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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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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41 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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45 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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67 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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How do “holographic plates” work?

I asked a question about laser stage lighting over at Audio Video Production, and received an excellent answer that explained that laser clusters are generated from a single beam via something called ...
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85 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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44 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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8k views

Why is a 1mW laser dangerous?

In our Physics lab we have a 1 milliwatt (0.001W) helium neon laser. Despite the low power, we were cautioned not to even look at reflections of the beam as it could cause permanent eye damage - why ...
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155 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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67 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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14 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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32 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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55 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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17 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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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
84 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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14 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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36 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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2answers
61 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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3answers
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Three polarizers, 45° apart

If light is passed through two polarizing filters before arriving at a target, and both of the filters are oriented at 90° to each other, then no light will be received at the target. If a third ...
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56 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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75 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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62 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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147 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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1answer
60 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 ...
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57 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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74 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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102 views

Is “microbunching” in a free electron laser limited by the Pauli exclusion principle?

As I understand it, a free electron laser can basically be pictured as a synchrotron light source with an undulator which by the particular setup causes the electrons to self-attune so that they ...
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75 views

Does chirp (GDD, TOD ) affect the temporal coherence of a laser?

Lets say we have a laser beam with finite temporal coherence. A broadband spectrum with a transform limited pulse of 100fs. If we measure its temporal coherence when the pulse is transform limited ...
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31 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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37 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 ...
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3answers
155 views

In what applications are lasers necessary vs. just convenient?

I’m trying to understand, given the wide array of current laser applications: Which applications actually require laser characteristics, as opposed to just use lasers because they are the most ...
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273 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 ...
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1answer
97 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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49 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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77 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?
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Why does a laser beam diverge?

I was wondering why a laser beam diverges. If all the photons are in the same direction, I would imagine that it would stay that way over a long distance. I am aware that a perfectly collimated beam ...
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4answers
372 views

Focusing and collimating laser light on a table top scale

I am looking for a summary of practical methods of focusing and collimating laser light, which I guess are contradictory objectives, or are they? For example, when I use typical small diode lasers, ...
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40 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 ...
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3answers
701 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 ...
5
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1answer
147 views

Options to correct rectangular laser beam profile?

We recently switched to a 405 nm laser diode which has a terrible beam profile -- it is a well-defined rectangle with an aspect ratio of about 10:1. The image below shows the collimated beam which ...
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2answers
119 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
56 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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42 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?
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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?
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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 ...
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1answer
147 views

What causes light to travel through a curved fountain of water?

Today I observed a tilted fountain spurting water upward (the water fell smoothly; no detectable turbulence). A colored light was shown upward into the water as it left its source. This light traveled ...
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1answer
54 views

Non resonant modes in cavity

I have a simple question. Suppose we have a laser with a cavity such that the frequency of the light that the laser emits does not match with any longitudinal modes allowed by the cavity. In ...
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1answer
565 views

Michelson interferometry - is a compensator plate necessary?

I am studying the Michelson interferometer shown in figure 2 (similar design shown below) of the AMRITA vlabs tutorial. There it is stated that Since the reflecting surface of the beam splitter ...