# Tagged Questions

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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### view angle independant focal point

Is there any way to design a lens or system of lenses where I see the same part of the image below the lens, irrespective of direction from where I am viewing. In the image uploaded, there is a black ...
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### How does one calculate how big something has to be, to be seen at a given distance? [closed]

Ignoring curvature of the Earth. How do I calculate the size an object would need to be in order to appear to be approx 1cm tall at a given distance?
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### Superluminescent LED [closed]

How do Superluminescent LED generate amplified spontaneous emission? Moreover," a superluminescent LED combines the spatial coherence of a laser diode and the temporal incoherence of an LED. " Please ...
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### Question related to optics [closed]

My teacher asked me a question, the question is this "Sunlight enters into a room thorugh a triangular aperture, when i place a screen nearer to the aperture it casts a triangular image, but when the ...
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### Why is intensity related to number of photons?

I have been reading up on Doppler broadening and have found a number of sources (for example here and here) which seem to be taking the number of photons in the range $[\nu,\nu+d\nu]$ to be the same ...
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### Michelson interferometer finding $\frac{\Delta \nu}{\bar \nu}$?

Let us say we send light with wavenumber $\bar \nu \pm \frac{\Delta \bar \nu}{2}$ through a Michelson Interferometer. Using the intensity at the center of the interference pattern $I(x)$ (where $x$ is ...
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### combination of lenses for undefined focal length

Good morning! I am not an optics specialist, but I need to know if it's possible to do what I tried to visualise in my picture. Basicly I want to merge two beams into one. I am thinking of using a ...
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### Why rainbow doesn't happen in each drop independently?

When rainbow happens,we see the rainbow as a whole. When the light enter each drop,the chromatic dispersion should happen in each drop independently and we should see multiple small rainbows. So why ...
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### How do pulse properties relate to the pulse's peak power?

Let's say we know the temporal shape of an optical pulse, which is $E(t) = E_0 \cdot f(t)$, where $E(t)$ is the electric field, $E_0$ its amplitude and $f(t)$ the shape function (e.g. $sech^2$, ...
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### Printing zone plate with laser printer

I tried to print my own zone plates on transparent plastic with laser printer with this generator. I prepared a lot of plates with different settings - focus from 4 to 60 cm, 3 wave lengths, etc. Yet ...
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### Why does a specific static image “move” when moving my head? (glass user)

I am a daily PC user. As most users, I have a taskbar (using Windows) that shows icons of programs. My two screens are big (24") and I'm at ~60cm distance from them, so fairly often I need to turn my ...
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### When will an extraordinary wave refract at normal incdence?

Under what circumstance will an extraordinary wave refract at the surface of a (uniaxial) birefringent martial when at normal incidence? My educated guess would be that it refracts whenever the ...
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### How could you add magnification to prism glasses?

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=prism+glasses These are prism glasses I'm trying to devise a way to modify the them so that I can get magnification in ...
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### How to determine the distance between the principal planes?

How to determine the distance between the principal planes ? If you know the lentgh of both focii, $\overline{FH}$, $\overline{F'H'}$ and additionally the distances $\overline{E1H}, \overline{H'E2}$,...
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### Best collimation at focal point of lens?

From geometrical optics it is clear that we get the best collimation when the object lies at the focal point of the lens. I know that this carries over into cases where diffraction happens, but have ...
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### Attenuation of light through a simple lens, and is it important?

I have an object with incident light rays traveling away from this object. Some of these rays are traveling from the left-hand side through a simple lens (say, a double-convex converging lens). As ...
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### Can I simulate the motion of resonant scanner with a laser beam incidence and reflection using Comsol? Or I need to use different software?

I'd like to see the motion of the beam incidence onto a resonant scanner travels with 20 degrees wide. It is important to see the reflection inside a closed hollow geometry
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### Michelson interfermetory point source types of fringes?

When we illuminate a Michelson interferometer with a point source with the mirrors at $0$ separation and with an angle between them, I have read we get linear fringes at infinity. Is it also true (...
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### Why do beams of light (from torches or other directed sources) not extend to infinity?

When I'm in a dark environment, and I turn on a torch, I can see the beam of light from the torch. To the best of my understanding, the main reason why I can see the beam of light is that the light ...
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### Focus correcting screen [closed]

With the rapid approach of VR, and being someone who's always needed glasses! I have been curious about this for a while. Is it possible to correct the focus of a lens by adjusting the image on a ...
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### Is there an optical filter which exclusively passes right or left circularly polarized light?

Is there a circular analog to the linear polarizer filter, which can be configured to pass only right (left) and block left (right) circularly polarized light?
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### Perspective Redux (why objects seem smaller as the distance increases) [duplicate]

Last time I brought this up, the best answer featured an image that looked something like this: The argument here is that as the distance increases between the eye and the object, the angle gets ...
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### How to measure an image's contrast?

I'm studying Fourier optics and Interferometry and I intend to determine the contrast of an image using computer software. My teacher of Experimental Physics didn't tell me how to do it, and so, I'm ...
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### How does magnification work in lensless optical setups?

