10 Mile Distance Laser

One of the sales reps from o-like recommended this one

Crown upgrade 400mW green laser torch/adjustable/waterproof [OL-CGL-400] - $185.99 : Zen Cart!, The Art of E-commerce

Not too sure about it though

I would guess your best bet is a JetLasers PL-E Pro 2 W 445nm which are onsale for $279 + beam expander at $99

500mW PL-E Pro 445nm blue Laser

You need experience in handling and safety precautions---is a dangerous laser not a toy As a first laser without any experience in handilng--- it is very dangerous thing ---in less time that a human blink reflex - .25 seconds - it can easily cause occular damage. One mistake is all it takes to be blind forever.

Encap said:

I would guess your best bet is a JetLasers PL-E Pro 2 W 445nm which are onsale for $279 + beam expander at $99

500mW PL-E Pro 445nm blue Laser

You need experience in handling and safety precautions---is a dangerous laser not a toy As a first laser without any experience in handilng--- it is very dangerous thing ---in less time that a human blink reflex - .25 seconds - it can easily cause occular damage. One mistake is all it takes to be blind forever.

Click to expand...

Thank you for your suggestion, most likely going to order that one but im giving it some time to settle

Safety is an absolute top priority for me, I don't intend on using this as a "toy" (getting the safety goggles too)

I'm probably never going to use it outside of the house (other than serious applications) because I do not want to attract attention from the authorities or injure somebody

When I was a child, I had a 5mw green laser. That was my first experience. I went through the lightsaber phase and got all of the trouble-making // "laser fun" out of my system (well, most of it)

:angel: :na:

I don't think you should go for a high power blue at all - too dangerous, low visibility, high divergence and too much scattering. Don't go with DPSS (532nm) either, too unstable.

I'd go for an overdriven 520nm 50mW diode with a 3-element lens to get about 70mW. That's the best low divergence/high visibility diode you can get, and it costs $50. I remember someone quoting it as 0.5mrad (never done any measurements myself). With a 10x beam expander (which is expensive and *absolutely* needed) you'd get 0.05mrad - at 10 miles you'd get a "dot" of ~1m diameter. This is the very best case calculation, so you should allow for at least 2x that size. A ~2m dot from a 30mW 520nm laser I have is visible at night, though not very bright.

A 300mW single mode 650nm diode is also a decent choice, as it has very good divergence and low scattering.

Note that there's going to be a lot of guesswork here. If you have, for example, a very foggy/dirty air it's unlikely you'll be able to perform the experiment at all.

Atomicrox said:

I don't think you should go for a high power blue at all - too dangerous, low visibility, high divergence and too much scattering. Don't go with DPSS (532nm) either, too unstable.

I'd go for an overdriven 520nm 50mW diode with a 3-element lens to get about 70mW. That's the best low divergence/high visibility diode you can get, and it costs $50. I remember someone quoting it as 0.5mrad (never done any measurements myself). With a 10x beam expander (which is expensive and *absolutely* needed) you'd get 0.05mrad - at 10 miles you'd get a "dot" of ~1m diameter. This is the very best case calculation, so you should allow for at least 2x that size. A ~2m dot from a 30mW 520nm laser I have is visible at night, though not very bright.

A 300mW single mode 650nm diode is also a decent choice, as it has very good divergence and low scattering.

Note that there's going to be a lot of guesswork here. If you have, for example, a very foggy/dirty air it's unlikely you'll be able to perform the experiment at all.

Click to expand...

So anything non-DPSS should be applicable for cold weather. Do you have a vendor for your recommendations?

http://www.laserbtb.com/productshow.asp?id=76# This is one I've found so far but not with a 0.5mRad divergence

Right now it's between the recommended 50mW 520nm (+$$ beam expander)

... or the $450 2w 445nm blue

You get what you pay for (usually), so i'm more inclined toward the 2w blue but I have no problem with spending $200-300 less on something that can just get the job done

And yes, I'de rather have the safer laser, but only if it's going to work

Thank you all for your considerations

$50 is for the bare diode at DTR's: https://sites.google.com/site/dtrlpf/home/diodes/pl520-520nm-laser-diode
You can either order a host and assemble it yourself or buy from a member. If you assemble yourself the total cost should be < $150.

AFAIK the cheapest assembled handheld is laserbtb's for $87: HL 520nm 30mW-500mW

The problem with custom lasers is the beam expander. It has to fit the host and/or be modified to fit the host. I've never had a beam expander so I can't really suggest anything. But I can guarantee you won't manage your experiment without a beam expander, no matter which handheld laser WL/power you choose.

I'm pretty sure any 2W blue will have at least 3x the divergence of the 520nm - those divergence numbers listed by manufacturers are almost always bullshit (this is valid for all handheld manufacturers). You need a single mode diode for this, or an expensive beam-corrected multi mode (which will blow your budget).

