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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Minimum spread of frequency and wavelength in neodymium laser

What is the equation linking the minimum spread in wavelength and frequency of a pulsed laser, in relation to the lasers pulse time and operational wavelength. For example: If a Neodymium laser ...
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1answer
11 views

How to propagate a (tilted) gaussian beam through a telecentric f-theta-lens

My questions has two parts: First of all let's assume I have a gaussian beam and I send it through a telecentric f-$\theta$-lens (e.g. http://specialoptics.com/products/scanning_confocal.html) with ...
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0answers
20 views

Inexpensive, Ultra-High Resolution Manufacturing Techniques for Polymers? [on hold]

I know this isn't strictly a physics question, but this is the most appropriate community I could find. What are the most precise/high-resolution manufacturing techniques out there for polymers (such ...
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3answers
98 views

Calculate the rise in temperature from directed radiation [closed]

For example I have a 1 watt laser and direct it to a sheet of metal (copper), if I were to direct it for say a time interval of 1 minute what would be the change in temperature? I can predict that it ...
2
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0answers
15 views

Phase noise and linewidth of laser

I learned that the linewidth of a single frequency laser is closely related to the phase noise. But this sentence from a book completely confuses me: "A quantum-limited beam in a so-called coherent ...
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2answers
34 views

Practical Uses of Laser Attenuation

In my college physics lab, I am studying the attenuation of a laser through different concentrations of copper sulfate. I am curious about the practical uses of laser attenuation. Why do we study it? ...
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10answers
387 views
+50

How far can light go?

When a ray of light is projected, (say) from the surface of Earth to outside in space. The condition is that, there is no obstruction to it till infinity (it travels only in vaccum). My question is ...
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2answers
35 views

Gaussian beam modelling, location of the beam waist?

In reference to the specifications of a laser diode below: http://www.thorlabs.de/thorcat/11900/L780P010-SpecSheet.pdf I wish to be able to model it as a gaussian laser beam. I understand there is a ...
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5answers
2k views

Quantum random numbers from a laser — simplest setup?

I'm a software / maths guy who would like to build a physical setup for generating quantum random numbers. I have no physics background, so bear with me. Background The project is for a public ...
6
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2answers
116 views

How is the phase of the stimulated emission in a laser first “chosen”?

As I understand, once you have a population inversion and the excited atoms decay they will emit in random directions, and the ones that emit along the axis of the medium will cause stimulated ...
2
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1answer
39 views

Why are laser pulses Sech Squared in temporal shape?

Ultrashort pulses from mode-locked lasers often have a temporal shape which can be described with a squared hyperbolic secant ($\mathrm{sech}^2$) function: $$ P(t)=P_0 \mathrm{sech}^2 \left( ...
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3answers
2k views

Is it possible to make laser beams visible midair without smoke?

My question is: Is it possible to make laser beams viable midair without smoke? I thought it would be a great idea to have a (second) smartphone or pc screen without having a solid screen. The reason ...
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0answers
16 views

Stop CO2 laser firing through holes in glass

How would you prevent a CO2 laser with interlocks used to mark glass from firing if there were holes in the glass. Usually the interlocks prevent the laser from firing unless it is pressed against ...
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2answers
50 views

Accurate way to measure angular spread of a laser beam

While doing an experiment to measure the angular spread (or say divergence) of a beam of laser (which in my case was an inexpensive diode laser), what is the most accurate way of measuring the ...
0
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0answers
44 views

Lasers without Population inversion?

When I made a study on lasers, I found a webpage saying that the quantum mechanical principles enable us to create laser action without population inversion, which Einstein suggested as one of the ...
6
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1answer
106 views

How legit is this paper claiming to have observed Hawking radiation? [closed]

I recently stumbled upon this paper. In it, the author claims to have found a signature for Hawking radiation in a condensed matter system. I know that experimentalists have been trying to find ...
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0answers
29 views

When optically pumping a lasing gain medium with another laser, does Stimulated, or Spontaneous emission dominate?

