Laser beam Definition and 124 Threads

Hi all, I am interested in finding the power of a laser diode as function of the distance z, assuming a free space propagation. I think to have enough information to work it out but I am stacked at the moment. Given: the initial power, P0 = 1mW beam width clip (e-2 = 13.5%), wx = 3μm, wy =...

if I have laser beam irradiated normally on the target surface and in the same time time it is p- polarized. under these conditions, we will have the electric field which is completely parallel to the target surface and have a great effect on the target surface. my questions is; is this...

What is the intensity in W/m² of a laser beam used to burn away cancerous tissue that, when 94.0% absorbed, puts 539 J of energy into a circular spot 2.11 mm in diameter in 4.00 s?? I've tried a couple different equations and I keep getting the answer wrong. This is due tonight, I'm super...

I think I am in a misconception concerning laser beams: Even the best lasers have a small line width. The spectral line is gauss-shaped. therefore the wave in position-pace is also a gauss-shaped wave packet, that travels with a certain group velocity. But this gauss shaped wave packet has a...

When blaster or laser is used to make a hole in a piece of metal is any of the matter of the metal completely eliminated from the universe?

Homework Statement The mirror in the image below deflects a horizontal laser by angle θ. What is the angle φ if θ = 60°. Homework Equations θi=θr The Attempt at a Solution So I know that, if I draw a line normal to the mirror, that will make it so that the incident angle and the reflected...

If I were to replicate this experiment http://arxiv.org/pdf/1505.04254v1.pdf but was limited to the purchase of only one laser which frequency and what power should I choose? I know the research team that conducted this experiment purchased their lasers from jetlasers.org but they unfortunately...

When an excited molecule absorbs a photon two coherent photons are emitted. If one of these photons is absorbed by a second molecule, since the emission was coherent then that molecule will absorb the second photon too. If the second molecule was in the ground state then it will become excited...

During optical pumping in a laser, is the wavelength of light that corresponds to the transition from the metastable state that yields the laser light removed? Otherwise, wouldn't a population inversion not be possible as these photons from the optical pumping would cause stimulated emission...

I posted a question about Rabi frequency here https://www.physicsforums.com/threads/what-is-rabi-frequency.331082/ some times ago. The replies there answer some of my questions but I am still looking for detail explanation on the relation between Rabi frequency and the power of the beam. I read...

I want to create a visible pattern of light from 1-5 feet away. The pattern would have a bright dot in the middle (ala sniper sight) visible in bright light at 5 feet. The cheap toy pointers seem to work just fine. It would also have a filled circular pattern around the dot, 8" in diameter at 4'...

I need to reduce the beam diameter of a laser I am using. I plan to do this by first passing the beam through a positive spherical lens with focal length f1 and then a negative spherical lens with focal length f2 and f2 < f1. By placing the lenses so that the two focal points overlap I will have...

Assume I have an ideal laser pointing which light will always move parallel to where the laser pointer is pointing. This mean that no matter how far I stand away from the laser pointer, I will see the same spot of light with the same light and intensity. In that case is it possible to determine...

Dear all, I have pretty simple problem in terms of understanding but I can't write an analytical solution. Consider you have a laser beam (without divergence, single wavelength). You can see the intensity distribution on the screen perpendicular to the beam. Then you insert a thin glass layer...

Hi Friends, I want to know that why one can't achieve diameter of a laser less than the wavelength of the beam in order to get more power through a lens. please explain in simple Physics

http://www.iflscience.com/physics/physicists-develop-reversible-laser-tractor-beam-functional-over-long-distances In this article, they said they could control the particle's direction by changing the laser's polarization. Could someone explain this to me? I have to do a presentation on it...

Homework Statement A riffle barrel and a laser point directly towards a target some distance away. General relativity says that the bullet and the light experience the same downward acceleration during horizontal travel, yet the bullet hits the target well below the laser beam. Explain...

Homework Statement An intergalactic cruiser is approaching a hostile spacecraft . Both vehicles move at a constant velocity. The velocity of the cruiser relative to the spacecraft is vCS=+0.7c, the direction to the right being the positive direction. The cruiser fires a beam of laser light...

I am somewhat confused about the connection between divergence and solid angle for a beam. I know individually what each term means... but I'm confused as to how (or even if) one can calculate the solid angle of a beam, given the divergence. I have some notes from a previous lecture series I...

Hi there, I'm looking for some information on the current limits of the beam width of currently available lasers. I'm less interested in experimental setups that are not on the market yet, but I suppose if one of them is markedly different it would be interesting to know. Specifically...

Homework Statement In an experiment a laser beam is focussed on a sample by a lens. The sample has micro structures spatially separated by 5 microns. In the experiment, each micro-structure has to be studied individually using the laser, so that illumination of two or more adjacent...

I realize that there are two factors that must affect the directivity of a laser. 1, The length of the cavity and number of reflections and 2. The aperture of the exit or the subsequent optics. This must be related somewhat to the respective directivities of Endfire and Broadside RF...

