Optics is the study of light, and its interaction with matter. It includes topics such as imaging systems, fiber optics, lasers, quantum optics, and more.

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In what direction will this magnet move?

What will be the direction movement of small ringshaped magnet when place inside the big ringshaped magnet with the same poles?
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Why are certain opaque objects so biased?

Why is it that most of the opaque objects only block em waves in the visible spectrum but fail to block waves with frequency higher and(or) lower than the visible spectrum?
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30 views

How does a laser emit light in a coherent state?

Lasers work by stimulated emission of atomic transitions. Stimulated emission produces two photons which, because the particle number is well-defined, projects the field into a Fock state. However, it ...
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Why does a circle of light appear when I shine a laser pointer at a wire? [duplicate]

When I point a laser at a wire , a circle of light appears on a wall behind it . why this happens. What is the circle of light and why does it appear? Could anyone give some tips on what I should ...
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53 views

Light reflecting inside a sphere [on hold]

I'm having a bit of trouble cracking this problem. The diagram is given below. My job is to find $\phi$ as a function of $\theta$ and the index of refraction $n$. For this part of the question, I ...
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Why zone-plate photography is not monochromatic?

Zone-plate photography produces somewhat "blurry" photos. However, according to Fresnel's equation, I'd expect the resulting photos to be somewhat monochromatic, due to the dependence between $r,f$ ...
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Why grating is an essential part of a monochromator?

From looking at these two images, it appears that the dispersed "rays" of the reflected light could be manipulated just as well if the reflecting mirror would be turned to a fixed angle. So why is ...
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Optics Network NEED good Reference or TEXT

I am using Optical Networks: A Practical Perspective, 3rd Edition (Amazon link) as a reference for studying optics network. The main focus of the course is rather on the layer, data, and protocol side ...
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Optics problem: Determining the new focal length when changing from film to CCD detector [on hold]

An older camera has a lens with a focal length of 50mm and uses 34-mm-wide film to record its images. Using this camera, a photographer takes a picture of the Golden Gate Bridge that completely ...
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Making sense of sinogram of perspex block in air

I'm confused trying to visualize what happened exactly during this experiment: Setup with a laser and a photo diode on the opposite side. A perspex block (2x2cm) in between. Take 200 measurements ...
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59 views

Is possible carry light using a rectangular mirroned tube? [on hold]

I'm newbie and I want know if Is possible to carry light using a rectangular mirroned tube and create a illumination system with this principle.? I think is possible using schemas with mirrored ...
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29 views

Optics (rainbows) [on hold]

A passenger in an aeroplane shall (a) never see a rainbow. (b) may see a primary and a secondary rainbow as concentric circles. (c) may see a primary and a secondary rainbow as concentric arcs. ...
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30 views

Reflection and refraction of light [duplicate]

When a light ray strikes an interface a part of it gets reflected, a part of it gets absorbed while another part gets refracted. Why does light reflect? Why does it refract?
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37 views

Lasers : Threshold Pump Power for Laser Oscillation [on hold]

I was working my way through some basic laser problems , when I cam across this one : Consider the ruby laser for which we have the following values of the various parameters: $N =$ $1.6$ x ...
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25 views

Highest NA available [on hold]

I am curious, what is the highest NA for an objective available now? Most of the manufactures offer something like ~1.4 (for immersion objectives), but I think about half a year ago I heard someone ...
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1answer
19 views

Ray diagram for refraction

I'm having trouble finding out any errors in a ray diagram. The question is as follows: A ray of light falls normally on the curved face of a semi-circular plastic block, it hits the horizontal ...
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1answer
35 views

What is a lineshape function $g(\omega_0)$ in a Laser?

I am a newbie to the world of lasers and was working my way through some basic problems, when I encountered this one: Optical Electronics, A.K. Ghatak and K. Thyagarajan (Cambridge University ...
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36 views

geometrical optics

I doing an experiment now. My structure has 700nm periodicity. The surface of the unit structure is sloped at 45 degrees from the normal incidence angle. My laser is 500 nm. I can expect there ...
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3answers
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Two mirrors paradox revisited

If I connect a video camera to a screen, so that whatever is seen by my camera appears on the screen, what do I see when I point it towards the screen itself? Is it, in terms of optics, this ...
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38 views

What is the total reflectivity/transmissivity of a pack of a semi-transparent glass sheets [closed]

Consider a pack of $N$ layered semi-transparent parallel glass sheets (like a 'cake'), each having the reflectivity coefficient and thickness $(r_k, d_k)$ for $k=1 \dots N$. Consider a light beam of ...
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25 views

Intensity of waves in single-slit diffraction

So I am trying to determine the relation between intensities of waves in single slit diffraction. Since I am pretty new to this topic, I couldn't find a way how to calculate the ratio between the ...
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1answer
70 views

Is lasering some natural phenomenon soemwhere?

Laser is actually the simplest kind of light, from a physical point of view. Many people think it is some rocket science simply because it is not natural but takes some human efforts to create. So, ...
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44 views

Is there a correct yet more compact way to write these equations?

I've got the following equation which denotes the total absorbance $A$ as determined by the sum of the absorbances of individual molecules: \begin{equation} A(\nu,c_{1},...,c_{n}) = \sum_{mol=1}^{n} ...
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If any, what would be the ideal modulation frequency for a phase-sensitive light sensing experiment in a non-dark environment?

