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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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 ...
5
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4answers
460 views

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 ...
3
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2answers
53 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 ...
3
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1answer
55 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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1answer
78 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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1answer
73 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
60 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
128 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
75 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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0answers
22 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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0answers
39 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 ...
1
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1answer
38 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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13 views

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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12 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
40 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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0answers
25 views

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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3answers
66 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 ...
1
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1answer
60 views

Are there any CO2-Laser notch filters? [closed]

I'm searching for a notch (band-stop) filter (like [1]) for a 10.6 $\mu$m CO$_2$-Laser and I have yet to find one. Is there some physical reason such filters don't exist or is there just no demand? ...
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2answers
100 views

White Laser Light

I have heard that recently researchers have developed white laser light by combining semiconductor laser sources of different colors. However, I have heard that before these lasers become a practical ...
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2answers
45 views

Would it be possible to have light that is a cross between a laser and a none laser light? [closed]

Normally light moves through all three dimensions which is why it's intensity at any particular point depends on the inverse of the distance squared. For practical purposes we can say that laser ...
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0answers
27 views

How to find the focal spot size of a TEM 33 mode laser

I have a laser that has a TEM 33 mode beam profile. I would like to calculate the beam spot size when foucsed with a lens of a given N.A. I also know the M^2 for the beam. can I use the equation for ...
2
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1answer
55 views

Dispersion in ultrafast lasers

In mode-locked Ti:sapphire lasers, positive dispersion is caused mainly by the crystal. A prism pair placed in the laser resonator can compensate for some of the dispersion by introducing negative ...
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0answers
15 views

Why is the coupling constant in laser theory assumed real?

I'm reading the laser dynamics book "Light Vol. 2 Laser light dynamics" by Haken. On Page 123 of the book, the coupling constant g is assumed to be real. However, from the definition of g (see ...
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0answers
48 views

Trapping force in optical tweezer

I am reading a paper on theory of optical tweezers in ray optics regime by A. Ashkin. For reference "click here". It is given that Gradient force $F_g$ is directed perpendicular to the light ray and ...
3
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4answers
209 views

Shining a laser onto a mirror

Theoretically, if I shined a laser at a mirror at an angle of 0 degrees so that the light was perfectly reflected back to the light source, then I should not be able to see the light because it is not ...
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1answer
39 views

How a rangefinder works? [closed]

The speed of light is too high so how does a laser rangefinder calculate such a short time taken by the light to come back?
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1answer
52 views

Find alighment — Sacher diode laser littrow configuration

For a Sacher Diode laser Littrow configuration, I knocked it out of alignment. Does anyone know how I can find back the alignment? I was able to tilt the cylinder a little bit to find the bright spot. ...
1
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1answer
156 views

Does a laser beam converge and diverge without lens?

In the case of $TEM_{00}$ mode laser produces gaussian beam. I read in wikipedia that it converges till some point called 'beam waist'and then it diverges to infinity. If there is a lens placed along ...
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29 views

Could two electrolasers be used as a cutting tool for non-conductive materials like rock?

An electrolaser is an ionizing laser that turns the air molecules in its path to a conducting plasma. There have already been experiments with electrolasers as thunderpoles. You can also inject a ...
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1answer
57 views

Stimulated emission role in laser cooling

Laser cooling can be achieved by exciting an atomic system, in order to "pump" atoms in the excited state. This gives a recoil momentum $\hbar k$ the the atom, which then emits spontaneously. As ...
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0answers
29 views

How efficient is a self-cooling Zeeman slower?

Suppose a Zeeman slower is set up such that the cooled atom beam output is used to extract waste heat from the laser, then recirculated. Assume further that the magnetic fields are provided by ...
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1answer
59 views

how to scan a diode laser wavelength in certain range?

Is it possible to scan a sacher diode laser in certain wavelength range? For example, when piezo offset is 0 volt, the wavelength of laser (read from a wave-meter) is x. When I set the piezo offset ...
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0answers
21 views

Could an electrical pulse with the right properties reach a person's head after striking their chest?

I am trying to figure out if it is possible to build an electrical gun that could instantly and reversibly render a person unconscious. The trouble is that the gun should work when aimed at the ...
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0answers
43 views

How do we calculate the adjustment factor for hyperbolic secant pulse for calculation of peak power in ultrashort laser pulses?

