Laser Definition and 1000 Threads

Hello, iam new to polariton lasing and have to hold a speech about it. So I've got some questions and it would be great if someone could answer them. In a polariton laser, lower polaritons form a quasi bose einstein condensat at k=0. [My most important question:] I don't get it when the...

I have to measure the depth of the cavity in an object which is in the micrometer(10^-6 m) order. I'm given a laser, mirrors, neutral density filters, photodiode, and the object which is to be measured. Can anyone suggest scientific articles that are related to this problem provided with the...

hye ~ i want to ask some help from u guys about the rate equation MATLAB coding for linear or ring cavity laser..i have problem to find the coding by my self..do anyone of u know the full coding to be share here??

I'm looking for a good laser for optic experiments. All the professional papers I've read show the use of a 351nm Argon Ion laser. A new 30 mW one of these is about $6,000, but I see used ones pop up on Ebay from time to to time. My question is, is there a difference between this laser used...

Hi the problem i am dealing with is that we want to heat samples up with a laser in our lab. For estimating the required laser power, as you know better than me, the main loss will be the heat diffusion in the material. My heat equation is in the following: \frac{du(x,y,z,t)}{dt} -...

What is the difference between a laser and a one-atom photon amplifier? Can we just say that a laser is many one-atom photon amplifiers put together? Is there any difference in the resulting photon statistics?

Background I am currently doing a project that requires me to construct a probe which dentists use to transmit laser light to a patient's teeth to determine if the teeth is vital or not. Wanna know if it is feasible for me to extract the laser from an optical mouse and use it to construct...

I have laser drilled hole thin ceramic specimens and I am required to measure the diameter of the holes. Suggest me some methods.

For a pin photodiode, risetime=bandwidth/0.35 i get ~3ns for s5973 will it be affecting the measurement of 10ns laser pulse? How can i reduce the rise time?

Hey guys, I've been wondering what would happen if you had two lasers pointed at the same spot emitting pulses of visible light such that the pulses would meet the spot at the same time(lets assume the spot is in midair, no screen). the lasers could either be directly opposite each other or they...

Does anyone know if it is possible to design an excimer laser that produces a continuous beam well into the UV frequency range (enough to througly ionize the air in the path of the beam). I have been reading up on excimer lasers and it sound like they operate in pulses, which may be ok for the...

Hi people, please excuse me if this is the wrong forum to ask, I am new. I want to build a cheap DIY trip wire that records how many times it is set off. If I could use some sort of laser to be more discrete that would be a bonus (and just cooler). Also if it is possible to record the time that...

I'm trying to compare some figures of power for continuous wave vs. pulsed lasers. I have a known application which uses pulsed nitrogen lasers (λ = 337.1nm, http://www.newport.com/images/webdocuments-en/images/12224.pdf) to produce fluences of ~20-200Jm^-2 and pulse widths on the order of...

Hello all First off, I'm afraid I do not have much in the way of electrical engineering knowledge or experience, hence why I am here. I hope you will be gentle with me :) I am trying to determine the process (i.e. components, equipment etc) that I would need to set up an laser activated...

I am working on theoretical laser amplifier model for a pulsed input beam. However, my model is based on a top hat pump beam and laser beam profile, I want to update to a super gaussian and gaussian distribution respectively. The parameters I know are: beam radius w Pulse Energy E and...

I'm doing a very short presentation on a laser. I want to discuss the most important concepts of a laser (in less than ten minutes). What should I include? I was thinking about stimulated emission and amplification. (But I'm not sure I really grasp these concepts) For instance, does...

Hello Everyone, Here is my situation: I am using a laser to take distance (height) measurements on a variety of surface types (e.g. mirror, machined surface, plastic, etc.) and I would like to quantify the repeatability of the laser measurements on each surface type. Please note that I care...

i am buying Pulsed Laser Diode in Plastic Package 25 W Peak Power SPL PL90 and there is some parameters about semiconductors lasers... Forward current = 40 A why all this current ? then in the catalog Reverse voltage= 3 Volt then they say the Threshold current = 1A ? what is the...

Hi Gain comptetion in a laser is explained very nicely here...

Hi In the Wiki article on longitudinal modes (http://en.wikipedia.org/wiki/Longitudinal_mode) they state that: "The analysis of longitudinal modes is especially important in lasers with single transversal mode, for example, in single-mode fiber lasers. The number of longitudinal modes of such...

Homework Statement Suppose that total population inversion could be achieved in a ruby laser. If half of the electrons in E2 could then drop to E1 in 30 ns, what would be the avg power of the resulting laser pulse over this time interval? Assume that the ruby crystal is a cylinder 5.00cm long...

Hi In almost every book on photonics I've seen, the following expression for the steady state gain is derived 1 + flux/fluxsaturation = gsmall signal/g, where I by flux mean intracavity flux and g is the gain. When talking about lasers, then in the very same books (e.g. Saleh/Teich) the...

i need a equation that discrip the movement of laser ray in the tube in a way that it won't get out

Hi all, I was reading Lasers and i read something like this: for spontaneous emission, the rate of decay of electrons in high-energy state to low energy state is given by: \frac{dN_2}{dt} = P_{21}N_2 where P21 is equal to the probability of electron to drop from higher energy state...

Are photons in the laser output beam mutually independent and can the multi-photon output be described as the tensor product of individual photon states?

