The difference between 637nm&650nm Red

[edison]

Ok what about these two pictures wich one is 637?

[lloyd33]

....... Both?

[StarryEyed]

The left

StarryEyed

[planters]

I'm still trying to understand what the image is showing. A series of lower intensity segments punctuated by high intensity spots, right?

And Brad: the "halo" you see around the 637 nm red is an artifact of the camera. It doesn't look like that in real life.

I'm also wondering about that. Why is the camera producing this artifact only around the 637nm laser? I am inclined to think that this is not an artifact of the camera, but is in fact present and not seen because of the nature of our vision. Maybe, it is producing a subtle reduction in contrast, but not bright enough to be detected near the brilliant primary beam.

At these power levels, both of these beams must represent multi-diode arrays. What are the optics involved with each? That might explain some of these differences.

[flecom]

probably brighter and farther away from the IR filter of the camera, causing it to bloom

[Solarfire]

I'm still trying to understand what the image is showing. A series of lower intensity segments punctuated by high intensity spots, right?


I'm also wondering about that. Why is the camera producing this artifact only around the 637nm laser? I am inclined to think that this is not an artifact of the camera, but is in fact present and not seen because of the nature of our vision. Maybe, it is producing a subtle reduction in contrast, but not bright enough to be detected near the brilliant primary beam.

At these power levels, both of these beams must represent multi-diode arrays. What are the optics involved with each? That might explain some of these differences.

Well for one the 637nm has much lower divergence and therefore a much higher power density then the 650nm. The vertical fringes are indeed there but are less perceived by the human eye due to the high contrast/power ratio of main beam verses fringe when scanned. Where the beam gets static (the highlighted interpoling points of the graphic) the fringe appears more visible. These fringes are more or less typical of the 637/638nm 71, 73 Mitsu diodes.

[White-Light]

This is 637nm in my Kvant. No halo in this picture (the double beams top right and bottom left are in the cue):




or here:





I'd have said it was a brightness artefact as here you see haloing on every colour:

[Solarfire]

First of all, wrong perspective, we’re looking at a graphic on a projection surface.
Second of all, I doubt that your Kvant has 71 or 73 Mitsu diodes in it, if so they are doing some major cleaning up via spatial filtering.
I haven’t seen one build with the Mitsus yet that didn’t more or less have this fringe, it's a dead giveaway.

[planters]

First of all, wrong perspective, we’re looking at a graphic on a projection surface.

Agreed. These scanned beams may or may not show this fringe depending on the contrast level. In fact, when you look at these images there is in fact some luminescence outside of the beams and the first thought is well... that is due to haze or scatter within the camera optics. That MAY be true.
Just to be accurate, is the 637nm beam in this comparison from a Mitsu 71 or 73 diode? I had assumed not. Maybe I was wrong.

I haven’t seen one build with the Mitsus yet that didn’t more or less have this fringe, it's a dead giveaway.

Just wait.

[White-Light]

Second of all, I doubt that your Kvant has 71 or 73 Mitsu diodes in it, if so they are doing some major cleaning up via spatial filtering.
I haven’t seen one build with the Mitsus yet that didn’t more or less have this fringe, it's a dead giveaway.

I don't believe any type of diode was mentioned in the original post just a comparison between 637 and 650. If we are looking specifically at Mitsu diodes then fair enough.

I would still say on a non mitsu 71 or 73 diode it was the camera though.

Here's a pic I've taken of a red line projected against a door:



To the naked eye its a perfectly red sharp line with no difference in colour.

To the camera, the inner is glowing a hot orange and the outer spatial refelction off the door, red.

Here's a zoom of a part of a graphic projected on the same door - again the camera sees 2 zones of differing colours, but the eye not:



What I can confirm though if you turn the diode right down on power is that the emitter appears as a " + " shape or maybe I should say its probably a stripe but the beam is 2 diodes cross polarised into a cross.