Lasers Definition and 222 Threads

I'm getting ready to do some testing, and need to decide which lasers to use . I need both left and right circularly polarized laser light . I was told that green diode lasers, the kind readily commercially available (usually around 200 - 500 mW.) , are LEFT CPL. 1. Is that usually true, and...

Hi friends! I solved the problem 8.3 of ``Problems in Lasers Physics'' book (by Cerullo, Longhi, Nisoli, Stagira and Svelto) but I think there's a mistake on the solution presented in this book in page 196. This is a problem book with problems and solutions that follows closely the laser...

Hi all, When you look at the IR absorbance spectrum of dry air, there's a big peak at ~ 2400cm^-1 due to vibrational transitions in CO2. But CO2 lasers always operate in the region between 9um and 11um, which is about 1000cm^-1 by my math. What are the practical criteria that make the ~1000um...

If you shine two lasers at the same spot that are the same frequency, and; exactly out of phase; would there still be energy at the one spot they are pointed at?

Hello, I am pretty new to physics but have a large amount of experience with Calculus and other sciences like chemistry. The theory I have come up with is that if I combine 6-8 5w laser beams together in a convex lens that can be moved forward or backward to change the focal point distance, I...

What is the difference between solid-state (SS), semiconductor and gas lasers? I know SS lasers are optically pumped (generally), while semiconductor and gas lasers are electrically pumped (laser diode). The active mediums are also unique. Beyond this though, I'm not entirely sure about any...

Homework Statement Fresnel losses occur between two different media that have different refractive indices. To reduce these losses we can change the angle of incidence to brewster's angle. At this angle, the amount of reflective loss is minimized for p-polarized light. Do we assume that laser...

I'm learning about multi-axial mode lasers. From what I understand, a multi-axial mode laser has more modes with which it can amplify light at. I'm trying to understand: 1) What are the advantages and disadvantages of a multi-axial mode laser? 2) What applications do this lasers have?

I am confused. In harmonic oscillator problem in quantum mechanics eigenstates of operator ##\hat{a}## are called coherent states. So we practically get Gaussian. In problem of quantum linear harmonic oscillator we have phonons ##|n \rangle##. In case of laser we have photons ##|n \rangle##...

Homework Statement My textbook on lasers has mentioned thermal conductivity a few times, but hasn't specifically mentioned it's importance. I'm at a part talking about Nd:Glass lasers and it says that glass has a lower thermal conductivity than Nd:YAG lasers, which prohibits continuous wave...

Why do Lasers need to be cooled? I understand say, optical pumping with a flashlamp will cause a lot of waste in the form of heat. Is this heat in the lasing medium or in the flashlamp itself? I'm trying to understand where the waste heat actually goes, and why the laser needs to be cooled...

Homework Statement I'm reading some text on solid-state lasers and a passage that struck me was this: "The low-lying energy levels of the ion are determined by the forces acting on and between the electrons in unfilled shells. (The electrons in unfilled shells can be regarded as inert.)" If...

I have two systems that are approx. 300-400ft apart that I am connecting via a 10 Gig fiber connection. The fiber I am using is a 100um core MM fiber and the switches will be using a 50um core OM4 (4700 MHz*km) SFP module. Is there a way to find out what type of loss I should be expecting, is...

Hi All, I am a student of Master of Technology course in Applied Physics, specializing in Lasers & Electro Optics from, India. As part of the curriculum of the course, I have to do internship in an industry or a R&D Lab working in Lasers & Electro Optics. I would be highly grateful to you all...

Hi, I'm doing a module on quantum optics and lasers. Most of the texts and online source I have read simply state that 'population inversion is essential for amplification in laser operation'. My question is, why? Amplification/Gain is essentially the result of stimulated emission. Can't...

I'm working on a project which will involve placing a superluminescent diode in a rocket, which will get launched in desert (obviously the SLD is just part of a greater system, the objective is not the operation of an SLD) What I need to know is if you think I could make, or where I can track...

My question is very basic concerning gas lasers. I wanted clarification that a gas laser gets its light from a cell containing only that gas with a few other constituents and a high voltage being applied to it. Basically I'd like to understand what is happening with a CO2 laser and why it...

We use lasers containing various elements in vacuums on Earth all the time. Is it possible to use lasers in the dirty vacuum of space to take pics and transmit at near the speed of light?

If I have 2 identical laser pointers, is it possible for me to point them both at the same spot on a wall and see no light at all due to complete destructive interference?

First allow me to apologize should this thread be in the wrong forum, I am not entirely sure whether Quantum Physics is the right one. I am also unaware of the exact level to which this question belongs, which is why I went for intermediate. Please inform me if this should be changed to...

For a certain science fair working model, what should I use to detect the collimated light of a HeNe laser(in the red;653nm if that is necessary)?After some surfing on the net, I found that I should use a 'photodiode'. The desired result should be solely to detect whether the laser's light is...

By surfing the net I learned that lasers can be used to ionize air and even produce "bangs" for some reason. Now, what I'm after is to ionize hydrogen or deuterium gas, at either 1 atm pressure or reduced pressure, say 40 mbar. Now what kind of laser light would be best to use? A hideously...

Hello I've been wondering how certain solid state lasers could have a continuous lasing action (Nd YAG laser for instance ) If so,the understanding that the best lasing conditions are when the temperature Is lowest gets disproved(considering that a commendable quantity of heat is produced during...

