Long-range Laser Night-vision

[Oneironaut] is back at it again, churning out yet another great hack in this long-distance night vision build. This isn’t the first time we’ve seen him build a night vision device, you may remember the monocle he put together using the view finder from an old camcorder. This time around he’ll give you look at distant object by using a laser instead of LEDs. He pulled an IR laser diode out of an old CD burner, then used a lens to spread out the dot in order to illuminate a larger area. A standard rifle scope is used as the optics, along with a security camera which can detect the infrared light. As always, he’s done a fantastic job with the images and the write-up. You’ll find his overview video embedded after the break.

24 thoughts on “Long-range Laser Night-vision

  1. Thanks for posting my hack!

    @Mathew, thanks for pointing out the error – the scops is indeed a 4×32, but the 4 was worn off, leaving only the “x32” part, and combined with the zoom of the CCTV lens, it did seem like x30.

    That mistake has been fixed!

  2. RadBrad,

    Creative use of laser diodes and nicely documented. Thank you, I enjoyed it. One thing that you probably know but is worth mentioning is that most low cost 532 nm (and other color) lasers use frequency doubling crystals to convert the output of an IR laser to visible light. So, at the heart of most cheap green or blue laser pointers is a IR laser diode.

    (Wikipedia reference: http://en.wikipedia.org/wiki/Laser_pointer)

    – Robot

  3. Thanks for the comments.

    In the video, I ended up using a 250 mW laser diode with no lens at all, and the patterns that can be seen are actually dust particles being projected onto the scene. Once I took some cleaner and a qtip to the diode window, the patterns were gone.

    My original version used the infrared laser diode pulled from a green pointer, and it was a lot of work to extract it! I did a writeup on the early version in 101 Spy Gadgets for The Evil Genius.

    With the cost of green laser pointers these days, I think that would be the best source for an infrared laser diode in the 100 to 250 mW range.


  4. Nice pictures, but a 250mW laser in the near infrared is nightmare stuff. No reflex blink, no filtering. If this bounces off something shiny and back into your eye focussed by Lady Luck, the your retina is going to seriously warm up to the subject.

  5. Woops. I posted on the earlier hack.

    This is really cute, safety warnings aside.

    But notice all the newton’s rings in his images? That’s the short answer for “why lasers don’t make particularly good spotlights”.

    It’d be nice to see a comparison of his laser setup to commercial infrared spotlights.

  6. @ Brent,

    Those patterns are actually microscopic dust particles being projected onto the target, not Newton’s rings. I was using the bare diode (no lens), and the dust on the tiny glass window caused the patterns.

    Once I took some cleaning alcohol to the window, all of the rings (patterns) were completely gone. Of course, the oblong beam is just a characteristic of the unfocused laser diode, but that was a plus in this system, not a minus.

    Yes… this is NOT an eye-safe project. Oddly, commercial systems output as much as 1watt of laser radiation, and focus the beam to a much smaller target and claim “eye safe” operation. I am not taking any risks though… I want to keep my one good eye in working order!


  7. Drake: no. Loonquawl is right. Reflections are a very serious matter in laser safety.

    Since he’s causing the beam to diverge, it’s not that bad. I wouldn’t exaggeratedly warn people not to do very specifically exactly what he did. But:
    1) Personally I wouldn’t fiddle around with high-powered invisible lasers without the kinds of safety precautions (goggles are a last resort that can teach you bad habits, not a first line of defense) one would find in an industrial or academic laser lab.
    2) (Because) You could screw up and hurt yourself trying this at home if you deviate much from the script.

  8. Brad, I meant commercial infrared spotlights of the sort that use infrared filters or IR leds.

    The dust particles aren’t just getting projected, they’re diffracting and the diffraction is causing those interference patterns. Again, that’s an inherent issue when you use coherent light.

  9. Also- @ macona- explain?

    How would a 1550 wavelength be safe? It’s still high powered laser light at the cornea. Am I missing something?

    If this could be made with a laser that is completely eye safe without goggles (which I don’t know to exist), this would be the ultimate.

    Could a filter be placed between the laser output and exiting the case to polarize it, rendering it viewable only from polarized optics, or modifying the wavelength of the beam to something not viewable by commercial ir sensitive equipment?
    What modifications through filters or lenses would be possible?

    I mean, if you were using this for stealth, it’s pointless if others are looking for you with night vision equipment- this would broadcast your position like the tailstream on a launched model rocket- instantly spotted. Although, I like the adjusting focus- start with the normal pin sized beam to spot a point, then adjust just enough to illuminate the key area- a sort of adjustable long range spotlight.

    If you could, through a filter, change the properties of the laser to be viewable only to something that sees the modified range beyond the sensors of normal night vision equipment, then you would be truly stealth, even against others with night vision equipment.

    I want a version of this using a panning scanning IR laser to pick up and map thermal signatures at a distance- I could finally become predator.

    Finally- for serious hunters, make the scope a Burris Eliminator with it’s range finding bullet drop laser dot calulator, and you could snipe deer at night with all headshots at 500+ yards, assuming you live somewhere where night hunting is legal. Yeaaaah.

  10. Nice idea…but standard, cheap, silicon, focal plane arrays are not responsive at 1550nm.

    About the best you could go with is 1060nm..


    To visualize 1550nm would require something along the lines of an InGaAs focal plane array and those cost $$bank$$

    And 1550nm is often deemed “eye safe” (often incorrectly), because as you increase wavelength, above our ability to visualize(800nm), it requires more optical power, and/or a longer exposure time, to physically damage the human eye.


    The human eye is also an optical filter and (go figure) it is the most responsive to light that we can actually see (400-800nm).

    As you move outside of that you are not completely immune to damage, because you have a higher risk of exterior eye problems….like cornea burns (similar to cataracts).

  11. I used to build some pretty interesting 3rd gen based night vision systems for surveillance use.

    That is some very nice performance, but the laser causes concerns already voiced above.

    Probably one of the few aspects of that job that I miss.
    That, and the esoteric video and audio gear.

    Anyhoo, well done!

  12. eye safety: since there’s no blink reflex with ir this is a big concern. but a laser beam that gets widened by a lens can be on the safe side.
    important is not the total output power, but the intensity (power per area). take a 200mw laser and widen it to a 4 foot circle and the intensity is way below a normal 1/4mw laser with a 1/4inch beam.

  13. Please be careful with the IR people. Please.

    Also on the monacle using the viewer from an old camcorder:

    Be careful about pumping too much voltage into one of those old tiny CRTs. They can generate X-rays if the voltage is off. Sometimes when you take one apart there is a warning sticker in there.

    Finally, keep in mind that a security camera on the cheap is not the only CCD type device you can use. Try a search on low light cameras and you will find there is a whole world out there full of specialized (but pricey) cameras that can see in the dark without infrared sources.

    It would be nice to see the output on a small LCD, ending up ultimately with a rifle scope similar to the sniper scope in Halo.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.