Laser Definition and 1000 Threads

i am not able to understand this line.. in semiconductor laser the transition probablity for a radiative transition across the conduction and valence gap must be high and must exceed the probablity for non -radiative transfer of energy to the lattice. please explain this theory.

solar "laser" (for the lack of abetter word) Im new here so I am sorry if this is in the wrong spot. but i was wondering if it would possible to take a sun tunnel and like a laser have a partial mirror at one end and a mirror at one end reflecting light back and forth then take fiber optic...

When laser light is reflected from a diffuse surface, what is the reason that it appears speckled?

Can laser eye surgery/anything fix cross eyes? 2 of my friends are cross-eyed and they're adults ty

My next project is to build a simple TEA nitrogen laser, as seen here: http://photonics.tfp.uni-karlsruhe.de/1/a-homemade-uv-laser.html Would it be acceptable to substitute two strontium titanate ceramic caps, each rated 50KVDC @ 910pf, in place of the suggested aluminum foil / plastic...

you are on the millenium falcon, going at the speed of light, and you fire a laser. does the laser go anywhere? if you were on a truck moving at 50m/s and threw a ball forward at 20m/s, then the ball would go at 70m/s. not the same when dealing with c, right? so then how can the laser go...

Does anyone know how to simulate the pulse laser drilling? I am trying to use Comsol or MATLAB to simulate the laser interaction with a specified piece of material. Following, plot the time (X axis) versus temperature (Y axis) diagram to see the temperature distribution. Any help in...

Hi, i have a question about optical fiber and CO2 laser Can a CO2 laser be cabled with optical fiber? Wavelength of 10 micron

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...

"Laser Flashlight" possibility Maybe some of you have seen the video, where they make a match-lighting capable laser pointer out of a DVD burner laser, like the youtube's video CgJ0EpxjZBU. Now, it's well known that youtube's bogon emissions are off the charts, nevertheless, having an ample...

1) When you excite amolecue and it releases photons off a given frequency, is that frequency the the very frequency which would best excite an identical molecue? 2) or are the release frequency(ies) and absorption frequency(ies) different? 3) If you excite a hydrogen atom with a certain...

have absolutly no idea where to put this but ill put it here My eyesight is something like +6.25/+6.50 Now the eye man (optomotrist?) said that they only make contact lenses that go up to +6. I was wondering why this is? Also why can't long sighted people have laser eye sugery? Is there...

http://optics.ph.unimelb.edu.au/atomopt/publications/littrow_rsi_vol72_p4477_2001.pdf The picture of the ECDL I explain can be found from the above web site. The purpose of piezo is to change the cavity length of the diode laser, so that the wavelength can be varied. From the picture...

Has anybody ever tried adding mirrors around a laser tube cavity where a lot of spontaneous emission can be reflected back into the tube? The idea is like this - if there is a low probablitity of absorption, perhaps the emissions will be induced to occur down the main laser tube where the...

Hi Knowing that i live in France (40 USD to import from USA which is expensive) I am currently looking for : 1) A Laser mouse (around 25 - 50 euros) is this one good : Mouse : http://www.amazon.com/dp/B000U75V02/?tag=pfamazon01-20 Mouse pad ...

How i can build a cheap and big Laser ? (please insert pic)

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. How...

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...

have a wave equation: (∂^2 p)/〖∂z〗^2 -1/c^2 (∂^2 p)/〖∂t〗^2 In my case, (fields propagation within a semiconductor laser) Which can be factored into forward propagating photon density: (∂p^+)/∂t+C_g (∂p^+)/∂z=C_g Gp^++〖1/2 βR〗_sp And backward propagation wave (photon density)...

Okay, I have been reading the article Laser Deceleration of an Atomic Beam by William D. Phillips see attachment. But I have a few problems: 1. Optical Pumping. On page 1, 2. column they write: I don't quite get the last part. How can the Zeeman effect change the selection rules? 2...

Hi: Is it possible to make a free-electron laser that emit coherent gamma rays? If so, could this laser be used to ignite Hydrogen-Boron fusion? Thanks, Radium

For my senior thesis I'll be spending some time in the laser lab, though I am not familiar with practical considerations of lasers. Does anyone have any good reads on equipment and procedures for experimental optics? Thanks

What are the limitations on the phase velocity of laser light? Is it true to say that the phase velocity of laser light is limited to <c?

I know that Bragg cell used in laser doppler vibrometer (LDV) is used to give information about the direction of the velocity of the object that we measure. I also know that Bragg cell will shift the frequency of the laser beam(modulation frequency is reduced) when the object is moving towards...

Hey! What would happen if you were orbiting a neutron star and shot a powerful laserbeam at the surface, at some angle? Would it reflect? Would it be absorbed? Thinking (if you picture the star as a perfect neutron star) that the surface is absolutley smooth, it would reflect light...

I'm working with a couple different diode lasers, attempting to automate control of them (on and off mainly) by modulating the source currents externally. One of them is a green laser that draws ~1.4A, 3.3V but has no modulating chip in the power line. I've got another smaller red laser module...

