Laser Definition and 1000 Threads

1. The maximum electric field strength in air is 3.0 MV/m. Stronger electric fields ionize the air and create a spark. What is the maximum power that can be delivered by a 1.3 cm diameter laser beam propagating through air? 2. I = P/A = c*epsilon0*E2/2 3. Using E = 3*106 for E, I...

hi, pls can someone help me with converting FWHM bandwidth of a laser from metres to hertz

I've never understood how diffraction is possible, which has led me to mistrust a good deal of quantum physics. I'm mystified as to how light starts spreading out in all directions after passing through an aperture. Supposedly it's because light spreads out like a wave, but then how is it...

I'm making a laser torch based audio transmitter n receiver using 2n5777 phototransistor as receiver what must be the min power of the torch

Why did they land on the other side of the Moon? And how did they place the Laser reflector (http://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment) on the front side of the Moon?

I feel like a moron for not knowing the answer to this. I'm looking for a laser that can deliver a single 3mJ, 10nS pulse. Most of the laser specs I've found report the laser power in watts rather than the energy in mJ. So I did the following calculation: 3mJ/10nS=3x105J/S=300kW But...

hi, I'm working on Tm3+ fiber laser rate equation modeling using Mathematica. The rate equations I'm using for the model are largely based on the work of Jackson and King ("Theoretical Modeling of Tm doped silica fiber lasers", 1999), albeit neglecting some factors so as to simply the model...

Hey everybody, this is not exactly a homework question, but I am writing a term paper on the topic of laser trapping and cooling, and would appreciate any good sources that anyone could provide. This is an undergraduate thermal physics class, and does not need to be extremely technical...

Homework Statement A laser beam enters a 10.0cm thick glass window at an angle of 30 degrees from the normal. The index of refraction of the glass is 1.46. At what angle from the normal does the beam travel through the glass? Homework Equations sin theta 1 / sin theta 2 = n1 / n2 = v1 /...

Is it be possible to produce from the Intensity return of reflective IR laser the true color of the object causing the reflection of the laser? My though is that surfaces of the same material, but of different colors would cause slight changes in wave length of the laser light. These changes...

Can anyone tell how the intensity of lasers beams is measured. What equipment is used. Any relevant equations?

Hey I am trying to create a comsol model to simulate laser forming using comsol. As a starting point I am using the heating with a moving laser tutorial and adapting from there. The first stage is to model the beam modes. I the tutorial the beam is treated as being infitesimally thin and is...

Hi, I am a physics undergrad and this term I have to write a 3000 word essay on one of about 10 possible topics. One topic which caught my eye was laser fusion. Whichever topic I choose, I will need to find information from a variety of proper sources (not just trawling google). This is what I...

Wow. Here's a video of the laser system. They need to get these manufactured and shipped out. And they're going to make a killing when they go mainstream! https://www.youtube.com/watch?v=eYXPqrXZ1eU Here's an article page on it...

Does a laser have a recoil since photons have momentum. Would a moving laser be slowed down (even a fraction) if was locked in the on position and then thrown at the ground

In a gas laser, an electron in the highest energy state absorbs photon for stimulated emission to occur, but now since it has more energy than its highest state, shouldn't it escape the atom and the active medium be left only with positive ions?

Hello. I've been struggling with this problem for some time, and honestly I do not know how to solve it. Homework Statement Two positive lenses are to be used as a laser beam expander. An axial 1.0 mm diameter beam enters the short focal length positive lens, which is followed by a...

i know light is also a particle, but if a laser can hit an open slit and spread out i can't see how it couldn't be more spread out when it came out of the laser in the first place

Homework Statement I have a laser focused into a lithium niobate crystal and an analyzer placed after the crystal. The analyzer and laser are cross polarized. I'm trying to derive the equation that relates the phase difference of the o-wave and e-wave after the analyzer. I know it is...

Hi, I am working on building a laser range finder and wanted to know if there is any relation between the frequency/wavelength of laser wave and the maximum distance it can measure. I read that the maximum distance it can measure depends on the power of the laser. Any other links...

Homework Statement A laser of frequency f0 is connected to a spring which oscillates in one dimension with a period T and amplitude A. The laser excites the 1st four Paschen series lines of hydrogen. What is f0 Homework Equations I'm assuming that I'll need the Doppler shift equations, f =...

Homework Statement A helium-neon laser beam has a wavelength in air of 633nm. It takes 1.38 ns for the light to travel through 30cm of an unknown liquid. What is the wavelength of the laser beam in the liquid? (IN NM) Homework Equations v=wavelength*frequency v= d/t The Attempt...

I don't know if this is the right place to post this but here goes. I'm a Highschool student building a nitrogen laser for an independent research project. I don't know much about lasers besides what I've read in physics textbooks and amateur laser pages. My and my mentor have already...

Hello! I recently purchased a basic 6-inch Equatorial Reflector telescope. I bought it because I loved doing astronomy with large binoculars, and I assumed the next step was a small reflector telescope. However, I find myself barely using the new scope because the bulky Equatorial mount is...

Hi guys I'm reading a section in a book about non-linear optics. They have an expression for the polarization for the second harmonic field. They say that this expression has a linear and a non-linear contribution at frequency 2ω, but they don't explain this any further. I am a little...

I'm aware that photons carry momentum while technically having no mass. However I recently saw a video of a laser used to propel a small silvered object up several meters in the air just using the momentum of the light. So what about the reaction force? As the light is coming out of the laser...

