Laser Definition and 1000 Threads

Recently in the news NASA has transmitted an image of the Mona Lisa via a laser beam and i was wondering about some of the theory behind how they did it and maybe trying to recreate something similar on a (much) smaller scale. I've seen some articles online that show a method for transmitting...

I have pulse frequency as 2.5kHz. How to calculate laser pulse duration at FWHM (full width half maximum)

Hi Guys, I've felt the need to post a few times in 3 yrs, and this is one of them :) I tried to go back and thank contributors of another thread, but it was locked (likely because it was resolved, or 3 years old!). I'm writing for a camera equipped computer, tracking a red laser beam...

I use a green laser pointer at night to do astronomy related work. I got a cheap $5 green laser pointer off of ebay, and when it's a warm summer night, the device works fine. However, the second it touches the cold, it fizzles out and gives me almost zero output. My idea was to use a...

I understand that stimulated emissions produce coherent photons. What happens as a result of their coherence? My guess is that the laser beam does not spread out as much allowing it to travel further. Also, what is the property of a laser that allows the beam to travel great distances?

Scientists can produce laser pulses of order one wavelength in "length" see, http://www.bbc.co.uk/news/science-environment-19489384 Do Maxwell's equations admit solutions of such short pulses? Can one approximate such a solution by multiplying a plane electromagnetic wave by the...

hello, I'm interested in make an fibre laser to engrave in aluminum, however in all foruns where i ask this question everyone sugest me to buy an professional machine. but I'm interested in learn more about this tecnology so i would like to make my own fibre laser. of course some componets i...

Hello, I wish to switch ON and OFF a high-voltage (that generates a high electric field) using a ultra-fast laser as a trigger. Basically I have a flow of charged particles that I want to quickly deflect using an E-field. The timing must be correct and controlled by a LASER. Does anyone...

So the laser test with the slits is as followed as far as I understand. When observed, electrons act as particles. When not observed, electrons act as waves. How can electrons know if your eyes are open or closed? Unless your eyes give off some wort of radiation that it can pick up on...

hi , does input light signal for laser amplification has to be provided by the external source or it is created by lasing material itself?

1. LiNbO3 is a negative uniaxial crystal. Consider a LiNbO3 crystal used for frequency doubling a laser operating at 1064 nm. The non-linear coefficient is d=3.4x10-23. For the setup considered it is desirable to have a non-linear conversion efficiency of 0.04 %/W, Assume constant fundamental...

Hey all! I am gearing up for next year to do a senior project, I want to knock it out in my spare time for the next 10 months. Ideas are: 1) Laser guided missile- 2 phase motor, one to go up then again to go to 'lazed' target. 2) Wifi barrier- setup focused jammers to create a 'wall'...

Hello Everybody, I'm trying to plot the frequency spectrum of RIN using Matlab. I've the following code function p=rateblock tau_s = 3e-9; N0 = 1e24; A =1e-12; P0 = 1/(A*tau_s); TSPAN = 0:1e-2:10.23;; Y0 =[0 0]; [T,Y] = ODE45(@rate_equation,TSPAN,Y0); subplot(2,1,1)...

Hi, having a bit of trouble with this question "In an argon ion laser ( λ = 514nm) the minimum beam waist is 1.0mm and is close to the plane mirror. Calculate the radius of curvature of the beam at the output mirror. 1.15m away" Attempt at a solution: θ = 2λ/pi W02 R = Z + ZR2/Z ZR =...

I have a couple of questions regarding laser cooling. I should preface this by saying that I've taken a course in Modern Physics, so I don't have more than a very basic understanding of QM. In this case, I am familiar with absorption/emission lines, Zeeman effect, degeneracy and quantum numbers...

Homework Statement In the units of watts (J/s) calculate the overall power of the laser light generated by Nd/YAG laser operating with a 10 Hz repetition rate in the third harmonic (355nm) at 150mJ per pulse Homework Equations I can't figure out how to do this problem see attempt below...

There are materials which block laser beams (or light globally) or weaken its intensity via shading i.e. a beam must have crossed a specific energy barrier in order to pass this shading where beams with less energy will fade and won't pass. The question is, is there a material or a type of...

So, it seems this is the most appropiate forum section for this question... Can anyone give a simple explanation of the parts that make a laser designating system and how a typical unit works. Also, once a coordinate is established, how does this information get communicated to other...

Hello there. I am wondering if anyone can shed some light on this topic. I am searching all over the Internet to find reliable sources on the possibility of gamma ray lasers. I know that it requires an atom that can be "pumped" without spontaneously emitting its energy so it can be triggered by...

Homework Statement A laser produces an average power of 7.0 W in a light beam 1.0 mm in diameter. Find (a) the average intensity and (b) the peak electric field of the laser light Homework Equations Intensity = P/ A Unsure about part B The Attempt at a Solution For part...

Do photons used to produce the Sagnac effect (interference) have to have their phase in a coherent state or will a collection of random photons have the same property. Along the same lines, if you purchase a simple laser pointer are the photon produced here in a coherent state? Finally, is...

Homework Statement Calculate the Q value for a krypton laser with λ=0.569 microns, 0.568m cavity and mirror reflectance of 100% for the rear and 52% for the output window. Homework Equations For a laser cavity=> Q=(4πL)/(λ(1-R1*R2)) The Attempt at a Solution Q= (4*π*...

Homework Statement Two astronauts are at rest in outer space, one 15.3 m from the Space Shuttle and the other 30.6 m from the Shuttle. Using a 123.0-W laser, the astronaut located 30.6 m away from the Shuttle decides to propel the other astronaut toward the Space Shuttle. He focuses the laser...

