Questions tagged [laser-interaction]
The laser-interaction tag has no usage guidance.
124
questions
1
vote
2
answers
81
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?
- 185
1
vote
0
answers
30
views
Solving $2\frac{\partial S}{\partial z}+\left(\frac{\partial S}{\partial r}\right)^2=0$ [migrated]
I have been trying to solve this PDE $$2\frac{\partial S}{\partial z}+\left(\frac{\partial S}{\partial r}\right)^2=0$$ The solution of this equation corresponding to a spherical wave of radius of ...
- 11
0
votes
1
answer
70
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 ...
9
votes
1
answer
176
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 ...
- 267
0
votes
1
answer
31
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 ...
0
votes
0
answers
13
views
Is the transparence of a partially-silvered crystal independent of the intensity of an incident laser ray?
I have been trying to look for graphs describing the relationship between the transparence of a partially-silvered surface and the intensity of an incident laser ray, but so far have been unable to ...
1
vote
1
answer
62
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 $\omega$. ...
- 13
0
votes
0
answers
81
views
In a 3-level system governed by the optical bloch equations, is it possible that the expectation of the dipole can be negative?
I have set up optical bloch equations for a 3-level system (in a suitable rotating frame), which is driven by 2 light fields. The lasers are driving the transition
\begin{align}
|g \rangle <-> |...
- 6,515
1
vote
0
answers
30
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 ...
2
votes
0
answers
28
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 ...
- 97
1
vote
0
answers
23
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 ...
- 11
1
vote
1
answer
60
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 ...
- 13
2
votes
1
answer
39
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) ...
- 255
1
vote
1
answer
87
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 ...
- 162
3
votes
0
answers
137
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\...
- 1,359
3
votes
1
answer
115
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 ...
1
vote
1
answer
36
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?.....
- 23
0
votes
1
answer
26
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 ...
- 255
1
vote
0
answers
50
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 ...
- 633
1
vote
1
answer
49
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 ...
- 21
0
votes
0
answers
28
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 ...
- 33
0
votes
1
answer
138
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 ...
- 101
1
vote
2
answers
549
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 ...
- 170
2
votes
1
answer
262
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 ...
- 129k
0
votes
0
answers
84
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 ...
- 4,681
2
votes
1
answer
111
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 ...
- 593
0
votes
0
answers
31
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 ...
- 247
-1
votes
1
answer
407
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?
- 2,463
0
votes
1
answer
268
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 ...
- 2,463
1
vote
1
answer
27
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 ...
- 13
1
vote
1
answer
77
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 ...
- 353
0
votes
1
answer
288
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'...
- 123
1
vote
1
answer
108
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 ...
- 123
1
vote
0
answers
53
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 ...
- 161
0
votes
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?
- 81
0
votes
1
answer
457
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 ...
- 81
-9
votes
1
answer
192
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 ...
- 91
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.
- 33
0
votes
1
answer
832
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 ...
- 4,095
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 ...
- 186
2
votes
1
answer
176
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 ...
- 186
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 ...
- 4,681
6
votes
2
answers
193
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”? ...
- 4,681
0
votes
1
answer
73
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 ...
3
votes
0
answers
106
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 ...
- 377
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 ...
- 1
2
votes
0
answers
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 ...
- 397
2
votes
0
answers
322
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 ...
- 21
0
votes
1
answer
261
views
What is the exact usage of internal heat generation term used in a general heat conduction equation?
∂/∂x (λ ∂T/∂x)+ ∂/∂y (λ ∂T/∂y)+ ∂/∂z (λ ∂T/∂z)+ q_v= ρC_p ∂T/∂t------1
T - Temperature (Temperature of the material)
ρ - Density of the material
C_p - Specific heat capacity of the material
t - ...
2
votes
2
answers
1k
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
- 143