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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0answers
30 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?
1
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0answers
21 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 ...
0
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3answers
49 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
38 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? ...
41
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6answers
8k views

Why do lasers cut? Is this a case of light acting as matter?

All I found in Google was very broad. From a physics models perspective, why can photons emitted from a laser cut? Does this cut mean that the photons are acting like matter?
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2answers
89 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 ...
3
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1answer
93 views

Does chirp (GDD, TOD ) affect the temporal coherence of a laser?

Lets say we have a laser beam with finite temporal coherence. A broadband spectrum with a transform limited pulse of 100fs. If we measure its temporal coherence when the pulse is transform limited ...
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3answers
365 views

How to be sure that a He-Ne laser light is monochromatic

How can I be sure that the emission of a He-Ne laser contains only one single mode of laser cavity? The only thing that I know is that if I use a diffraction grating and the light isn't ...
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2answers
40 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
11 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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2answers
39 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?
4
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2answers
443 views

Gamma Ray LASER Theory and Technology

I am aware that a similar question has been asked by someone else in the past, but in a very general form. Due to the physics interest and technology, in this question I put emphasis on the detail of ...
2
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1answer
48 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 ...
3
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2answers
3k views

Would a laser with four possible energy levels be better than three?

I'm wondering about achieving population inversion for a laser. I learned that without an active medium, it's not possible to create a laser with only two energy levels, but it would be possible with ...
0
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0answers
12 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 ...
3
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1answer
80 views

Would a giant satellite laser work as a weapon?

If someone built a satellite to float about in space, which used mirrors to focus and magnify energy from the sun directly into one direct spot (like in the James Bond film Die Another Day) would it ...
5
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1answer
1k views

Laser, wire, and a circle of light

So, when I point a laser at a piece of wire (pointed at a specific angle), a circle of light appears on a wall behind it (see image below). I am trying to see why this happens and if there are any ...
0
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0answers
44 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 ...
0
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1answer
33 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
40 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
99 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 ...
0
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0answers
23 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 ...
0
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1answer
46 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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1answer
135 views

How does airborne laser system deflect the laser beam?

In the Airborne Laser system, the laser beam is directed from the nose of a Boeing airplane towards the target. In this system, the angle of laser beam with respect to airplane body can be changed at ...
0
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1answer
36 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
21 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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0answers
19 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 ...
5
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2answers
257 views

Is there any physical quantity that does not have uncertainty?

I saw this video and I got a thought: Is there any physical quantity that does not have uncertainty? Basic models are: for lenght for time end energy (so for mass too) and I realized that ...
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0answers
25 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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0answers
17 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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1answer
65 views

Could laser speckle patterns be used in diagnosing vision defects?

At the London Science Museum some years back, I saw a device which projected a laser speckle pattern and had a sign explaining that it would appear stationary for people whose eyes were correctly ...
1
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0answers
47 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 ...
2
votes
3answers
449 views

How does optical phase modulation produce photons with different frequencies?

The classical description of electro-optic modulators is an index of refraction that depends on the applied voltage. For example, for a sine modulation $\sin(\Omega t)$, a monochromatic laser of ...
0
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1answer
38 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
29 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
70 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) ...
0
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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
119 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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3answers
2k views

Can energy be extracted from clouds?

Can cloud charge imbalance be used as an energy source? First off quite some energy must be present in clouds: a lightning path is quite long, and electrical breakdown of air requires about 1MV/m. ...
0
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0answers
27 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
106 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 ...
11
votes
3answers
6k views

Why do green lasers appear brighter and stronger than red and blue lasers?

This is mostly for my own personal illumination, and isn't directly related to any school or work projects. I just picked up a trio of laser pointers (red, green, and blue), and I notice that when I ...
2
votes
1answer
150 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. ...
0
votes
0answers
65 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
36 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 ...
0
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1answer
30 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 ...
1
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0answers
45 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? ...
0
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0answers
23 views

How to read CO2 a laser line label?

A line emitted from a CO2 laser is often labelled as 9P36, 10R18(13C), 9R32, etc. What do these labels mean? For example, does 9P36 mean the line is 9.36um from the P-branch? What difference does it ...
4
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4answers
2k views

Can 2 beams of ultraviolet light intersect and be visible where they intersect?

Is it possible that if you have 2 ultraviolet lasers, that are invisible to the human eye, and if you aim their beams to intersect at some point, that the place of intersection will show a lower ...
2
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1answer
156 views

How does a laser emit light in a coherent state?

Lasers work by stimulated emission of atomic transitions. Stimulated emission produces two photons which, because the particle number is well-defined, projects the field into a Fock state. However, it ...