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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Cross-section of a wave packet

In text books, wave packets are one-dimensional drawings. But we live in a three-dimensional world. Suppose a wave packet from a HI-cloud (frequency 1420 MHz) is approaching the earth, distance about ...
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1answer
229 views

Can solar furnace achieve higher temperature than sun surface? [duplicate]

Can solar furnace achieve higher temperature than sun surface? I guess not, but I'm not sure about that. Can you check my reasoning: -------- My reasoning ----------- Consider Sun as a black body ...
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771 views

Why does a glass window reflect white objects white from an atomic scatterers’ viewpoint?

Related: Is a white object always white? If you are standing in front of a glass window during the day, you can see your dim white t-shirt’s reflection in the window. The reflection is dim because ...
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58 views

How does an optic-mechanical laser read and send binary bytes to a CPU?

Thid greatly concerns physics, since a more refined version of my title will be rehearsed below: How is the physical structure of the mechanical eye use a laser to read binary bits held on an optical ...
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192 views

about laser wavelength and wave form

I watched a short introduction video online. There are few concepts which are a bit confusing. 1) The video said the laser is single mode (monochromatic), the wavelength is 780nm, so what is that ...
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364 views

Where in the atmosphere is the blue light scattered?

I have searched Wikpedia and the Physics Stack Exchange archieves, and I cannot find the answer to these two related questions. If it is, please guide me to where this information is located. If ...
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3k views

Effective Refractive Index

Can some one please explain in simple words that what is effective refractive index? How it is different from the refractive index? And how we can calculate the effective refractive index?
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267 views

Eigenvalue of Optical waveguide [closed]

Consider you have a slab waveguide having n1=3.5 and n2=1.45. The value of critical angel is 24.5 degree approx. Similarly effective refractive index will be in between 1.45 and 3.5. How can we find ...
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109 views

3D coherence of light speckles- difference between Airy and gaussian speckles

In this article, http://www.dfm.uninsubria.it/laboferri/web_page/articoli_pdf/PRA_2009-Magatti-Three_dimensional_coherence_of_light_speckles-experiment.pdf, the 3D-coherence properties of light ...
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1answer
1k views

Calculating minimum object distance for a lens

I am trying to figure out the Minimum Object Distance based on a simulation available here. In case you can't open it (it's a Java applet...) I'll describe it briefly. It shows an object emitting ...
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54 views

SHS Interferometer and diffraction limit

I'm currently researching Spatial Heterodyned Spectrometers (SHS) and I'm a bit at a loss understanding the influence of the diffraction limit. I'll be measuring a diffuse visible light source with ...
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3answers
321 views

How Does $\epsilon$ Relate to the Dampened Harmonic Motion of Electrons?

I realize that the permittivity $\epsilon$ of a substance is easily calculated based on diffraction angles, but I am not satisfied with merely measuring it experimentally. I wish to understand its ...
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109 views

Line-shape asymmetry in undergraduate Hydrogen-Deuterium experiment

I'm working as an LA (undergraduate TA) for an undergraduate physics laboratory experiment where students test the Bohr model and use reduced mass to determine the approximate mass of the neutron. In ...
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1answer
241 views

Laser action on one side mirrors (half silvered) and prisms

I know that half silvered mirrors are used in the production of laser emission. Can half silvered mirrors be used outside the instrument so the rays get reflected back on one side of the mirror and ...
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1answer
384 views

Why cellphone cameras don't have optical zoom

I have just basic understanding of Physics from elementary school. But I still wonder, why after 10 years of cameras in cellphones, there is no "small-pack" optical zoom. I think there should be no ...
5
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1answer
272 views

Is this a Fata Morgana?

I took this photo. Above the horizon there is a thick layer that looks like a cloud, but it surely isn't. Is this a Fata Morgana? What do you think? EDIT: I think the more appropriate name is ...
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1answer
95 views

Is there a way to define a function of a meniscus curvate?

If you cut a thin slit in thin opaque material and then put it into water and pull it out, the meniscus will be formed in the slit. For my research I need to know if it is analytically possible to ...
2
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1answer
124 views

Optics for projecting OLED screen DLP style

I just bought a small OLED screen and was wondering is it possible to make a screen surface a little bit bigger ( 2x ) by projecting it through some optics on translucent surface. It reminds me of ...
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309 views

polarization of the lower mode gaussian beam

In most introductory analysis of Gaussian beam optics, Helmoltz scalar optics is assumed. Hence polarisation is ignored. But I'm not clear what are the possible orientations for the lower transverse ...
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2k views

Relation between Radiance and Irradiance

I know the radiance is expressed as $$\text{[Radiance]} = \frac{W \cdot m^2}{\text{sterad}}$$ and $$\text{[Irradiance]} = W \cdot m^2$$ But what's the relation between theese two quantities? Is the ...
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1answer
2k views

Focal length, power and magnification

In refracting (lens not mirror based) telescopes, to have a large magnification the objective lens needs to have a large focal length. if $\text{Power} = \frac{1}{\text{focal length}}$ then that ...
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1answer
276 views

Reflections in a glass of water

I've noticed that if you take a full glass of water and look from above, through the water, you can't see through the glass sides - instead, you see a reflection. I tried with a laser pointer and the ...
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2answers
191 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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1answer
245 views

Effect of slits and a lens

We have a screen with two slits (Young style) separated by a distance $d$, one of them receives a planar wave of $600nm$, the other receives a planar wave of $400nm$. Behind the slits there's a screen ...
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1answer
226 views

What is the largest diameter an optical fiber can have? - for nonimaging visible light transmission

Is there any theoretical limitation on the size of the diameter of an Plastic optical fiber? I would like to transmit visible sunlight through it. I see bundles of small cores available but wouldn't ...
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1answer
217 views

Formation on image on screen?

