Questions tagged [laser-interaction]
The laser-interaction tag has no usage guidance.
114
questions
0
votes
1
answer
27
views
+100
What is the theoretical range of temperature the air must be in order to reflect/refract light (for a volumetric a 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 ...
3
votes
0
answers
80
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\...
3
votes
1
answer
78
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 ...
0
votes
0
answers
10
views
What is maximum chirp coefficient in ultra-intense laser pulse?
Are there any formulas for examining limitations on the linear chirped value of ultra-intense laser pulse?
0
votes
0
answers
12
views
How can neutral, even-numbered atoms like strontium be trapped in a magnetic trap?
Since the beginning of this year, there has been a lot of attention paid to newly-created 'Pauli crystals', also known as 'Pauli-blocking crystals'......
Using ionized atoms, or at least odd- numbered ...
1
vote
1
answer
25
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?.....
0
votes
1
answer
24
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 ...
1
vote
0
answers
34
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 ...
1
vote
1
answer
28
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 ...
0
votes
0
answers
24
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 ...
0
votes
1
answer
73
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 ...
1
vote
2
answers
228
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 ...
2
votes
1
answer
131
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 ...
0
votes
0
answers
28
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 ...
2
votes
1
answer
81
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 ...
0
votes
0
answers
28
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 ...
-1
votes
1
answer
360
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?
-1
votes
1
answer
75
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 ...
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 ...
1
vote
1
answer
57
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 ...
0
votes
1
answer
123
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'...
1
vote
1
answer
64
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 ...
1
vote
0
answers
27
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 ...
0
votes
0
answers
12
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?
0
votes
1
answer
255
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 ...
-9
votes
1
answer
160
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 ...
0
votes
1
answer
21
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.
0
votes
1
answer
349
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 ...
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 ...
1
vote
1
answer
75
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 ...
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 ...
6
votes
2
answers
161
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”? ...
0
votes
1
answer
65
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 ...
2
votes
0
answers
59
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 ...
0
votes
1
answer
30
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 ...
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 ...
2
votes
0
answers
295
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 ...
0
votes
1
answer
179
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 - ...
1
vote
1
answer
964
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
2
votes
3
answers
216
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 ...
1
vote
0
answers
47
views
What is the fastest way to photodissociate/bleach melanin - with lasers or LEDs - without heat?
Melanin is the chemical that makes our skin dark. Melanin absorbs in very well in the UV, but when one does so, the solution/molecule gets very hot.
Is there a way to photodissociate melanin without ...
0
votes
1
answer
44
views
Does the optical transmittance of pulsed laser through a transparent material differ quantitatively from a continuous wave laser?
The absorption & transmittance of light through a transparent medium is described by the Beer-Lambert law. But the equation does not factor in the time parameter so I assume it describes ...
0
votes
0
answers
139
views
Saha-Boltzmann Equation
I am following Ahmed, Ahmed, Rafiqe & Baig A comparative study of Cu–Ni Alloy using LIBS, LA-TOF, EDX, and XRF paper on Laser Induced Breakdown spectroscopy.
It mentions two versions of Saha-...
0
votes
1
answer
162
views
Angular momentum and Zeeman effect
Supposing an Alkali atom positioned in magnetic field in $z$-axis. I understand linearly polarized laser propagating in $z$-axis can induce $\sigma$ transmission. But I could not figure out how laser ...
1
vote
0
answers
201
views
Quantum Coherence in a Two-level System in the Density Matrix Formalism
Dealing with semiclassical light-matter interaction, in particular the interaction between an electromagnetic field and a two level system using the density matrix formalism, I learned that the system ...
0
votes
0
answers
123
views
Direct energy weapon vs kinetic energy
Good day,
I would love to ask this question. Lets say that I have a energy source capable of delivering 10^30 watts with capacitors to match it and I would like to use this energy as a weapon (sort ...
0
votes
1
answer
66
views
What angle does light leave a 400micron fibre if it entered from a single mode fibre (0.14NA)?
We would like to connect a single mode coupled laser to a 400micron fibre. Ideally, we'd like the light to come out of the 400micron fibre at all angles or close to the maximum divergence angle, ...
1
vote
1
answer
43
views
What laser frequency is needed for the Doppler cooling of iron?
What laser frequency is needed for Doppler cooling iron? How do you determine this frequency?
3
votes
2
answers
384
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 ...
1
vote
0
answers
79
views
Optical tweezers : dipole force or radiative pressure?
Two types of forces are usually considered to describe light-matter interaction. On the one hand, the radiative pressure, which corresponds to absorption - spontaneous emission cycles, is proportional ...