I've never ordered from jetlasers, they're kinda expensive but at least they sell beam expanders for their lasers. You could contact Gray and ask him about the divergence of his various lasers with the expander.

Atomicrox- will a 70mW single mode 520 with a B.E. reach the distances the OP is needing? Wow! I had no idea it could travel miles and the dot still be visible.

To the OP- good luck mate sounds like a very cool experiment. Yay science!

Almost made a thread in the buy/sell section but read the sticky, need 20 posts and a green rep. I dont want to test or piss anybody off so ill just wait until 9 more posts

Because I'de much rather buy something from someone here rather than from one of the Chinese vendors (or ebay). Im kind of skeptical about ordering from them

Wouldn't mind building one myself but I would want to buy something as my first. I have a rework station with soldering iron and some very basic experience (reflow/reball/pulling caps/etc) so i will consider it

And yes, I was totally ready to pay extra for the beam expander the second I first read about it, I don't mind at all

I will look for "Gray" and send him a message, thanks for your advice

nwfreefly said:

Atomicrox- will a 70mW single mode 520 with a B.E. reach the distances the OP is needing? Wow! I had no idea it could travel miles and the dot still be visible.

To the OP- good luck mate sounds like a very cool experiment. Yay science!

Click to expand...

Thank you! I will upload the results

wellexcel said:

So anything non-DPSS should be applicable for cold weather. Do you have a vendor for your recommendations?

HL 520nm 30mW-500mW This is one I've found so far but not with a 0.5mRad divergence

Right now it's between the recommended 50mW 520nm (+$$ beam expander)

... or the $450 2w 445nm blue

You get what you pay for (usually), so i'm more inclined toward the 2w blue but I have no problem with spending $200-300 less on something that can just get the job done

And yes, I'de rather have the safer laser, but only if it's going to work

Thank you all for your considerations

Click to expand...

The specs on laserbtb's 520nm just say divergence < 3.0 mrad, beam diameter < than 2.5mm----the data sheet from Osram don't indicate better divergence for higher output powers----if you go that way maybe consider the higher output for the few dollars extra.

The big and expensive problem will be a custom beam expander and way to mount it with stable and fine adjustment on the laserbtb unit.

Maybe email Gray at Jetlasers and ask his best advice on which laser with their beam expander would do the job email: jetlasers@gmail.com

Take a look on ebay at beam expanders and have a look at this thread http://laserpointerforums.com/f49/diy-beam-expander-42814.html

nwfreefly said:

Atomicrox- will a 70mW single mode 520 with a B.E. reach the distances the OP is needing? Wow! I had no idea it could travel miles and the dot still be visible.

To the OP- good luck mate sounds like a very cool experiment. Yay science!

Click to expand...

I'm not sure. AFAIK this hasn't been attempted in LPF, so all we have is some basic math/science and speculation. IMHO the biggest unknown is how much of the beam 10 miles of air will scatter/absorb (it probably won't work with any available handheld if there's fog or very polluted air).

wellexcel said:

Almost made a thread in the buy/sell section but read the sticky, need 20 posts and a green rep. I dont want to test or piss anybody off so ill just wait until 9 more posts

Because I'de much rather buy something from someone here rather than from one of the Chinese vendors (or ebay). Im kind of skeptical about ordering from them

Wouldn't mind building one myself but I would want to buy something as my first. I have a rework station with soldering iron and some very basic experience (reflow/reball/pulling caps/etc) so i will consider it

And yes, I was totally ready to pay extra for the beam expander the second I first read about it, I don't mind at all

I will look for "Gray" and send him a message, thanks for your advice

Thank you! I will upload the results

Click to expand...

Good luck and don't forget to keep us updated.

BTW I just tried various lasers with the furthest target I have (~350m) and the best results were with the 520nm 30mW and the 650nm 200mW (on my sig). The 650nm was slightly better, actually, but that might be because our eyes have an easier time focusing on red at long distances. Either way those reds are very cheap on chinese websites, so you might as well give it a shot!

The 1.5W 462nm gave pretty bad results as expected, despite it's higher visibility compared to the 445nm's.

Encap said:

The specs on laserbtb's 520nm just say divergence < 3.0 mrad, beam diameter < than 2.5mm----the data sheet from Osram don't indicate better divergence for higher output powers----if you go that way maybe consider the higher output for the few dollars extra.

The big and expensive problem will be a custom beam expander and way to mount it with stable and fine adjustment on the laserbtb unit.

Maybe email Gray at Jetlasers and ask his best advice on which laser with their beam expander would do the job email: jetlasers@gmail.com

Take a look on ebay at beam expanders and have a look at this thread http://laserpointerforums.com/f49/diy-beam-expander-42814.html

Click to expand...

