Mitsubishi ML520G71...Red Holy Grail or Flashlight Fail ??

[LaNeK779]

Hi all:
just saw this on Ebay:
Mitsubishi 638nm 500mW CW ML501P73-02/Orange Red Laser Diode/1 pcs | eBay
I bought four--waiting on Kiyoukan's group buy optics to make a 4 Watt 635!

you are aware that 4 watts out of 4 diodes involves fearlessly pushing these diodes (some serious overdriving), aren't you?

[steve-o]

^ Agreed. I wouldn't push them over 750mW at the upper extreme. We know nothing about these diodes yet. You may blow them all out at once. :[
And 750 is just a SWAG. Don't quote me on that !!!

[Fearless]

I saw one driven at 1.6 amps, putting out 1.1 watt over at LPF. I'll go easy on mine, and work my way up.

[LaNeK779]

start with the upper limit of the recommended current (from the spec sheet)
in any case, do you have 4 watts of green to counter 4 watts of this red?

you might find that it knocks your colour balance seriously out of line

these get hot quick and in doing so, they lose power

[Fearless]

Well I have in my current projector I have 500 mW of green, ~ 2 watts of 445 blue, and around 2 watts (8 Loc diodes) of 660 red. I have to turn down the blue a bit to color balance, but it is a nice white beam. As for the new projector, I'll start with the Mit's p73 diodes, driving them to ~3 watts, make up a quad 445 at 4 watts, and wait on the green until Kiyoukan explains how he is going to do a 1 watt greenie for 400 bucks. Winnie sent me a current price list for a CNI 1.5 watt 532 MGl-H for $795.

[LaNeK779]

the mgl-h series is my favourite.
you start off with 3mm/2mrad beam and if you expand it to 5mm, you match exactly your red and blue
with this setup you will not need anywhere near 3 watts of red. you will be mega just with 2w.
and that quad blue would be overkill, but then again it is your setup

wait and you'll see!

ps. there are no free rides in dpss lasers, especially if they are home-grown... i wouldn't wait for too much to come out of it.
Of course i would be more than happy to be proven wrong

[Fearless]

Yes, I have a MGL-H at 500 mw and it is a great laser. The 4 watts of 445 maybe over kill, but run it through a PBS and corrective prisms, and the dicros--always losses. The red is going to be even worse. Green just bounces once in the mirror and then your done. I can always turn down the power down to match if it is too much. One never knows until you build the thing how much power ultimately you will get.

[steve-o]

Sooooo, the infamous mitsubishi 638nm 500mW ML501P73-02 laser diode has re-surfaced.. hmmmm. I wonder what the -02 stands for? Maybe rev 2, as in something was wrong with rev 1?? The price seems ok, considering less optics and less complexity due to less diodes for the given power output would be nice. IF-- the emitter size is the same.. AND .. if the optics that have been perfected here for the G71 (that is, Dave's lens and Dr Lava's and Kiyoukan cyl lenses) will work for this diode. I guess Time will tell. If they're still available after a month or so , I guess we'll seeee ....

[CDBEAM]

Thanx LC...I did use the M3 x .35 tap to thread the positioner holes...and then modified two taps to function as the positioners themselves. I went with a friction fit to attach knurled nuts to the ends of the taps. Considering that the " 100TPI Positioners" from Thor Labs are about $ 19.00 each....and the taps are about $ 3.00...seemed like the way to go !! Plus I got a " Steam Punk " look to boot !!

The real challenge was to machine concentric bores in the LD Position Disc...without the benifit of a lathe or DRO's !!! I ended up using the two modified end mills seen in the attached pic. I attached some stop sleeves to set the depth !! Worked good. Next time I will possibly use couter bore drills and as the final operation open up the bore thru hole to the correct dia. Lotsa ways to accomplish things !!

Also attached are close-ups of the LD position disc with the G71 pressed in. Work continues. An adjustable diode will likely make the optical alignment less complicated..IIRC

As a sidebar...I would not overdrive the P73-02 over 750mW....and that would be only under the condition with TEC !!

BEAM

CDBEAM great machining as usual!
Hey did you use a modified tap bit for your adjusting screws like was mentioned before on this?
Also, I cant recall the reasoning behind adjusting the diode mount rather than the lens mount... This was discussed I believe, yet I cant seem to remember!

[lasertack]

Anybody interested in a GB for the 500mW Mitsu? I´ve a cheaper source.

10pcs -> 125 USD each
20pcs -> 115 USD each
50pcs -> 110 USD each