Does anyone know if it is possible to get on web an exam sample or quiz or exercises, on "Quantum cascade lasers"? Thank you.

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...

Why for quantum cascade lasers used only intersubband transitions in the conduction band. Although in a heterostructure there are also quantized levels in the valence band, which I think also can be used for lasing? Thank you.

Suppose lasers become a common weapon for medium range anti-drone use. Maybe they've gotten too good at dodging gunfire. What kind of laser countermeasures exist? I was thinking, maybe some kind of mist generator to block out vision of the drone. But that would be limited to drones moving at low...

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...

Hi all, I'm new to the forums. I recently tried to take an image of two laser dots on a white wall, using my laptop's USB camera. I saved them to PNGs. I have a number of questions... 1. There was an artifact with the green laser, where a smaller second dot appeared for some reason. What...

I am experimenting with a LiDAR system, one of my goals is to detect falling objects. The scanning frequency is 100Hz with an angular resolution of 1°. I have been able to detect an object if it is a certain size or greater moving horizontally but I'm not sure what I should focus on to make sure...

A laser is amplified exponentially, with spectral intensity I (\omega,z) = I (\omega,0) e^{\alpha z} The small-signal gain coefficient is given by \alpha_{21}(\omega-\omega_0) = N^* \sigma_{21}(\omega-\omega_0) = N^* \frac{\hbar \omega_0}{c}B_{21} g_B(\omega-\omega_0) = N^* \frac{\hbar...

Hi, am a student who studies physics in university. I want to know does laser technology is good choice for career.

So I've been looking into the Law of Reflection with Specular and Diffuse Reflection. I understand that electrons have a certain vibrational frequency in objects, and if a light wave matches that, that color wouldn't be observed. My question is, what if I took a red laser pointer and shined it...

I was reading about LASER production when I came by the concept of stimulated emission. The book I was reading doesn't elaborate the topic much,so far I have understood what stimulated emission is but not how it happens. When a photon strikes an excited atom the atom falls to it's ground state...

What is a purpose of a substrate in an electronic device? In particular semiconductor lasers, why is it made of semiconductor? Thank you.

What is means by transverse and longitudinal effects in lasers. It is mentioned in some material I am reading, but I was unable to find what is meant by this. Like here for instance...

A friend and I would like to try communicating (Morse code signaling) with off the shelf laser pointers from two hill tops (~350m above sea level) separated by about 16km. It would be nice to do this without binoculars but I’m not sure if that is possible with readily available off the shelf...

Homework Statement The fact that a laser's resonant cavity so effectively sharpens the wavelength can lead to the output of several closely spaced laser wavelengths, called longitudinal modes. Here we see how. Suppose the spontaneous emission serving as the seed for stimulated emission is of...

I know this might sound basic to a lot of you but in school I've started taking lasers and laser mechanics in my physics course and so we reached the whole four-level system and three-level system lasers and I have a question.. Why do four-level systems require less energy than the third-level...

I am thinking about a possible experiment, and would like to measure the temperature of gas in various places inside of a glass enclosure. Is it possible to use an infrared laser to this? Thanks

In thinking about what it would take to make a feasible invisibility cloak or holographic disguise or perfect hologram room, I've imagined something that works like this: A light beam "image" is projected onto a device designed to refract or reflect it in all directions, but only 1 color in any...

Hi all, I have a question and ask for a discussion. Can the pumping current of the semiconductor lasers such as DFB laser and FP-LD, be smaller than zero? Best Regards, Jason.galq

I have a 1550nm diode laser. I have a function generator sending a triangular function into the fast input of the laser; however, if I am within the bandwidth of the laser (under 10kHz), my output power of the laser mimics my fast input signal, so I get a triangular function on my O-scope with...

"A diode laser has a divergence of 5mrad in the p-direction and 1 mrad in the s-direction. Design an optical system in front of the laser which will make the output circular, and calculate the resulting divergence." Attempt; I am taking the course optic and waves, and the instructor did some...

I hope this is the right place to ask this. It is an experiment question. I have a 785 nm laser and a 1550 nm laser and I need to converge them down to a point. Now I could just manually align the lasers on the same XY-plane and have them hit that spot, but for reasons I don't want to...

Hi! Recently I have began to read up on my passion in physics in my spare time. I have encountered an experiment where lasers are used to decrease the speed of sodium atoms. The lasers are a wavelength that the sodium atoms absorb and then proceed to emit a photon. If the atoms are traveling...

Hello. I just joined this wonderful community, so excuse me if I'm doing something wrong. I'm new to using forums. Anyway, I had a question. SF usually features 'phasers' as weapons, but from what I hear it doesn't sound too realistic. I thought maybe lasers would be better weapons, say if...

At DARPA Robotics Challenge while robots could solve a numbver of things, they were still slow and clumsy compared to humans, and required some amount of remote control, when they had to face with complex tasks. Of course, it isn't good to send humans into radiation and hazards like that, but...

Homework Statement Consider an amplifying medium, composed of homogeneous broadening four-level atoms as show in figure 26.5, page 557 of textbook. http://img689.imageshack.us/img689/6108/lt2f.png Amplification is to occur on the 2-to-1 transition. The medium is pumped by a laser of...

Greetings everyone, I am confusing the definitions in the title of the post all the time. I have books about lasers, yet none of them explain these concepts lucidly and clearly in my opinion. For example, what is our reference plane when we are dealing with semiconductor laser diodes and...