Light Amplification by Stimulated Emission of Radiation. A means of creating coherent light by either driving an atomic or molecular transition in an optical cavity or firing a beam of electrons through an undulator.

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What's the difference between stimulated and spontaneous emission in lasers and diodes?

I know that an LED emits light by spontaneous emission. To get more coherent and Monochromatic light, we should use a laser. What is the reason that laser light is the most coherent and ...
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68 views

Can a high-watt laser's scattering light be damaging to the eyes? [closed]

Heyo, I recently purchased a S3 Arctic Class IV laser pointer. I bought the 3500mW. (In case that page expires, it's 445nm wavelength, 1.5mRad variant, NOHD is 279m, beam distance at 0.25 Lux 72km.) ...
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45 views

Introductory books or good review paper on Free Electron Lasers

I am looking for a beginners' book on Free Electron Lasers, particularly regarding the principles of the mechanism rather than the details of the implementation. I am particularly interested on the ...
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37 views

“Classical” Coherence

I'm having a couple of courses where the concept of coherence is quite important. I know the traditional definition of coherence and it's connection to the phase of a wave. But often, I found, that ...
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49 views

Laser shone at liquid jet

When a liquid jet of water falls in laminar flow, it hits a surface. If this contact point, between the surface and the jet, is illuminated by a laser. Rings of light can be seen forming around the ...
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27 views

Stimulated emission process in lasers, Is the atom making transition a correct statement?

I was studying the Lasers, there is a section on absorption and the author is giving the statement as "An atom in lower energy state E1 may absorb the incident photon and may be excited to E2 . This ...
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53 views

LASERS: How do we get all the emitted photons of equal wavelength & equal phase? [duplicate]

As far as the working of lasers is concerned, I was convinced till the part that the light flashes on a ruby stone and the electrons are excited and then again go back to their ground state and then ...
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28 views

Compare how much a coherent laser visible green light beam spreads out with a incoherent green light beam.

Suppose I am mathematically modeling a visible green laser pointer beam which starts from the ground and ends up a half mile or full mile in the sky, projected upon an aircraft window 2 inches thick. ...
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68 views

how to find a laser beam

Let's say that you want to know if there is a laser beam around a big area, like a stadium. Or an airport. How could you detect and find a such laser beam (could be by a laser pointer or something ...
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1answer
65 views

Is there any issue/concern for a slight wavelength shift of the laser light in the LIGO experiments? [duplicate]

A friend and I were having a discussion about the LIGO experiments and were wondering if there is any issue with the laser light undergoing a wavelength shift as a result of the gravitational wave? ...
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62 views

DIY optical band pass filter or another alternative

I need to detect laser using a solar cell which would need me to either detect the laser wavelength or use pulse modulation and detect the frequency so I'm kinda here to ask if it's possible to simply ...
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30 views

optoelectronics-smallest wavelength of light

Sorry this maybe a stupid question , but i need to know: A few minutes ago i have read an article about optoelectronics: worlds first optical single atom switch The writer of the article ...
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56 views

Will I see the light?

There is a perfectly smooth wall. We have a slit parallel to it. Through that a laser beam passes. As the slit is parallel to wall the laser beam will hit it normally. So now if I see obliquely I ...
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2answers
162 views

Why does a laser beam stay collimated?

I am looking for a simple way of explaining the collimation of a laser beam. The typical discussion of the two slit experiment of quantum theory relies heavily on the Huygens principle. Its ...
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1answer
41 views

Drawing in the air with lasers Question

Are there two different lasers that can be invisible when not overlapping, but visible when overlapping? I desire to build a hologram-ish thing, but with lasers. The system would use many lasers that ...
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1answer
54 views

What would happen if light was stored in a circular path? [closed]

This is like an idea for experiment. Lets say one has an optical cable that makes a circle. There is a little Y junction/valve to the circle, through which one pumps some coherent light in. The ...
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1answer
46 views

Is it possible to get a lasing from every luminescent media?

