What is laser pointer: Definition and 32 Discussions

A laser pointer or laser pen is a small handheld device with a power source (usually a battery) and a laser diode emitting a very narrow coherent low-powered laser beam of visible light, intended to be used to highlight something of interest by illuminating it with a small bright spot of colored light.
The small width of the beam and low power of typical laser pointers make the beam itself invisible in a clean atmosphere, only showing a point of light when striking an opaque surface. Laser pointers can project a visible beam via scattering from dust particles or water droplets along the beam path. Higher-power and higher-frequency green or blue lasers may produce a beam visible even in clean air because of Rayleigh scattering from air molecules, especially when viewed in moderately-to-dimly lit conditions. The intensity of such scattering increases when these beams are viewed from angles near the beam axis. Such pointers, particularly in the green-light output range, are used as astronomical object pointers for teaching purposes.
Laser pointers make a potent signaling tool, even in daylight, and are able to produce a bright signal for potential search and rescue vehicles using an inexpensive, small and lightweight device of the type that could be routinely carried in an emergency kit.
There are significant safety concerns with the use of laser pointers. Most jurisdictions have restrictions on lasers above 5 mW. If aimed at a person's eyes, laser pointers can cause temporary visual disturbances or even severe damage to vision. There are reports in the medical literature documenting permanent injury to the macula and the subsequent permanent loss of vision after laser light from a laser pointer was shone at a human's eyes. In rare cases, a dot of light from a red laser pointer may be thought to be due to a laser gunsight. When pointed at aircraft at night, laser pointers may dazzle and distract pilots, and increasingly strict laws have been passed to ban this.
The low-cost availability of infrared (IR) diode laser modules of up to 1000 mW (1 watt) output has created a generation of IR-pumped, frequency doubled, green, blue, and violet diode-pumped solid-state laser pointers with visible power up to 300 mW. Because the invisible IR component in the beams of these visible lasers is difficult to filter out, and also because filtering it contributes extra heat which is difficult to dissipate in a small pocket "laser pointer" package, it is often left as a beam component in cheaper high-power pointers. This invisible IR component causes a degree of extra potential hazard in these devices when pointed at nearby objects and people.

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  1. M

    A IR Laser diode focusing and module selection for CSEL Laser pointer

    I'm attempting to build an IR laser pointer. It needs to operate at 850nm (IR spectrum). It has to be as close to a "dot" at 250 feet as possible (columnated beam, and not a wide "flashlight" type beam). Power output should be around 150mW. I need to control the brightness from 5mw to 150mw...
  2. S

    How to show light from laser pointer is plane polarised?

    The answer key is the light is directed through one polarising filter then filter is rotated and the light changes intensity. I don't understand how that proves that the light is plane polarised. I think if the light is unpolarised, the intensity will also change when it passes through...
  3. B

    I Question about this "Quantum laser pointer" that I bought

    I bought one of the lasers from quantumlaserpointer.com If I remove the cap I can see the two thin slits cut in it. If I hold the laser around 3ft from a surface it appears to show the refraction pattern. Is this actually working like the dual slit experiment and the laser photons are going...
  4. A

    B Observational Effects of "FTL" spotlight from laser pointer?

    So from what I understand, it's possible to have a very powerful laser pointer where you point at an arbitrarily large and far away surface and make the spotlight appear to move at faster than light. E.g. you can be holding the laser in your hand and you simply flick your wrist. My question is...
  5. J

    Distance Traveled by a Laser Pointer in Outer Space

    Homework Statement A 50 g, 420 mw laser pointer is floating in outer space (don’t ask how it got there) at rest with respect to an observer. The laser pointer is turned on and let go. If the battery runs continuously for 250 hours before dying, what is the final speed achieved by the laser...
  6. barryj

    Can a Lens Increase the Power of a Laser Pointer?

    I have a green laser pointer. I assume that the beam is nearly focused a infinity because it does not spread much when shown on a wall. My question is, can I use a lens to focus the beam to a smaller spot. when I see videos about burning laser pointers I do not see any of them using a lens to...
  7. J

    B Laser Pointer at Speed of Light: Does It Point Ahead?

    This is just kind of an odd question that has to do more with concept than practice but if you were going 1m/s slower than the speed of light and were holding a laser pointer would the laser only point one meter ahead of you? I know that light doesn't add like normal vectors but this is...
  8. D

    Finding a Class I Laser Pointer for a Science Fair Experiment

    I am doing some experimentation, for a science fair. And I want to make sure I the laser pointer I use is Class I (conceivably, I may change that, but any class of laser can be used to replicate results similar to the double slit experiment correct?). Can anyone direct me as to where I may be...
  9. C

    How to estimate the power of a laser pointer

    Not sure if this is the right place, but I'm hoping to ask two questions: 1. I shine a laser pointer at a mirror at night, and the reflecting beam glaces off of my eye. Obviously it's quite bright, and I want to know if this has caused any serious damage. Of course I shut my eye, but apparently...
  10. H

    Seeing a laser pointer from 16km away

    A friend and I would like to try communicating (Morse code signaling) with off the shelf laser pointers from two hill tops (~350m above sea level) separated by about 16km. It would be nice to do this without binoculars but I’m not sure if that is possible with readily available off the shelf...
  11. D

    Best laser pointer for optics lab?

