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Thread: Cheap! 100mW/700mW 613nm (Orange) Laser Module

  1. #11
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    That makes sense!
    Thanks for clarifying!

  2. #12
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    With the mention of the liquid nitrogen video by tech ingredients, I looked and found it. He went down to 608 nm, but one heck of a lot of trouble to get there. Your unit to produce 613 nm is viable for both hobbyists as well as commercial sale, his, far too complex and large for most of us to want one. I like what you are doing and want one too, so from what I understand, that will be two of us so far.

    To save those who might not have seen the Tech Ingredients YT video showing his large liquid nitrogen cooling setup some time to find it, here's the link: https://youtu.be/0w4czym1FFg

    Perhaps this is basic stuff for you as a laser professional, but today I found this information regarding wavelength shifting of a NIR diode by as much as 10 nm just from the feedback produced when turning a grating in front of the diode inside an optical cavity, drawing below. Since feedback into the diode from the collimator and reflections forward of it can affect wavelength, this technique might be useful for your project too:

    Click image for larger version. 

Name:	Grating shift.png 
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    Perhaps by incorporating both the grating and TEC adjustments together you can reduce the wavelength even further? I just emailed the full article to you.
    Last edited by Laser57; 11-01-2021 at 23:51.
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  3. #13
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    Last edited by Laser57; 11-04-2021 at 01:27.
    Avatar is camera photo flash reflection. Doggy was found as a six week old puppy near dieing of thirst in the desert here in Qatar, she's a Saluki mix. I'm from Ohio, just working here.

  4. #14
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    Quote Originally Posted by Laser57 View Post
    With the mention of the liquid nitrogen video by tech ingredients, I looked and found it. He went down to 608 nm, but one heck of a lot of trouble to get there. Your unit to produce 613 nm is viable for both hobbyists as well as commercial sale, his, far too complex and large for most of us to want one. I like what you are doing and want one too, so from what I understand, that will be two of us so far.

    To save those who might not have seen the Tech Ingredients YT video showing his large liquid nitrogen cooling setup some time to find it, here's the link: https://youtu.be/0w4czym1FFg

    Perhaps this is basic stuff for you as a laser professional, but today I found this information regarding wavelength shifting of a NIR diode by as much as 10 nm just from the feedback produced when turning a grating in front of the diode inside an optical cavity, drawing below. Since feedback into the diode from the collimator and reflections forward of it can affect wavelength, this technique might be useful for your project too:

    Click image for larger version. 

Name:	Grating shift.png 
Views:	3 
Size:	129.7 KB 
ID:	58409

    Perhaps by incorporating both the grating and TEC adjustments together you can reduce the wavelength even further? I just emailed the full article to you.
    Probably not.
    I believe these gratings are used to narrow down the band from the available band you have.
    This is to make a laser a more narrow band by throwing away the rest (Makes the peaks sharper).
    I believe the grating is just becoming a wavelength selector so to speak for whatever is actually available within that laser.
    Or at least that's what I remember.

    I bet if that's the case though you will throw away a lot of your light.

  5. #15
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    Here's the article I was reading:

    https://photos.imageevent.com/qdf_fi...20external.pdf - password: yellow

    And now you pointed that out, the article is about LINEWIDTH, not reducing wavelength (edit: but the article ALSO mentions 10 nm wavelength shifting can be achieved).

    I just received a communication regarding the Sterling Cryocooler I posted the link to, no way I can afford that device, far too expensive for hobby use, but it would have been awesome to see how far down we could shift the wavelength if chilling below -200 C.

    Chris
    Last edited by Laser57; 11-04-2021 at 22:10.
    Avatar is camera photo flash reflection. Doggy was found as a six week old puppy near dieing of thirst in the desert here in Qatar, she's a Saluki mix. I'm from Ohio, just working here.

  6. #16
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    Quote Originally Posted by Laser57 View Post
    Here's the article I was reading:

    https://photos.imageevent.com/qdf_fi...20external.pdf - password: yellow

    And now you pointed that out, the article is about LINEWIDTH, not reducing wavelength. I sure got off on the wrong foot. I just received a communication regarding the Sterling Cryocooler I posted the link to, no way I can afford that device, far too expensive for hobby use, but it would have been awesome to see how far down we could shift the wavelength if chilling below -200 C.

    Chris

    Wouldn't be able to tell what but there are always surpluss products which may fit this need.. not great for wanting a steady supply to sell but for own use sure

  7. #17
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    I'm buying one of these units shown in the first post of the thread, but to build something myself I'm still looking for a chiller which will go lower than -100 C. with a five watt heat uptake, perhaps I will use a cascaded TEC module the same as Farbe is using in his design. However, I did find two more articles which demonstrate a grating can reduce linewidth as well as lower the wavelength of a laser diode by as much as 10 nm. So, now I have three sources of information confirming the wavelength can be reduced as much as 10 nm.

    See the attached document.

