Lasers Definition and 218 Threads

Does anyone know what gain guiding and index guiding mean in the context of lasers?

Warning: This is a potentially stupid question! Is it possible to induce photosynthesis with laser light? What kind of published work is there on it? Thanks!

photons or lasers fired through a slit. an electron can be two places at one time. or are the electrons split into a rainbow. in spacetime towards a black hole are you drawn in or do you get thrown out. electrons maybe "visit" neighbour nuclei then maybe come back. if an electron accidently...

Do you fancy argon-ion lasers?? I sure dont. =/ Homework Statement I dont. This is a practice test problem and I cannot figure it out. Frustrating! An argon-ion laser emits a blue-green beam of light with a wavelength of 488 nm in a vacuum. What is the difference in energy in joules...

Advice needed - Photonics - Telecoms or High power lasers and systems ? Hi ! I recently concluded a masters in photonic comms with a distinction, and I'm currently contemplating : 1) Studying further (PhD) and if so which path with respect to Future of Photonics 2) Relocating (better...

Okay, so I've been thinking about diffraction experiments and light, but not having a laboratory, I would like to know some specifics about what happens in a diffraction experiment. I know that laser light diffracts when it passed through a narrow aperture, but does it diffract as it passes out...

If using 314mW red laser and cylindrical optics to project a line 500mm x 2mm, will it have brightness as 1mW laser that projects a dot with r=1mm since the area difference? 1000mm / (1mm^2*3.14) Would the projected line of that brightness be dangerous if bounced off the reflective surface...

My roommate and I are working on a backyard physics/engineering project, with the intent to hopefully scale it up to massive proportions. One of the issues we recently came across, though, was the matter of focusing our electromagnets for both efficiency and to keep from effecting anything else...

For a certain sexah project I'm going to do, I have a bunch of lasers that have an intensity of "<5mW". I have 780nm IR lasers and 650nm red lasers. When i made a lazy hookup to a 3V power source, the red laser was briiiiight which leads me to believe I've only ever used <1mW lasers in our labs...

I saw some green lasers on dealextreme recently, they have units that go up to 200 mW: http://www.dealextreme.com/details.dx/sku.1997 This thing looks a bit unsafe to me! My intention is to show the daughters some stars here in our polluted skies, not much else. How much power is needed for...

Hi, I would like to know how we can use indirect band semiconductors in lasers. Such type of semiconductors do not emit photons when transition takes place. Energy is given up as heat to the lattice. Regards,

I am curious about the operation principles of semiconductor lasers, but I never had the chance to go through the basic flow. I'd be grateful if someone posts a brief description of how the light amplification is achieved in simple terms.

Homework Statement Hi all. When talking about sound, we tak about the fundamental frequency, the first harmonic, second, third etc. Does this also work for lasers, i.e. for light? So if I have a laser at 500 nm, then the third harmonic is 3 times the frequency that corresponds to 500 nm...

http://news.yahoo.com/s/space/20090408/sc_space/friendlydeathstarlasertorecreatesunspower

I am trying to wrap my head around what it would take to bring water vapor to superheated state. It seems that if you had a vapor stream and shot it with continuous laser energy (CO2 or other gas laser) you could instantly create a high quality steam. I am teetering between buying a diode...

In my math class we were given an assignment to model lasers, we have been given equations, and terms have been somewhat defined, but I do not know what the following terms are when relating to a laser. Any help in defining them would be awesome! What is: Mirror Transmission, Pump...

hallo all, I was wondering the following thing: when using a He-Ne laser, you pump some energy in the system to get the He excited, but why only the He atoms? If you pump energy in the systems, wouldn't the Ne atoms get excited too ? (and I am not speaking about them getting excites because...

Do fiberoptic cables use lasers, or regular light? (or can they use either depending on the situation)

Does someone here know about high energy lasers? As I understand it, at a certain field strength you damage your optical media, but I know high power cw lasers do exist, so I wonder: 1) How do you shutter a high power laser? 2) Is it possible to join two laser beams. The only way I see...

Hi does anyone know where i can find an online version of the quantum mechanical theory behind lasers and masers. regards Dave.

In the book I am currently reading one of the causes stated for homogenous broadening in lasers is the ".. finite lifetime of the emitting state". Now this really confuses me because I would have thought that that a change in the time it takes for this spontaneous emission should affect the...

If you were to amplitude modulate a laser such the helium-neon with a microwave signal for instance at 10 GHz, and if you were to shine that laser into a tuned 10 GHz resonant cavity, would the modulated laser excite the cavity? That is would the rise and fall of intensity of the laser beam...

This is something that I was just playing around with in my head that I was curious about. Photons have momentum (p = E/c). That would mean that they could transfer that momentum, and I was curious about collisions between a lot of photons and large objects. I was curious if anybody here...

I get the photo-electric effect but I am just wandering, is that the only principal on which lasers function? I mean do lasers "cut" materials by ionizing the atoms?

Why is it that we are able to use a laser beam with optical fiber but not with a white light source?