    I'm serching around the web to find the best laser poiter (with real safety class). the below one is the only thing that I could find: https://www.amazon.com/dp/B00NQCF35G/?tag=pfamazon01-20 Do you know any other brands suitable for educational goals? we need to use laser pointer for some...
  12. T

    Not a scientist, just wondering -- Shining a laser pointer into space

    Thought Experiment 1: I shoot a laser into space for one second. Just before I let off the trigger, the face of the beam is ~186,000 miles away. What happens to the beam when I let off? Does it instantly cease to exist? Does the tail compress into the stopped head and go poof :)? Does that...
  13. M

    Tracing a laser pointer with IR camera

    Hi! a very basic question that probably has a simple answer: would it be possible to trace a laser moving over a generic surface such as a wooden floor with an IR camera? The idea would be to calculate relative movement based on that... If I'm not clear enough feel free to follow up with a...
  14. Hxopblxvj

    Harnessing Plasma with a Laser Pointer and Nitrogen

    I was wondering if I could create plasma inside my own apparatus using a laser pointer and nitrogen..
  15. A

    Simple laser using magnifying glasses, lenses and a laser pointer

    Hi guys, sorry new to this, I'm looking to build a simple laser using magnifying glasses, lenses and a laser pointer. How would I go about it and can I get away with using the pointer or do I need a laser diode?
  16. Roodles01

    CD Phenomenon: Exploring Young's Fringes & Heisenberg's Uncertainty

    Hi. When I point my red laser pointer at the playable side of a CD at an angle the spot becomes diffracted, a bit like the fringes you can get if you put a hair across the beam. Could you keep to the CD phenomenon, when trying to explain and whether it really is related to Youngs Fringes or...
  17. S

    Laser cutting device to cut paper of few mm from a red laser pointer

    Hi, i wanted to make a laser cutting device, not the big one but a small device just to cut a few mm thick paper. I just learned from a site(www.ehow.com/m/how_6692865_make-homemade-cutting-laser.html) that you can actually convert a laser pointer to a laser cutting device by rotating the...
  18. C

    Reviving a Dim Laser Pointer Life

    I have a keychain-type red laser pointer (5mW typical type) and I was using it for something when all of the sudden it is really dim. Even if I bump up the voltage it is still dim and I'm suspecting it is fried. I overvolted it for about 2 sec with a weak 5v source off an arduino but it worked...
  19. E

    Laser pointer shined on photographic film?

    What would happen if I bought highly sensitive photographic film such as ASA 800 and shined a laser pointer on it? When I get it developed will the photons that the laser emitted show up on the film?
  20. D

    Laser pointer for start viewing: something affordable?

    I have a cheap $8 USD 5mW green laser for pointing out stars to my daughters and neighbours. This laser does not have a safety rating on it, so I treat it as a class 3. It is getting weak and I need to replace it. My first thought was to order from Wicked Lasers [1], who had been recommended...
  21. R

    Are There Safe Laser Pointers for Eye Use in Clubs and Shows?

    Are their laser pointers that are totally safe for the eyes? What kind to look for?
  22. I

    Physics of laser pointer attachments: stars, butterflies, etc.

    http://nerdapproved.com/misc-gadgets/dolphin-laser-pointer-keychain/" So in the above image they have little attachments for laser pointers that can make different designs. I've played around with similar types of attachments for laser pointers and have never thought about the physics...
  23. M

    Shining a laser pointer towards the star vega

    Homework Statement (1) A Physics lecturer, on a dark night, shines his laser pointer towards the star Vega. (a) Roughly, how many optical photons from the Sun per second enter the eye of an astronomer standing on a planet orbiting Vega ? Assume that 50 % of the light from the Sun is...
  24. B

    Buying a Laser Pointer: What Can It Do?

    I recently bought a laser pointer offline, it claims to be able to reach up to 12 miles, and from what I can tell it is pretty strong. It says the max output power is < 5mW, and the wavelenght is 532nm. Its just a regular laser pointer, and I was wondering if there are lasers that you can buy...
  25. M

    Unusual Color Effect of Laser Pointer on Red Plastic: A Scientific Investigation

    so I was playing with my 532 nm (green) laser pointer when I noticed something strange. You can shine it at virtually any surface it will appear as a bright green dot - nothing unexpected there. However by chance, I noticed that when I pointed it at this red bottle of laundry detergent i have...
  26. F

    Tracing the Light Path of a Green Laser Pointer

    How is it possible to see the light path of a green laser pointer?
  27. M

    Wicked Lasers' new 1 W laser pointer hits the market

    http://www.wickedlasers.com/lasers/Spyder_III_Pro_Arctic_Series-96-0.html The laser in this thing is an Indium Gallium Nitride multimode laser diode which is very cutting edge stuff - they have only entered the market this year, and are being used in high-brightness modern DLP projectors...
  28. R

    Connect Laser Pointer to PC Wirelessly: Step-by-Step Guide

    Hi all, i am doing a project to make a laser pointer that can connect to the PC wirelessly. Here's how it works. -using the modified laser pointer, shine it on the screen from anywhere in the room and the dots/lines will remain on the screen until the user changes slide. Background: once...
  29. G

    How Can a Simple Laser Pointer Cause Destruction at Light Speed?

    I feel kinda silly asking this question. If you were traveling near the speed of light towards another ship and you shone one of those simple red lasers towards that ship would that ship blow up?
  30. V

    I can't put a 5mw laser pointer on my sharks?

    When did being an evil doctor become illegal? I just got a reply from Dealextreme that told me my green 150mw laser order was canceled because they can't ship anything more powerful then 5 mw to the united states?
  31. T

    Laser Pointer Wave Energy and eyes seeing

    Homework Statement A typical “laser pen” pointer has a power output of 3mW at 670nm. If the angular divergence of the beam is 2mrad, estimate the maximum distance at which it could be seen by a day-adapted human eye. You can assume that in bright light, a normal eye will give a signal from...
  32. H

    Laser pointer and battery life

    I got a 5mW (class 3A), 650nm laser pointer yesterday and it came with 3 AG-3 button cells and over a day, it was on for about 60 seconds, maybe more however I noticed the beam wasn't as bright as it was when I first put it on. Over 30 seconds worth of use, it seemed to dim further until I...