Laser beam Definition and 124 Threads

For my experiment I need to take a 0.8 mm HeNe beam to 20 mm beam. Since we just want illumination, it appears there is not need for beam expander or a setup of special lens (there are a few configurations online). It was suggest to use a Plano-convex cylindrical lens. I talked to...

Homework Statement A 200 mW horizontally polarized laser beam passes through a polarizing filter whose axis is 25 degrees from vertical. What is the power of the laser beam as it emerges from the filter? P=mW Homework Equations E (transmitted) = E (incident)cos() The Attempt at a...

If two lasers are pointed emitting end to emitting end in a vacuum (for lowest divergence), and emit 2 beams of light 180 out of phase, could both beams destructively interfere completely (no light coming from either emitting end after the beams converge)? If the experiment was done under...

hello forum. a question about light and uncertainty: If a laser beam has a 2 cm diameter when it passes through an aperture that is 6 cm wide, the beam is not affected by the aperture. Why? What happens to the uncertainty principle there? Isn't the probability wavefunction affected by...

Hi all, I would like to ask a question. Some people tell me that the red light emitted from the ball pen (I don't know the exact word in English, I mean the pen that lecturer uses to focus light on the slides when conducting presentation, in Power point eg) is the laser light. Is it true...

This is probably just nuts but let's say you switch on a laser, point it to the sky and leave it on for billions of years until the beam has traveled billions of light years. Then you rotate the laser 360 degrees in let's say 1 RPM. Does the laser spot that is now billions of light years away...

Information is stored in a series of pits on the disc. These pits are scanned by a laser beam. An significant limitation on amount of information that can be stored on a disc is width of laser beam. I knew why the width of laser beam is important coz diffraction effect of loght. But, i...

Mirror and laser beam angle...please help! Homework Statement The mirror deflects a horizontal laser beam by θ=59°. What is the angle φ? Homework Equations The Attempt at a Solution I don't understand this. How am I supposed to figure out φ?

Homework Statement If a 20-W laser beam, which has an initial diameter of 2.0 mm, spreads out to a diameter of 2.0 m after traveling 10,000 m, what is the final intensity of the beam? A. 20 x 10-4 W/m2 B. 20 x 10-6 W/m2 C. 20 x 10-8 W/m2 D. 6.4 W/m2 E. 6.4 x 10-6 W/m2 Homework...

Homework Statement A scientist needs to focus a helium-neon laser beam (lamda = 633nm) to a 10 micrometre diameter spot 8.0 cm behind the lens. a) What focal-length should she use? b) What minimum diameter should she use? Homework Equations w = (2.44lambda * focal length) /...

Homework Statement How long would it take a laser beam to go to the Moon and back if the distance to the Moon is 3.8 x 10^8m? Homework Equations a=2d/t^2 d=v1 t + 1/2a t^2 The Attempt at a Solution a=2d/t^2 9.8m/s(Gravity)=2(7.6x10^8)/t^2 t^2=15.2x10^8/9.8 t= 12453.99698 secs...

Homework Statement A laser beam (\mathrm{Power} = 1\ \mathrm{W}) is completely reflected by a mirror perpendicular to the beam. Light is made of photons, and each photon carries an energy E = h\nu and a momentum P = h/\lambda, where \nu is the frequency, \lambda is the wavelength and h is...

A laser beam passes through a single slit of width 0.0186 mm and produces a pattern with an intensity distribution like that shown in Figure 13a (page 208), on a screen 105.6 cm away. If the spacing between the minima on either side of the central maximum is 7.16 cm (in other words, 2y1 in...

Homework Statement A stationary particle of charge q = 3.0 10-8 C is placed in a laser beam whose intensity is 2.5 103 W/m2. (a) Determine the magnitude of the electric force exerted on the charge. (b) Determine the magnitude of the magnetic force exerted on the charge...

Hey all, I am currently trying to figure out how I can control the direction of a laser beam. Galvos are widely used in order to electronically change the direction of the beam. Although, I was hoping to find a way to do this without mechanical parts. There are two ways I have looked at...

A few months back there was a thread with a pic of a visible beam being emitted by a green laser pointer. There was some discussion as to whether or not it was a photochop. Here is a pic I took of "my" green beam laser. I am not at liberty to say a lot about this laser, but it is 1064nm and on...

Question A laser beam travels from air into a symmetrical prism at right angles close to its upper edge. The refractive index of the prism material n = 1.4 and its angle is 30 degrees. i) Calculate the critical angle for the prism-air interface. Possible Answer: Critical angle =...

I saw this awhile ago, I don't remember where though. Supposdly some scientists accelereted the beam of a laser faster then the speed of light, by shooting it through a high density gas. The opinion being that Relativity only states that nothing can go faster then the speed of light in a...

A while ago a group of scientists teleported a laser beam from one area to another, proving that this is possible yes? If I remember rightly the problem with teleporting a human is that while the physical self would be transported, the mind would not be, leaving you with a physically fully...

An Intresting thing about laser beams that I noticed is that you always find thousands of small dots in the spot that is formed by a laser beam on the surface? What could it be? Maximas of light beams caused by constructive interferences? I am yet to find out. Please let me know if you have any...

Bending a laser beam ?! I was surfing the web when I encountered this photo: http://www.ieav.cta.br/soldagem/LASER%20verde.gif I can only read English and Persian, unfortunately the page was in another language I can't get even a word of it. Anyway I'm badly interested to know a bit...

A lithium atom (mass doesn't matter) is being pushed from rest by a laser beam whose power is 1mW. Find the velocity of this lithium atom as a function of time So here goes what i have done v(t) = \frac{1}{2} at^2 now F = ma = \frac{\Delta p}{\Delta t} so then a = \frac{\Delta...

Hello everyone! I'm having a real tough time with this one, maybe I can get a little help. A small helium neon laser emits red visible light with a power of 3.2 mW in a beam that has a diameter of 2.5mm. What is the intensity of the laser beam? Does this intensity obey the inverse square...

How much force (in Newtons) is exerted on a mirror when a 12.0W laser beam of red light (675 nm) strikes the mirror normal to its surface? (Assume no light is absorbed) How how how how? kthx