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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Examples in which the light maximizes the optical path length

I posted a similar question about geodesics on Math.SE. Many sources (Wikibooks for instance) claim that the light could maximize the optical path length in some cases. But I don't think it's actually ...
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Why is fluorescence often associated with Raman scattering?

In Raman scattering, the Stokes signal is at a longer wavelength compared to the excitation signal, leading to fluorescence. Why is it the case that this would lead to fluorescence? I don't ...
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34 views

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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4answers
2k views

Optics of the eye - do we see Fourier transforms?

I've recently been learning about Fourier optics, specifically, that a thin lens can produce the Fourier transform of an object on a screen located in the focal plane. With this in mind, does the ...
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1answer
49 views

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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0answers
158 views

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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1answer
87 views

Diffraction and $k$-space

Regarding diffraction I am a little bit lost reading about reciprocal space and the space of $k$'s. As I understand it the Fourier relationship between a wavepacket $\Psi(\vec r,t)$ and the complex ...
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1answer
34 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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15 views

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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2answers
189 views

Fiber optics with broadband, incoherent light

I wonder if someone could help clarify waveguiding with broadband, incoherent light please. If we take a telecomms fiber, which is single-moded above ~1.4 μm and couple a laser beam in, we assume ...
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2answers
60 views

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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1answer
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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1answer
12 views

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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1answer
3k views

What is the near point for the eye

So I am a teaching assistant for an introductory physics class. One of the problems on this weeks workshops is: Where is the near point (far point) of an eye for which a contact lens with power of ...
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1answer
2k views

Refractive Index formula for denser to rarer medium

I learnt that the formula for refractive index when light travels from rarer to denser medium is $$\frac{\sin i }{ \sin r}$$ where $i =$ angle of incidence, $r =$ angle of refraction. Is the same ...
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1answer
33 views

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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0answers
15 views

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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61 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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3answers
113 views

Missing factor of 1/2 in the definition of light intensity

The light field can be written as $E=A \cos\theta$ where $\theta=kz+wt$ is the phase of light wave. What we measure or see is the intensity which is the square of the light field $$I=E^2=A^2 ...
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0answers
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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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1answer
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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1answer
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 ...
4
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1answer
776 views

Sign convention for mirror and lens formulas

I have just started learning optics at school and my teacher derived the lens and mirror formulas. While doing so, she applied the sign convention for $u$, $v$ and $f$ and arrived at the final ...
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0answers
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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26 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
20 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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2answers
268 views

Magnification in compound microscope

I was studying about compound microscope here I don't see why we multiply linear magnification of objective with angular magnification of eyepiece. Shouldn't it be both angular or both linear? Can ...
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1answer
72 views

Luminance from multiple light sources

I have a LED diode: Given Luminance intensity [I] of $1.85$ cd. I want to have Luminance [B] from the light source of $75 \ {\rm cd/m^2}$. From $B=I/S$, where S is light source plane area, I get ...
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2answers
555 views

Perfect pinhole diffraction pattern with sharp fringes using a 632nm laser

I'm trying to produce a diffraction pattern with pinhole using a laser of 632nm wavelength .The pinholes' diameter are ranging from 10um , 25um , 50 um , 0.1mm and so on . I also have good lenses for ...
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2answers
83 views

Frequency difference of absorbed and emitted photons?

In a transparent medium, how does the frequency of incoming light compare to the exiting light? I thought it was the same, but doesn't there have to be an energy difference in two electron states in ...
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1answer
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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2answers
95 views

Describing a single photon with creation and annihilation operators

Since I am not fully aware of the creation and annihilation operator formalism for single photons, I want to ask, if the following is correct: I am considering a photon in the vacuum which travel ...
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2answers
149 views

Light-matter interaction and an object's appearance

I am taking a course in Computer Graphics, and the teacher said we could put materials in there main categories: mirror like glossy or specular diffuse He suggested that the law of reflection is ...
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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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2answers
175 views

Quantum theory of light

What's the scattering matrix for a PBS (polarization beam splitter)? Is it just unitary? If one polarization never couples into another polarization (then there's a lot of zeroes in that 4x4 matrix) - ...
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1answer
66 views

Apparent depth and virtual image position

Why does the virtual image appear right on top of the object and not a little to the right, for example? Is it explained by some formula or just symmetry of the geometry?
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0answers
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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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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
24 views

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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3answers
478 views

Beam splitters and Mach-Zender interferometers

I have a question (my very first here) related to 50/50 beam splitters as used in the Mach-Zehnder interferometers (see for example the Wikipedia page). Let's concentrate on the input beam splitter: ...
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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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0answers
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How would we see the earth if refraction of light was significantly stronger?

On worldbuilding.SE there is a question about the cosmological consequences of a world with super-high refraction and atmosphere opaqueness. I'm assuming the easiest way to minimally change the laws ...
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1answer
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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6answers
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Why are most metals gray/silver?

Why do most metals (iron, tin, aluminum, lead, zinc, tungsten, nickel, etc.) appear silver or gray in color? (What atomic characteristics determine the color?) What makes copper and gold have ...
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1answer
44 views

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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2answers
36 views

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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1answer
24 views

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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1answer
50 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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1answer
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How to propagate a planar e/m field in free space using plane waves?

I read this great answer to this question: Numerical software to manipulate a light beam in its plane wave representation? The main thing that I am trying to clear in my head is the following: ...