Laser Definition and 1000 Threads

Hi, it is known that second order correlation function (g2) is a constant( =1) for ideal laser or single frequency light sources. So, what is the second order correlation function for non ideal laser? Is it still a constant or something related to the coherence time of the laser?

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...

Homework Statement For large intensities, what is the maximum ratio of atoms in N1 compared with N3? I suppose this is just a bit of maths I'm struggling with, seems simple I just can't get it for whatever reason D: Working through previous question, I got to: N3= (Ip/Is) / ((Ip/Is) +1 ) N1...

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...

Mobile, airborne, and terrestrial 3D laser scanning gives an unprecedented amount of data to companies, organizations, and governments. However, I am wondering whether or not 3D laser scanners have ever been used in astronomy, astrophysics, and in astrocartography... If they haven't, I believe...

Is it possible to have a laser without a resonator? My guess is you can as you would still get some proportion of light coming from the inverted medium. My question is how would this light be different (from that of a laser with a resonator) and are there any practical uses for such a device?

To give a little idea for what I'm aiming for: I want to make a prop laser gun. It doesn't have to actually do anything, but I've decided it'd be awesome if it did. I could use a 2-5W blue laser diode like some people who make awesome contraptions with lasers show on YouTube, but I'd frankly...

This is probably an impossible question to ask, but I feel bound to give it a try. Assuming a level of technological know-how that has enabled human beings to journey beyond the heliopause - if not to the nearest stars - just how far can it be reasonably supposed for message-bearing laser beams...

Does laser light from a powerful violet laser with wavelength 405 nm create significant ionization in a gas (Hydrogen or Helium) if shone through it? Will there be a streak of ionized molecules/atoms in the beam, so to speak? Can that ionization be detected easily with a voltmeter? How effective...

Laser action by definition requires the presence of stimulated emission in the laser medium. The typical way of treating this semi-classically is to introduce the Einstein coefficients, in essentially an ad hoc way, then derive the Einstein equations for the various level population transitions...

Does anyone have a good book on focussing laser beams? I'm working on a project and I want to know more about focussing high energy pulsed lasers, M^2 factor, top hat beam shapers, ray tracing and fiber optics. I've read Renk, Basics of Laser Physics but these subjects are only discussed very...

Hello, I am Miles. My interests are very broad. I work in the fields of energy, communications, and space transportation, developing new systems that can hopefully solve some significant problems in these areas. My primary backgrounds are chemistry and electrical engineering, but I've...

Do you guys know a low-cost low-threshold optical beam limiter, with cost somewhere ~$100. Or if you know certain method to fabricate such. I would be greatful if you could include links and/or references. I am still noob in photonics so I am only familiar with a beam limiter that blocks the...

Hi, I'm trying to use LIBS technique to figure out elemental analysis of human nails. But every time i run the experiment, i get the emission line of metal instead. The sample holder is indeed made up of metal. What should I do to overcome this problem? Since i have small size sample, I'm...

I bought some laser diodes on amazon. They're the typical small red 5mW lasers. Just wanted to see if the diode handle more power so i put about 20 - 30mW through it. Nice bright red dot on the wall, but then it dims and dims. The diode didn't get super hot it just got a little hot. But I've...

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...

Is there anyone who has experience in setting up optical system for exciting a sample using Q-switch mode of Nd:YAG laser? I am currently looking at the optical system which I did not setup (someone else did, but the person is absent and cannot contact). I have no background whatsoever in...

What determines which TEM mode will the laser output have? Why some lasers emit in TEM00, while other in a donut mode, and other in a superposition of multiple modes. Thank you.

I am developing a math model to describe laser ablation process considering the plasma. My supervisor want to know the exactly difference between the laser induced breakdown and laser induced plasma. After a lot search, I personally think that the 'breakdown' is the first step of plasma...

Not sure if this is the right place, but I'm hoping to ask two questions: 1. I shine a laser pointer at a mirror at night, and the reflecting beam glaces off of my eye. Obviously it's quite bright, and I want to know if this has caused any serious damage. Of course I shut my eye, but apparently...

I am into photonics research, and have been searching about this topic in vain, but almost nothing from Google shows up. So i turned here for some light. Do you guys know any material that changes its transparency when a laser (or light) illuminates from its side?

Hi I know little about this but I am wanting to wire up my 1mw green laser to my usb port to use it as a power supply it is 3 volts I'm wondering is there a program you can use to change the 5 volt output to 3 volts or would I need to use a resister in the wiring ?

Hello, I am kindly asking for some help with following theoretical problem. Imagine at least two lasers emitting light at certain wavelength, each from different angle. Imagine that the rays cross at some point. Is is possible to observe at the crossing point light of different wavelength...

Does anyone know what the best recirculation compressors are for a high power CO2 laser. I would like a small foot print low flow positive displacement compressor (rotary vane or diaphragm maybe?) that is not an expensive noisy monstrosity for maybe a $100 or so. Also does anyone know of a...

