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Building a orange (613nm) Laser from scratch with off-the-shelf parts (and for cheap!)

CurtisOliver

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Thanks 18LJ, I’m bookmarking that
 



farbe2

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I did already see that. However pressure chamber seems like a little understatement.

They did use 21kbar or 2100000000pa or 304579 psi thats equivalent to a water depth of just 210km or 130miles.
The deepest thing on earth is the mariana trench, thats just a mere 21km or 7,5 miles deep.

A .44 magnum reaches 35000psi inside the barrel.. so 10x more.

This would also increase the cooling power. The whole apparatus needs to be cooled because the diode gets suspended in a fluid.
I don't think i can achieve this, let alone in a pointer with tecs as a cooling method.
 

18LJ

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Ya i didnt anticipate anyone would be able to pull this off without access to some legit lab equip. i just thought maybe it would be helpful/ give ideas maybe cuz ur the first person ive seen in awhile try and pull of a temp wl shift. Plus its 2021 & about damn time we start seeing some orange around here!
 

Encap

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Ya i didnt anticipate anyone would be able to pull this off without access to some legit lab equip. i just thought maybe it would be helpful/ give ideas maybe cuz ur the first person ive seen in awhile try and pull of a temp wl shift. Plus its 2021 & about damn time we start seeing some orange around here!
Nice reference site.

Good graph of temperature effect tuning/26-28 nm tuning range for 635 nm Osram LD here: https://www.unipress.waw.pl/wtlab/index.php?file=kop26.php
 

farbe2

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Hello Guys,

i didnt sleep and got something to show.
Everyone ready for some nice 610nm photons? Sorry to disappoint you.

Progress:
I milled a case for the "Cryolaser". It consists of a outer aluminium shell that houses the TEC and diode.
The lid is fastend with 12 M3 screws. Tec is 4 stages and should get me down to -70°C (in theory at least).

Now i only need to get my hands on a vacuum pump to evacuate the casing.

image2.jpeg

I will keep you updated.
 

farbe2

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Hello Guys!

I did it! I managed to fire the thing up. First without vacuum. I got down to a promising -40°C! I didn't measure the wavelength at this stage. However it already looked like a deep orange.
IMG_0483.jpg

Next step: connecting the vacuum pump. The pump I currently have, only gets me down to 2mBar, not nearly enough to make the thermal insulation nice and good. However its better than nothing.
Turning the pump on made the temperature plummet. I got down to -62°C!!!
I got the spectrometer and started measuring.

621nm.jpg
Low and behold, I already got 621,5nm!

Thats only 14,5nm down from the start, with around 87k temperature difference.
That makes the drift around 0,166nm/k.
So getting to the maximum of the tec I am currently using (100k difference) would make that wavelength to around 619,3nm. Using the better but more expensive 5 stage tec with 120k delta gives me 616,08nm.
Using the 633nm diode to start with would give me 613nm! Just like my first prediction. Nice that everything works out.
I will get a better vacuum pump this weekend. I will see how good this gets.

This is a picture of the spot from 621nm and 638nm. The cam does not show the difference very well. Its clearly orange.
IMG_0485.jpg
 

farbe2

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I do have the 5mW version of this diode. It does not show the promised 0,2nm/K. It’s only 0,18nm/k from 25C to -40C. I do have a other diode that promises 0,3Nm/K, but I don’t think that’s true.
 

Sowee7

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Hello Guys!

I did it! I managed to fire the thing up. First without vacuum. I got down to a promising -40°C! I didn't measure the wavelength at this stage. However it already looked like a deep orange.
View attachment 73152

Next step: connecting the vacuum pump. The pump I currently have, only gets me down to 2mBar, not nearly enough to make the thermal insulation nice and good. However its better than nothing.
Turning the pump on made the temperature plummet. I got down to -62°C!!!
I got the spectrometer and started measuring.

View attachment 73151
Low and behold, I already got 621,5nm!

Thats only 14,5nm down from the start, with around 87k temperature difference.
That makes the drift around 0,166nm/k.
So getting to the maximum of the tec I am currently using (100k difference) would make that wavelength to around 619,3nm. Using the better but more expensive 5 stage tec with 120k delta gives me 616,08nm.
Using the 633nm diode to start with would give me 613nm! Just like my first prediction. Nice that everything works out.
I will get a better vacuum pump this weekend. I will see how good this gets.

This is a picture of the spot from 621nm and 638nm. The cam does not show the difference very well. Its clearly orange.
View attachment 73153
your getting real close to orange! i should make one of theese things
 

RA_pierce

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Really great work! Looks like all that effort is paying off.
Is the seal for the diode chamber good enough to hold vacuum for a while?
 

ZRaffleticket

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I'm curious about that and if the diode you have is canned or not. This is making me reconsider even bothering with a 622nm diode at all.
 

farbe2

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Really great work! Looks like all that effort is paying off.
Is the seal for the diode chamber good enough to hold vacuum for a while?
I am hoping to archive that. I did every „good practice“. The casing should hold the vacuum just fine. I did go to grate efforts to make every seal a metal/metal or metal/Glas seal. Everything should be very tight.

The diode is still in it’s can. There is only one Bar pressure difference, so no problems with the can window.
I will do experiments on longevity (keeping vacuum) and best diode. If I do have these Informations, I am thinking about a groupbuy for the 120k Tec. Price should be around 100€. Power usage would be around 80w. Maybe I could even offer CNC milled casings.
nice thing is: we could make this fully tunable from 613 to 640nm (heating and cooling).

I will keep all of you updated.
 

ZRaffleticket

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Yup nailed it, wasn't sure how the can would handle the pressure difference... but if it lost the vacuum and water got in, uncanned might also have an issue at those temps.

If you do end up selling these, I'd probably be in for two to cover ~613nm and ~621nm.
 




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