best lens for this 650nm?

If I understand this correctly the acrylic lens that comes with this diode from DTR isn't optimum.

Would this lens here give me a brighter beam with good divergence?

What adjustable driver would be best for this diode?
Thank you

I've got two lasers I built with that diode, and just kept the acrylic on it. I'm not 100% sure, but I don't think a 3-element lens will improve beam/dot quality. With the acrylic, it's a very nice beam. Check out my build thead in my signature, I've got a video using it to do optical trapping.

As for the driver, the only one I can think of is the flexdrive. If you can find an x-drive with a low current range, that would probably be your best bet. I used moh linear drivers in my builds, but he closed his laser store, so no more of those.

Thanks thats very helpful. Wow! what is this trapped particle effect? I have never seen anything like that!

Found this on wiki-
General description[edit]
Optical tweezers are capable of manipulating nanometer and micron-sized dielectric particles by exerting extremely small forces via a highly focused laser beam. The beam is typically focused by sending it through a microscope objective. The narrowest point of the focused beam, known as the beam waist, contains a very strong electric field gradient. It turns out that dielectric particles are attracted along the gradient to the region of strongest electric field, which is the center of the beam. The laser light also tends to apply a force on particles in the beam along the direction of beam propagation. It is easy to understand why if one considers conservation of momentum. Photons that are absorbed or scattered by the tiny dielectric particle in its path impart momentum to the dielectric particle. This is known as the scattering force and results in the particle being displaced slightly downstream from the exact position of the beam waist, as seen in the figure.

Optical traps are very sensitive instruments and are capable of the manipulation and detection of sub-nanometer displacements for sub-micron dielectric particles.[12] For this reason, they are often used to manipulate and study single molecules by interacting with a bead that has been attached to that molecule. DNA and the proteins[13] and enzymes that interact with it are commonly studied in this way.

For quantitative scientific measurements, most optical traps are operated in such a way that the dielectric particle rarely moves far from the trap center. The reason for this is that the force applied to the particle is linear with respect to its displacement from the center of the trap as long as the displacement is small. In this way, an optical trap can be compared to a simple spring, which follows Hooke's law.

Thats truly amazing. Did you encourage this to happen or was it just random chance occurrence?

nwfreefly said:

If I understand this correctly the acrylic lens that comes with this diode from DTR isn't optimum.

Would this lens here give me a brighter beam with good divergence?

What adjustable driver would be best for this diode?
Thank you

Click to expand...

Yea you don't need glass. Glass will not give more power or a different dot shape just when you go to higher power diodes they need glass so they don't melt.

As for the driver I also suggest a Flexdrive but I am out of them and don't think more are coming anytime soon. You can use an X-drive but it has to be one with a continuous ground since the cathode and ground are common on the diode ie case negative. That is a special order driver but I think Jeff(Flaminpyro) had some recently. See here.
http://laserpointerforums.com/f39/x-drive-x-boost-88589.html

Or you could just build a cheap linear driver for it.
http://laserpointerforums.com/f67/laser-driver-can-done-rog8811-87507.html

I saw a post somewhere around here about it and dug around till I found examples. From that I gathered using a lowish powered laser (~250mW) at 650nm or 405nm, IIRC, worked best. This was perfect, as at the time I had only my first build, which was this diode being discussed. The power peaked at ~230mW, and it worked great.

Basically I turned on the laser and focused it so the focal point was ~2in from the aperture, about as close to laser as possible. Then take a sharpie and stick the tip into the beams focal point, just for a split second. It should start smoking immediately, so remove it quick, but try not to disturb the air. Most of the time, I would get one or more very short lived particles that flowed down beam. Twice I got one particle trapped in the focal point that hung around until I had to turn off the laser!

It's definitely worth trying, and much more interesting than burning holes in crap.

Oh yeah, I used my Galaxy tab to view/record my trapping sessions. Safety glasses make it difficult to get the sharpie in the beam, and impossible to tell if you managed to trap anything. Since I wanted to capture it on video, I used my tablet to view it as well.

@Chaoslord- that is really incredible stuff. Man, lasers are so cool! The more I learn the more I want! Seriously, I just ordered another custom host today. I have a problem. "My name is Jeff and I am a LaserAholic, its been 12 hours since my last order" lol!

@DTR- Thanks for the info. I will be making an order pretty soon. I have 4 custom host on the way so I'm just trying to figure out what to build into what. The only problem is that I have expensive and high powered tastes.

Its a shame the 638's have such awful divergence. From my reading it doesn't sound like there has been a good solution to this problem in relation to handheld lasers. So I think my best bet for a red laser is a single mode 650nm. Is there any reason that they don't make 650 diodes greater than 250mw? Is the beam very visible at 200-250mw's?

I see the pic on DTR's webpage showing the 638 bright ass red beam! Its lovely. Is the divergence as bad as I hear? I know that was an indoor pic but the beam looked awesome. Such a nice color red too.

Low divergence/power reds I recommend:

https://sites.google.com/site/dtrlp...170mw-635nm-single-mode-laser-diode-hl63133dg

SF502B 650nm Red

though the second is sold out currently

the oclaro is brighter, it's more of a red orange, but doesnt really seem that way until you have it next to other colors, like 650 and 589

DTR's pics actually show the color really well, but it sometimes seems more red, depending on other colors present. even our perception of color is relative

DTR basically carries all the best diodes one could want. well, reasonable cost ones. Don't know what we'd do without him

And yeah I know the feeling. it's been quite some time since my last order, but that's probably because I am running out of lasers I don't already have

Shakenawake said:

Low divergence/power reds I recommend:

https://sites.google.com/site/dtrlp...170mw-635nm-single-mode-laser-diode-hl63133dg

SF502B 650nm Red

though the second is sold out currently

the oclaro is brighter, it's more of a red orange, but doesnt really seem that way until you have it next to other colors, like 650 and 589

DTR's pics actually show the color really well, but it sometimes seems more red, depending on other colors present. even our perception of color is relative

DTR basically carries all the best diodes one could want. well, reasonable cost ones. Don't know what we'd do without him

And yeah I know the feeling. it's been quite some time since my last order, but that's probably because I am running out of lasers I don't already have

Click to expand...

Do you know if SciFi uses the same diode as DTR sells?

I do know actually. It's different, a LPC 826

they have superb divergence, esp with a 3 element, but even with a single. might be the best divergence of any of my lasers

there are a few diodes DTR doesnt have, that happens to be one

I second Shakenawake. I have a build with one of those Oclaro 120mW diodes. At right about the same power (~220mW), the 638nm is much more visible to me, while still having an nice beam.

i was talking about the 170mW, but yeah. Oh and 650-660nm lasers are about as bright to me per mW as 405nm, so not very, but I think I may see red more dimmly than others, IDK

my single mode 638 is about 200mW (i dont max drive my lasers) and my 660nm is about 320mW, the 638 is still brighter by quite a bit.

Shakenawake said:

i was talking about the 170mW, but yeah. Oh and 650-660nm lasers are about as bright to me per mW as 405nm, so not very, but I think I may see red more dimmly than others, IDK

my single mode 638 is about 200mW (i dont max drive my lasers) and my 660nm is about 320mW, the 638 is still brighter by quite a bit.

Click to expand...

That's about the way I see ~650nm as well. At times, seeing the beam of 650nm seems harder than 405nm.

I prefer 638nm over 650nm just because it's much more visible.

Great thx for the info. I think that will be my choice for my red. http://www.ebay.com/itm/Oclaro-Opne...148?pt=LH_DefaultDomain_0&hash=item2a45cd9fe4