Let's assume that there is a cavity with a couple of mirrors and gain media between which possesses luminescence under some external excitation/pumping. Let the absolute quantum yield of the gain ...
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40 views

Natural linewidth of hyperfine levels?

The D2 line of $^{87}Rb$ is the transition between the $5^2$$P_{3/2}$ and the $5^2$$S_{1/2}$ states. Its linewidth $\Gamma$ is always quoted to be $\sim 6 MHz$. But both states have hyperfine ...
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36 views

Frequency combs: comb line spectra from periodic pulse train?

Stabilized frequency combs can be generated using femtosecond mode-locked lasers after $f_{CEO}$ and $f_{rep}$ stabilization. Numerous sources have also pointed out that the periodic pulse train ...
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33 views

Frequency modulation in laser locking - what frequency?

In laser locking, e.g. using the PDH technique, the light (say of frequency $f$) is modulated so as to add two symmetric sidebands of frequency $\Omega$. I know the maths, I understand how this leads ...
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46 views

If I aimed two identical lasers at a screen, what would the interference pattern look like? [duplicate]

If I aimed two identical lasers at a distant screen, what would the interference pattern look like? Could this be modelled as a wavefront passing through two slits, i.e. the double slit experiment? I ...
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35 views

Coupling into FC/APC fiber

I am currently attempting to couple a 405nm laser diode into FC/APC fibre. The fibre is mounted on a flexure stage approximately 15.3mm from an f=15.29mm lens. I have managed to couple into the core ...
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Resources on solid state laser resonator design and modelling

I'm an experimentally oriented physics student and have been fascinated by lasers for a longer time. I'm currently building a diode-pumped, frequency-doubled Nd:YVO4 laser from scratch. Before I start ...
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Do free-electron lasers actually lase?

Free-electron lasers are devices which use the motion of highly energetic electron beams to produce bright, coherent radiation in the x-ray regime. More specifically, they start with a high-energy ...
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2answers
30 views

Can you pass 400mJ laser light through a fiber?

What is the energy limit for fibre optics? For a dual-pulsed nd:yag laser firing at 10Hz with energy roughly 2x 400mJ, and pulse width ~5-10ns. My gut says that this is far too high to pass through ...
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66 views

Is an x-ray maser possible?

I was wondering if lasers evolved from masers. They applied the same principles to a different wavelength. Would it be possible to create a maser at a higher wavelength, using x-rays, gamma rays, ...
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40 views

Minimum Power Required to Maintain a Population Inversion

According to many sources, the minimum power required to maintain a population N in the upper level of a two level laser system is $$P_{min}=fA_{21}Nh\nu$$ where $f$ accounts for the lack of 100% ...
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18 views

Is Light Amplification Synchronise Electron/Positron Radiation possible?

Light Amplification Stimulated by Emission of Radiation vs Light Amplification by Sychronised Electron/Positron Radiation By applying a "custom" undulator(a series of powerful magnets) to break up ...
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65 views

What will happen in this LASER setup?

If I have 3 rectangular mirrors, say of dimensions length of 1 meter and width of 0.5 meter and I arrange them in the form of an equilateral triangle, which is of side 0.5 meter.(The mirrors are ...
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33 views

Book on spectroscopy (line dependency on parameters)

I am trying to find a book (undergraduate level) on Spectroscopy. I am interested in how molecular absorption lines depend on parameters like temperature and pressure (for example with gases). Can ...
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53 views

Does laser light with less than the work function still ionise some atoms?

If a gas is illuminated with a laser of a frequency less than (but more than half of) the work function of the atoms in the gas, the atoms will be excited into Rydberg atoms. Is there a finite chance ...
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103 views

Laser cooling of atoms: more area or more power?