Greeting PFers, I need to use the low pressure region inherent within the cross section of a laser beam for a project. However, I don't know how to calculate the necessary laser power to generate a sufficiently low pressure. The topic is briefly dicussed *here*, but I see no relevant...

Hi Please help me to know : if i have a laser beam with 5 millimeter diameter that reduced to 0.5 millimeter diameter with a lens, Can i reduced the 0.5 millimeter diameter beam to 0.05 or less that 0.5 with another the same lens...

Hi, I was wondering what the diffraction pattern would be like if the suns light is diffracted through a pin hole or double slit diffraction grating compared to that of a laser beam? thanks.

Is it ok to use anodized aluminum with anolok (dark brown) finish to terminate laser beams? Most use black anodized aluminum, but can the former be used instead?

Hello everyone, I am an undergraduate student studying lasers. I have hard time to comprehend why does the beam diffract upon leaving the laser, does it have something to do with the wavefront being limited in size? Can you explain why does the following formula exists and how is it derived...

If I understand things correctly, the coherent state of a laser beam implies that the photon quantum field is a superposition of states with different particle numbers. This also implies that a laser beam is not in an energy eigenstate. To get energy conservation, I assume that this...

I am modeling a non-linear phenomenon. For that i need to calculate electric field distribution of a laser beam. I will be using pulsed laser beam with following parameters: " Laser pulse with 500-microJ pulses(Ep) at 1.064 micro-m with 12.5-KHz (f) repetition rate, pulse duration = 20 ns...

Holography is based on the simultaneous record of the phase and intensity of the interference pattern. I'm wondering if one can figure out a way to record the phase of the reflected laser beam from the 3D object without the reference laser beam?

Homework Statement A 50W lamp radiates isotropically and has a spectral width of 750 nm and a centre frequency of 600 nm. How much of its total output power is emitted into a solid angle of 10^-6 Sr? What is the diameter of the spot that a beam subtending this solid angle makes on a...

Hi, I'm new to this forum so please don't get mad if this post is in the wrong place. I have a laser beam pointed at a solar panel (regular PV cells) and the current comes out as expected on my oscilloscope (small waves varying like pulses between 0.45 and 0.50 V regularly). I tried...

i want to create laser expander, that scan the wall; with 3m x 3m dimension and 50m distance from this expander. and using with two Rotary Prism mirrors; one for "x" movement and another for "y" move. is there anyone help me.

This is a question for knowledge not for any assignment, but I was wondering what type of equation describes the damping or extinction that the light beam coming from a laser endures. I googled and couldn't find much although I may be using the wrong terminology. Could someone point me toward a...

Homework Statement Determine the amount of energy carried in 1 m of a 3.5 mW He-Ne laser beam if the cross-sectional area of the beam is 5x10^-6 m^2. Homework Equations J/s = Watt The Attempt at a Solution I converted the mW to W. I feel like I should put .0035W over 5x10^-6 m^2 to...

Homework Statement A continuous wave laser beam in free space carries a power of 15w and has a circular cross section with diameter 1mm. Calculate peak values of the oscillatory electric and magnetic fields Eo and Ho repectively. Homework Equations Eox = (\mu/\epsilon)^1/2 Hoy \pir^2...

Please refer the attached setup. * The laser source is moving at very high speed (say, V=c/2). * The slit is very close to laser source. * The screen is far away from the laser source. I would like to know, On the 'screen', where the laser beam will fall. A or B? -Jubair

Hi guys, I'm trying to make a rudimentary projector of sorts using a low power (class 1) laser diode. I'd like to shine the laser onto two mirrors: one would control the horizontal portion of the scan, and the other would control the vertical portion of the scan. My problem is this: what...

Hello, A few questions which i could not find complete answers online (for a physics noob). I'll try and break them down here: // Comment: as for a good noob, i know nothing of the real calculation. // How do i calculate the amount of energy i will need to release as a LASER beam in order...

Is it possible to widen the spectral FWHM of a laser beam. Any ideas? I understand the lasing process leads to the monochromaticity, but such a intense light source can have other uses. Thanks

I'm working on tracing the beam path of a HeNe laser through two prisms, and I'm stuck on trying to find the incident plane in which to use Snell's law. Basically I have the equation of the angled surface of the prism, and I have the point where the beam intersects that plane. Now I need the...

Homework Statement A 655nm gaussian laser beam has a waist of 15mm located at a lens with focal length of 12 cm. What is the minimum beam waist and where is it located? Homework Equations Beam radius w = w0*sqrt(1-(z/zr)^2) w0 = min beam waist; z = distance, zr = Rayleigh range The...

Hi all, can someone kindly advice on how to model a femtosecond laser beam profile when it is focus on/into a transparent material. Regards Jim

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 /...

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...

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...

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...

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...

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'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...