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thats correct . power density is most important when it comes to burning . and yes , you can focus 5mw beam to a small area , so the power density will be thousands of watts / area . the problem is , the optics thats needed to do so , will be more expensive then ready made burning laser . when...

lol did you read the last paragraph of my last post? this is exactly what i said . the aperture size controls the BRIGHTNESS , and magnification does not control brightness . so for most binos , the aperture is narrow , no matter the magnification power ,so they DECREASE brightness due to...

you are wrong . you can do a simple experiment - take a regular light bulb . look at it from close distance , then take a bino , and look at the same light bulb from a distance that shows the bulb at the same size . does the brightness looks the same? no. without bino , the bulb will be much...

its a bit confusing as far as i know , its "bad" to look directly at the dot of a powerful laser and it can cause eye damage . so what would be the difference between me aiming a powerful laser at the wall 1m away from me and looking at the dot , compared to me aiming the same laser at the wall...

blaster said i dont need protection . you say "retina injury is even higher with binos" so how do you say blaster is right ? so , can , or cant i look at a powerfull laser dot from a distance , using binoculars/telescope - without safety glasses ? (the beam is not pointed towards me, just...

hello lets say somebody is using a powerful burning laser , burning stuff at his backyard . if i'm located 100m away , but using binoculars and look directly at his laser dot burning stuff , should i wear safety goggles? tnx

so why do you need a huge diameter output element , if the beam itself uses only a fraction (the middle part) of the lens ? unless you spread the beam over the entire lens , why is the need for huge lens ?

what is "apperture size"? i know apperture in photography , and its not measured in meters (f stops) . and telescopes are measured by focal length , right? so what is apperture size in meters?

I wrote in first post - trying to lower beam divergence. Expander makes the beam "bigger", but also reduces divergence, so at long distance, the dot will be smaller with expander used.

I contacted thorlabs, their expanders are rated at 100w/cm^2.thats still not enough if i lase 2mm^2 beam through it.

so no way to lase 3.5w through it , unless i can make the beam spread over more then 2cm^2

most of the beam expanders are rated at 500mW/cm2 , what does it mean? also , any drawbacks using expander with multimode diodes ? any other ways to lower the beam divergence? thanks

agreed . i think 90% of people comming here looking for burning laser :) i understand that .we used to see this stuff in movies when we were kids , i think this fascinates people . i also bought 30mw green laser a long long time ago , and i was pretty amazed by the beam at night . unfortunately...

you guys are funny . i NEVER asked how to burn stuff . my use for a laser is mentioned in the thread title . what type of electrical device is located at the other end is my own business and i never asked anyone of you helping me to design it . maybe i'm writing a patent for remote powered "X"...

i guess i should have started a thread asking for help popping balloons at 100m , sounds much more legal and "normal" around here . sorry , unfortunately i dont have the balloon popping fetish yet . maybe i'll get some if i'll continue reading around :tinfoil:

can you post a link ? this was probably done with green laser with good divergence . but theoptics are interesting . by mirror type , do you mean reflector telescope ,like the ones used for astronomy ? those can be bought on ebay for less then laser expanders . 1ft solar cell will unveil...

easy to say huh . where do i get this laser and optics ? looks like those ir laser are really poor with high divergence . i'm not sure if beam expander would help to reduce the beam diameter to approx 5cm at 100m. is it possible to focus the beam at the expander input to a tiny dot , so at the...

device requiers approx 400-200ma @ 3.7v ,but as already stated , the solar cell will only charge the battery when its not used .

great , so i'll need ir laser with some optics . about the optics , i read that beam expanders improve the divergence . so if i use 10x beam expander , does it means that it will expand the beam by 10 ? so if the beam diameter at entry is 1mm , the output beam is 1cm ? and by using this expender...

what wave length is needed to power a solar cell and is it safe enough ? i have no problem using solar cells if its a better solution . the power from distant laser / whatever will be used only to charge a battery .i'll choose the battery voltage thats best suited for the laser reciever ...