Stupid how to drive this diode question...

[Alaskan]

Hello,

Someone please tell me how to drive this diode, since it is cathode case ground and most drivers are regulating the negative output, do I need to insulate this diode from the case of a laser pointer?

Specifications

Diffraction Limited Beam
TEM00 Single Transverse Mode
Package: 5.6mm J1 TO-56 Window Package
CW Output Power: 260 mW
Center Wavelength: 985.5 (±3) nm
Spectral Width: 3 nm
Slope Efficiency: 0.80 W/A
FWHM beam divergence: 10 degrees parallel, 29 degrees perpendicular to junction
Threshold Current: 40mA
Operating Current: 370mA

 

[The Lightning Stalker]

You need something continuous ground like
a Flex Drive or blitz. Flaminpyro sells them.

 

[Alaskan]

I guess that means the positive side would be regulated instead?

 

[The Lightning Stalker]

Yes, cathode (-) negative continuous ground
means positive (+) regulated output.

 

[Alaskan]

Thanks, I was pretty sure that is what you meant, but can't afford to make mistakes of understanding with these expensive diodes

 

[joeyss]

why arent you using a regular 980nm?

Just curious as what you may need the exact 5nm for?

 

[Alaskan]

No reason in regard to that, I just wanted a single mode diode close to 1000nm, this is the least expensive one I could find which could put out up to 300mw, perhaps higher for intermittent limited duty cycle use. The reason for wanting something close to this wavelength is because atmospheric absorption is lower at about 1000nm compared to 808nm.

Why single mode? I want to expand the beam to reduce the divergence to an uber low amount, with it's tiny 3.5um aperture in the slow axis, if letting the raw output of the diode expand for about 40mm beyond the diode before collimation and then use a fairly large diameter PCX lens, you can really have something that will go a long way without much divergence. Optic gurus please check my math, but by having such a small output aperture diode, on paper I can get the same or lower divergence with a lens that is close to 60 X smaller diameter than if using a multimode 200um aperture laser diode, if correct, that's incredible. However I believe the diffraction limits of a 67mm lens will substantially reduce the performance, but still, I expect the divergence to be extremely good, especially for IR.

I bought the white light version of this LED flashlight which appears to be a good host for the diode, if I modify the pill and put a different driver in it, with its 67mm diameter lens and inch and a half of focus adjustment I'm hoping I can adjust to an infinity focused output. Although in my opinion the aspheric lens on the unit isn't well suited for use with a laser diode because small distortions can be seen in the output pattern of light, so I'm replacing it with an Edmund Optics lens of the same diameter and FL I found on ebay. The distortions are very minor, but annoying to me, it's like the glass was poured into a form and then polished, not made like high quality lens glass is made, but perfectly suitable for LED's, with an LED you can't see any problem at all.

Being invisible, I don't know how I'm going to adjust to infinity with it yet, anyone have a suggestion?

 

[joeyss]

Some camcorders will pick up 980 amazingly well in night vision mode.AKA the darkness setting.

I have a Samsung one that's 720p with a 10x zoom and I use it to focus my 150mw 980.

It will even pick it up in a bright room as a white dot.

Makes a great NV device since I can take the lens off the diode.

 

[The Lightning Stalker]

Here is an example of a typical glass LED lens
doing its best to focus a laser.

 

[Alaskan]

OMG, excuse the caps, that's terrible, I thought that pattern was on purpose instead of a poor lens. I was thinking about using a camera to pick up the beam and spot it on a close and far wall to get it close to infinity, but I've found when I do that with a visible light laser, it really isn't at infinity until I can do so outside at night and watch the beam shoot out for thousands of feet to get it set closer. I imagine we can't really get our beams set exactly to infinity, once out miles and miles they will still have added divergence due to having the focus ever so slightly adjusted too close or too far out for a perfect infinity focus.

Im still looking for a continuous ground 1.7 to 2.2 v 370-500 ma driver for this diode which can take up to 8.4 V battery supply but I can use 4.2v if i put a dummy battery inside. I need it in a round 16.8mm form with battery contact spring on reverse side.

 

[The Lightning Stalker]

That was the Ghost Laser project. I was
hoping a large diameter LED lens would
provide a closer focal point, but the
quality was so poor that it scrambled the
light all over the place. There are some
YouTube videos of lenses being diamond
turned. They look much better, but I have
no idea where to get them and they will
probably be expensive.