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...

What does the following statement tells about the laser output, i can understand the literal meaning but what does it tell about the power levels, temporal profile etc.? "the pump laser delivers 500-μJ pulses at 1.064 μm with a 12.5-kHz repetition rate" Thank you for your time.

Homework Statement Revered Members, An electron in ground state makes its way to an excited state upon absorption of photon of energy, equivalent to energy difference between ground state and excited state, and after some time, it decays by emitting the photon and returns to the ground...

Hi, I need a book about laser plasma interactions for my thesis. I'm reading P. Gibbon book "Short Pulse Laser Interaction with Matter" and further reading the autor suggests to use Kruer book "The physics of laser plasma interaction". This book is not available in my university and before...

I am trying to use an Nd:YAG laser for pulsed laser melting My laser is an EKSPLA NL313, which has a 5 ns pulse. I need to produce a decent size spot (~1 cm2) with a fluence of about 1 J/cm2 for the laser melting, which is no problem with this laser. However, the spot needs to be very uniform in...

hi my question has to do with this energy level diagram http://upload.wikimedia.org/wikipedia/en/e/ed/Hene-2.png" i was wondering, what the meaning of this "fast radiative transition is"? as far as i understood this, the light that you mainly want to get is the transition from 3s to 2p. but...

In several papers, diagrams, etc. about atomic experiments I saw pairs of lasers beaming in opposite directions. Naive question: why two lasers are used instead of one and a mirror? Or even further: why six lasers are used (2 in each axis) instead of just one and bunch of mirrors?

Hello everyone, new to the forum. I've been planning to make a compound bow using a cad program(Pro E), and I need a good laser cutting company to fabricate my parts. The part that concerns me most is the bow riser(black, center piece with the grip) as I want it made out of one solid piece of...

Hi Here they explain the concept of gain clamping in steady state lasers...

I have some serious doubts regarding He-Ne laser: 1. In He, the ground state energy value is taken is 0 eV and the meta stable state is taken as 20.61 eV. similarly in Ne the meta stable levels are taken as 20.66 and 18.7 eV respectively. How these values are arrived at? In Bohr's expression...

As a quick heads up, I'm buried over my head in an imager project, and the portion that has given me the most headache is the UV source. Essentially, I need the source to make nice little 13 micron dots in the 405 nm range. I've been assured by a pair of vendors that this is an easy matter...

If I combine 2 laser beams of different wavelengths, would I get a beat frequency of the difference between the 2 lasers? Thanks, Bill

Hello! I have for you some questions about the lasers. When ordinary laser beam directed at a small ball (few millimeters) on the screen I saw a bright spot in the middle of the shadow. What it is due?

I have a strong green laser, about 200 mw. I discovered this a long time ago and have wondered why it does this ever since... I shine my laser at a mirror. It bounces back, with a brighter beam. That's not what confuses me. What confuses me is when I try to aim the bounceback beam to...

I am working with a Laser Diode and I need to observe the intensity of the diode in TE and TM polarizations. the Diode is polarized in the horizontal axis (linear polarization). Is it sufficient to use a half wave plate and rotate it by 90 degrees to observe TE and TM modes? Also, what kind...

i want to know how neutrinos interact with strong beam of laser , if laser beam is going in opp direction along a neutrino beam?

I have read this millions of time on internet that laser spot can move faster than light. but i can't understand how. For example if we point our laser source towards moon then after 1.2 seconds our laser light reaches the surface of moon and creates a spot there, now if i move my laser...

Hey... I want to consider my research work on DFB laser as Sensor applicstions. I need to write a Research proposal on this topics. DFB Laser/DFB Fiber Laser as sensor for Hydrophone, Accelerometer, Seismic operation, Aerodynamics sensor, Flow control, Humidity Control, Temperature control...

Hi, In studying about lasers, it was mentioned that lasers are highly focusable, and this was because of the high spatial coherence of lasers. Just want to ask: 1. Why and how does spatial coherence affect focusability? 2. How is a laser typically focused (using a lens?) 3. Why do...

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?

Hello guys, I've been trying to solve Maxwell's Equations in a laser cavity, with length L. However I cannot... I've searched over the net to find a proper solution but I couldn't. I started by taking a field E(x,y,x,t)=E0 e(x,y)e-jw te-jb z. I take the phasor E(x,y,z)=e(x,y)e-jb z and...

Homework Statement Consider a Fabry-Perot laser, length 0.1m, with an unsaturated gain coefficient, \gammao=1m-1 one of the mirrors of the Fabry-Perot cavity is perfectly reflecting, the other reflects 95% of the light and transmits 5%. wit the aid of a brief calculation explain why steady...

Hey You may have seen the mosquito killing laser system from the intellectual ventures lab. In the description of the system they say the zoom camera identifies an object (mosquito) and from that they are able to direct a green laser on it and track it. What I am wondering is how the...

Homework Statement consider a two level atomic system , solve the rate equations for the two levels to find expressions for N1(t) and N2(t) in terms of the intial populations N1(0) and N2(0) Homework Equations i have been able to derive the rate equations as...

Hey everyone! Im currently an MSc student in laser physics. My work focuses on high power thulium fibre lasers. I would like to do my PhD overseas, in the same field (not necessaily a similar topic). So I have browsed around earlier rather than later and doing my PhD overseas is definitely...