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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30 views

What is the typical strength of the electric field in a particle accelerator?

I am working on a research project involving the closed orbits of hydrogen in the presence of an external electric field and I am curious what a reasonable approximation for the electric field ...
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18 views

Limits on the information obtained through optical measurements

Consider a Gedankenexperiment shown in the figure below. There are two lasers $S1$ and $S2$ with exactly the same specifications on paper. In practice, they are of course somewhat different but ...
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12 views

Doppler and recoil limit on temperature

I havent't understood the causes of Doppler limit and recoil limit. I have found on the net different observations about them ("Doppler limit is due to the fact that the atom can't have a smaller ...
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0answers
17 views

Why does a circle of light form around a wire when a laser is pointed at it? [duplicate]

Referencing this video: https://www.youtube.com/watch?v=9Q_4SNbpBfo Why does a circle of light form? I've seen previous Phys.SE posts on this topic relating the answer to reflection, but I have ...
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2answers
46 views

Decoherence of a Coherent Beam

If retarding films (i.e. wave plates) can retard the electric components of light (based on the films thickness) without affecting it's direction, couldn't I use a retarding film of randomly varying ...
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12 views

Laser Welding of Copper/its alloys [closed]

I wanted to know about the different techniques that can be used for joining Cu/bronze/other Cu containing alloys to Stainless Steel by Laser Welding( specifically Nd:YAG laser ). I read abt some ...
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0answers
20 views

coherent length measurement of a monochromatic laser source

i need to learn about how to measure coherent length of a monochromatic laser source.I know that I can use michelson interferometer or spectrometry.For laser which has long coherent length michelson ...
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14 views

Plasma wakefield acceleration for Protons

Laser plasma acceleration is a promising technology that could replace the current method of accelerating particles (which is via electric fields). It is somewhat cheaper also as it makes the ...
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2answers
46 views

How to measure temperature of a laser cooled sample at picoKelvin temperatures?

I'm reading about laser cooling.. my question is: how can the temperature of the sample be measured? (using laser cooling we can reach $10^{-12}K...)$
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15 views

Modeling simple laser induced population transfer via adiabatic passage in python [migrated]

I'm trying to model adiabatic passage between two levels in a three-level atom interacting with two laser fields using Scipy and Numpy.. I'm not sure if my model is wrong due to my incorrectly ...
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0answers
29 views

Relation between minimum spectral linewidth and pulse duration

Is there a difference between minimum bandwidth and minimum spectral line-width of laser? What is the relation between them and the duration of a pulse?
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7 views

What is meant by the (aperture size) of optical deflectors in laser scanners?

How do you measure the aperture size in a laser scanner.
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2answers
34 views

Calculate required power output for a laser

How to calculate power rating required for a laser in order to produce a dot at a specific distance after reflection? For example, the laser is 10cm from the mirror, at an angel of 30 degrees it ...
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55 views

Why is it necessary to supply constant electricity to make a laser work?

As we know that in lasers there are excited atoms. When energy is provided in the form of light, heat or electricity to these atoms, these excited atoms after sometime go to a lower state of energy ...
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45 views

Would it be efficient to run a solar panel with laser?

Would it be efficient to run a solar panel with laser? I know this question is unsual as we are using electricity powered laser to run a solar panel. Actually i am paricipating in the Google Science ...
3
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1answer
68 views

How I can launch light into PM fiber

A polarization maintaining fiber preserves the linear polarization of the light at the output, the light at the input must be linear polarized to see signal at the photodetector... However I can't see ...
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2answers
67 views

Can a laser work forever if constant electricity is provided?

Can a laser work forever if constant electricity is provided? If we take a laser and provide it with constant electricity will the reactions in the semiconductor generate photons forever?
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36 views

Would an inverted design of a laser phosphor display (LPD) work?

Background info... It is my understanding that a laser phosphor display works by emitting RGB laser beams through a mechanism that cycles them in a pattern similar to a cathode ray tube. When I read ...
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61 views

How do I model this Quantum Cascade Laser (QCL) using COMSOL? [closed]

I'm trying to model this: GaAs on-top of a heat-sink made of Copper. It's trying to simulate a type of Quantum Cascade Laser, I'm looking at the effect the temperature has by running a 10V voltage ...
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0answers
24 views

How much energy does a PV cell need to work?

How much energy does a $1m^2$ photovolatic/solar cell need to work? Can it work using a bunch of Laser lights? Edit: Ok so this PV cell is $1m^2$ is dimesions. The N-type has silicon doped with ...
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27 views

What is the “Obscuration Factor (OBF)”?

In a paper I am reading for my master thesis I came across this "obscuration factor (OBF)". The authors indicate that it is a measurement of the average intensity of reflection. They do not give a ...
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176 views

Does my green laser pointer emit three distinct frequencies, or is my measurement flawed?

I was playing around with a cheap diffraction grating and my set of laser pointers, and I noticed that while the red and the blue pointers produce a single point in the spectrum, my green laser ...
3
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1answer
48 views

Laser diode spectrum vs LED spectrum, why so much difference in broadness?

I've been reading about how light is produced in both laser diodes (the most common types of lasers) and LED's. The mechanism seems very similar if not exactly the same: one applies a potential ...
3
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1answer
40 views

Is it possible to directly pump a laser using sunlight?

