Pioneer 112 Results (red Hot)

[carmangary]

I have yet to find a spec sheet for any DVD burner diode that says it will handle over 150mw or so continuous. Aixiz has one that says it will do 200mw but some people have suggested it is not correct. Anyway, even 200mw is a long ways from 350mw. I almost decided to notify Ebay that the seller is making grossly false claims about his item but then I decided I don't have time to worry with it.

[kaz]

The thing is carmangary as you know there is a trade off the more power that goes through the diode the shorter the life, most spec sheets tell you the max operating power fo a given life time, none of them as far as i am aware and you so rightly state give you a power spec for a diode that will run on double or triple the rated max power for an x amount of hours. its a bit like the pioneer diodes i am testing i still have one running in my work shop at 250mw and has been now for a few weeks if i could find spec sheet for it it would probably state some thing like max power 140mw at x wavelength but its running at 250mw how long it will stay at that who knows, iv been exspecting it to die for the last 3 or more weeks but just because it has lasted that long i would not class this dode as a 250mw diode im just saying abit like the guy on ebay that it can go as high as 250mw( and has for weeks) and it probably would go as high f as 350mw but for how long? 5 minutes an hour who knows the thing is the guy on ebay is on pasty ground but the thing is it might run at 350mw but what he doesent state is for how long thts the only problem i have with the add

[Zoof]

You first measure the horizontal difference between the refracted (or diffracted) spots of your two standard lasers. Now divide the distance between the two spots by the difference in frequency of the two lasers. Presto! You just found a millimeter-per-nanometer constant that you can now use to measure the wavelength of *any* visible laser.
<SNIP>
The only assumption is that the diffraction response of the grating is linear for all visible wavelengths, which is a reasonable assumption.

Hi Adam, thanks for the explanation and making the physics behind the diffraction and wavelength measurements accessible.
However, for the record, I need to say that the excel sheet I posted a few days ago does NOT use your quick and dirty approximation. The actual equation used in the spreadsheet is the exact equation describing diffraction as derived in the popular textbook `Optics' by Hecht (equation 10.7). In fact the diffraction angle varies constant with wavelength so the relation between the measured distances and the wavelength involves a nonlinear sine function.
Anyway, the mathematics are exact and, as a result, the calculated wavelength is as accurate as the accuracy of the taken measurements. So with a bit of patience and a good setup the wavelength can be determined pretty accurately.

As for the pioneer diode I'm looking forward to its lifetime. It is good to see that the higher power ones are also of a shorter wavelength.

best,
Matthijs

[andyf97]

I agree with you 100%, I only use these low power diodes for tinkering with ideas so I am just commenting/exchanging thoughts. We use 532m lasers in the regions of 3w-19w and have 6 x 3watt 650nm projectors based on combined heads. Actually we have around 30 projectors of various types even 15watt rgbs. The diode based lasers are getting interesting with the small size and low cost. Its just a shame its complicated to combine many of them and maintain alignment.

[andyf97]

it would be interesteding to find out what exactly kills these diodes when running them at maximum, is it a simpe case of over heating or do the diode junctions fail for another reason.

Kaz, are you measuring the diode temp during these long test, is it running hot to the touch?

I have some IR C-mount pump diodes that failed, I looked at them closely with a microscope and see the tiny gold wires connected to the chip had melted in the middle and these diodes had not been over worked. I am looking at this a lot as many chinese lasers that fail usually due for the same reason. I am wondering if the diode area was filled with an inert gas or another oxigen removal method may stop these wires actually burning away just in the same way inert gas is used in lamps to prevent the filliment burning away.

[buffo]

The actual equation used in the spreadsheet is the exact equation describing diffraction as derived in the popular textbook `Optics' by Hecht (equation 10.7). <snip> as a result, the calculated wavelength is as accurate as the accuracy of the taken measurements.

Hi Matthijs;

Thanks for the clarification! I didn't realize you were compensating for the non-linear effects of the grating. That's cool! And yeah, that will make your wavelength measurements very accurate indeed. (Assuming you've got a long throw so that you get good measurements on the spacing of the dots.) That's much better than the quick and dirty estimate method I described above.

Adam

[survey]

http://cgi.ebay.com/ws/eBayISAPI.dll...ayphotohosting

Hi there ppl, what do you think about these one?

A Pioneer 22X... 350mw? do they mean pulse or cw???

I'm working with mitsubishi's ML101J27 they are rated at 130mW CW
and 350mW pulsed and they are very good.

http://www.mitsubishichips.com/Globa...nm/ml1xx27.pdf

But i'm not using those colimating lenses that everyone his using.
As usual i'm on a industrial (heavy???) stuff, they have three lenses and a prism to correct astigmatism (all glass).
Results are a very nice round beam. See this picture to figure what I mean.

[carmangary]

Where did the mount come from? Looks nice.

[andyf97]

it certainly does look good and nice quality

[survey]

Hi Carmangary in fact it looks nice indeed.
And to all of you laserists, the best items I have like optics, motors,
multiface mirrors, first surface mirrors among others, are from dead
laser copier machines.
Don't you have a scrap yard nearby? prefer Konica, Minolta, Canon but remember they must be laser copier machines or heavy printers.
Old ones like QMS, APPLe , XEROX have plenty items too and with lucky
maybe some hene tubes.