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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22 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 ...
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9 views

Optical Depth or total attenuation in an optical medium

In an optical pumping experiment, I want to calculate the output power, which is governed by the relation Power Output = Power Input * exp (-optical depth) Case 1: Without taking beam diivergence of ...
44
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2answers
3k views

How to measure the wavelength of a laser pointer?

I'm working on something and I need to know the wavelength of the laser pointer that I'm using. Can you suggest me a way, using some optics formulae, or anything else to calculate the wavelength?
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0answers
18 views

Deconvoluting Raman spectras from different wavelengths

I am using a laser source that is wider than typical laser source for Raman spectroscopy. This mean that the full width at half maximum (FWHM) of the laser is about 5-10 nm, compared to the normal 1-3 ...
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0answers
23 views

How does an electron deexcites during stimulated emission? [duplicate]

During stimulated emission in laser,the electron de-excites by supplying energy,generally it must excite,right? My doubt is then why does it de-excites?
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22 views

Laser beam receiver

Problem: I have an object that can move in the $x,\,y,\,z$ direction. The goal is to measure the $x,y$ variation as the object travels along the $z$ axis. Typically the distance traveled is less than ...
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1answer
31 views

Using a transfer matrix to calculate beam width of off-axis Gaussian beam?

I have been reading a lot about ABCD matrices that are used for ray tracing. I can calculate the output offset $r_{o}$ (with respect to the optical axis) and the angle $\theta$ of the ray by $$ ...
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0answers
40 views

What causes this pattern in the reflection of a laser on a screen? [duplicate]

When I shine a red laser behind me at a wall I see a strange reflection occurring on my laptop screen Why does this happen? The pattern on my screen occurs exactly where the laser is hitting the wall. ...
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1answer
30 views

Gaussian beam shape

In this diagram of a Gaussian beam, why does the radius vary with z position? Is it assumed that a Gaussian beam is always being focus by a lense? Why can the beam not go any smaller than $w_0$ and ...
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1answer
47 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 ...
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1answer
37 views

Can infrared lasers still do damage to things if they are powerful enough?

So I get that infrared light is not visible to the human eye without some sort of device to assist in helping you see it, but I was just wondering how that plays into things like lasers. I know you ...
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0answers
27 views

Laser output below, just above and way above threshold?

I've been reading up on lasers recently and learnt that within the cavity while the laser light is amplified by the gain coefficient, it loses power due to transmission and absorption. Suppose the ...
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1answer
19 views

how to calculate the minimum spectral linewidth in cm-1 of pulsed laser with pulse duration of 10 fs?

I calculated the minimum spectral linewidth given here using the uncertainty principle that delta E.delta t =h/2*pi will this be correct?
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1answer
49 views

does photon travels in a helical path in an optical vortex?

The wave front of the optical vortex beam is helical. Does it mean that the photon travels in a helical path? When the optical vortex beam is focused on a screen, an annular ring with dark center is ...
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2answers
80 views

Why can't LIDAR be implemented with traditional antennae?

In robotics, LIDAR and RADAR are both used for obstacle detection. The data they produce are very similar, but they do have different qualities (LIDAR is more precise but less robust). There are many ...
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2answers
63 views

Why lasers and not light? [closed]

Some laser applications consist simply concentrating light into a small spot (e.g., image projection, welding, cutting, etc.). Why are lasers used instead of a simpler light source?
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0answers
11 views

Regenerative Amplifier

I want to ask the questions dedicated Optics (or Laser Physics). What is the difference between laser amplifier and laser regenerative amplifier? What is the average pulse duration of Nd:YAG laser ...
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0answers
30 views

Focusing light from a laser shot into one point [migrated]

Im planning to build a laser shooting target. Something like this: In the long term I want to build something advanced like a professional grade target, in which the able is able to tell exactly ...
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1answer
39 views

What is the typical strength of the electric field in a particle accelerator?

I am working on a research project involving the closed orbits of hydrogen in the presence of an external electric field and I am curious what a reasonable approximation for the electric field ...
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0answers
29 views

Limits on the information obtained through optical measurements

Consider a Gedankenexperiment shown in the figure below. There are two lasers $S1$ and $S2$ with exactly the same specifications on paper. In practice, they are of course somewhat different but ...
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0answers
16 views

Doppler and recoil limit on temperature

I havent't understood the causes of Doppler limit and recoil limit. I have found on the net different observations about them ("Doppler limit is due to the fact that the atom can't have a smaller ...
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0answers
21 views

Why does a circle of light form around a wire when a laser is pointed at it? [duplicate]

Referencing this video: https://www.youtube.com/watch?v=9Q_4SNbpBfo Why does a circle of light form? I've seen previous Phys.SE posts on this topic relating the answer to reflection, but I have ...
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2answers
58 views

Decoherence of a Coherent Beam

If retarding films (i.e. wave plates) can retard the electric components of light (based on the films thickness) without affecting it's direction, couldn't I use a retarding film of randomly varying ...
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0answers
13 views

Laser Welding of Copper/its alloys [closed]

I wanted to know about the different techniques that can be used for joining Cu/bronze/other Cu containing alloys to Stainless Steel by Laser Welding( specifically Nd:YAG laser ). I read abt some ...
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0answers
25 views

coherent length measurement of a monochromatic laser source

i need to learn about how to measure coherent length of a monochromatic laser source.I know that I can use michelson interferometer or spectrometry.For laser which has long coherent length michelson ...
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1answer
34 views

Plasma wakefield acceleration for Protons

Laser plasma acceleration is a promising technology that could replace the current method of accelerating particles (which is via electric fields). It is somewhat cheaper also as it makes the ...
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3answers
112 views

Is the output of a laser pointer polarized or not?

