, and after a while of fidgeting, (while multitasking talking to Bloompyle and Laserman121 on skype) I gave them a slight show as I cracked open the head and did my work. after I reseated it, it's now giving its rated 10mW+....!

Put it through a few thermal cycles tonight and it seems to be holding. output is 10-11mW stable on my wooden desk. would probably be more stable on something aluminum to sink the heat to, as it cycles between the two powers slowly over the course of a few minutes up, and then back down etc. It has a most glorious TEM00 that I have EVER seen from a DPSS head, rivaling that of a gas laser! Simply amazing!

Executing a power reference command has always spat out an ugly 10.5 in my face...so now its the truth! ~10.5mW +/- 0.5mW basically. Making it a +/- 5% power stability head.

Metering at 11mW:

The brightness of this wavelength is insane! it is very hard to look at even at 10mW. Its rather impressive to see despite the color being so odd. Quite an amazing laser! :tinfoil:

Free beamshot off of a Silver (Ag) first surface mirror :beer:

 

[crazyspaz]

Awesome 561 is a wavelength I hope to have some day...
Just curious, do you have any idea of the pump power?

 

[Sigurthr]

Very similar layout to the 473s I worked on. Glad to see you got it back to full health!

 

[ultimatekaiser]

Awesome 561 is a wavelength I hope to have some day...
Just curious, do you have any idea of the pump power?

Not sure, but I'm estimating around 1 watt. The 1123nm line is about 15x smaller than 1064nm. And a 1.1W pump gives around 160mW+ of green 532 on average if done really well.

 

[Cyparagon]

The brightness of this wavelength is insane! it is very hard to look at even at 10mW.

Sorry to tell you this, but it's in your head, d00d.

11mW of 561 is just as bright as 12.3mW of 532.

 

[ultimatekaiser]

I know the relative brightness isn't much higher. But it really is noticeably brighter than 10mW or so of 532 to be sure. Especially as the beam diameter is sub mm at the aperture. It's almost blinding intensity-wise to shine it on a white surface within a foot or two of the head.

 

[crazyspaz]

I believe it- looking at the spot from one of my hene's at abiut a foot away on a white surface seems stupidly bright. Granted, the spot is probably ~.5mm or smaller. All about power density, I suppose (well not ALL about)

 

[bloompyle]

Nice to finally see the annotated picture. Very interesting how just the pickoff alone can single-handedly screw up the entire cavity. Sending the wrong signal to the TEC, cooling or heating the diode more, throwing off the wavelength, and messing up the conversion ratio. On top of modes and every other nuisance that thing prevents.

Was very insightful to see this alignment process happen in real time. I only hope to do be able to do the same in the future with upcoming projects of my own. You've already been a great help during this transition.