638nm laser divergence issue

[Laik]

You are right, i have never had one but im going off what DTR said.

Also I would like to point out that when driving these diodes so high you will see a lot of wavelength shift. They are more than likely about 10-20nm higher than the data sheet average of 638nm. Looking at the datasheet you have a 12nm jump just going from 500mA-800mA with 644nm being the result @ 800mA and that assumes you can keep the diode under 40°C. My bet is they are passing 650nm when being driven this high. Just wanted to note this as some people have had concerns and stated to me that their higher power builds with these look the same color as their 650/660 lasers

 

[Just4FunReally]

You are right, i have never had one but im going off what DTR said.

And so says the man selling the lasers himself. Thank you for finding that Laik, I was looking for that.

Personally I prefer looking at the high powered multi-mode diode myself, I think that the powerful red glow looks supremely bad ass. I just want to make sure firelaser know's what he needs to know .

 

[grainde]

^^ nice work you two :beer:

 

[Laik]

Thanks, grainde

 

[ChaosLord]

I like to defocus my mitts into a flat, wide ribbon and blow vapor into it. It's a pretty cool effect.

 

[Just4FunReally]

I like to defocus my mitts into a flat, wide ribbon and blow vapor into it. It's a pretty cool effect.

Pre-warning: Please wear safety goggles because what I'm about to describe is seriously dangerous for your eyes.

If you think that's fun, try gluing a small mirror onto a fan or anything that rotates at a decent speed. Elevate one of the corners so that placing the laser in a tripod (or some makeshift stand to hold it steady) makes the beam reflect in a circle. Then blow smoke through that. It looks something like this.

Post-warning: Again, this is really dangerous without proper safety goggles. If you want to enjoy the effect, record it with a camera or at the very least set it up with goggles on, and then after confirming that the lasers are pointing in a completely safe direction, remove your goggles to enjoy the view.

 

[firelaser]

so from what i am reading if i get a 638nm 800mw-100mw laser it will gradually get a darker red as it heats up? or as the power increases?

 

[Just4FunReally]

so from what i am reading if i get a 638nm 800mw-100mw laser it will gradually get a darker red as it heats up? or as the power increases?

I'm assuming you mean 800mW to 1000mW, but the first of those two guesses is what we're saying. As the laser runs and heats up, the wavelength will quickly rise before leveling off as the heat sink starts to pull off less and less heat from the diode. If you have a sizeable heat sink or use the laser with a short duty/rest cycle, the wavelength can be kept lower for longer periods of time, but eventually the wavelength will rise with the heat. As Eradicator said previously, the difference to your eyes should still be pretty apparent at those currents while the diode is still cool. But it is inevitable that at these higher currents the diode will heat up and the wavelength will rise. I'm not trying to put you off from buying them, I actually recommend you get it (I'm getting one of the 300mW versions myself!), I just want to make sure you are happy with your purchase.

Also a warning, do NOT try to chill your lasers in a refrigerator or freezer before using, nor cool them down with one after using the laser. Either of which can cause damage to the diode. If you want to look into TEC (thermo-electric cooling) then you can get extended duty cycles with very little change in wavelength, at the cost of a much larger (read: non-portable) set-up. I hope I could help you along with Grainde, Eradicator and Laik .

 

[Eradicator]

I gotta tell you mine is not even comparable to a 650, so much more orange in it. Maybe some people got diodes that start at 640, in which case they would hit 650, but mine must be closer to like 632 at startup, cause there is no way its shifting past 640, it is twice as bright as my equal power 1w 650, and has a TOTALLY DIFFERENT shade of reddish orange, as opposed to the straight blood red of a 650.

Like I said every diode is unique, but I think you will find that most do not wavelength shift nearly that high.

 

[EpicHam]

I'm actually considering what parts to use for my RGB laser...
I am thinking of incorporating the 638nm... but at long range... the divergence would split my beam into a rainbow beam....
Crappy divergence you see...
That REALLY bugs me

 

[Laik]

Get an opnext 120mW. It is a single mode 638nm. DTR has them.

 

[ChaosLord]

Get an opnext 120mW. It is a single mode 638nm. DTR has them.

I just built a laser with one of these. They are nice, but if you want raw power, go with the mitts.

Or do like me and get both .

 

[Just4FunReally]

I gotta tell you mine is not even comparable to a 650, so much more orange in it. Maybe some people got diodes that start at 640, in which case they would hit 650, but mine must be closer to like 632 at startup, cause there is no way its shifting past 640, it is twice as bright as my equal power 1w 650, and has a TOTALLY DIFFERENT shade of reddish orange, as opposed to the straight blood red of a 650.

Like I said every diode is unique, but I think you will find that most do not wavelength shift nearly that high.

Yeah, I remember when DTR (I think it was him at least) got one of the most efficient M-140's we've ever seen. It was one of the first 445nm's to break the 2.5W output before the 9mm diodes came along. It's certainly a possibility .

 

[firelaser]

ended up getting a 160mw single mode from wannaburnstuff
http://laserpointerforums.com/f39/wts-638nm-fixed-focus-leadlight-chrome-83297.html
this one

figured id start with that, the only thing i dont like about my blues is the divergence but its not too bad, and the 638's are twice as bad, so i figured id start with this as my first 638nm,,
cant wait till i get it in the mail

and dont worry im not gonna freeze it, saw a youtube vid on that,, thought, wow your retarded lol

probably get a powerful multimode one later on

 

[Laik]

You got a sweet laser! Those leadlights make great little pen hosts and that singlemode 638nm diode will look sweet. I hope you enjoy it!

 

[IsaacT]

I am sure he will I sold it to him for less than the cost of the parts due to a cosmetic scar on the aperture cap, so I think he got a good deal