Questions tagged [laser]

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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Energy of electron during Tunnel ionisation

I have been studying an emission mechanism that exploits the ionization, disassociation and subsequent fluorescent recombination of nitrogen molecule by a femtosecond laser for velocimetry. The ...
Nikkhil Chander's user avatar
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How to adjust the phase shift in a fiber optic inteferometer?

In a free space Mach-Zehnder interferometer adjusting the phase of the interfering beams can be accomplished by changing the length of the path that light travels in any given arm. How a phase ...
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What are the disadvantages of using a single mode Fabry-Perot laser diodes in interferometry, as opposed to distributed feedback laser diodes?

What are the disadvantages of using a single mode Fabry-Perot laser diodes in interferometry, as opposed to distributed feedback laser diodes? I'm specifically interested in potential problems that FB ...
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If lidar is used underwater, would passing through a turbulent surface into a pocket of air (e.g. a "moon pool") distort the resultant image at all?

I have zero experience with lidar systems, but I have been under clear water and looked up at the interior/ceiling of an indoor pool, and even the slightest turbulence at the surface distorts what I ...
rccapps's user avatar
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Deriving the dephasing operator in the master equation for atom laser interactions

Consider a two level atom where the two levels of the atom are seperated by energy $\hbar\omega_{0}$ and are coupled via the dipole interaction induced by interaction with a laser of fluctuating ...
Adrien Amour's user avatar
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How does a laser from Earth manage to hit the Moon with precision?

A question I've been asked is how a laser, fired from earth, would hit the moon without "leading it" (or hit it with precision). When firing a laser at the moon, it takes about 3 seconds to ...
Marco Chacon's user avatar
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Do high powered lasers refract differently than other light?

So I have a question: I am told that there are naval lasers that target over 100's of miles ship-to-ship (not ship to air). Someone asserted that powerful lasers would refract differently than light. ...
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Incidence angle in pulsed laser deposition (PLD)

Why is an incidence angle of 45° the best choice in pulsed laser deposition (PLD)? Why not 20 or 30 degrees, if reflection is effect or not?
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Dark states, velocity selective coherent population trapping

I am looking at papers that discusses existence of dark states, e.g. the classic "Laser cooling below the Doppler limit by polarization gradients: simple theoretical models". Is it true that ...
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Converting time-bin diagram to second order correlation function

Considering characterization of single photon sources a second order correlation function $g(𝜏)$ is used to determine the purity of a single photon source, specifically its value at $g(0)$. Now ...
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Is it possible to make a dual-mode, multi-band laser?

Understanding how N2 and CO2 gas lasers work, Is it possible to make a gas laser (i.e. with the right gas mix and excitation source) that: has more than one mode of operation, emits light in more ...
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Measuring Temperature of Water-filled Methacrylate Capsule: Laser Thermometer Accuracy and Penetration Depth Inquiry

Imagine that I have a methacrylate capsule filled with water (8cm in diameter and 30cm in length). If I wanted to measure the temperature with a laser thermometer pointing at the capsule, what ...
Eladio's user avatar
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Why some laser diodes have angled window?

Why some laser diodes have angled window? Here is an example
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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 ...
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Determining Gaussian beam parameters of a laser

The intended output of many lasers in laser scanning is Gaussian. At distance $z$ from the waist, the radius of a Gaussian beam is calculated as $$w(z) = w_0 \sqrt{1+(z/z_R)^2},$$ where $w_0$ is the ...
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How powerful of a continuous wave laser do you need to create a laser induced plasma channel

I have been researching electro lasers. However I keep on finding resources of pulsed electro lasers however I have not found any resources on continuous wave electro lasers. So could continuous wave ...
I like lightning 's user avatar
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Measuring longitudinal modes of a laser with a scanning Fabry-Perot spectrometer

Given a laser operating at a wavelength $\lambda = 1.084 \mu m$ on two longitudinal modes $300 MHz$ apart, I have to find the minimum free spectral range $FSR_m$ necessary to correctly measure the two ...
Tom Avery's user avatar
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Are there any nonlinear crystals or other transparent materials that can produce anti-Stokes, phase matched, frequency shift of laser light?

