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Questions tagged [laser-interaction]

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Would the use of LIPC's for Lasers avoid eye damage for bystanders?

Laser Induced Plasma Channels (LIPC) can create a tunnel of plasma in the air for a brief moment (milliseconds). But the formation of a LIPC is a process and not something instantaneous when it comes ...
Fulano's user avatar
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52 views

Fermi-Dirac integrals of different orders

Which physical quantities are related to the Fermi-Dirac integrals of different orders? If fermi-dirac integral, write like this: $$F_\xi(\eta_c) = \frac{1}{\Gamma(\xi+1)} \int_{0}^{\infty} \frac{x^{\...
xing zheng's user avatar
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1 answer
86 views

Will a laser with low power - operating as continuous wave - generate supercontinuum in nonlinear materials?

Some nonlinear optical materials, such as for example glass doped with As2Se3 or As2S3, are able to generate supercontinuum if a single mode laser pulse, in range of a few watts, is launched into the ...
Jimski's user avatar
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Frequency Dependent Absorption According to Wu

I was reading the paper "Theory of strong-field attosecond transient absorption" by Wu, and he says that the difference in energy of a material interacting with an electromagnetic field (...
Rich Hard Fine Man's user avatar
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1 answer
25 views

Laser cooling for an electron

In laser cooling, atoms can be slowed down by momentum transfer. Laser cooling relies on the change in momentum when an object, such as an atom, absorbs and re-emits a photon (a particle of light). ...
HolgerFiedler's user avatar
1 vote
2 answers
128 views

Second Harmonic Generation in metals

Assuming a metal driven by a femtosecond laser pulse could generate second harmonics, are these harmonics radiative? In other words, do they reach the far-field?
Ali Kefayati's user avatar
0 votes
1 answer
86 views

Cooper-Zare-Theory - Photoionization simulated in Python

My concrete problem is that I want to calculate cross-sections for photoionization transitions in argon in Python. For example from the excited state 3S^23p^56d into the continuum. For this, I found ...
LaserLennart's user avatar
9 votes
1 answer
380 views

Mechanism causing red fluorescence from green (532nm) laser in household glass

Background / Experiment I was surprised by this toot by @gigabecquerel, where the author shows red fluorescence in the thick bottom of a (drink) glass when exposed to a cheap consumer-grade green ...
Marcus Müller's user avatar
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1 answer
35 views

Can combine a reflected laser beam with a refracted laser beam accurately?

If a laser beam is refracted and exits from the other side, and we project another laser beam so that it is reflected in the refraction of the first ray (regardless of the reflected half of the first ...
FOXDeveloper's user avatar
1 vote
1 answer
118 views

Oscillation velocity of an electron in an electric field greater than c?

In relativistic laser matter interaction it is usually defined a parameter $a_0$ as $$a_0 = \frac{e E}{m_e \omega c},$$ with $E$ the amplitude of the oscillating electric field of frequency $\omega$. ...
ariel67's user avatar
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1 vote
0 answers
36 views

Recording Analog Data in Optical Disc Using Laser Beam Mechanism [closed]

Is it possible to storing/writing any Analog Audio Signal (i.e. Vinyl Record & etc) into a little bigger and thicker Optical Disc as compared to the other conventional Compact Disc while using the ...
Shankar Majumder's user avatar
2 votes
0 answers
52 views

How does intermodulated fluorescence spectroscopy work?

Via intermodulation of two counter-propagating laser beams, a Doppler-free resonance spectrum of a gaseous sample can be observed in the fluorescence signal (see e.g. [1] Sorem+Schawlow (1972)). Can ...
faber's user avatar
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1 vote
0 answers
30 views

What is adiabatic transfer?

In the context of atomic/quantum states preparation, what does adiabatic transfer mean? I'm currently reading about atom preparation using lasers and they talk about using adiabatic transfer to obtain ...
AdiabT's user avatar
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1 vote
1 answer
245 views

What is meant by "low-lying" electronic states?

In the context of electronic structure and spectroscopy, the term "low-lying electronic states" is quite common but it really isn't defined anywhere. All google search results lead to ...
PestoPotato's user avatar
2 votes
1 answer
43 views

Laser on metal surface: What happens in terms of photons, plasmons, phonons and their interactions?