Much of my reading seems to indicate that laser pumping results in a fluorescent stokes shift but somehow photon vector is maintained. I've seen the phrase "Spontaneous Fluorescence by Stimulated ...
4
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2answers
169 views

Spectrum of generic $\mathrm{CO_2}$ laser

It is often quoted, that it's emission is 10.6um. But we also know that CO2 lasers have huge number of possible emission lines in 2 main bands: 10.6um and 9.6/9.4um. But what is emission spectra of ...
3
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1answer
40 views

How to create a barrier for sound waves?

Is there a way to create a barrier so that sound waves cannot pass through? Does laser light have this ability to act as a barrier or bounce sound waves back? This came to my mind when I was ...
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1answer
43 views

Beam of electromagnetic wave, with radius of 3cm or less

I need to create a beam of electromagnetic wave, with radius of 3cm or less, for distance about few meters. What is the minimum frequency (maximum wavelength) that it is really possible?
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2answers
37 views

Lowest detectable power of a laser?

What is the lowest power of a laser beam which is still detectable? More precise: If the intensity of my laser beam is reduced by a factor of $10^{-8}$, can I still detect it? Of course this depends ...
1
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0answers
29 views

How to represent a laser pulse in quantum optics

Every quantum optics textbook that I've found says something like "a coherent state represents the output of a laser", but a coherent state is a static thing (aside from the oscillating phase of the ...
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2answers
26 views

Laser Refraction

Can you take a laser beam of high intensity and refract it in a way to convert it to a safe level? White light traveling through a prism refracts into the individual wavelengths, could something ...
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0answers
26 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 ...
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1answer
63 views

Why can light from a laser burn things, and from an LED or lamp cannot?

Considering a focused laser beam of 1000mW power, it will burn paper or wood slightly. Focussing the light of an 1000mW LED does not do so. Why is that? Is it because the laser is monochromatic? What ...
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0answers
30 views

Can multiple lasers be concentrated in a circular area using some optical arrangements?

Can multiple lasers be concentrated in a circular area using some optical arrangements such as using a paraboloid surface? If yes, why do in high laser power systems do they use only 2D arrays of ...
0
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1answer
24 views

Proton 'Laser' ? could we get a laser-like effect? [closed]

This is a speculative question. question: Can we gain protons, by smashing a high speed proton into a hydrogen plasma? Background: I was thinking about how lasers repeatedly send the photons thru ...
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16 views

Calculate rotational duration of magnetic levitation inside a vacuum chamber?

Background Numerous examples show rotating pyrolytic graphite (or similar diamagnetic material) that can be moved using a laser. Problem The problem has the following objects: An N52 grade ...
2
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1answer
45 views

Is it possible for two holograms to be on the same holographic film?

I was thinking if you could use a laser of a specific frequency to write a hologram on a film, and then to try to record over the same film but with a laser of another frequency the the first. Is it ...
0
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2answers
62 views

Safety glasses for a CO₂ laser

I am working on a CO$_2$ laser project and I know glass blocks the wavelength of the laser, 10,600 nm, well. So, should normal glasses work good as safety glasses or do I need to buy a specific one? ...
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1answer
37 views

Why does an external laser drive only couples certain levels?

I was always wondering how is it that all the quantum optics levels schemes are depicted as if the laser couples only two certain levels with some frequency. For exmaple the standard lambda system ...
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0answers
13 views

What is meant by spatially multimode states of light?

I came across this term while reading texts on Quantum Optics and Lasers. While I know something about multimode laser oscillations, I am unsure about what is exactly meant by multimode light?
2
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1answer
62 views

Stimulated emission in Nd:silica glass, energy levels broadening and lasers

It is known that due to absence of uniform crystalline structure in Nd-doped glasses (comparing to Nd:YAG and Nd:YVO4 crystals) energy levels of Nd+ are significantly broadened. This means that we ...
2
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2answers
101 views

What does $g^{(2)}$ signify in quantum optics? And how to calculate it?