Hi! I hope this is the right forum. I know how laser works (population inversion, electronic transitions etc...), but I can't understand why the light emitted is coherent

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...

Is it possible to send information by laser? If so, how much faster is this than radio signal?

I want to simulate the reference’s passive Q switch process. The reference is Shengzhi Zhao, Lei Chen, Hongming Zhao, Guiqiu Li, Lu Zhang, Kejian Yang. Laser–diode-pumped passively Q-switched Nd3+:NaY(WO4)2 laser with GaAs saturable absorber. Optics & Laser Technology 37 (2005) 187–191. I...

Hi I just started a PhD where I am going to use lasers to measure fluid flow among other things. I am looking for some helpful information about otpical components and techniques mainly relating to lasers. How to correctly design a setup, how to split beams, how to expand/contract beam...

I apologize if threads on this topic have been posted already. I don't frequent the medical sciences forum. My question is whether there are any rigorous scientific results published in peer-reviewed journals on the efficacy of what seems have been dubbed "low level laser therapy" (LLLT) as a...

Hi At continuous-wave oscillation the gain is equal to the threshold gain, i.e. g = gthreshold. Now in my book, I have the following expression for the steady-state population-inversion for a three-level laser N2, steady state - N1, steady state = (P-Γ12)/(P+Γ12)NT where NT=N1, steady...

Hi there. i solved most of this question, but am not sure about the last part and i was hoping someone would help me. As part of a laser light show a technician is adjusting a diffraction grating. A green laser with a wavelength of 532 nm is shone on a diffraction grating with 2700...

I'm interested in hearing stories about the very early days of lasers. This is easily one of the top few inventions of the last century, and it's turning 50 next year. I'm particularly interested in the first half of the decade, from handbuilt instruments in labs to on-the-shelf product in many...

I'm interested in hearing stories about the very early days of lasers. This is easily one of the top few inventions of the last century, and it's turning 50 next year. I'm particularly interested in the first half of the decade, from handbuilt instruments in labs to on-the-shelf product in...

I've become interested in lasers and this question came to me today. Let's say we have two 10 mW lasers. One has a spot size of 1mm and one has a spot size of 10mm. Therefore, the first laser has a greater intensity. In classical physics we are told the wave amplitude increases. In modern...

Homework Statement I am to calculated the wavelength of the laser I shone through different slit patterns to create diffraction patters on a screen. For the single slit diffraction, Data: xm is the distance from the central image to the mth minimum. x1 0.008 x2 0.015 x3 0.023 x4...

Homework Statement A laser passes through a body of water and later hits a screen, as shown: http://img80.imageshack.us/img80/7417/20478103.jpg However, suspended in the water is a piezoelectric quartz crystal which can produce waves within the water. When set at 5.5MHz, the following is...

Does anyone know what those tiny spots are you can see inside a laser spot on a wall. They seem arranged something like a honeycomb - hexagonally packed tightly against each other. They seem to follow the motion of your head around when you see them too, so I guessed that maybe I'm seeing my...

A small spaceship, with a mass of 1500 kg (including occupants), is at rest in outer space with negligible gravitational forces acting on it. If the astronaut turns on a 10kW laser beam that points out of the ship into the deep of space, what speed will the ship attain in 1 day because of the...

I found this nice book on Google http://tinyurl.com/yh2y2zb that does a great job explaining relativity, however, even though the conclusions make perfect sense to me so far, I'm stuck on a conceptual issue when reading over the classic thought experiments that makes me feel like I'm still...

Homework Statement An argon laser emits 1 watt of continuous light (λ= 5.145 x 10-7 m) in a parallel beam of 2 mm diameter in vacuum. Homework Equations (a) What is the wavelength, frequency, period, wave number, velocity, intensity, and amplitude of the electric field of the laser...

I know that lasers can be extremely dangerous to the eyes. Causing severe vision damage and/or blindness if a laser gets in your eye. I know that this holds true with laser pens, but does the little red laser from a laser mouse pose that same hazard? Or is it harmless?

Homework Statement A rubidium atom traveling at the speed of sound absorbs photons from an oncoming laser beam Each photon can be viewed as a tiny ping pong ball having momentum 7.79 x 10-28 Nt/sec. The atom absorbs a photon which is then reradiated in any direction. Hence, on average each...

I suppose this thread should belong to a separate group called Light - that is, I suppose this should be where Quantum Physics should be. As for the question, I'd gladly explain that it is of a laser. I wanted to get a laser at Wicked Lasers (I know, with the LaserShades, of course), but here...

Homework Statement A laser emits a monochromatic beam of wavelength \lambda , which is reflected normally from a plane mirror, receding at speed v . What is the beat frequency between the incident and reflected light? I know that the f_{beat} = |f_2 - f_1|. When the wave hits the...

How is fusion initiated with a laser? What are the difficulties that are preventing physicists from using it?

I've looked for this subject but perhaps I'm asking the question the wrong way. Please advise. Is there an extension of magnetic field (flux) beyond the beam axis of a laser? In other words, can one detect (or has anypone attempted to detect) the magnetic field around the a light beam in a...

Apparently the nano laser is a key component necessary for practical application of optical computers. "Conventional lasers are limited in how small they can be made because this feedback component for photons, called an optical resonator, must be at least half the size of the wavelength of...