wavelength selected blue laser diodes

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Originally Posted by buffo

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.

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

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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.

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.

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