In my optics classes, I have only ever seen magnification defined in conjunction with the thin lens equation. However, in a lensless optical setup such as lensfree in-line holography, how does one ...
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### Jones matrices of a mystery device

When considering a Jones matrix $$J=\ \left( \begin{array}{ccc} \cos\phi & -\sin\phi \\ \sin\phi & \cos\phi \\ \end{array} \right)$$ I understand that the effect of a device described by ...
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### Birefringence not caused by polarization?

Is there any other way for a material to be birefringent apart from it causing double refraction based on polarization? I.e. can a material cause double refraction in a way that does not depend on the ...
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### Amplitude-Modulated Wave in a Dispersive Medium

Amplitude-Modulated Wave in a Dispersive Medium. An amplitude-modulated wave with complex wavefunction $a(t)=[1+m\cos(2\pi f_st)\exp(j2\pi\nu_0t)$ at $z=0$, where $f_s\ll\nu_0$, travels a distance $z$ ...
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### Help understanding the wave number in light

For my final optics project I want to implement the beam propagation method using Fourier transforms. I came across the following document http://ecee.colorado.edu/~mcleod/pdfs/NMIP/lecturenotes/NMiP%...
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### If energy of a wave is proportional to frequency, why are higher-powered lightbulbs brighter?

E = hf. Got it. P = dE/dt, right? Not seeing an amplitude anywhere in the formula, so shouldn't the power rating on the lightbulb only be driven by the color? Is it a problem with the way the ...
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### Classical wave equation - validity

I know that classical wave equation carries for spherical wave fronts. In addition, Huygens' principle states that any wave front is a superposition of many spherical wavelets, so why does the ...
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### Connection between coherence and monochromaticity of a light source?

Is there any connection between the coherence ( length, time ) and monochromaticity of a light source?
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### Slit width of a diffraction grating monochromator?

I am trying to find an equation for the bandpass of a diffraction grating monochromatic. I have found this source (link to google books) which indicates that it is given by: $$sD^{-1}$$ Where $s$ is ...
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### How lens for specs are manufactured for a given power? Do thickness, refractive index play role? [closed]

I read some where that if the prescribed glass power is more, glass must be made of higher refractive index to lessen the thickness. But from knowledge of physics, power just depends on focal length(...
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### Can you concencrate paralel laser beams?

I've seen some videos of laser toys but they all seem to use either one laser or lens with some specific range of focus. What I was thinking is this: But it seems like it might violate the 2nd law ...
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### Why does looking through an LCD panel make things blurry?

When you take the back off an LCD panel and remove the backlight, you are left with a translucent panel. But when I look through the panel, even in its "clear" state, objects look blurry. Why is this? ...
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### Why do electromagnetic waves diffract? [duplicate]

The expansion of electromagnetic waves due to diffraction can be easily explained with Huygens' principle (and in introductory courses this is usually how it is explained). But Huygens' principle is ...
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### Holography, what is difference in it and photography in detail and in concern with physical meaning? [closed]

I don't understand what new will we get by it, mean I know it will get phase difference and features like that but physically what will we get? And it's reconstruction of image method?
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### Please explain this optical phenomenon, as seen from the top of the cup [closed]

So here is a cup, and i poured some water in it. The question is why do i see those multiple reflections? What causes these images?
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### Can decoherence occur just by simple reflection?

I create an entangled photon pair. One photon is sent inside a resonant cavity which reflects the photon many number of times. Will there be decoherence between photon in the resonant cavity and its ...
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### Why is this laser beam being scattered(and not)?

I was shining a laser beam through a liquid filled test tube(an ester particularly),and I found this phenomenon rather intriguing.Have a look. Now when I passed the laser straight through the ...
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### What is this optical phenomenon, as looked from outer space? [duplicate]

I just saw a photo from NASA. This is it. This is beautiful. But i am not being able to understand, what are those red and green lines above the earth surface? These cannot be due to Rayleigh ...
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### What is exactly an ‘virtual object’ ? ( From the point of view of lens maker’s formula )

Here’s an image from my textbook It shows, how an image is obtained from a convex lens. The second and the third images, shows in depth , that how a convex lens behaves. They say, that suppose (...
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### Why should the ray become parallel to base in a triangular prism at minimum deviation?

In the case of minimum deviation, the refracting angles at two surfaces are equal. Then the ray inside the prism should be parallel to the base only if it is isosceles triangular prism. But everywhere ...
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### Using Huygen's principle to draw diagram of wave propagation within uniaxial crystal?

"A beam of unpolarised plane wave is incident normal to the surface of a slab of the crystal, with optics axis 45 degrees to the surface. Based on Huygens’ principle, draw the beams propagating in the ...
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### “Classical” Coherence

I'm having a couple of courses where the concept of coherence is quite important. I know the traditional definition of coherence and it's connection to the phase of a wave. But often, I found, that ...
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### Laser shone at liquid jet

When a liquid jet of water falls in laminar flow, it hits a surface. If this contact point, between the surface and the jet, is illuminated by a laser. Rings of light can be seen forming around the ...
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### Optical Frequency Divider?

Is there an optical frequency divider that works to make 1064nm light from 532nm light? The opposite of KDP crystals?