I have been studying research papers on Quantum Optics and non-linear optics. I frequently come across the $g^{(2)}$ value. What does it signify? What is its importance? How to calculate it? And ...
3
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1answer
88 views

Low-cost 532nm DPSS laser modulation

Could anyone suggest modern means of modulating 100mW CW 532nm DPSS laser? This should be low-cost(<50$) in high volume. Frequency bandwidth is 10Mhz, so modulation of pumping diode would ...
2
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0answers
40 views

List of laser-cooled atoms and ions

I'm familiar with the requirements for an atom or ion to be cool-able with laser cooling -- a closed transition -- or close enough that the leaks can be plugged with repumpers. But is there a list of ...
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0answers
94 views

Definition of spatial and temporal coherence in QM?

It is often said that lasers are spatially and temporally coherent. Is there a simple definition of spatial and temporal coherence in the language of quantum mechanics? More specifically, can these be ...
6
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2answers
449 views

Homemade Spectrometer

Recently I have had ideas of how to build a spectroscope, but I'm not sure if it will work. As can be seen in the diagram, the experiment is simple: it consists of a laser that generates the light ...
3
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1answer
34 views

What is a vectorial vortex beam?

I know that a Laguerre-Gaussian (LG) beam with topological phase non zero has helical wavefront, but still linear polarization. So if LG beams are not vectorial vortices, what could they be?
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0answers
25 views

Diode lasers tapered amplifiers

I'm trying to understand how a tapered amplifier works, but I can't find any good resources. Can anyone point me to any resources where the way they work is explained? Or could anyone here explain it ...
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0answers
16 views

Ellipsometry measurments

Why it is good to measure on a wavelength range in ellipsometry instead of using a single wavelength. I understand this that the measured data (ψ and ∆ ) plotted against wavelength and if we have ...
2
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1answer
102 views

Laser beam divergence

How can I calculate the divergence of a laser beam by diffraction? I want to find the following relation, $$ \Delta\Omega = \frac{\lambda^2}{A}, $$ where $\lambda$ is the wavelength and $A$ is the ...
5
votes
2answers
203 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 ...
1
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1answer
35 views

In real laser applications, how big is the complex parameter (i.e. <n>) of the corresponding coherent state of the field?

In quantum optics, the output from a laser is modelled using a coherent state; what are some orders-of-magnitude for the complex parameter (usually denoted $\alpha$) of the coherent state ...
2
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3answers
86 views

How to shift a laser wavelength?

Recently I have read something about the laser surface velocimeter, and after I have to rebuild from scratch (university project), I got a question: In the description they wrote that one of the laser ...
4
votes
2answers
106 views

A light so strong it has a shadow

I have recently taken an interest in shadows. I know that in order for a shadow to exist that you must have a solid in the way of the light. My hypothesis is that there can be a light so strong, like ...
1
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1answer
57 views

What would a laser beam's E-M waves actually look like if you zoomed in?

I am trying to understand how a real world beam of laser actually reflects the physics description of oscillating electromagnetic waves. So say we are looking side on at a vertically polarized laser ...
3
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1answer
64 views

Is “microbunching” in a free electron laser limited by the Pauli exclusion principle?

As I understand it, a free electron laser can basically be pictured as a synchrotron light source with an undulator which by the particular setup causes the electrons to self-attune so that they ...
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2answers
63 views

How is photon time of flight/range over sub-millimeter distances measured?

I was reading a paper that described how the force a low-thrust torsion pendulum was measured. In it, the paper states a laser is bounced off a mirror and the displacement is "...based upon the beam ...
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1answer
52 views

why not just pumping to the 3rd level directly in a 4 level laser system?

why pumping to the 3rd level in a 4 level laser system will decrease the output PL intensity?