Hi, Could somebody please explain or refer to a good page which explains why it is necessary to first excite electrons into a higher state than the metastable state in LASERS? I checked so many sources but did not find anything. thank you VVS

Has anyone had any experience in using a laser system for measuring distance or location? I am looking for the laser emitter as well as the receiver as kind of like a matched pair. I haven't really been able to find anything other than laser emitters on their own, and wanted to know if...

Hello to all, I need to be able to power 10 laser pointers at the same time all running from one adapter. Each laser is normally powered by 3 LR44 batteries, which are 1.5v each (I don't know how many amps). The DC adapter ill be using for the project is 6v and 500 mA. Is that...

I've read from several sources that says the inverse square law doesn't apply to lasers, but I've been told that it does apply. Which is right? Also if it does apply in today's lasers what about in a perfect laser? Thanks.

Say you shoot a beam of light in a laser or flashlight. Does the photons exert a backwards force on the laser. I understand how some of Einsteins relativity works out on the train with adding velocities and all. It just makes sense that energy is being lost by not adding velocities so the...

Lasers in combat? That used to happen only in "star wars" but not any more. That cute essential little laser diode in your DVD drive/printer/PS3 etc has been put to more dynamic uses. Such as being used in trouble spots such as Iraq, Afghanistan and Liverpool. This article gives full...

hello every one The thing I can't understand is 1) In He-Ne laser the He atoms in the excited state interact with the Ne atoms in the ground state how it is possible? 2) In all the textbooks they wrote that "atoms exite". Wil the atoms exite or the electrons? because to my knowledge atom...

Hello, I'm finishing a Masters in Optics and Photonics a the moment (and I have a Bachelors in Physics) and I'm planning on working on short laser pulses for my PhD next year. I have applied to Imperial College London, UC Berkeley, ETH Zurich, Max Planck Institute in Munich, Ecole...

Is there a way to make a laser affect water and what would it do to it? I am trying to figure out a way to aggitate the hydogen and oxygen molecules in water to make them want to break apart. Would a laser make a difference? Any other suggestions. Thank you all for your help in advance.

i know that the military is producing a powerfull laser that can potentially knock down hazardus misiles (possibly ICBMs) wouldent all you need to have is an estreemly powerfull VERY SMALL laser. size doesn't matter if your cutting straight through it. wither the cut is 5 inches, or 2 cm. its...

how exactly do lasers work? i know there are many kinds of lasers, but why can't you shine a light in a sphere with the inside as a mirror, then leave a hole and put a long tube on the hole, so the rays going sideways won't escape i hear that the light just won't stay inside the sphere. it...

Lasers are safer for the following reasons: Once you point them into sky, it's hard to bring them down. Hence, one could safely distribute the technology to both friends and enemy. Iran can't hit us with a laser (from Iran). You can have a bunch of lasers and mass produce them for...

how does a automatic door works? anythings about the photodiode? and lazer? plx help~~~~

Hi, just out of curiosity, i heard about a new electron gun (if that's the proper term) using a laser pulsing at about 3.333 x 10e14 Hz to increase the frequency at which the electrons are emitted. How does the laser reach such pulsing frequencies? Thanks.

http://www.physics.utoledo.edu/~ljc/photonsnap.doc --shows a photon in stop action ... But some of those photon samples are 180&deg; out of phase ... Would that be a technical equipment problem, or do lasers sometimes emit anticoherent photons? Ray.

First of all excuse me if I'm posting in the wrong section or you are simply annoyed by my questions. It just happens that i love all this scientific stuff and althoughi don't always understand everything i try to. I just finished reading a very basic article about a laser operates and it...

I was wondering if anyone could tell me about fiber lasers. I don't mean those used as transmitters on optical fiber systems; I mean lasers that contain optical fibers as components. I know that it can be done, but I don't know what the structure is like. What part does the fiber play? Is...

Hi, I need to know about lasers. Has anyone got any websites or links describing lasers?

Lasers are now used in eye surgery. Given that the wavelength of a certain laser is 514 nm and the power of the laser is 1.9 W, how many photons are released if the laser is used for 0.052 s during the surgery? HELP: You know the energy released per second (the power) and the time the laser...

There are two questions I wanted to ask. The first is what substances are used in a maser? The second is how can the wavelength of a laser using a certain substance be determined without physical testing?

Q) Why is it easy to see the output of a laser pointer on a screen illuminated by an overhead projector. Assume 1mW laser and 500W quartz halogen bulb. Explain quantitatively, and state all other assumptions. Im not sure whether it involves the coherence length/time of the two waves...

I'd like to know where I can find the most powerful laser systems in the world right now. Anyone who's into this?

A question to people coupling lasers to optical fibers. What is the power and exposure time of laser beam directed in the eye which is considered dangerous? The ones I´m currently working with are 15 mW. Are there any ways to couple laser beam to a fiber without having to look into another end...

I am trying to find out, what is the affects the velocity of the light wave projected by the laser? I am going to ITT tech and this is a very diffucult thing to try and find on the web. I have been searching for over an hour trying to find the answer. I would really appreciate the help.

Hi! I have to make a presentation about the usage of lasers in measurements, but I am not sure what I should include. I thought of something like using laser beams for measuring distances, but I don't know how exactly this can be done and what else can be measured with lasers. I'd be greatful if...