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Gregg, thank you for showing us the other app. It looks very useful. I look forward to trying it out. Steve, I suspect the problem with your model is the 10 mRad divergence combined with 0.001 waist/emitter size. I doubt any real diode could recreate this model in the real world. Lastly, I...

I know what it says. That's why I included it in the picture snip. That phrase, however, means nothing to me nor do the very sparse search results for it. Obviously the concave lens will expand the beams, but that can be corrected. The point of my post was whether a concave lens could be used...

Then how is this accomplished?

It seems like most, if not all, of the discussion for combining beams involves mirrors. Has using lenses been explored? Here's a rough concept I was thinking about. Does anyone know if some form, however different, of this concept would work?

Alaskan, I love what you are doing. I always admire anytime someone takes an idea to the fullest extension possible. In your case, beam expansion and low divergence. I recently ordered some beam expansion optics from Thor Labs and am waiting for them to arrive. They should give me a beam...

I purchased today two cylindricals from Thor Labs. For the major axis, a focal length of 25.4mm and for the minor axis, a focal length of 150mm. This should give me a beam profile of 20x28mm and divergence of 0.039mRad x 0.093mRad, respectively. I decided to collimate the minor axis at a larger...

Couldn't agree more. The raw divergence, however extreme, is completely correctable with optics. What is not correctable, however, is the quality of the beam based on the size of the emitter. It would be fantastic to have a chart of all available diodes and their emitter size. I'm sure if we...

I agree, but a common lens should behave in one dimension exactly as a cylindrical lens does. This is why I have a model for each dimension.

Yes. I have a 150 watt CO2 laser for burning and cutting things. My interest in visible handheld lasers is just that, to create the most visible beam at the longest distances physically possible. In one of our earlier discussions, we hypothesized that instead of starting the optical train with...

Does anyone have a source for this information? I'm specifically interested in the NDG7475.

Yes, that is why I was initially saying the first lens would need to be placed very close to the diode. The raw divergence is quite extreme. I just took this image below of my NDG7475. It is 36 inches from the wall. The measuring tape is extended to about 50 inches.

The first part of your statement is profoundly accurate. As noted in Application 2 in this link, which I referenced in an image before, the divergence of the beam can be calculated by dividing the emitter size by the focal length of the lens. The second part of your statement is not accurate...

Your models have a low initial beam divergence. Shouldn't we be using the divergence directly from the diode? Edit: There are 17.45 milliradians in one degree. The Light Machinery app allows up to 1000 milliradians, or one radian, or 57.29 degrees.

My initial impulse to place it so close was simply because of the extreme divergence of the raw output from the diode. The necessary width of the lens quickly becomes very large the further it is from the diode. According to the NDG7475 datasheet (link) the "typical" divergence is 11 degrees on...

Firstly, brilliant pics. Amazing how much light comes out of such a small area. The only problem with needle thin is that it will have high divergence. Maybe if you are after a burner that is OK, but I'm after low divergence and a beam that is visible for as far as possible. I want to scare...

To achieve correction of the beam profile prior to collimation, I assume that would involve placing a cylindrical PCV almost directly against the diode, correct? Another benefit of using this approach would that there are now only two total steps (correction, collimation/expansion) rather than...

It is the mark of an educated mind, according to Aristotle, to be able to entertain an idea without accepting it. Machining an aluminum or copper block with a hole that holds a diode on one end and a small lens on the other is very simple. As such, if substantial gains in efficiency or...

The Galilean style expander is what I'm planning with Edmund parts listed somewhere above. By collimator, I mean something to replace the G2, three lens, etc. Correct me if I'm being naive, but with regard to high power laser diodes, the perfect optics setup for low divergence is an initial...

I agree, 30% wasted power is unacceptable. Once I'm finished with the corrective optics, I'd like to examine the initial collimator optics. If I wanted to build a collimator from scratch, I assume I'd need to look into aspheric lenses, correct? Further, once I have perfected this setup and...

The three element gave me the tightest spot out of the following collimators that I have tried: DTR G2 (Won't screw far enough into my OPT TO-5 brass diode housing to focus) DTR three element OPT three element OPT single lens Sanwu G7 (hasn't arrived yet, will test when it does) A pair of 25mm...