Questions tagged [laser-interaction]

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11
votes
1answer
305 views

How can one recover the classical frequency-modulation Bessel sidebands from a quantum emitter in a harmonic well?

Consider an atom that emits at frequency $\omega_0$ that's located at a position $x$ that moves under the influence of a harmonic oscillator at frequency $\nu$. In both classical and quantum physics, ...
8
votes
3answers
558 views

What causes a simultaneous transition of an electron from a higher orbit to a lower one when exposed to a photon of suitable wavelength?

I know this is the basis of LASER action but why does an electron fall to a lower vacant orbit when exposed to a photon of energy equal to the difference between the initial and final orbit? The ...
6
votes
2answers
157 views

Opposing Laser Beams Turns One Laser Off

When I send two separate laser beams directly into each other one of the beams goes completely out. These are inexpensive 5mv red diode lasers. What’s happening inside the laser to make it “turn off”? ...
5
votes
1answer
1k views

The difference between parametric and non-parametric linear and nonlinear optical processes?

There are plenty of linear and nonlinear optical processes, that can be divided into two groups: parametric and non-parametric (link). However, why are they called parametric (non-parametric)? What is ...
5
votes
2answers
2k views

What is "Radiation Friction"?

From this report on generating high intensity magnetic fields (emphasis added) The Faraday effect has been known for a long time. It refers to the polarization plane of an electromagnetic wave ...
4
votes
3answers
14k views

From power of a laser beam to electric field amplitude

In my experiment, I use a laser beam with wavelength $\lambda=894 \text{nm}$ for some magnetic resonance experiment. Right now, I'm doing some calculation using Quantum Mechanics, which requires the ...
4
votes
1answer
144 views

BEC interaction with light

I would like to ask when we describe coherent light interacting with atoms, what's the difference in hot atom case and BEC regime? In hot atom vapor, I know we could start with a simple interaction ...
4
votes
1answer
338 views

Laser speckle reduction for integration time of microseconds

How to reduce laser speckle noise for an imaging system that demands integration times of microseconds? I am aware of these two commercial solutions: Optotune laser speckle reducer. It has a ...
3
votes
1answer
126 views

Why does a near UV laser show as a green path in tap water?

i am using a 405nm laser and shining through a glass with regular tap water, also i noticed that it shows as an almost white path in the thick glass bottom, what causes this?
3
votes
2answers
281 views

Bending of laser beam wavefront

It is intuitive to me (correct me if I am wrong), that the direction of the wave vector in (real, not modeled) laser beam is not aligned with the direction of propagation everywhere in space. It means,...
3
votes
1answer
100 views

shock waves generated by ultrashort laser pulses

I am reading about shock waves and their origin. During my study i have found that the long pulse lasers (nanosecond-miliseconds duration) are used to generate the shock waves in the materials, ...
3
votes
1answer
453 views

Electron momentum distribution and wavefunction in momentum space

Does there exist any relationship between the electron momentum distribution used in above threshold ionization and the wave function in momentum space? In other words, starting with the wavefunction ...
3
votes
1answer
177 views

Electromagnetically induced transparency (EIT) and Stimulated Raman adiabatic passage (STIRAP)

What is the connection between Electromagnetically induced transparency (EIT) and Stimulated Raman adiabatic passage (STIRAP) in case of lambda system? can we achieve STIRAP with different shapes of ...
3
votes
2answers
353 views

Where does laser reflection (1) come from?

I have the above experiment setup where a triangulation-based laser scanner projects a laser (line) towards a transparent glass material. I then took a picture using my phone (indicated in the above ...
2
votes
1answer
233 views

What happens to charge during laser ablation in water?

One of my friends from lab makes gold nanoparticles in the following manner: He puts a gold plate in water (without surfactants or other additives) He fires laser at the plate After 5 minutes ...
2
votes
3answers
182 views

Why do lasers need mirrors at the edge of the cavity?