I'm looking for a laser safety glasses. The biggest laser I'm going to use is a <20 mW green (532±10 nm) laser, with no infrared leakage (though I checked it with only a phone camera in night-vision mode), so I will need something good enough for this. I also have other green and red lasers, but...

If I shine a laser at a mirror, it would be reflected back. If I got a super powered laser, could I still reflect it back? Would it start burning through the mirror? I'm thinking it's a case of imperfect reflection. If there were such a thing as a perfect reflector, you could reflect any...

Hello PF! I've got a strange question for you physics boffins; assuming for a moment that lasers obeyed the inverse square law, what range would a typical 1mW red laser have in the atmosphere?

Say, has anybody ever heard of this stuff? http://spie.org/x35504.xml It seems that certain specific frequencies/wavelengths in the near-IR band can have a very pronounced effect on parts of the cell, like mitochondria and on production of ATP and ROS. So is it conceivably possible to...

A single slit is illuminated with a helium-neon laser whose wavelength is 633 nm. If the slit width is 2.2 x 10 e-5 m, calculate the position of the third maximum in degrees 2. Homework Equations Sin Theta(m) = (m + 0.5) Lambda/w 3. The Attempt at a Solution Sin Theta(3) = (3 +...

kindly help me understanding energy conservation in laser

I was reading the wikipedia page on laser light, and on a linked article, I saw this image: http://upload.wikimedia.org/wikipedia/commons/b/b0/Flickr_-_Israel_Defense_Forces_-_Nachal_Brigade_Reconnaissance_Battalion_in_%22Commando%22_Training_%282%29.jpg What is causing those red specks to...

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?

So, here I am again, and I have now built a strong laser which can set things on fire. Yay me. :D But, the second step comes in..how am I supposed to expand the laser beam? The beam is a 0.2 cm circle, and I need to get it to at least 2.5 cm. Can somebody explain how I can do this? (Try not...

I would like to have at least a vague idea how coherent is light from an inexpensive 1 mW red semiconductor laser which I have. I tried to find the manufacturer using Google, but I haven't found it. I would like to know the coherence length and the degree of spatial coherence. Is there...

I'm sure someone has tried this, and I'm sure there's a reason it's not something that is widely used, but here's a question: Can a logical NOR gate be created by shining two lasers (an A and B input) through tiny slits (like the double-slit experiment), and determining an output at a known...

Parallel laser light with wavelength 633 nm are incident perpendicular against a double slit. 2.50 m behind the double slit is a screen where the pattern can be seen (link below). Determine with the help of the figure the slit-with and slit-distance...

Hi Homework Statement I have to calculate the force of a laser. Given are the power P= 100W and the velocity of light. Homework Equations equations I considered using: E=f \cdot h and p=\frac {h}{\lambda} The Attempt at a Solution Actually that's all I got so...

Hello, How does an external cavity laser produce ultra narrow line width when it's larger cavity should reduce the free spectral range and thus introduce more longitudinal modes? Thanks.

Homework Statement Currently cd players use laser light in the red portion of the spectrum. What changes would be required in the manufactering of cds if blue laser light were to be used? Homework Equations The Attempt at a Solution Well I'm pretty sure it has something to do with...

I wonder whether an electron can make a transition from one metastable state to an another metastable state, if so it leads to a paradox(atleast according to me) viz for the refrence frame of the metastable state A from which electron makes the transition, it will be a radiative transition and...

Quantum laser diodes. How does light escape? I recently became very interested on the functioning of these amazing devices and so I read online about the topic of quantum wells, semiconductors and lasers. After much reading I believe I can now understand the basics of lasers, resonant...

I am just curious if it is possible to reduce the plasma shielding effect during ns laser ablation on metals by applying an electric field across the sample, and if so, how strong the field needs to be. Also, any experiments or papers you know.. i searched but could not find the right keywords..

Homework Statement I would like to learn how to calculate whether a laser can burn through a material, or not. For example right now I need to calculate whether a laser from a DVD burner (which supposedly is max. 400 mW strong) can burn through steel. Homework Equations I can imagine...

Hi everyone, I'm attempting the laser audio transmitter project. And example of it is found here: http://www.freeinfosociety.com/site.php?postnum=2310 I'm quite new to electrical engineering type work, and am a little confused by why the circuit works the way it does. The diagram is this...

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...

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...

***Note: I am not trying to make a laser that I can sell or profit from (well at least not now anyways :biggrin:); I'm just focusing on trying to make a laser that is crude and simple, but also one that I can be proud of; thanks.*** I have done a decent amount of research on lasers, and...

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...

Hey guys, A simplified diagram for the energy levels involved in Nd:YAG laser can be found here: http://upload.wikimedia.org/wikipedia/commons/6/69/YAG2.svg Two (short) questions: 1. Selection Rules The lasing transition happens between ^{4}F_{3/2} and ^{4}I_{11/2}. In the process J (of the...

It occurred to me today that I really don't know much about lasers. When dealing with electromagnetic waves, we always talk about plane waves, which are infinite in extent, or spherical waves, which spread out as they travel. What then is laser light? A finite plane wave? How do you treat...

Hi I have read the following online (http://tf.nist.gov/general/pdf/1819.pdf): "Regardless of the application, the basic goal of locking the frequency of a laser to a cavity is to reduce the frequency fluctuations between the laser and cavity. The noise spectrum of the laser’s frequency...