Typically in the old days one would use a flash tube to pump a ruby crystal. Is there any way, or any lasing material, that could use concentrated sunlight directly for either continuous or pulsed ...
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31 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 ...
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3answers
632 views

What causes the specific pattern of sparkly light from a laser pointer

I have a fairly cheap green laser pointer that produces a fairly big spot of light (actually two spots most of the time!). I'd guess the size of the spot is about 1/100th of the distance from the end ...
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2answers
59 views

Laser tattoo removal

I would like to know if someone could please briefly explain how laser technology of tattoo removal works? And second, could there possibly be any dangers to cells, specially on bones?
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69 views

What laser and BBO are needed to create entangled laser streams?

I have been reading about entangled particles, lasers, the two slit experiment, etc. I really know nothing from physics (i.e. equations, formulas, theory); so please respond accordingly. From my ...
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30 views

Any suggestion of laser pointer for everyday life study of fluorescence?

I want to buy a laser pointer to study fluorescence in my kitchen. Any suggestion? What kind of laser pointer? What stuff for demonstration?
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46 views

Is it possible to efficiently extract phonons from a lattice?

The population inversion generated in lasers occurs in multi-level atomic systems. As an example, the Nd:YAG energy diagram is shown below. The pump pushes the Nd ions up to the upper levels, and ...
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22 views

Losses in a laser diode

How do I convert loss/gain from units of /cm to /s? Intuitively, I would say multiply loss in /cm with the group velocity c/n, where n is the refractive index. Am I missing anything?
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1answer
31 views

Cooling atoms using emitted photons from a laser cooled atom

In Doppler cooling procedure, is it theoretically possible to use the emitted photons from the target atom (cloud) to cool more atoms? The idea is to cool the atoms rapidly by using energy emitted by ...
5
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1answer
123 views

What causes light to travel through a curved fountain of water?

Today I observed a tilted fountain spurting water upward (the water fell smoothly; no detectable turbulence). A colored light was shown upward into the water as it left its source. This light traveled ...
2
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1answer
41 views

Non resonant modes in cavity

I have a simple question. Suppose we have a laser with a cavity such that the frequency of the light that the laser emits does not match with any longitudinal modes allowed by the cavity. In ...
2
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30 views

Carbon fibre laser beam dump material?

A few years ago I came across a material used as a high power laser beam dump. It was made from carbon fibre which looked like a mat made of high density bristles ie all the fibres on the top of the ...
3
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1answer
262 views

Michelson interferometry - is a compensator plate necessary?

I am studying the Michelson interferometer shown in figure 2 (similar design shown below) of the AMRITA vlabs tutorial. There it is stated that Since the reflecting surface of the beam splitter ...
2
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2answers
64 views

Coherence length interference pattern

I recently watched this video that illustrates a laser's coherence length: https://www.youtube.com/watch?v=LixwAXsN8vg I've learned in class that coherence length of a laser with several wavelengths ...
3
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2answers
74 views

Michelson interferometer interference pattern [duplicate]

My friend and I recently did an experiment on Lasers where we shot a laser beam through a Michelson interferometer and observed the interference pattern on the wall. Here is the basic setup: One ...
3
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1answer
61 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 ...
2
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1answer
44 views

2 level atomic system interacting with Black body radiation. Relaxation time issue

I am studying the transient regime of a 2 level atomic system ($N_1,N_2$) interacting with a blackbody radiation from a source at constant temperature $T_{nr}$. The initial state of the atomic system ...
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39 views

Entangled Photon (laser pointer)

From a laser pointer emission; is it creating entangled pairs of photon? is it possible to get more than "pair" entangled, like group of photons all entangled?
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34 views

Laser travelling through a radially graded index of refraction

A laser beam propagates through a region whose refractive index varies as $\mu=\mu_0(\frac{r}{r_0})$. At a distance of R the beam makes an angle of 30° with the normal. Find the minimum seperation ...
2
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1answer
25 views

Laser cutting - ignition

How is that sometimes laser cutting by burning material or "flame cutting" causes ignition of the whole material like here where the whole paper starts to burn and sometimes doesn't allowing precise ...
2
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1answer
70 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 ...
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2answers
351 views

Why does a circle of light appear when I shine a laser pointer at a wire? [duplicate]

When I point a laser at a wire , a circle of light appears on a wall behind it . why this happens. What is the circle of light and why does it appear? Could anyone give some tips on what I should ...
1
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2answers
80 views

What wavelengths to combine to get 488nm?

Is it possible to combine a blue and green lasers to get cyan? If I used 405nm and 532nm, would I get (405+532)/2= 468.5nm? Is this a correct calculation?
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1answer
79 views

Lasers : Threshold Pump Power for Laser Oscillation [closed]

I was working my way through some basic laser problems , when I cam across this one : Consider the ruby laser for which we have the following values of the various parameters: $N =$ $1.6$ x ...
1
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1answer
71 views

What is a lineshape function $g(\omega_0)$ in a Laser?

I am a newbie to the world of lasers and was working my way through some basic problems, when I encountered this one: Optical Electronics, A.K. Ghatak and K. Thyagarajan (Cambridge University ...
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42 views

Maximum laser power that mirror can handle?

Can I use standard mirrors used for lasers used for laser shows to build some laser that has higher power and is able to burn materials? What are power and power density limitations that cannot be ...
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45 views

Photons and gravity [duplicate]

A very powerful laser pointing to the empty space next to small object in space. The photons in the laser beam does not hit the object. Will the small object be gravitationally affected by that laser ...