Help - I need distance

Alaskan said:

What I learned in a nut shell:

You don't need high power if you can get a low divergence laser diode which has a tiny emitter and expand it, they can be only a couple hundred milliwatts if single mode and produce a beam which can stay in a relatively tight beam to be viewed as the brightest spot of light coming from the earth (if you are away from other light sources so it can stand out). However, if the beam is uber tight, it is also uber difficult to put on a target too, perhaps too difficult.

Here's what I'd do, I'd mount and align a low divergence IR laser diode which has been expanded to a few inches diameter directly on a telescope, mount it right on top of the telescope so you can spot properly. Alignment is going to be extremely tedious and might not work out very well for extremely long distances over a couple hundred miles, but I haven't researched that aspect well enough to give advice on it.

You can also use a high power source (which I just said isn't necessary) and get the same low divergence of a single mode low power diode by expanding the beam to a very wide beam. Doing so can produce a beam just as tight as an extremely low divergence diode, but with more power. However, still difficult to put the spot on something because the output won't be very wide a long distance away.

If you want to attract something out there, might be better to use a 1064 nm YAG laser, expand the output as wide as you can and then collimate it. After that put a large number of optical line rods in front of the collimated beam, just stack them to cover the entire output. Now you will have most of the power converted into several laser lines and can sweep a very large area without missing your target, that is, if you want to make a beacon. The power which will land on the target will be extremely reduced, but if you are using a YAG laser with several million watts of peak power all packed into nanosecond pulses, I think it might still show up at the distant end as a very bright source, even if 100 or more miles away.

What I don't know is how safe this is, it might not be safe, might not be at all advisable. If you hit someone close by, especially since it would be a wide line, it could blind someone. So, I don't advise doing something like that until you have had a professional run the numbers to give you a good idea how hazardous the beam could be to someone close by, or within a mile or more distant etc. Off the top of my head, I'd guess this is very hazardous as well as illegal. Maybe this isn't a reasonable project to build, maybe too dangerous, I just don't know. However this might produce a flash of IR light which can be viewed from extreme distances and then you don't have the trouble of trying to target something with a very tight beam which is nearly impossible to put on something and keep it on it if they are moving, or even if stationary, when very far away.

Maybe better not to go the YAG route, you could however use the same concept with a single mode laser diode which has much lower power and constant, instead of a short pulse. Just expand the output as big as you can get it and put a bunch of line producing rod lenses in front. You could make a fairly small hand held laser pointer to do this with, but I don't know I would build something like this in the visible spectrum. Expanding the beam will produce a very low divergence output, putting a line lens in front will produce a line which expands very little in thickness as it travels forward and you would be certain to be flashing a lot of aircraft out there which is illegal. Would the line be weak enough it doesn't matter? If it is that weak, then it isn't effective for your use either, but if you can get enough power at IR into a line being produced from a uber low divergence beam, it might work, but still hazardous close up, I am sure.

Some membeers will certainly caution you against doing this, I am too, but wanted to share some ideas, might be work arounds so it can be done safely, but the beam will need to be expanded to a huge diameter to reduce the power density to be safer.

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Encap said:

The problem with it is NeedDistance's budget for such an activity----keep in mind the OP only had funds for this lowest level quality and output mass produced laser 303, see: 10 miles Green + Star Cap 5MW 532NM Laser Pointer Pen Lazer Light Beam Zoom Burn | eBay based on typical Chinese reseller misrepresentations as too distance and output.

I doubt anyone even imagines any ability to contact people, places or things in space with minimum quality and output, mass produced laser 301 303, or 305/just generic toy quality 532nm laser costing almost nothing --$5-$15.

Many $1000s of dollars or more on a hope, wish, and dream chase, in this case, are probably out of the question.

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Alaskan said:

I agree, the cost and time required to do something like this right probably keeps us all safe

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Alaskan said:

I've seen some craft I thought were alien, so advanced I was sure they were, but they could be ours, we very well may have secret advanced anti-gravity vehicles which regardless of being secret, are flying around a lot, hovering over cities and making a show of themselves



All of the vets here know my position on this subject, personally I think there must be a way to travel through space without being limited by our theory of nothing with mass being able to travel near, or beyond the speed of light, but warp space and you are not violating that law. Doesn't matter if what I think is correct, I simply don't know anything in regard to these things for sure, but I can guess.

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Alaskan said:

I'm walking a fine line suggesting such high power put out into the open air, these threads can stay for years and I have to speak for anyone else who comes along how unadvisable this is.

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Alaskan said:

I'm walking a fine line suggesting such high power put out into the open air, these threads can stay for years and I have to speak for anyone else who comes along how unadvisable this is.

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NeedDistance said:

Hi Alex,

~~~I have had many sightings and they're getting madder so I want to get to the bottom of this, so to speak. ~~~

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BobMc said:

Using your own words;

If their getting "madder" why would you want discourse with them? Sounds like they don't have your best interest at heart?

:thinking:

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Alaskan said:

My primary interest in lasers is low divergence, or lasers which deliver the highest power density and smallest beam diameter at great distances as possible. I wish I was here to give me this information when I first started, I spent a lot of money on high power lasers I didn't need to spend. If I had known low power single mode diodes with tiny emitters produce the least divergence, compared to other laser diodes, I would have bought them instead. However, for even lower divergence, expand the beam of a single mode laser diode to 6 inches using a large photographic condenser plano convex lens, and now you have something with extraordinary low divergence. There is more to this than that, the diffraction limit comes into play, but you won't bump up against it at six inches diameter with a single mode laser diode, probably not for most any laser diode. Someone with more understanding in that area would need to post, or google it. I haven't read up on diffraction limits for a couple of years and rusty on the subject now.

If you PBS cube combine two single mode laser diodes you can get near twice the power of two diodes into a single axial output. Using a single mode laser diode with a big lens seems to be the best way to get power a long distance without much spreading, but as I wrote before, pointing and keeping it on a target which is many miles away is near impossible by hand, probably impossible. I'd put a large plano convex cylinder lens in front as big as the collimated lens used for the laser diode to produce one line and try sweeping with that. I wish I knew how much power power is lost when putting the output of an uber low divergence laser into a line, I just don't know. I'd be willing to pay money to get someone to work up some figures for me.

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NeedDistance said:

By 'madder' I mean more unbelievable and impressive, thus I want more of this 'madness', but closer

I've had years of sightings - not one anal probe, yet

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