In the formula for peak power it is equal to total energy divided by FWHM pulse width multiplied by an adjustment factor 'a' the value of which depends on the shape of the pulse. For hyperbolic secant ...
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2answers
52 views

What will happen if there is no spontaneous emission in laser? Will the working of the laser be possible?

We can use the Einstein's coefficients and omit the spontaneous term. How do I proceed after that?
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0answers
19 views

Interferences while using two ToF cameras

Im using two time-of-flight (ToF) cameras, a DS325 from SoftKinetic and a Creative Senz3D, at the same time with the DepthSense-SDK and the Point-Cloud-Library (on Ubuntu 15.04). But I got strong ...
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0answers
55 views

Acquiring an Active Q-Switched Laser

I'm working on a senior undergraduate project in engineering physics, and I am building an instrument that will use a Q-switched laser as a short-pulse, low-pulse-repetition-rate light source. We need ...
0
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1answer
57 views

Can we weld two dissimilar metals without using LASER welding? [closed]

It is said that one of the many advantages of LASER welding over ordinary welding is that it can be used to weld two dissimilar metals, what problems do we face while welding two dissimilar metals by ...
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0answers
30 views

Why do we use alcohol as active medium for dye laser?

Why do we use alcohol or ethylene glycol as active medium for dye lasers, they are not liquid organic dyes right? Or do they(alcohol etc.) serve some different purpose here?
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0answers
107 views

Lang-Kobayashi rate equation derivation

The Lang-Kobayashi rate equations of a semiconductor laser experiencing feedback are as follows: \begin{align*} \frac{d}{dt}\left(E(t)e^{i\omega t}\right) &= \left[\omega_N(n) + \frac{1}{2}(G(n) ...
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0answers
29 views

Coloring the clouds with lasers

What strength of laser would be needed to color or make projections of images upon clouds in the sky? I am assuming that this is possible, if not, please explain why. For the purposes of this ...
2
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1answer
185 views

Intersecting Lasers

What happens at the point of intersection of 2 lasers. If 2 lasers of different colour intersect, what will be happening at the point of intersection? Won't colour mixing happen?? Won't that point ...
1
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1answer
131 views

Simple derivation of the doppler limit and recoil limit

Im doing an essay on laser cooling, and I've got two questions about the derivation of the two limits. Firstly, in the derivation of the Doppler limit, it is stated in many places that the scattering ...
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0answers
28 views

Lower Threshold optical beam limiter?

We would like to implement a very fast beam limiting, so far google search shows that the common threshold ranges is in 1J/cm^2 or more, this could take seconds to activate as our laser ranges from 1 ...
2
votes
1answer
133 views

Why does the laser change colour? [duplicate]

In the first image, the laser colour is green. When it is shined on the plastic cap of the pink highlighter, the colour changes, why has this happened? Tech Details about the Laser Source are; Max ...
2
votes
1answer
266 views

Does laser beam expand along distance or not? [duplicate]

Why does laser dot become bigger at bigger distance? e.g: from millimeter to inches so that it distracts pilots in aircrafts. I knew that laser beam should't expand over distance, but remain stable. ...
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0answers
110 views

Gain clamping and threshold gain in quantum optics

We increase the pump power of a laser to the point where laser action starts, i.e. the threshold gain is reached. Now we increase the pump power even more, which increases the intensity of the cavity ...
0
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1answer
43 views

Can a laser class be lowered by lowering the input duty cycle? [closed]

According to this description, class II lasers have a power output of less than 1mW, class IIIa lasers have a power output of 1-5mW, and class IIIb have a power output of 5-500mW. Can a class IIIb ...
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0answers
69 views

Difference between steady state intensity and saturation intesity in laser

Can some one explain the diffrence between steady state intensity and saturation intensity in lasers. And diffrence between gain at threshold and gain at steady state,why are these two gain equal? ...
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1answer
46 views

How to classify laser output

What are the quantifiable criteria that are used to assign a safety classification to a laser? Googling finds me only vague subjective descriptions, like "safe to use under normal conditions" or ...