Mode-hopping!

[goninanbl00d]

Just when you thought it wasn't physically possible, this one diode decides that TEM04 is fun and dandy.

Unlike most laser diodes mode-hopping (between TE modes), this one actually dares to wander outside what can be loosely classified as TEM00.

Don't believe me? See for yourself.



The diode is from a DVD burner, power unknown. The diode is a short closed can, driven at 150mA for 90mW out, which is more or less reasonable.

I've checked that it's not vibrations, it's too regular to be vibrations. The laser was glued to the table during the run, too.

 

[millirad]

Yeah, that's one sick looking beam and not in a "good" way. LOL

 

[Benm]

That's odd... i guess the dvd burner in question was broken?

 

[goninanbl00d]

The DVD burner worked fine beforehand.

I suspect the diode is being overdriven.

It happens in bursts- it's been stable so far today.

 

[Trevor]

That's mad cool.

Sorry about the laser though...

-Trevor

 

[Toaster]

I had always knew this was possible. My 445 always seems to go into a strange mode when firing up, then quickly going to the regular dot. I realize this probably isn't the same, but it is interesting. Very cool

 

[goninanbl00d]

That's what actually happens with the 445 diodes, except with them it's actually intentional.

You see all the thin lines across it when you turn it on without a collimating lens?

Each of those bands is a mode running within a cavity.

Now, except with these diodes, they're designed to run multimode. Hence the larger die area (to allow for several modes to coexist).

Meanwhile, the diode has stopped trippin' balls, so I've gotten it an enclosure. Pics to follow soon.

EDIT: The diode is now LED'd. Flicked the power switch, and it went out after half a second. RIP.