Those specs are usually not accurate (that's the reason for the <) - I think the PL520 is, at the very worst, close to 1mrad. I'm not sure of the divergence of the PLP520-B1, but it's multimode (bad sign).

Agreed with the rest of your post

I was thinking a pl520 or a lpc 826. the divergence is great on the lpc 826, but I didnt know if a 300mW expanded 660nm would be bright enough. I agree the red seems a bit better than the 520 single mode when it comes to divergence.

I have been able to clearly see the dot of my lpc 826 @ 1 mile with no expander, so maybe a 10X expander could work to give a small dot @ 10 miles.

good news is this is one of the cheapest lasers around, bad news is I've never seen one with a BE, but I'm sure it could be done.

perhaps a custom host builder could make a focus adapter that accomodates say a jetlasers BE

Atomicrox said:

I'm not sure. AFAIK this hasn't been attempted in LPF, so all we have is some basic math/science and speculation. IMHO the biggest unknown is how much of the beam 10 miles of air will scatter/absorb (it probably won't work with any available handheld if there's fog or very polluted air).

BTW I just tried various lasers with the furthest target I have (~350m) and the best results were with the 520nm 30mW and the 650nm 200mW (on my sig). The 650nm was slightly better, actually, but that might be because our eyes have an easier time focusing on red at long distances. Either way those reds are very cheap on chinese websites, so you might as well give it a shot!

Those specs are usually not accurate (that's the reason for the <) - I think the PL520 is, at the very worst, close to 1mrad. I'm not sure of the divergence of the PLP520-B1, but it's multimode (bad sign).

Agreed with the rest of your post

Click to expand...

I think 30-50mW is way to weak to punch through 10 miles of sea level atmosphere and make a dot on something even with excellent divergence and a beam expander but perhaps I am wrong.

This guy is talking 10 miles ---52,800 ft ---- 16,000 meters

Atomicrox said:

I'm not sure. AFAIK this hasn't been attempted in LPF, so all we have is some basic math/science and speculation. IMHO the biggest unknown is how much of the beam 10 miles of air will scatter/absorb (it probably won't work with any available handheld if there's fog or very polluted air).



Good luck and don't forget to keep us updated.

BTW I just tried various lasers with the furthest target I have (~350m) and the best results were with the 520nm 30mW and the 650nm 200mW (on my sig). The 650nm was slightly better, actually, but that might be because our eyes have an easier time focusing on red at long distances. Either way those reds are very cheap on chinese websites, so you might as well give it a shot!

The 1.5W 462nm gave pretty bad results as expected, despite it's higher visibility compared to the 445nm's.



Those specs are usually not accurate (that's the reason for the <) - I think the PL520 is, at the very worst, close to 1mrad. I'm not sure of the divergence of the PLP520-B1, but it's multimode (bad sign).

Agreed with the rest of your post

Click to expand...

We are going to try to choose the best days that we can, and may have to repeat the test a few times. Unless the scattering is severe, we will at the very least be able to determine if it passes the convexity. Even better, if the weather allows, we can measure the height difference between point A and B.

The most important part of the test would be the measurement of curvature in real time. At ~10 cm above water level or so, light should not travel the full ~10 mile distance of the lake (with atmospheric refraction accounted for), and should NOT be seen by the helper standing on point B.

If there were a third observer viewing the beam perpendicularly, they would be able to see the laser elongate toward point B of the shore as the tripod rises above water level (regardless of scattering/refraction, the beam should "grow")

Shakenawake said:

I was thinking a pl520 or a lpc 826. the divergence is great on the lpc 826, but I didnt know if a 300mW expanded 660nm would be bright enough. I agree the red seems a bit better than the 520 single mode when it comes to divergence.

I have been able to clearly see the dot of my lpc 826 @ 1 mile with no expander, so maybe a 10X expander could work to give a small dot @ 10 miles.

good news is this is one of the cheapest lasers around, bad news is I've never seen one with a BE, but I'm sure it could be done.

perhaps a custom host builder could make a focus adapter that accomodates say a jetlasers BE

Click to expand...

Sounds great, do you know who to ask?

Worst case scenario, I'll have to mod the B.E. myself (if it's within my capability)

Encap said:

I think 30-50mW is way to weak to punch through 10 miles of sea level atmosphere and make a dot on something even with excellent divergence and a beam expander but perhaps I am wrong.

This guy is talking 10 miles ---52,800 ft ---- 16,000 meters

Click to expand...

Well, there is another lake that is ~4.5 miles but I would need permission to access the other side of the shore, and at this time of year it gets flooded (marsh)

There is a 12.1 miler too, but that's reserved for doing last or with one of the lab style lasers

My best bet is the ~7.5 mile lake, and I can reduce the distance down if necessary. What I may end up doing is 3.5 miles one day, 5 miles the next, and finally the full length

Then I can try doing the 12.1 miler once I've covered those distances

I want to order a laser ASAP so I'll probably make my decision by tomorrow or Weds. at the latest.

