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Dealextreme 50mW red is actually a 635nm red laser !!

Blord

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When I bought this red laser from dealextreme, DealExtreme: $12.80 50mW 650nm Red Laser Pointer Pen (2*AAA), I was confused about the real color of this red.
I posted a picture of the dot comparison in this thread, http://laserpointerforums.com/f50/quiz-guest-wavelength-red-laser-58722.html
Visually the color looks very similar to the 40mW 635nm Sanyo diode from Ebay. But it was not a real proof of a 635nm diode.
I was thinking about a scientific way to measure the wavelength with the diffraction gratings. It is possible to determine the exact wavelength of the laser when the lines/mm of the grating is known. Because I already have the 635nm diode, all I need is measure the distance between the main dot and the secondary dot and compare it to the existing diodes.

I did an experiment and the result is surprising. For the distance comparison I used several lasers :

voilet 405nm measures 21.0cm between the dots.
green 532nm measures 29.5cm
red SOC from dvd-burner measures 40.5cm
red Sanyo 635nm measures 38.5cm
surprisingly the 50mW 650nm red laser from Dealextreme also measure 38.5cm

I have real evidence that this a 635nm laser. I don't have a LPM for power measurement but the brightnees is less than the 40mW Sanyo 635nm diode.
At the price of $12.80 this laser is a real bargain.

reddiffraction.jpg
 
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anselm

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That's a very smart idea, a job well done, and as a result a very interesting discoverey.
Way to go.

Also interesting is the fact that the reviews on DX mention the nice and visible beam,
which I think wouldn't be the case for 50mw @ 650nm. :)
 
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DJNY

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How many people are interested in this?

I may do a GroupBuy. Shipping from Austria to the US would be $7 standard, $9 priority without the batteries and case.
 

DJNY

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^ They all look the same.

Actually there is a <30mW description on the DX laser Blord mentioned in his OP. Saw it in the DX photo gallery.

@Blord, do you insert the batts case positive or negative?

Maybe you just got a lucky better WL unit. A second same one for comparison would be nice!
 

Blord

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The case is battery positive. There is nothing unusual about this laser. It just looks like all the other penlasers I have. This is not the self-made 635nm penlaser I made before.

635nmpen.jpg
 
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Ohhh...well guess i can confirm it is 635nm because time ago i bought one along with my dilda and noticed the dot was little orange but since im a newbie i really didnt care too much about it. :eek:

Its dead now and posted some pics of it in this thread:

http://laserpointerforums.com/f51/help-dx200mw-50mw-went-dim-57110.html

This pic shows a "dead" dot from it, but still is good enough see the difference in color:
30081d1288049327-help-dx200mw-50mw-went-dim-dsc00618.jpg


Also before it died, i noticed the beam was as visible as my 200mW, so i tot maybe it was a little overspec and that my dilda was underspec (making both laser have similar power lol).

But now ive read this thread, being a 635nm explain it all. :shhh:
 

joeyss

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I just got my 50mw from gadget town and I'm sad to say this ,but I'm 90% sure that it's a generic red and not a 635nm but for the price it has great divergence even better then the o-like dilda and it's on par with a green pen.
 
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DJNY, I want one.

If you order one from DX for me, i'm there. I'll pay in advance. :p Or wait for the GB.
 

Tonga

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Hi DJNY I would also be interested in one of these. I have a 635nm at ~5mw. I like the orange cast of its beam. I can pay however you decide. Thanks,
 
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Maybe DX made a mistake and sent 635nm lasers? Maybe the others who order will get real 650 nm lasers? I don't know. What you think?
 

joeyss

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Maybe DX made a mistake and sent 635nm lasers? Maybe the others who order will get real 650 nm lasers? I don't know. What you think?

I was thinking that too, but it's still worth taking a gamble on. I didn't even know there where cheap 50mw 635 diodes around.
 
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Is the laser just 5mW 635nm and "looks" like 200mW of 650nm brightness?
Because 635nm would look MUCH brighter than 650nm.

I know my 5mW greenie looks every bit as bright as my 180mW 405nm.
 




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