I'm trying to better understand what exactly happens when a laser beam hits a surface (apart from reflection). Say I have a thick gold surface (could be coated with gold nanoparticles if that helps) ...
MrFu's user avatar
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1 vote
1 answer
90 views

What is the theoretical range of temperature the air must be in order to reflect/refract light (for a volumetric display)?

Well, the only question I found in this website about volumetric displays on air was this one, but it specifically suggests making air denser in order to make it work, but my question is specifically ...
Fulano's user avatar
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3 votes
0 answers
146 views

Canceling the remaining time-dependence in a "cyclic" Hamiltonian for which rotating frame transformation (RFT) fails?

Question: Is there a transformation or simple approximation to use to cancel the time-dependence in a Hamiltonian of form $$ H_{G} = \sum_{(m,n)\in E,\ m<n}\Omega_{mn} e^{-i\Delta_{mn} t} |m\rangle\...
prolyx's user avatar
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3 votes
1 answer
161 views

How to measure the wavelength of a laser? [duplicate]

I'm building an enclosure for a laser engraver that emits light at ~455nm. I want to be able to measure the wavelength of the light that is refracting off the item being engraved. I would want to be ...
Philip Edwards's user avatar
1 vote
1 answer
53 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?.....
Abel's user avatar
  • 23
0 votes
1 answer
30 views

How to relate laser pulse characteristics to the degrees of ionization of a target (i.e. how many electrons get removed per atom)?

Say I have a lithium foil as a target for a laser. Li has $3$ protons and $3$ electrons and therefore $3$ degrees of ionization associated with $3$ ionization energies (for removing the first, second ...
MrFu's user avatar
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1 vote
0 answers
73 views

Weird pattern for a laser beam spot

I am trying to measure the gaussian profile of a laser beam, which is supposed to be T00. The profile shown in the specifications looks very Gaussian, and the laser is brand new. I am using this ...
JohnDoe122's user avatar
1 vote
1 answer
73 views

Requirements for Z-scan or I-scan measurements of nonlinear optical materials

I am looking to understand what requirements there are for any version of Z-Scan technique or the I-scan technique. These techniques are used for measuring nonlinear absorption and nonlinear ...
jgk5141's user avatar
  • 21
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0 answers
30 views

Does the interaction between 2 photons change its traveling directions?

As I understand from the Hong-Ou-Mandle effect, the interaction between 2 photons is possible. Can 2 Photons interact with each other in free space? Suppose that the 2 photons met in the spacetime ...
Wael Khatib's user avatar
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1 answer
179 views

How does a light source / laser transfer energy to a material?

I am trying to understand the physics of how a laser is able to heat a solid. My understanding so far is that when photons are incident upon a body (e.g. a metal) the momentum of the photons is ...
Junkers's user avatar
  • 101
2 votes
2 answers
853 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 ...
abir's user avatar
  • 328
2 votes
1 answer
384 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 ...
Emilio Pisanty's user avatar
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0 answers
144 views

Help finding a laser that will pulse with my signal generator

When I connect my 5mW red laser to my signal generator the laser fails to deliver clear square wave pulses once I go below the 2000ns mark. The signal generator is capable of producing pulses as low ...
Lambda's user avatar
  • 4,711
2 votes
1 answer
123 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 ...
Riccardo.Alestra's user avatar
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0 answers
32 views

Doppler cooling Ethanol

Is it possible to use laser cooling to cool Ethanol in it's gas phase? I've seen research on IR diode cooling when you reverse the electrodes but laser cooling was/has always been limited to atoms and ...
G Gr's user avatar
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-1 votes
1 answer
416 views

Why is the frequency of emitted photon of laser different from the frequency of incident photon? [closed]

Why is the frequency of photons emitted from a laser different than the frequency of the incident photon?
Harish Chandra Rajpoot's user avatar
0 votes
1 answer
391 views

Why the transition of electron from an excited state to metastable state in a lasing medium is radiation less?