While some nonlinear crystals can convert incoming laser light into harmonics, thus for example doubling the light frequency, are there any crystals or other transparent materials that can reduce the ...
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Why is the rate of induced absorption not equal to the rate of stimulated emission?

Even though the probability of induced absorption is equal to the probability of stimulated emission, the rate of induced absorption is not equal to the rate of stimulated emission. Why?
Ismail Warsi's user avatar
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How to estimate power attenuation of a laser using distance and divergence?

Whats the attenuation relation for a laser power or intensity for a given beam angle and distance? For instance, if the beam angle is 2 degree and the distance is 10cm whats the power attenuation?
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What does $τ$ mean in second-order correlation function?

I have this question to which I cannot find a simple explanation to. In most articles about single photon sources people use second order correlation function $g$$^{(2)}$$(τ)$, to show that their ...
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Is a neutron deflected sideways by a laser beam?

Is a freely moving neutron deflected sideways when a laser beam is directed at it from the side? It would be great if the question could be considered from the two points of view that the laser beam ...
HolgerFiedler's user avatar
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What is the temporal and spacial coherence of photons?

I understand what spacial and temporal coherence mean when we speak waves, but when we start speaking photons I can't wrap my head around the concept. So what does it mean for photons to have temporal ...
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What's the scattering force in a Magneto-Optical Trap (MOT) due to multiple lights fields?

I'm trying to simulate the loading of a Magneto-Optical Trap (MOT), and I'm not sure what's the scattering force of the atom. The issues arise due to there being multiple MOT laser fields being ...
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OPTICS - How to achieve "infinity projection"?

I'm trying to learn a little bit more about how huds in military planes are able to get their info projected onto "infinity" (whatever distance is enough, like 10 meters or so??) so that ...
Satamanster's user avatar
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Is HHG recombination a tunneling event?

When the electron returns to the ion at the end of its path I understand that it has more kinetic energy than the binding energy of the atom. Does this mean the capture relies on reflection by a ...
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How solid state laser is tuned?

My understanding about solid state laser is sample as a source of exciting (lamp ,laser beam, ..) pump the crystal wich emite a certaine range of infrared wavelength sometime in visible range, this ...
Tintin's user avatar
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3 votes
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Can two laser diodes of the same type and wavelength, be synchronized to emit light in the same phase, while working in a CW mode.?

Can two laser diodes of the same type, power and wavelength, be synchronized to emit light with lightwaves in the same phase, while working in a continuous wave mode (CW) ?
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Is reflection from pockel cell normal?

We are trying to align a laser for a 2-photon microscope and we noticed a reflection from the pockel cell. The reflection can be caught on the edge of the waveplate or the iris that are before the ...
Noushin Ahmadpour's user avatar
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2 answers
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Do there exist materials whose Opacity varies with temperature?

Do there exist materials whose Opacity varies with temperature? E.g a Material that becomes more Opaque as it gets hotter?
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Does population inversion in the Dicke model result in the production of a coherent state of the cavity field?

The Dicke model describes the quantum dynamics of $N$ identical two level atoms (with energy seperation $\hbar\omega_{0}$ between the ground and excited energy levels $\{|g\rangle,|e\rangle\}$) each ...
Adrien Amour's user avatar
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4 answers
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Is it possible to combine two (or more) laser beams into one beam with double intensity? What are the caveats of this method?

Here is a schematic for what I mean:
John Smith's user avatar
2 votes
1 answer
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How can an attosecond pulse be shorter than a single photon (quantum) emission?

I have read this question (no answer, just comments): Light, including pulses of light, consists of many photons. A very short pulse has a wide range of frequencies. See The more general uncertainty ...
Árpád Szendrei's user avatar
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1 answer
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Stimulated emission of radiation

Laser light is monochromatic, coherent and (in many cases) collimated. Are these properties due to stimulated emission of radiation? Also, is it true that a photon emitted as a result of the ...
Grzegorz Kruk's user avatar
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The Stark-Lo Surdo effect

What does the Stark-Lo Surdo effect consist of in the interaction of the electromagnetic field and the active medium in a laser? I thank those who want to give a clear and concise answer. In my ...
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Why are no industrial diode lasers deep cooled?