If you zap a n-type semicond. with a laser with energy at, say, the band gap, what happens to the donor electrons? For sake of argument, let's say we're at low temp. where the occupation of electrons on donors is high. I know technically, you should only get transitions at the energy of the...

I am slightly unsure about how the divergence can be increased by the use of either bi-concave or plano-concave lenses. I understand the general theory behind it but am having trouble putting numbers to it. e.g. if you have a laser beam with a diameter of 2mm and a divergence of 2mrad what...

1. The problem A HeNe laser (wavelength = 633nm) is used to illuminate an opaque plate containing a a specified aperture. The light which passes through the aperture falls on a screen at a distance of 4 m from the aperture plate. c) The aperture is replaced by two long rectangular slits...

Hello! My textbook quotes the probability W of a transition between the levels 1 and 2 of a laser that appears in the rate equations. For E_2 = E_1 +h\nu it is supposed to be given by: W = \frac{1}{\tau VD(\nu)\Delta\nu} where \tau is the lifetime of the level 2 (probably for...

I am doing some basic heat calculations about a CW laser illuminated tungsten tip (which should be used for photoemission) - I started to play with the tip geometry to try and find a way to get more flux Watts/metre^2 onto the tip without it melting. I found that after solving the 1d heat...

Does anyone know where I can find a derivation how/why a light beam disperses? I'd like to see some sort of solution to Maxwell's equations for a finite width EM wave in free space. If the beam is a linear superposition of frequencies and Maxwell's equations are linear, does a laser beam...

In 1975 I've got the job in lab constructing middle power one mode CO2 lasers for outer space object location (they used C and O isotopes for reducing losses in atmosfere). The main joke for newbies of our lab's boss (Yuri Vasilievich Pechenin) was to breathe sigarette smoke from mouth into...

Do opaque materials like wood or plastic block the harmful radiation from a laser? I understand how laser safety glasses filter out IR radiation. So does a piece of Aluminum or black plastic block it completely?

The laser is able to vaporize an Earth sized planet in about a second.

looking for information about phenomena when light through fiber out before through and photon reverses at exit time to negate entering photon leading to equilibrium of energy transfer. think it was coated with iridium or something. not sure. saw it reported on shortnews.com about a year or so...

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?

According to wikipedia below: > Huygen's principle states that each point of an advancing wave front is in fact the center of a fresh disturbance and the source of a new train of waves; and that the advancing wave as a whole may be regarded as the sum of all the secondary waves arising from...

Eigenstates: What would happen if you had a laser aimed at a mirror 45 degrees... I know this post might fit under some of the other post in this forum but i would like to ask it as a new topic because I am just getting into a lot of Quantum information ever since I noticed this part of the...

So I have a couple of cheap <5mw red laser modules. And I also have mirrors. And I'm bored. You can guess what happens next (profit). Some really strange effects that I'd love to know the origin of: 1.) The speckle effect from the laser beams - it doesn't actually matter where your eyes are...

Hi, So I have a lab question for which I have to drive a formula to find the optical cavity length of a laser, L . I have results from testing the fringe patterns when I move one of the mirrors in a Michelson interferometer. It shows the typical \frac{\sin x}{x} pattern. To find the cavity...

Why is it that when looking at a laser (not directly, but from an angle) it is possible to see a pattern of spots which flicker around randomly?

Does anyone understand the physics that is used to explain this relatively new research project on use of laser fusion for energy production ?: http://www.guardian.co.uk/science/2007/may/30/energy.nuclearindustry From what they say, it appears they propose to use laser energy to "fuse"...

Hello, I'm quite intrigued as to why when a mist of water particles (clouds etc) is being shined by laser light, the laser beam is seen clearly, all throughout the mist, but if you take the mist off, the laser beam is no longer seen. What's the theory behind this? Thanks a lot From Steven

I just wanted to know, what causes laser speckling? interference with air? uneven projection surface?

I've just finished reading the book "Time Traveler - A scientist's personal mission to make time travel a reality", by Dr. Ronald L. Mallett, professor of physics at the University of Connecticut. In this book Mallett explains a new theory to travel back in time using a laser ring, which creates...

Next month I am going to be teaching my 9th grade "Physics First" classes about optics, and I'd like to use a set of lasers to show them how rays diverge and converge in various situations. Students will literally be able to see things like this...

Suppose I am in an inertial non-accelerated reference frame, and I observe a laser pen moving in a direction perpendicular to its length at a uniform constant velocity of one meter per second. If the laser pen were to fire very briefly, say for 1 millisecond, while in this state of uniform...

Alrighty, I have 2 simple questions about Laser Beam Combination. I was wondering if I could take multiple Laser Diodes and direct them all at the same point and have the combined energy of the lasers at that single point. Would phase cancellation be an issue? If that doesn't work, I was...

Ok, so recently I've moved on to sound waves in my high school class. I was wondering if sound waves could be harnessed for demolation with accuracy? I was thinking the sound would have to move in a linear vibrational path, without dispersing (making a cone shape), is this possible?