If the avalanche stimulated emissions start from the first absorbtion that occurs in the cavity then why are mirrors needed? I imagine a photon that even without mirrors stimulates extra coherent ...
2
votes
1answer
113 views

Why was the AC Stark effect only discovered after the laser was invented?

I was reading a paper about the theory of the AC Stark effect, and I was struck by the following assertion: For instance, the first observation of the AC Stark effect initiated by the laser radiation ...
2
votes
1answer
534 views

What if the optical length of a cavity is not a half integer scalar of the standing wave wavelength?

Pardon the confusing title, but I'll try and rephrase what I'm asking. Longitudinal modes in a wavelength of light require the optical length of the cavity to be such that the wavelengths need to form ...
2
votes
1answer
107 views

Optical pumping without stimulated emission

If I want to pump Rubidium 87 atoms From fg = 2 to fe=1 level with a laser tuned to D1 transition and avoid stimulated emission then it is sufficient that I use a laser power which gives me an ...
2
votes
1answer
51 views

How does yag Laser is LASIK work? And what is its lowest precision (till now)?

I am in a undergrad Vison Science class where the professor recently talked about LASIK surgery. In the surgery, a special type of laser that could heat up a specific point (a sphere actually) and ...
2
votes
1answer
97 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 ...
2
votes
1answer
70 views

Photon - Neutrino interaction

Suppose we have a laser source, that means a coherent laser beam formed by 'in phase' photons. Is it possible to calculate how many photons can change their wavelength in neutrino - photon interaction ...
2
votes
3answers
607 views

In a laser, why are modes near the resonance frequency favored?

Before asking my question, I will illustrate how our lecturer treated a Fabry Perot interferometer, because my question is linked to this topic. Of all the different models to describe laser ...
2
votes
1answer
1k 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 ...
2
votes
0answers
53 views

Rigorous adiabatic elimination for $N$-state quantum system under harmonic perturbation

I am interested in a rigorous derivation of the coherent evolution of a quantum system with $N$ states under the application of a harmonic perturbation. I have read several articles about the use of ...
2
votes
0answers
28 views

Is it possible to produce shock waves in air using low intensity pulsed lasers?

Air has about 0.04% carbon dioxide. Carbon dioxide has a very strong absorption band around 4.2µm. Let's say I used a nanosecond pulsed 4.2µm MIR source and targeted it into air, part of this would be ...
2
votes
0answers
275 views

Calculating Laser Beam Intensity Absorbtion

This question pertains to the ability to calculate the laser beam intensity , at a particular point in time when using lasers for the purposes of Cutting and Engraving Materials. The parameters at ...
2
votes
0answers
111 views

How does self-amplified spontaneous emission (SASE) work?

Due to the new laser in Hamburg, the XFEL, the following question arised: How does self-amplified spontaneous emission (SASE) work? There is an official article here http://www.xfel.eu/overview/...
2
votes
0answers
45 views

Does a MASER beam stay un-dispersed like that of a laser?

We know that a laser beam has a very low dispersion rate. Does the same apply for a MASER (Microwave Amplification by Stimulated Emission of Radiation) beam?
2
votes
0answers
83 views

How does Gain-switching produce intensity spikes?

Gain switching is described in my lecture notes as "we simply control how long we supply energy to the laser for, and thus how long the laser remains above threshold for. As the laser only emits ...
2
votes
0answers
62 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 ...
1
vote
2answers
297 views

Laser slow motion

Something really strange happen and I was hoping someone could shine some light on this. I always play around levelers with red lasers. I decided one day to shine a laser through a magnifying glass (...
1
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1answer
63 views

Light and laser effects on surfaces. How and why do they cause a material to decay?

Anyone that's been in a museum knows that's it's forbidden to photograph mainly old or very deteriorated crafts using a flash, but what is the reason for this? I don't see how a burst of relatively ...
1
vote
2answers
123 views

Why does generating EUV frequency combs require femtosecond enhanced cavities?

