Laser Definition and 1000 Threads

Homework Statement (1) A Physics lecturer, on a dark night, shines his laser pointer towards the star Vega. (a) Roughly, how many optical photons from the Sun per second enter the eye of an astronomer standing on a planet orbiting Vega ? Assume that 50 % of the light from the Sun is...

Hi, I'm currently recalibrating an optical tweezer for my undergraduate thesis. The alignment did turn out well so far but I'm a little bit concerned about the power loss within the microscope (here's a picture of the relevant part, without prisms). I read in a paper that 20 to 100mW are...

Hi All, can anyone please suggest me about solving laser rate equations with langevin noise sources to find relative intensity noise (RIN) in matlab?

Why is a laser monochromatic? I read somewhere that the reason is because of a Fabry-Perot cavity, and not necessarily because of stimulated emission, so that if you have an ordinary light bulb in such a cavity, it would produce monochromatic waves. Can you just send the stimulated light...

I was setting up a 2.0 mW, unpolarized 543 nm (green) He-Ne laser today when I discovered something odd. I was using an iris diaphragm (like these: http://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=206) to align the beam parallel to the laser table. I found that if I placed a white...

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.

Homework Statement I did the single slit light diffraction lab. The diode laser we used was 630-680 nm. It produced an image very much like the one on this page: http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/fraungeo.html#c1 How does having multiple wavelengths in the laser change...

Homework Statement High power lasers in factories are used to cut through cloth and metal. One such laser has a beam diameter of 1.5mm and generates an electric field at the target having an amplitude of .854MV/m. speed of light= 3.0e8 m/s permeability of free space is 4pi x 10-7 TN/A What...

fastest modulation: laser diode vs LED... Hello Forum, in the telecomm industry, the most common and economical form of modulation is direct modulation, acting on the current operating LEDs or diode lasers. Using an external intensity modulator (OOK), like a super fast chopper, the...

Hello people, i have got a few thoughts which i would like to share. I few month ago i foundout that there are laser beams in the frequency range of of microwaves (maser beams). (http://en.wikipedia.org/wiki/Maser) I consider the following situation: If a conducting medium (lets think...

Homework Statement Im working on a lab experiment in my undergraduate physics degree requiring the use of a class 4 laser, i need to characterize this in terms of its power, coherence, pulse duration, wavelength and irradiance. This is a pulsed laser with rough parameters of 1-2J pulse energy...

Homework Statement You're helping with an experiment in which a vertical cylinder will rotate about its axis by a very small angle. You need to devise a way to measure this angle. You decide to use what is called an optical lever. You begin by mounting a small mirror on top of the cylinder. A...

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...

Hello everyone! I have a system with 2 lasers and a single camera. I have two trigger inputs going to each laser, they have a delay of minimum 350ms. These triggers are split and need to be connected to the camera to open it whenever the lasers fire. So i thought of a Tee junction where i...

I was wondering why laser on a hair makes the hair act like a single slit. I already know about Huygen's Principle behind it and all that. But what is it that can convince you that it actually is a SINGLE slit and not a double, other than just seeing it by measuring min. and using mλ = d * sinα...

Hi guys, I'm new to the forum, I'm a mechanical engineer but running a project a little outside my comfort zone which is to do with optics. I am trying to calculate the power density of a pulsed Nd:YAG laser but am getting in a muddle with the Average and Peak powers. The project is to model...

We have a 532 nm laser that we use with our Raman tool. The only power indicator on the control is in the form of a percentage. I know that at 100%, the laser has a power of 25 mW. Does this scale linearly with power percentage? In other words, does 50% power translate to 12.5 mW?

so I am testing out different designs on a nitrogen laser, and wanted a quick way to test whether or not one design had a more intense output than the other. without having to buy a sensor, my idea was to direct the beam onto a solar cell, then measure the output current. higher current wud mean...

What is natural line width of laser? how one can determine it e.g. for semiconductor lasers?

Hi. This has been destroying my mind all day. Take, for example, a semiconductor laser with no internal photons initially. By spontaneous emission, one electron falls from the conduction band to the valance band and emits a photon with the bandgap frequency and a random phase. As this photon...

Hi I was told that I2ω is proportional to Iω2. It does not say so in my book. How is it one can easily see that it is the case? Niles.

Hello, This is my first post to the forum. I'm an ex-physicist who had a short career with some universities and NASA in my early life, then went on to follow the dollars in the computer industry. Now, I work at sea for a living. Recently, I was reviewing laws pertaining to shipboard...

Hello, I am interested in modulating a laser beam with a radio frequency. Can I input the signal to the laser, or do I need to modify the beam with something like a heterodyne interferometer. If both approaches would work, would the resulting beam be the same? Thanks, Bill

If we pass a really high power laser through a prism, is it possible that the prism melts down.