Best case somebody can do a B.E. mod, USA preferably but international is fine. I have the funds available right now in an approved PP acc. with 300+ 100% pos. feedback on eBay, so I can make a purchase anytime

Thank you all,

This is quite interesting. I hope you check back with us and let us know the results. How much do you predict the bulge to be at 10 miles?

nwfreefly said:

This is quite interesting. I hope you check back with us and let us know the results. How much do you predict the bulge to be at 10 miles?

Click to expand...

About 2.873m (9.5 ft) on a 12.1 km (7.52 mi) lake

Using formula (calculator set to radians)

h = r - r * cos(b / r)
b = half of the distance to the lake in km
r = radius

And using that in comparison with
Distance to the Horizon Calculator

Gives us a rough estimate

At 6 ft the horizon limit should be ~3 miles, accounting for refraction is dependent on temperature but should raise it to no more than ~5 miles (that's also what we're going to find out)

If anybody can see that the math is wrong, feel free to correct me

---

I found these

Super Powerful Cute 250mW Red laser torch/Good burning [OL-CR-250] - $22.00 : Zen Cart!, The Art of E-commerce
+
YAG 10X 532nm green laser beam expander/glass material [OL-EP-10] - $75.99 : Zen Cart!, The Art of E-commerce


Beam Expander|Laser Beam Expander,collimator,3X/5X/10X
+
650nm 200mW Red Laser Pointer of Axe Series
(x20 beam expander)


Beam Expanders,3x, 5x, 10x
+
red laser pointer burning red lasers with 300mW output power for sale

http://www.ebay.com/itm/1W-638-to-6...9863?pt=US_Laser_Pointers&hash=item339116c1f7

wellexcel said:

I found these

Super Powerful Cute 250mW Red laser torch/Good burning [OL-CR-250] - $22.00 : Zen Cart!, The Art of E-commerce
+
YAG 10X 532nm green laser beam expander/glass material [OL-EP-10] - $75.99 : Zen Cart!, The Art of E-commerce


Beam Expander|Laser Beam Expander,collimator,3X/5X/10X
+
650nm 200mW Red Laser Pointer of Axe Series
(x20 beam expander)


Beam Expanders,3x, 5x, 10x
+
red laser pointer burning red lasers with 300mW output power for sale

1W 638 to 650nm Red Laser Kit MX 900 Host Copper Heat Sink Focusable Lens | eBay

Click to expand...

Wow, over 2 meters at the bulge! That's amazing. I never would have guessed. Thx


That first red laser from is an O-like and if you notice in the spec says the power is <250mW. So that could be as low as 1mW which is technically less than 250mW. Stay away from lasers rated as < than anything. It suggest Bullshit marketing if you ask me. Other wise you would just give a min and state greater than that. thats how a laser should be rated.

I own a few lasers from O-like and feel they have questionable track record. I actually own a supposedly >220mW red from them but haven't put it on an LPM to confirm the output. I have metered a 405 of theirs that was grossly under spec by over 30%. The red 650 I have is this one- Power Rock waterproof Red laser torch 250mW /Focusable [OL-PRRL250] - $45.99 : Zen Cart!, The Art of E-commerce

Considering how important this laser is to your project I highly suggest not getting it from them but rather have it built or buy from a reputably seller like Jet lasers. Jet Lasers is on the higher end of prices but along with the laser you get very knowledgeable customer service that from what I hear really care about your satisfaction with the laser. That's pretty priceless. You wont find that from O-like that's for sure. But, if a 650 250mW would work it shouldn't be terribly expensive anyway. You may want to email Jet Lasers first because that's quite a distance you need to spot.
Sounds like its pretty important for this laser to work as needed. Don't go with O-like mate. Just my 2 cents from owning 3 lasers from them. They're not the company to have your projects success balanced on.

I'm not familiar with Armlaser the other link you had so can't help you there. From what I know about this community I honestly wouldn't go with anyone not vouched for by people here.

One thing though I just read this on Armlasers site about their 2W blue laser and it gives me concern they are full of shit.
"The beam,with 50 miles range, is so bright that it can be seen from outer space! The most powerful and iconic handheld laser in the world is yours with affordable price."

Yes the space station saw a 2W blue laser flashing on earths surface in a controlled experiment but the way this is worded sounds misleading. Like the beam can be seen for 50 miles and that's absolute bullshit. Maybe you could see a flash of light from miles away but you will not see a dot on something nor a beam. The divergence of a 2W blue is too poor for the beam to be seen for miles. This doesn't sound very reputable IMO. Good sellers don't need a bunch of hype to sell their products knock off companies do. Also the wording is broken English and that says Chinese knock off to me.