    "...Using a combination of multiple-stage thermoelectric cooling and water cooling, the operating temperature of a laser diode is lowered to −64 ◦C, more than 85 ◦C below the ambient temperature. The laser system integrates temperature and diffraction grating feedback tunability for coarse and fine wavelength adjustments, respectively. For two different diode models, single-mode operation is achieved with 38 mW output power at 616.8 nm and 69 mW at 622.6 nm, more than 15 nm below their ambient temperature free-running wavelengths. The ECDL design can be used for diodes of any available wavelength, allowing individual diodes to be tuned continuously over tens of nanometers and extending the wavelength coverage of commercial laser diodes."

    Edit:

    I have found another manufacturer of a Sterling Cryocooler which appears to be able to uplift far more than 5 watts of heat while keeping the temperature at or below -100 C. which are priced at $4200 USD for a sample piece. Although a quarter the price of the first company (ametek.com) I reached out to regarding their -200 C. (and lower) 5 watt uptake Sterling cryocooler, obviously still too high for a hobbyist, ouch.

    Clearly, I'm not paying that kind of money for something I can do with a stack of TEC's, but to add the information I was able to find about the Twinbird cryocooler; the temperature of their cooler varies by heat load, as all of them do, but is able to uptake a lot more heat than the first device I checked on (although achieves -100 instead of -233). Here's a link to the $4200 USD unit: https://fpsc.twinbird.jp/products/detail.php?product_id=92

    Blog on Sterling coolers:
    https://www.eevblog.com/forum/projects/ebay-stirling-cryocoolers

    "I have a little experience with Sterling coolers in thermal cameras.

    1. The fill of Helium is at around 200psi
    2. The Helium fill leaks out over time, so reducing pressure and the ability to reach normal operating temperature (-196C)
    3. You cannot tell a good sterling cooler from looking at it.
    4. Untested Sterling coolers should be considered faulty and priced accordingly. A broken Stirling Cooler is an expensive paperweight.
    5. A Sterling cooler that is described as working can mean many things. The motor runs, the cold end gets frost on it or more helpfully, the cold end reaches -xxxC. A Stirling cooler with low gas fill will still cool, just to not the normal operating temperature.
    6. I have yet to come up with a safe way to refill a Sterling cooler. The fill port does not appear to contain a valve. It is a conical seat into which a threaded plug screws and indium is used as she sealing gasket. This needs a clever adapter to allow turning of the threaded plug whilst under 200psi of Helium pressure. I have all the required gauges and pipe work though.
    7. Ballon Helium from BOC in the UK is pretty good but not ultra pure, as normally required for a Sterling Cooler. Any water content will freeze, causing piston issues. Ultra pure Helium may be ordered from BOC but costs around 150 in total and you are paying rental on the cylinder. The Cylinder is at around 250psi so a regulator can provide the required 200psi fill pressure for the cooler.
    8. Air is being added to Helium tanks for ballon filling to protect the worlds reserves of this gas. A 20% air to 80% Helium mix is fine for balloons but will ruin the helium for Sterling Cooler use in my cameras.
    9. Suicide by Helium gas hood is a well known method for those wishing to end their lives. For this reason, some suppliers are very suspicious about why you want pure helium as opposed to balloon helium. The 20% air in balloon Helium tends to make it non lethal.

    I have two Sterling coolers that need a Helium refill. The OEM isn't interested and boding it and it would be very expensive anyway. If you buy an old Sterling Cooler, expect it to have lost most or all of its Helium fill. Helium molecules even get through the aluminium casing material of the cooler !"

    Fraser
    Last edited by Laser57; 11-08-2021 at 20:05.
    Avatar is camera photo flash reflection. Doggy was found as a six week old puppy near dieing of thirst in the desert here in Qatar, she's a Saluki mix. I'm from Ohio, just working here.

  8. #18
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    A Cryocooler is the way to go for lower temperatures. However quite expensive and with limited lifetime.

    The grating can be used to tune the wavelength, its not only used to lower the line width. Its also used to lower the wavelength.

    Tuningrange is not unlimited and depends on the gain bandwidth of the diode used. The 633nm diode that the paper and i use, can only be tuned by around 2-3nm at these temperatures.
    The paper clearly states that. A grating does have losses and also costs a lot. So i did not consider it in my design.

    I worked closely with my tec manufacturer and got around 115k delta T out of my tec.
    Stacking more tecs does not make much sense. The seebeck effect does taper off with lower temperatures, so going to above 5 or 6 stages does not make much sense. Cryo cooler it is if you want below -100C with any significant power.
    So my design (except for the missing grating) is almost the lowest reachable without going to really expensive for the cooler or optics or diodes.

    Thermal Design is also quite important at these temperatures. Having to much heat loss will have even the biggest tecs struggle.

  9. #19
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    Farbe,

    Thank you for the update. I am also researching the available TEC's to determine which company offers suitable devices for this use, stepping through the same path you took in your research. I will probably just reach out for a consult from one of the reputable US based companies to see what they suggest. Edit: I have the info now, there are several companies, appears Laird is a good one.