I want to optimise a Magneto-Optical trap. Laser beams come from the the x, y and z directions (positive and negative) and slow the atoms down. Would it be better to increase the beam spot-size ...
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18 views

Injection current modulation with a modulated RF signal to drive laser

I am using an RF modulated injection current to drive my laser in such a way that the modulation index = 0.8. At this point, I see the carrier and first sideband on the spectrum analyzer. If I now ...
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How can beam divergence be corrected for in a CO2 laser cutter?

I have a 90W RECI CO2 laser tube that I recently measured the beam divergence on. This was done by pointing the laser at a fire brick and melting it for a few seconds at different distances. Multiple ...
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2answers
51 views

What is crater's influence on laser ablation?

In many laser ablation experiments (especially Pulsed Laser Deposition), target is moving to avoid crater formation. But I can't find any source that says why it is needed to avoid it. So why is ...
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1answer
51 views

100x magnifying optics system for short laser pulse

I am now designing an experiment that consists of a 400 nm short pulse (~300 fs). In the experiment, we need to magnify the transverse profile of the pulse by 100x. That's the problem. I was ...
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73 views

Laser-induced electrical discharge

Attracting lightning with an ion beam has been done in a lab but how strong of a laser is needed to reach the clouds to redirect the lightning bolt?
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64 views

How to increase/decrease laser pattern size

I have a laser pointer with a diffraction grating lens that creates a cross-hair, like the one seen below. I'd like to be able to increase or decrease the size of the cross-hair so that it may ...
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2answers
59 views

Visible light excitation by heavy particles [closed]

Can I excite visible light from an atom by a proton or muon beam? How would that be possible?
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4answers
125 views

Why shouldn't we shine laser light back into the laser?

After every laser there is an optical isolator that ensures the laser light cannot re-enter the laser, if reflected and sent back. What would actually happen if this were to happen? Would the laser ...
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2answers
73 views

How to measure 8 μm surface bumps?

I want to measure surface bumps which are larger in size than $8\ \mathrm{\mu m}$ on a uncoated plastic mirror. So it can be any number of smaller bumps and that would not effect the application. I ...
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21 views

Phase matching type 2 in a uniaxial material

A uniaxial nonlinear material has the following refractive indices for a laser of wavelength 1000 nm and its second harmonic: $$\begin{array}{c|c|c|} & \text{1000nm} & \text{500nm} \\ ...
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34 views

How can I change the angle of a laser without mechanical aid

I'm trying to figure out a way I can bend change the angle of the beam coming from a cheap laser diode or laser pointer on the fly. One thought I had was a small prism or mirror that is attached to a ...
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1answer
37 views

How to collimate the LASER light using an electric field? [closed]

The He-Ne laser beam is passed through electric field plates. What is the mechanism occururing there and the principle of LASER light interacting with electric field?
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Derivation of resonance condition for free electron lasers

In the book Principles of Free-electron Lasers by H. P. Freund and T. M. Antonsen, it is written that to get the resonance condition for a free electron laser, we start from ...
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11 views

References on particle cooling

I am looking for references on the topic of particle and mechanical oscillators cooling, in particular: Doppler cooling Resolved sideband cooling and Lamb-Dicke regime Stokes and anti-stokes modes ...
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1answer
38 views

Bandwidth of laser pulses

I am working on a practice test for my optics class. The professor does not provide the solutions for the test. I was just wondering if someone could tell me if I am doing this correctly because it ...
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34 views

Right lens for my laser [closed]

I want to know if there is a way to find out size of lens(radius, it has to be sphere), when i know focal distance(120cm) and refractive index(1.7), for 2cm(diameter) laser ligting on it?
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In a superradiant laser, how does the collective dipole store the coherence of the photons?

In a standard laser, the stimulated emission is largely incoherent. How does a superradiant laser get around this? To my understanding, a magnetic field is usually applied to align the dipole moments ...
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62 views

Interference of two identical laser source

Do two identical but separate laser sources cancel out each other when point on the same spot? By the way both light will be coming from same direction. And of course, they will have a phase ...