I have constructed some equipment for sensing a beam of light. The equipment is enclosed in a rudimentary darkbox to block out the majority of the ambient room lighting, but is still partially ...
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Why the light bent towards the normal when they pass from rarer medium to denser medium?

Whenever the light rays are entering the rarer to denser medium they bend toward the normal. Then why the rays choose the path toward the normal? Why it cannot choose the path away form the normal?
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Does the color of refractive medium affects the color of refracted light?

Imagine if I have a red colored prism that splits white light ray into its seven components, would the red component be affected by the red color of the glass material of the prism in any which way? I ...
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How can diffraction happen in the Hubble Telescope?

I've seen people talking about the angular resolution of the HST is, if using Rayleigh's criterion, equal to: $$\theta = 1.220 \frac{\lambda}{D}$$ My question is, since the diameter of the HST $D$ ...
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Surface Plasmon-Polaritons in magnetic media

It's easy to calculate the dispersion relation for SPPs present in a vacuum-nonmagnetic metal interface. (See here) What about ferromagnetic metals? How can one calculate the dispersion relation of ...
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How to project anything in medium(air) like projection in wall, as in a free medium [duplicate]

I just go through books and the internet. But I didn't get my answer that, can I project light in the middle of the air, or wherever we want, not only on wall. I found neon lasers but it also didn't ...
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scintillation of U/HE cosmic rays in snowflakes

Suppose there is a U/HE, a snowflake, and a human observer. What range of energies would produce visible effects? What would the reaction cross section look like? I don't know enough about the ...
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How is it possible for the wavelength of light to change in a medium?

So my physics class has just finished a long unit on optics while at the same time I've been trying to teach myself relativity. I admit my understanding is probably rudimentary, but I figured all the ...
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28 views

What is the difference between the Franz-Keldysh effect and free carrier absorption?

What is the difference between the Franz-Keldysh effect and free carrier absorption? My first guess to this is that the Franz-Keldysh effect involves a bandgap potential of non-zero volts D.C. while ...
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Is there a wavelength of electromagnetic radiation that can penetrate iron but reflect off iron oxides?

We can see corrosion or rust because visible light travels through air reflects off the material back through the air and into our eyes. But I am wondering if you could see the corrosion through on ...
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Why is Terahertz radiation so hard to generate?

This paper (and many others I've read) claim that searching for ways of producing THz radiation is a high-interest research topic. However, something I've just never understood is why it's so hard ...
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Why does a glass acts like a mirror in viewed at an angle? [duplicate]

There is a conference hall , glass door parallel to my desk. whenever the door is open, I can see reflection of images perpendicular to the viewing angle. But when the door is closed, I can’t see any ...
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73 views

Could the sky on a planet theoretically be any color?

The sky on the Earth is blue. Could the color of the sky on a planet with an atmosphere be of any color theoretically? Which colors are the most likely? I think it would be really awesome to have ...
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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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Insect Eyes Vs Human Eyes?

Humans have frontal eyes. Less field of view. But better resolving power. Insects have lateral eyes. This means they have a large field of view. In some female insects the lateral eyes have much more ...
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doppler cooling temperature limit

Wikipedia shows a heating effect that causes minimum temperature achievable in doppler cooling as: "The atom performs a random walk in momentum space with steps equal to the photon momentum due to ...
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How much cheaper and smaller on average is SiPM technology over conventional PMTs?

I've heard it said that some of the major advantages of silicon photomultipliers are its low cost and compactness when compared to widely used photomultiplier tubes, but haven't found much information ...
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Lens with a mirrored coating [closed]

A biconvex lens of refractive index $n$ and radius of curvature $r$ and focal length $f$ floats horizontally on liquid mercury such that its lower surface is effectively a spherical mirror. A point ...
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Laser beam sensed by scattering

Can a laser beam, whether it is a IR laser or of the visible to human eye spectrum, be seen/sensed by an electronic eye like a photosensor/photodetector, not human eye, if the beam is just in air? For ...
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Sun in front of horizon after sunset; mirage or reflection?

The day before yesterday, I observed sunset while flying over the eastern Mediterranean. After the sun set, it seemed to 'continue' in front of the horizon. I managed to snatch a picture (sorry for ...
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How far away are we from a UV LED operating at around 100nm?

So far, we are down to around 250nm for UV LEDs. If I could get one at around 100nm that would ionize air I would find it very useful. Any ideas on whether this wavelength is feasible for a LED?
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Why is this way of calculating the diffraction pattern valid?

I've seen that in some books (Fowles) the intensity of the diffraction pattern is calculated in the following way. We place the source $S$ and the point at the screen $P$ in the line perpendicular ...
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Optics..caustic curve equation

I went through this article: http://users.df.uba.ar/sgil/physics_paper_doc/papers_phys/ondas_optics/caustica1.pdf But I think that when we do F=0, we are assuming the centre of the curve to be the ...
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Fresnel equations of S and T waves and Isofrequecy Curves: Feeling confused

First of all sorry for my (probably) bad english. I've been studying propagation of light in anisotropic media from the Born and Wolf and from Landau "electrodynamics in continuous media" and I'm ...
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Implementation of Expectation Maximisation tomographic reconstruction

I'm trying to implement iterative expectation maximisation reconstruction for emission optical computed tomography, very similar to SPECT reconstruction. The algorithm given in the literature is ...
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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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In Young's double slit experiment how can we determine the shape of fringes formed?

Does the shape of fringe change if the type of source is changed (point source or extended source) or if the relative position of slits is changed (both lie on a line either horizontal or vertical to ...