    I love the Sterling coolers, but not the price, even the less expensive ones are sky high priced for hobby use, so that isn't going to be something I will be using, unless I can find one at a good price on the surplus market. However, from what I'm finding on blogs, finding a used Sterling cooler with some life left in it is not something which can be counted on, as these devices have such limited runtime and have too many problems, unless you buy one for 20K USD, then those will last but the price is crazy for us.

    Do you happen to know how far these diodes could potentially be shifted a lot more towards yellow if cooled to -200 C.? Just curious, too expensive for me to do so, but do you know if there is normally a limit to the ability to shift the wavelength, or if the shift is no longer as linear at the lower temperatures approaching -200 C? I will continue searching for this information, but if you knew that would save me some time, perhaps a lot. So far, I've found the shift on some red diodes can be upwards to as much as .3 nm per degree C. (typically between 0.15 and 0.25 nm/◦C), but so far finding no mention on what happens below -100 all of the way to -200 C.

    Thank you for sharing the results of using the grating with this diode. 3 nm isn't much for the added complexity and cost, but I'm still interested, depending upon how much loss through the grating and added cost.

    Above graph from an article showing the wavelength shift of a red laser diode through temperature tuning, with and without the grating. Article attached.
    Attached Thumbnails Attached Thumbnails diode temp.png  

    Attached Files Attached Files
    Last edited by Laser57; 11-08-2021 at 19:24.
    Avatar is camera photo flash reflection. Doggy was found as a six week old puppy near dieing of thirst in the desert here in Qatar, she's a Saluki mix. I'm from Ohio, just working here.

  10. #20
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    A Less Expensive Option: Multistage TECs

    From: https://customthermoelectric.com/pro...tage-tecs.html

    "Multistage (cascade) TECs can produce a larger Delta T than a single stage Standard TEC. Each additional stage adds greater capability in temperature difference (Delta T) but each successive stage adds less capability than the one before it. This leads to a limit of around 8 to 9 stages, but for most puposes 5 stages is the practical limit due to costs versus useful delta T increase.

    The most common multi-stage peltier modules are 2 and 3 stage. A typical 2 stage TEC delta T capability can range between 80C to 95C. A 3 stage can reach 95C to 110C, a 4 stage can reach 110C to 120C, and a 5 stage can achieve around 120C to 128C. These limits do depend on temperatures, the specific multi stage TEC, the heat sink, and ambient conditions. Multi-stage thermoelectric modules often have much lower Qcmax capability compared to similarly sized single stage TECs. This is because increasing Delta T capability with multi-stage TE coolers decreases Qc capability. Each stage must move all the heat rejected from the stage above it and additionally lower temperature itself."

    I just came back to add some more, I've been searching for a thermistor to measure the ultra low temperatures a multistage TEC can produce and not finding any, they don't usually go below -50 C, the lowest I've found so far at -58 C! However, a T-Type thermocouple will measure down to as much as -250 C. and the probes themselves are cheap, but the meters used with them, if accurate to -200 C. or lower, aren't so cheap. Just adding this here for others who might want to measure these ultra low temperatures too.

    Another thing regarding these TEC's, the specified delta-T (or temperature difference between the plates) are specified without a heat load on them and usually (for multistage), the figure is only good in a vacuum, not in air or a gas.

    Questions for the group:

    1. I am still researching how the heat load affects the delta T and could use some help with understanding that, if anyone here might be able to help.

    2. Does anyone know how much different levels of vacuum (i.e. 10 to the minus 3, 4 and 5 Torr) affect the full specified cooling performance of a four or five plate multistage TEC to be realized (assuming the spec. isn't too generous)?

    Edit: Laird is telling me 10-6 Torr is ideal which is considered a hard vacuum. Investigating the cost of a pump which can pull down that far they are way too expensive for me, perhaps filling with argon gas instead could be a reasonable alternative over using xenon which although far better is very expensive to get in an easy to use gas canister.

    I suppose there could be some kind of work around to inject the xenon gas from a glass ampule, which for a small chamber would be far less
    expensive, but due to the higher diode temperature the output would still be about 2 to 3 nm higher in wavelength than if using a vacuum, close to another nm more higher if using argon gas instead of xenon.

    NOTE: I am making a lot of assumptions to throw these figures out like this without having any experinece in the matter, zero. So why am I filling up this page with this crap? I'm hoping someone might jump in here and show me better. I need to find what temperature can really be achieved with the available multistage TEC's when there is about 2 watts of waste heat from the diode. This could throw these figures way off if I am being too optimistic regarding how low we can get the diode temperature using a TEC, whether in a vacuum or not.

    It is quickly becoming clear to me how much easier it is to just buy one of these from Farbie, as I am. Just the research on this is taking a lot of time, hours of googling over a period of days.

    This graph shows the effect (to the delta T) of air, gas or vacuum upon both a single and multistage TEC:
    Attached Thumbnails Attached Thumbnails TEC in a vacuum or air (1).png  

    Avatar is camera photo flash reflection. Doggy was found as a six week old puppy near dieing of thirst in the desert here in Qatar, she's a Saluki mix. I'm from Ohio, just working here.

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