Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

Search results

  1. zyxwv99

    Is the "Star Shower Laser Light" (As seen on TV) safe?)

    Thanks for the feedback everybody. It never occurred to me that the same technology is used in nightclubs.
  2. zyxwv99

    Is the "Star Shower Laser Light" (As seen on TV) safe?)

    http://www.getstarshower.com/?uid=D3BC8E1884C8DA72426B90329025B568&gclid=CInx4NnW1McCFUzmfgodTswDrQ&gclsrc=ds:wtf: http://www.youtube.com/watch?v=gRaTgfnuI14 Yesterday I saw this TV commercial for a plug-in device that looks like two lasers, red and green, with a "stars" attachment...
  3. zyxwv99

    New large holes in Siberia.

    My first thought was methane ice. WIRED had an article about it maybe ten years ago. It's a single molecule of methane trapped within a buckyball-shaped water molecule (or group of molecules). If you take a handful of it and put it in an empty 1-meter weather balloon, then tie it shut, it will...
  4. zyxwv99

    Does anyone believe this - 10000mw laserpointer??

    I've ordered lasers like that. They are for real. AliExpress has plenty of them, some as high as 20000mW. You just have to know how to read the ad. Take the price in cents and divide by 20. That's how many mW you actually get. If it's $30.00, that would be 150 mW. Plus or minus a factor of two...
  5. zyxwv99

    Great read, should be mandatory IMO.

    It gets better further down, but the first screen-full (or two) is simplistic and heavy-handed, almost like a drill sergeant talking to juvenile delinquents at one of those boot-camps for juvenile offenders. "Listen up kids! I know you're stupid. That's why they sent you here. I also know you're...
  6. zyxwv99

    Trouble perceiving 445, how do you guys see it?

    What you're describing is known as "foveal tritanopia," the "central blue-blind spot," or the "blue-blind zone." It's normally about 0.25 to 0.4 degrees of the field of vision (the full moon is about 0.5), corresponding to the part of the retina called the foveal umbo or foveal reflex. Most...
  7. zyxwv99

    What is the longest wavelength of laser light you have seen?

    I'm the one who revived the topic. I was already researching human vision in the near infrared on my own, and was amazed to find someone else had thought of the same thing. I hope your eye is okay. New interest: single-photon vision.
  8. zyxwv99

    Taboo woo woo science?

    I tried watching the video, but most of it seemed to be about how brilliant minds of the past were misunderstood, the implication being that anything out of the mainstream must be brilliant. He didn't start getting to the point until more than halfway through a 14-minute video. That's why I kept...
  9. zyxwv99

    using sound to deliver a laser pulse.

    It seems that the primary focus of your problem is the switch and how to control it. For that you might need to know what kind of electricity that switch is controlling. That would probably be electricity coming from whatever sort of batteries you are using. Knowing the battery type and how many...
  10. zyxwv99

    i need a red laser with eye safe?

    Eye-safe has several different definitions. From a legal standpoint, an eye-safe laser is 0.4 µW (class 1). Anything higher and you could get sued if some kid looks into the beam. How far a laser can "go" depends on who or what is detecting it, for example if the laser is shined directly into...
  11. zyxwv99

    Another company that sells SUBPAR mw in their lasers?

    That's one of the known companies that sells seriously underspec lasers. Reminds me of the 20,000mW (20W) laser pointer being offered on AliExpress for $13.95. With free shipping.
  12. zyxwv99

    Question about UVC light.

    I think it was Ian Fleming who proposed the idea in 1956. Or Sean Connery in 1971, I forget, but the movie was called "Diamonds are Forever." The evil Dr. Blofeld has his minions steal diamonds, which mysteriously never turn up on the black market. Instead, they are used in an x-ray laser...
  13. zyxwv99

    Confirmed cheap multi-line 980nm/490nm pen

    Re: Possible cheap 2-line 980nm/490nm pen On a completely unrelated tangent, I found some more info on human vision in the near infrared. Until today, the best info I had was Sliney (1976) where a 1064nm laser with 3mm diam. beam shined into 20-minute dark-adapted eyes needed an average minimum...
  14. zyxwv99

    Question about UVC light.

    X-ray lasers are easy. http://upload.wikimedia.org/wikipedia/commons/1/13/Prague_asterix_laser_system-interaction_chamber.jpeg It's gamma-ray lasers that nobody has figured out yet.
  15. zyxwv99

    Confirmed cheap multi-line 980nm/490nm pen

    Re: Possible cheap 2-line 980nm/490nm pen I've never heard of fluorescence being limited a specific wavelength range or direction. For all I know, radio waves could cause something to fluoresce in microwaves. I'm not saying this is the case, just that from what I've read on how fluorescence...
  16. zyxwv99

    Confirmed cheap multi-line 980nm/490nm pen

    Re: Possible cheap 2-line 980nm/490nm pen According to my calculations, the output of the 490nm should be about 80 picowatts. It looks brighter than the 980nm, but is in the same range. The higher brightness could be accounted for by the tighter beam, so actual brightness would be very close...
  17. zyxwv99

    Can the eye differenciate @ night between a 532nm: 100mw vs 250mw vs 500mw vs 1.2w?

    It depends on how expensive the laser is, and what kind of optics it has. A point source is so small that you can't see the size or shape. One way to find out is to shine the laser on an eye chart, the Snellen chart. Somewhere at the bottom is a line of letters labelled 20/20. On that line is a...
  18. zyxwv99

    Can the eye differenciate @ night between a 532nm: 100mw vs 250mw vs 500mw vs 1.2w?

    Brightness function: Effect of area and duration R. J. W. Mansfield JOSA, Vol. 63, Issue 8, pp. 913-920 (1973) Optics InfoBase: Journal of the Optical Society of America - Brightness function: Effect of area and duration "fractional exponents: -(1/2) for point sources and -(1/3) for extended...
  19. zyxwv99

    Can the eye differenciate @ night between a 532nm: 100mw vs 250mw vs 500mw vs 1.2w?

    Perceived brightness is proportional to the cube root of the intensity (in this case measured in mW), except for a point source, where it's the square root.
  20. zyxwv99

    Fun-Fact thread

    Between 2000 and 2013 our planet got hit by 26 asteroids. They exploded in the atmosphere, but with power measured in kilotons, producing shock waves detectable thousands of miles away. B612 Foundation Impact Video | Sentinel Mission




Top