Hello, I am Noctua and i have 14 years old :D So, today i had the idea of building a sort of non powerful laser gun.I plan to focus the light with converging lens.I will use a powerful laser Pointer.So, here is my questions: If I absurdly concentrate a laser , the concentrated light would be...

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 have a few questions regarding an optical microscope and their white light sources... So white light generally first hits a diffuser, some kind of ground glass lens. What is the purpose of this? Then the light goes through a field diaphragm, which we can open and close. I have heard that...

I am looking for group of material that behaves according to the following: (1) When a certain laser light passes perpendicular to the surface of the material it enters and exits unimpeded (2) However, when another laser light (with direction parallel to the surface) enters the material, the...

How are these pictures taken of the electron wave function without the wave function collapsing? Does this mean that electron wave functions are real waves after all? Wikipedia Quantum cascade laser will give you the discription

The New Horizons results on Pluto are tantalizing. I was trying to come up with methods to get an orbiter or lander there. The problem is at a 31 AU distance from Earth solar power would only be 1/1000th as strong. However, with parabolic mirrors or Fresnel lenses we could focus a large amount...

can any tell me about laser diode, how it operate and I-v curve of laser diode?

http://www.iflscience.com/space/molecules-have-been-built-using-laser-beam-first-time Is there a way that fusion could be achieved with coherent control like this? If it can build molecules couldn't deuterium-deuterium be achieved?

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'...

Homework Statement It's not a homework, I'm just studying for the exam, but one question that I'm not sure of the answer is: "In the semiclassical model of a two-level atom interacting with a monochromatic field, how does the Rabi frequency scale with the laser intensity" Homework Equations...

Hi, if the laser emits polarized light, then why we use polarizer infront of laser?

I've been reading up on lasers recently and learned that within the cavity while the laser light is amplified by the gain coefficient, it loses power due to transmission and absorption. Suppose the pumping radiation comes from a monochromatic source whose energy is not exactly equal to the...

Hi all, the question which I'd like to share is the following: if you look at the formal theory of any random optics book for FP interferometer you will get to the formula of the FSR (Free Spectral Range), defined as "The wavelength separation between adjacent transmission peaks" (Wikipedia)...

If two cars are traveling either in parallel or in close succession to one another how can a laser determine which car it is gauging the speed of?

Homework Statement I have to study laser cooling. I'm actually trying to understand the Doppler limit on temperature. On the net I have found "at a certain point the cooling mechanism is foiled by heating due to the random absorption and reemission of photons...

(a) Suppose we split a laser into two beams "A" and "B". Is it at all possible to do something to one of the beams, so that, when we bring them back to overlap at the detector(s), they will follow the statistics of two-photon systems? (b) If we use two separate lasers that are phase-locked by...

I'm a novice studying laser physics and I came a across the condition for optical gain: \frac{N_2}{g_2} > \frac{N_1}{g_1} This is a basic set up where N_1 is the number of atoms in the lower energy state and N_2 is the number of atoms in the higher energy state. g_1, and g_2 are the...

Homework Statement Hi.I need an experiment to study and present it.the subject is how to measure coherence length of a monochromatic laser ? lm also search on google.However,is there any advice from you ? Homework EquationsThe Attempt at a Solution

No idea why this popped into my head on the drive home tonight, but here we go: Would it be possible to build a rocket filled with either liquid Nitrogen, or some other super-cooled substance, then use a battery of high-energy, ground-based laser beams pointed at the super-cooled propellant to...

I am trying to measure the linewidth of a diode laser using the self-heterodyne technique. The laser specs says that the linewidth is ~100kHz at 1us. I guess I am confused by the "at 1us" and how exactly that translates to measuring the linewidth myself by looking at the beat note on a spectrum...

Homework Statement a) Imagine that you are conducting an activity with a laser to create an interference pattern. Use the appropriate equations to predict two ways (other than the way described in the following example) to change the interference pattern in order to have closer fringes. Explain...

Hi guys, My name is Rogelio H. Aguirre, a grad student from the University of Waterloo working on MEMS sensors. Currently, I am working with micro laser welding suppliers to fabricate the packaging of a pressure and a temperature sensor. I have some experience on weldings, but not in micro...

Hi Everyone, A question in my latest Physics I lab wishes for a proof showing that if a laser beam is incident on a mirror that is then rotated an angle θ the beam is deflected an angle 2θ. I attempted to prove this geometrically below. In the diagram the angle γ, is the angle of deflection...

I need to do this graph "graphic locking range and stability laser" that equations are used to make the graph thanks

Why can't I find any LED's at 488nm? I am trying to find a cheaper light source than the traditional argon ion laser for a possible fluorescence activated cell sorter. See link below for schematic. Does anybody know a good retail site for lights in this spectrum I can't find good results with...