When generating extreme UV (EUV) frequency combs using high-order harmonic generation, why does the harmonic generation step need to be inside a femtosecond enhanced cavity for the comb to work? More ...
1
vote
1answer
199 views

Pair production at high laser intensity?

Using high laser intensity to produce electron-positron pair, is it still required interaction with nucleus as is the case when gamma rays are used? What causes the pair creation ?
1
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2answers
127 views

Alpha/Beta radiation and photoionisation of air

Which type of radiation is more likely to lower breakdown threshold when using focal lense focused pulse laser,for example 1064nm Nd:YAG. I reed three studies that said free electrons are most ...
1
vote
1answer
6k views

Heating metal with laser? [closed]

Can a laser be used to heat metal's to the point they glow red? How are laser cutters able to cut metal very easily? How much heat can a laser generate?
1
vote
2answers
171 views

Why the dipole interaction term in the Hamiltonian has all diagonal elements to be zero in the energy eigenbasis?

I have been studying the semi-classical light matter interaction from the book, "Light matter interaction" by Weiner and Ho. They have defined the total Hamiltonian of a two level atom ...
1
vote
1answer
54 views

How is three-dimensional laser cooling possible?

I am a bit confused about laser cooling an atom in all three dimensions. I think I have understood the one-dimensional case: The atom absorbs doppler-shifted laser light and the momentum in this ...
1
vote
2answers
250 views

Why doesn't a Gaussian beam converge to a point?

No matter what lens is put in the beam path of a Gaussian beam, it will always go through a waist of non-zero width. Why not just a point? I know the maths, I'm wondering whether there is any ...
1
vote
1answer
23 views

Can laser beam condense water vapour?

Suppose you pump humidity (water vapour) in an enclosed tank fitted with lasers in all directions, will the water vapour turn to liquid due to collision of photons and $\text{H}_2\text{O}$ molecules?.....
1
vote
1answer
55 views

Classical treatment of light-matter interaction, why light state changing is ignored?

In a semiclassical treatment of light-matter interaction commonly we treat atomic target (atom, surface, molecule, etc) quantum mechanically and the light is considered as a classical wave function ...
1
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1answer
867 views

What are the losses in a laser cavity?

I studied that to get the lasing conditions gain must overcome the losses. But what are the losses? Thanks a lot
1
vote
1answer
151 views

Plasma in solids

One way to create plasma is to focus a very powerful laser pulse to a small beam waist. In gaseous atoms, ionization will occur, yielding a soup of ions and electrons, which we call a plasma. But ...
1
vote
1answer
880 views

Can metals be ionized by radiation?

In gaseous state a laser can ionize metal atoms and create a plasma. But what about the solid state? Is a high intensity laser able to ionize a solid metal?
1
vote
1answer
55 views

Material that changes transparency when lased from side?

I am into photonics research, and have been searching about this topic in vain, but almost nothing from Google shows up. So i turned here for some light. Do you guys know any material that changes ...
1
vote
1answer
88 views

Power of several focused laser beams on a small surface

After viewing this: My Homemade 40W Laser Shotgun Will the initial 40W power of the diodes beams be roughly transferred to the targeted surface where the 8 beams are focused, or will there be a power ...
1
vote
1answer
1k views

What interaction generate the mechanical force?

It is said that there are four interactions which govern various phenomena of nature. Then when force applied on a body - what interaction really generate this force and make the body to move? Can we ...
1
vote
1answer
95 views

Using attosecond laser pulses to view electrons

It is often said in popular media sources that creating shorter and shorter laser pulses will allow us to view electron dynamics as they happen in chemical reactions. This is obviously beneficial in ...
1
vote
2answers
115 views

How organic impurities in the air affects laser?

We have a Nd YAG laser pumped Optical Parameter Oscillator in our lab. A technician came to our lab (my professor called him for its maintenance) and while he was working on it, he told me that ...