I'm looking for 441nm and 444nm diodes (at full power). Preferably looking for PLTB450B and GH04C01A2G but I'm open for offers.
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I'm looking for 441nm and 444nm diodes (at full power). Preferably looking for PLTB450B and GH04C01A2G but I'm open for offers.
Just grab any 445nm diode and temp control it. Playing with Py. Doped fiber?
445nm diodes can be as much as +-10nm off and they tune by 0.2nm/K. I'll kill most diodes before I move them to peak absorption
I think you can use a grating to tune them as external cavity in some cases. I usually have so much extra power I don’t care and just temp tune. My stuff doesn’t need power.Quote:
Originally Posted by atomd
I think you are underestimating just how robust modern blue diodes are. In comparison, Erick Meyers (Planters) was cooling red diodes (which are far more fragile) with liquid nitrogen back in the day to get orange out of them. That's a temperature drop of over 200 Kelvin compared to room temperature, and his diodes survived just fine.Quote:
Originally Posted by atomd
Even if you needed to shift the wavelength of a blue diode by 10 nm, that would only require a 50 Kelvin drop, which is quite achievable with a large peltier with a proper heat sink and very good insulation of the cold side. (The insulation is important both to maintain the cold temperature and to prevent condensation on the diode connections.)
With some careful selection of the diode beforehand, I think you'll be able to find a 445 nm diode that is within a few nm of 445, which only reduces the cooling you'll need.
More importantly, if you slave the temperature controller to a spectrometer, you should be able to control the output wavelength with great precision.
Adam
Guys, I think you underestimate my requirements. I want 10 to 20x 2W diodes, running at near full power. Building even 10 ECDLs takes an absurd amount of space and costs a ton of money. I can individually pull every one with maybe +-15K, but that still requires diodes reasonably close. To hand select them I'd need to buy a ton of diodes and select a few (especially for 441).
Keep in mind that there are plenty of blue diodes that can exceed 2 watts of output. The Nichia NUBM44 is rated for 6 watts, for example, although it's baseline output wavelength is 450 nm, not 445.
I suggest you reach out to Zach Collins (laserman121 here on the forum). He seems to have a knack for locating hard-to-find diodes that lase at uncommon wavelengths. It's possible he might be able to suggest a source for the 441 nm diodes you're looking for.
Adam
The problem is beam quality. I want to knife edge multiple low power diodes to get higher quality beam than form single, higher power unit.Quote:
Originally Posted by buffo
You could also reach out to Phritzler
Lasertack in Germany was binning 2 W blue laser diodes at 444 nm, but expensive!!! I don't know if he has any left now though.
On that note we did an experiment recently cooling a bunch of diodes using LN2. All red diodes survived all green and blue ones died around -150C.Quote:
Originally Posted by buffo
That's really odd. Historically the direct-injection blue and green laser diodes have been *far* more robust than any red diode ever was.
Although if you were using single-mode didoes, then all bets are off, as they tend to be very fragile no matter the wavelength. But it is quite surprising to learn that your reds survived the cooling when the blues and greens did not.
Adam
Building ECDLs may not be needed. I know of a projector with sixteen knife edged diodes that tends to "lock" on the back reflections and scatter of one diode. Turn the prime diode off or block it, everything else in the first bank of eight diodes noticeably went it's own way. The second block followed the stray light of the first. After observing that, I just had Thorlabs coat me two optics to play with injection locking or long cavity partial reflector ECDLs, ie 4% or less reflection on one side and AR coated on the other. In other words they coated one side and removed the stock window before coating the other side. Not too expensive for that action. I accepted "quality as coated" aka "Best Effort" in return for an excellent price. Uncoated side couples light to the grating or allows injection. Warning, do not inject more than a 10-100 mW into a high power device. Optical isolator not included, but a angle mistuned 80 Mhz AOM can act as a effective partial isolator for one direction in some cases, applying an 80 Mhz shift.
Steve
We have 56x OSRAM PLPT9 450LA-E unused diodes we are selling.
Let me know if these would work for you and you are interested.
Attachment 62275