Alright, I have sources (Wikipedia) that say that when a Laser hits a certain intensity it "blooms" and creates a plasma (around a megajoule). How does a Laser achieve this and how big is the laser? Can anyone help me?

I recently bought a laser pointer offline, it claims to be able to reach up to 12 miles, and from what I can tell it is pretty strong. It says the max output power is < 5mW, and the wavelenght is 532nm. Its just a regular laser pointer, and I was wondering if there are lasers that you can buy...

i am doing a research on optoelectronic components for communication. Can anybody explained me what a laser and modulator driver is and how it work? Regards

For these LFR's http://www.active-robots.com/products/sensors/hokuyo.shtml Where exactly is the laser being shot from and recieved? The circular top? or is there something we cannot see under neath/behind? Thanks

Hi everyone, I've been looking at the data sheet for a pulsed laser diode driver that I've been using, and I've managed to convince myself that there's a mistake. I was hoping that if I post my explanation of how the circuit shown in the data sheet works, that you guys can either confirm that...

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...

so I was playing with my 532 nm (green) laser pointer when I noticed something strange. You can shine it at virtually any surface it will appear as a bright green dot - nothing unexpected there. However by chance, I noticed that when I pointed it at this red bottle of laundry detergent i have...

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...

How could we see a hologram created by lasers if laser beams do not get in our eyes (it could be dangerous)?

Homework Statement "A 1 fs pulse of laser light would be 0.3 um long. What is the range of wavelengths in a 0.3 um long pulse of (approximately) 600nm laser light?" Homework Equations (delta omega)(delta t) >= 1/2 c = (lambda)(frequency) The Attempt at a Solution I replaced (delta...

Hi, This is my first post on this forum, just joined. I recently purched the S3 Spyder III Arctic portable 1W laser from wickedlasers. I bought it to try and make some cool photographs and photoshop them. After testing the device (glad I bought safety goggles with it) I was wondering how hot...

http://www.physorg.com/news/2010-11-laser-neutron-yield-energy.html DT produces 17 MeV per fusion, so that's an output of about 800 joules; a factor of about 150X short of break even for energy applied to the target, and perhaps ~1000X short of the gain required for a practical fusion power...

Hello All, I'm going through some lecture notes from a course on Lasers, and have come across something that is confusing me. In homogeneously broadened media, the gain coefficient depends on (1-I/I_s)^{-1}. where I_s is the saturation intensity. However, in an homogeneously broadened media...

I need help with a mini communication project. I am trying to receive signals from RJ45 Ethernet (10 BASE-T), which comes in three logic levels (-2.5, 0, +2.5) and convert it into two logic levels so I can drive a laser on and off. Would anyone know of any IC's that can accept these signals to...

How to calculate the fraction of stimulated photons that escape from a laser cavity with alpha=0.1 cm^-1 length of cavity=1mm refractive index of laser cavity=3.2 the photons are assumed to be escaping into air so approx refractive index is 1. Im assuming that alpha is some sort of...

Homework Statement Pulsed lasers used for science and medicine produce very brief bursts of electromagnetic energy. If the laser light wavelength is 532 nm, and the pulse lasts for 37 ps, (a) how many wavelengths are found within the laser pulse? (b) How brief would the pulse need to be to...

I am going to be pulsing a laser diode at around 2 Watt (room temperature) with a frequency of around 1-10 MHz. Right now I'm planning on using 26 AWG wire. Anyone have any thoughts on whether this is okay? Is the gauge okay? Since it's pulsed I assume I don't have to worry as much about heat...

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

Hello. I am am trying to find out why Hastelloy cracks during laser welding. What techniques are used to lessen the cracks etc. The main focus is to learn as much as I can about laser welding this material and what laser setting to start with . A simple google search has gotten me no where and...

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...

Greetings, I want build an interstellar probe. Given the power of the laser beam and the mass of a mirrored object a laser is shining on, how does one calculate the thrust or acceleration? Thanks

Hi newbe here. Can someone confirm an experiment I just made on a Meade 2x telextener (tele extender) and a Tele Vue 4x Powermate? I placed a laser collimator into the barlow and observed a nicely formed laser point exiting the lens. Then I placed the same laser collimator into the Tele...

How is it possible to see the light path of a green laser pointer?

I am interested if current laser technology exists such that a small laser can be made that emits non-visible light, is .5cm or less (at it's largest dimension), and can detect at distances of 6ft or greater. Please feel free to direct me to other areas of the forum to direct this question if...

what would a 5.8ghz laser look like. i am just wondering because it would be so much nicer to do a radio link with a laser instead of a 2m antenna

Hi all, I'd like some help calculating laser eye safety for a 905 nm diode laser system I'm building. It's for a scanning laser rangefinder and I need to figure out if my current design (a TOF rangefinder) can be feasibly be made Class 1 eye safe. The eye safety calculations are a little...