Endurance lasers showed that a 633nm laser diode could lase as low as 621nm when cooled to almost -80C. The wavelength shift for diode lasers can surpass 0.3nm/‘C. From my limited experience ...
selene flemming's user avatar
2 votes
1 answer
651 views

Why can't we use polychromatic light for making laser?

As far as I have read in my textbooks, we can only use monochromatic light for making a laser. Why can't we use polychromatic one? What if we try to make a laser out of a polychromatic light?
Syeda Hasnain's user avatar
1 vote
4 answers
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Material surrounding slit in laser experiment

Suppose light from a laser passes through a single vertical slit. The width of the slit is certainly a factor how the light scatters after it goes through the slit; the thinner the slit, the wider the ...
Craig Feinstein's user avatar
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Can a beam be expanded by Hermite-Gaussian modes having a different waist position?

Hermite-Gaussian modes of propagating beam are expressed as \begin{equation} E_{l,m}(x,y,z) = E_0\frac{\omega_0}{\omega(z)}H_l\left(\sqrt{2}\frac{x}{\omega(z)}\right)H_m\left(\sqrt{2}\frac{y}{\omega(z)...
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Locking of 480 nm laser using EIT

I am trying to lock 480 nm laser using EIT by frequency modulation technique. For this I have modulated the probe beam using 10 MHz phase modulated EOM, and trying to observe sidebands both right and ...
Monika Thakran's user avatar
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What are the causes for $g2$ ( intensity) value changes in a Mach-Zehnder setup at a fixed reference path and fixed sample?

I'm using a Multimode laser passing it through a Mach-Zehnder interferometer. I am able to get almost constant $g2$ (intensity) from the sample. However, the reference arm intensity keeps fluctuating ...
PSM's user avatar
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Can lasers really show microbes in water?

I used a 532 nm green laser and passed its beam through a water droplet. Can you explain me are these really microbes and if they are then how a laser is able to do so?
Akshat Parmar's user avatar
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1 answer
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What is the tiny dot of light in front of both lens in the image? I noticed it while trying to pass a 800 nm pulsed laser through the lens setup

The tiny white dots were formed in front of both the lens when I was trying to pass a 7W, 90 fs, 800 nm pulsed laser through the lens setup shown in the image. I noticed that the dots disappear when I ...
Nikkhil Chander's user avatar
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Attoseconds - generation of pulses of light for study of electron dynamics in matter

Related to the recent Nobel awarded for the generation of attosecond pulses of light I had a few doubts- In high harmonic generation, why does the intensity of the emitted light drop, then stay ...
user25385's user avatar
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How exactly does Ligo achieve complete destructive interference with just an interferometer?

Ligo works by destructively interfering light from a laser using an interferometer. Its said that no light enters the photo detector when all mirrors are the same distance. However,based on my ...
spicy-lemonade's user avatar
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Will light, from two different (but identical) lasers injected into one end of a long fiber, come out form the other end with the same polarization?

Two beams of light from two lasers of the same type, with the same wavelength but different polarization, are coupled with 2X1 coupler into a 100m long single mode regular fiber. Each laser can be ...
Jimski's user avatar
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Do attosecond lasers allow us to further constrain the location of electrons within the established probability clouds, via time?

It has only been within the last few years that I learned the atomic model I grew up with (the Bohr model) was wrong, and that I should instead be thinking about electron orbitals as a cloud of ...
Curious Layman's user avatar
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What is the transverse mode separation in a laser cavity?

I'm currently researching the intermodal distance of transverse and axial modes in optical cavities. But the equation defining the longitudinal separation contains the +- sign, does this imply that ...
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Laser beam quality problem: The laser beam showed very different during using the CCD testing directly or using the M2 measurment machine

Recently, we encountered a problem with the laser beam profile characterization, where two testing methods showed two distinct results of the beam profile of the same laser system. When we used a CCD ...
李文嘉's user avatar
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Can the principle of helium ion microscopes be generalized to heavier noble gasses for suitable substances?

I have heard helium ion microscopes offer extremely high resolution of features due to the shorter debroglie wavelength of the helium atoms. Naturally I was curious if anyone has built something using ...
Sidharth Ghoshal's user avatar

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