How to verify it? Is a laser necessarily polarized? I have a laser pointer with wavelength 532nm in hand.
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2answers
53 views

How to measure temperature of a laser cooled sample at picoKelvin temperatures?

I'm reading about laser cooling.. my question is: how can the temperature of the sample be measured? (using laser cooling we can reach $10^{-12}K...)$
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0answers
38 views

Relation between minimum spectral linewidth and pulse duration

Is there a difference between minimum bandwidth and minimum spectral line-width of laser? What is the relation between them and the duration of a pulse?
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10 views

What is meant by the (aperture size) of optical deflectors in laser scanners?

How do you measure the aperture size in a laser scanner.
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2answers
38 views

Calculate required power output for a laser

How to calculate power rating required for a laser in order to produce a dot at a specific distance after reflection? For example, the laser is 10cm from the mirror, at an angel of 30 degrees it ...
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1answer
58 views

Why is it necessary to supply constant electricity to make a laser work?

As we know that in lasers there are excited atoms. When energy is provided in the form of light, heat or electricity to these atoms, these excited atoms after sometime go to a lower state of energy ...
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1answer
53 views

Would it be efficient to run a solar panel with laser?

Would it be efficient to run a solar panel with laser? I know this question is unsual as we are using electricity powered laser to run a solar panel. Actually i am paricipating in the Google Science ...
3
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1answer
85 views

How I can launch light into PM fiber

A polarization maintaining fiber preserves the linear polarization of the light at the output, the light at the input must be linear polarized to see signal at the photodetector... However I can't see ...
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2answers
69 views

Can a laser work forever if constant electricity is provided?

Can a laser work forever if constant electricity is provided? If we take a laser and provide it with constant electricity will the reactions in the semiconductor generate photons forever?
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0answers
39 views

Would an inverted design of a laser phosphor display (LPD) work?

Background info... It is my understanding that a laser phosphor display works by emitting RGB laser beams through a mechanism that cycles them in a pattern similar to a cathode ray tube. When I read ...
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69 views

How do I model this Quantum Cascade Laser (QCL) using COMSOL? [closed]

I'm trying to model this: GaAs on-top of a heat-sink made of Copper. It's trying to simulate a type of Quantum Cascade Laser, I'm looking at the effect the temperature has by running a 10V voltage ...
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0answers
29 views

How much energy does a PV cell need to work?

How much energy does a $1m^2$ photovolatic/solar cell need to work? Can it work using a bunch of Laser lights? Edit: Ok so this PV cell is $1m^2$ is dimesions. The N-type has silicon doped with ...
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0answers
30 views

What is the “Obscuration Factor (OBF)”?

In a paper I am reading for my master thesis I came across this "obscuration factor (OBF)". The authors indicate that it is a measurement of the average intensity of reflection. They do not give a ...
12
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1answer
245 views

Does my green laser pointer emit three distinct frequencies, or is my measurement flawed?

I was playing around with a cheap diffraction grating and my set of laser pointers, and I noticed that while the red and the blue pointers produce a single point in the spectrum, my green laser ...
3
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1answer
68 views

Laser diode spectrum vs LED spectrum, why so much difference in broadness?

I've been reading about how light is produced in both laser diodes (the most common types of lasers) and LED's. The mechanism seems very similar if not exactly the same: one applies a potential ...
3
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1answer
43 views

Is it possible to directly pump a laser using sunlight?

Typically in the old days one would use a flash tube to pump a ruby crystal. Is there any way, or any lasing material, that could use concentrated sunlight directly for either continuous or pulsed ...
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0answers
34 views

Could laser speckle patterns be used in diagnosing vision defects?

At the London Science Museum some years back, I saw a device which projected a laser speckle pattern and had a sign explaining that it would appear stationary for people whose eyes were correctly ...
6
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3answers
650 views

What causes the specific pattern of sparkly light from a laser pointer

I have a fairly cheap green laser pointer that produces a fairly big spot of light (actually two spots most of the time!). I'd guess the size of the spot is about 1/100th of the distance from the end ...
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2answers
66 views

Laser tattoo removal

I would like to know if someone could please briefly explain how laser technology of tattoo removal works? And second, could there possibly be any dangers to cells, specially on bones?
3
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2answers
82 views

What laser and BBO are needed to create entangled laser streams?

I have been reading about entangled particles, lasers, the two slit experiment, etc. I really know nothing from physics (i.e. equations, formulas, theory); so please respond accordingly. From my ...
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0answers
34 views

Any suggestion of laser pointer for everyday life study of fluorescence?

I want to buy a laser pointer to study fluorescence in my kitchen. Any suggestion? What kind of laser pointer? What stuff for demonstration?
2
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0answers
49 views

Is it possible to efficiently extract phonons from a lattice?

The population inversion generated in lasers occurs in multi-level atomic systems. As an example, the Nd:YAG energy diagram is shown below. The pump pushes the Nd ions up to the upper levels, and ...
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0answers
22 views

Losses in a laser diode

How do I convert loss/gain from units of /cm to /s? Intuitively, I would say multiply loss in /cm with the group velocity c/n, where n is the refractive index. Am I missing anything?
1
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1answer
37 views

Cooling atoms using emitted photons from a laser cooled atom

In Doppler cooling procedure, is it theoretically possible to use the emitted photons from the target atom (cloud) to cool more atoms? The idea is to cool the atoms rapidly by using energy emitted by ...