When an electron transitions from an excited state to the metastable state, no radiation is emitted i.e. a radiationless transition. My question is: Where does the energy difference between excited ...
Harish Chandra Rajpoot's user avatar
1 vote
1 answer
36 views

Number of Ionization event estimation

First of all, I am new in this field and therefore if I ask a silly question please forgive me. I have a gas-cell (say 3$\times$3$\times$3 mm$^3$ volume) filled with a N$_2$ gas. The number density is ...
Bilash Krish's user avatar
1 vote
1 answer
109 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 ...
Christian's user avatar
  • 393
0 votes
1 answer
396 views

How to put laser field into the Hamiltonian of the Schrodinger equation of a 3-level quantum system?

I read a paper about using femtosecond laser to control a 3-level quantum system. The author wrote the Schrodinger equation for the system and wrote the expression of the laser field. But I still don'...
Junk Warrior's user avatar
1 vote
1 answer
152 views

Units of energy and frequency

I read a paper about using femtosecond laser to process an atom. The units used in the paper bothered me. I have four questions. (1) Why the unit of energy is cm$^{-1}$? (2) It seems that the author ...
Junk Warrior's user avatar
1 vote
0 answers
62 views

Features of plasmon and surface plasmon polariton

What is the difference between surface plasmon polariton and plasmon in the Hamiltonian? So let's say that I can diagonalize the Hamiltonian of the system I am studying no matter how complicated that ...
Yepman's user avatar
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0 answers
14 views

What is box shape in ion beam drivers for ICF?

What is the meaning of box shape in the ion beam pulses? i mean in plasma we say the ion beam irradiating the capsule is box shaped. what does it mean?
user68857's user avatar
0 votes
1 answer
563 views

What is the difference between ion beam and laser?

What is the difference between laser beams and ion beams, especially in inertial confinement fusion? In inertial fusion, we use lasers as well as ion beams for driving the reaction. What is the ...
user68857's user avatar
-9 votes
1 answer
242 views

How to kill an insect without touching it? [closed]

Apart from the interception by a sufficiently powerful laser, what would be the means to neutralize (kill/repel) an insect in full flight and indoors (so no water, pepper, etc), and without touching ...
Alex Dana's user avatar
0 votes
1 answer
23 views

How to calclate Drude dielectric function vs probe energy from time resolve spectroscopy?

How can I calculate drude dielectric function vs probe energy (in eV) form differential transmittance vs delay time plots.
Tom Jhonko's user avatar
0 votes
1 answer
1k views

How to calculate the Rabi frequency of a pulsed laser?

I read that the Rabi frequency $\Omega$ for a constant intensity laser with intensity $I$ is given by $$\Omega=9.95 \times10^7 \sqrt I$$ from Equation 3 in this paper. For a pulsed laser, how does ...
TaeNyFan's user avatar
  • 4,235
0 votes
0 answers
14 views

Photoelectrons could be detected in position space rather than momentum space?

In experiments, to study the interaction between atoms and light, experimenters use lasers ( i.e. coherent light) that interact with a gas of atoms. This treatment is pure statistics. To be more ...
Malek_Physics's user avatar
2 votes
1 answer
224 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 ...
Malek_Physics's user avatar
0 votes
0 answers
15 views

Oppossing Laser Beams Cause One Beam to Disappear [duplicate]

I posted a video early where I asked the question about opposing laser beams appearing to turn one laser off. Further experiments, however, have demonstrated that it is interference at play not that ...
Lambda's user avatar
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6 votes
2 answers
211 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”? ...
Lambda's user avatar
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0 votes
1 answer
85 views

New concept - fiber optic gyro

Dear people of laser science, my understanding of fiber optic gyro is: a single laser beam runs into a cube splitter, then the 2 beams are driven into the opposing ends of a fiber (coil). Then in the ...
Leventete's user avatar
3 votes
0 answers
165 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 ...
Quantum's user avatar
  • 397
0 votes
1 answer
31 views

Behavior of collimated beam inside tubular first-surface-mirror

Picture a cylindrical tube, the interior surface of which is a 1st-surface mirror coating. Visualize the diameter of this tube as circumscribing an equilateral triangle with sides A,B,C. The plane ...
Jim's user avatar
  • 1
2 votes
0 answers
32 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 ...
user1155386's user avatar
2 votes
0 answers
335 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 ...
Brett's user avatar
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