laser pointer Definition and 32 Threads

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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

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?

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...

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...

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...

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?

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...

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

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...

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...

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...

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...

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

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...

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...

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?

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?

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...

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...