When we first learn elementary geometrical optics, the first thing taught to us is the two broad divisions of the type of reflection.-Regular and Irregular or Diffused. The difference in cause for ...
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142 views

Seeing the image as explained by Geometrical optics?

I was thinking about how the human visual system perceives the position of an object. I assume it essentially does this by focussing the incoming rays onto the retina and then judging from the power ...
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mode-locking a laser on prime-powers' frequencies

Being rather a theoretician than an experimental physicist, I have a question to the community: Is it experimentally possible to mode-lock a laser (fixed phase relationships between the modes of the ...
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2answers
81 views

Art : A Particular Mirror

There is a particular mirror used here (1 minute 26 seconds) in this video, which reflects light in a way I've never seen. I was hoping maybe one of you might know what kind of mirror this is, so ...
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1answer
304 views

Simple Question: Speed of Electromagnetic Waves in a Medium

If the speed of an electromagnetic wave in a particular medium is such that $v = c$, the speed of light, does this mean that the permeability $\mu = \mu_0$, i.e. that of a vacuum and the index of ...
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414 views

Light scattering vs roughness

I've been searching for an answer to this question in professional circles for a while; now I'd like to ask here, to find out why the answer is not there :) In my optical modelling (computer ...
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178 views

3D holograms like Miku Hatsune? How do you make such things?

I am making a speech about Miku Hatsune 3D hologram, and I would like to know how they are made! I love Miku and Len...(drools) please help by explaining!
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1answer
515 views

What is a “lateral fringe displacement”?

I encountered the term "lateral fridge displacement" in my optics homework for a problem about inserting a thin plate of glass over one of Young's double splits. So what does "lateral fringe ...
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151 views

Perfectly focusing refractive surface

On reading Feynman's lecture on physics, in the geometrical optics section he said that a curve which focuses all the rays coming from a point to another fixed point beyond the refracting surface ...
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259 views

What is the sun's spectral series?

My physics book says that six colors can be distinctly seen in white light: red, orange, yellow, green, blue, and violet. Does solar light only use these six wavelengths and mix them additively, or ...
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110 views

What is “field size” when referring to perspective?

I'm trying to get my head around perspective. If you look at the animation in Wikipedia : You can see that the cube looks very distorted, then the edges go more parallel. From my understanding, ...
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407 views

Factors affecting the size of a shadow

What factors affects the size of a shadow and how would you derive the diameter of a shadow of a circular object on a flat screen?
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169 views

With a box that has perfect mirrors on the inside would it be possible to trap light? [duplicate]

With a box that has many perfect relective mirrors, would it be possible to trap a beam of light in the box indefinetly?
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328 views

Is it possible to surpass the diffraction limit for telescopes?

Telescopes have angular diffraction limit depending on the observed wavelength and aperture diameter. I've read that it's possible to go beyond the limit for microscopes. But is it possible to do the ...
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How to draw a ray diagram from focal length, object and image heights?

Q. An object of height 8 cm is placed in front of a lens. It's inverted image of height 4.8 cm is formed on the screen. If the focal length of the lens is 12 cm then by drawing at scale calculate the ...
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Why is Erbium Doped Fiber Amplifier (EDFA) preferred over Erbium Doped Waveguide Amplifier (EDWA)?

Why is Erbium Doped Fiber Amplifier (EDFA) preferred over Erbium Doped Waveguide Amplifier (EDWA)? The question has been asked from an engineering point of view, but obviously I would also be ...
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1answer
2k views

Calculate the distance between two points from iPhone Camera

I want to calculate the distance between two objects using an iPhone camera. Suppose I'm standing with my iPhone 10 feet away from the objects. Now, I want to calculate the distance between those ...
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2answers
142 views

Polarization of Light

How do materials polarize light? I know that they polarize light in the same plane, but light has two perpendicular directions with the two fields, so which direction is reflected and why? And if ...
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1answer
368 views

Photo of reflection in magnifying mirror shows normal magnification. Why?

I just took a picture of myself in one of those magnifying shaving mirrors and in the photo I am unmagnified! Why is this?
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1answer
61 views

Heat deposition at optical focus in a clear medium

This is an applied physics question for an engineering problem. The well known experiment we have all done--burn paper and wood with a magnifying glass and the sun's rays. My question is, if one were ...
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2answers
134 views

Penetration of light in the atmosphere

While I was considering an answer to this question, I wondered how much light that enters the atmosphere reaches the ground without colliding with air molecules—if any. I've taken a good bit of ...
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1answer
181 views

Manufacturing Fresnel Lenses with Sound

I understand fresnel lenses are manufactured using CNC machines. I was wondering, if it would be possible to use sound to vibrate liquid silicon and then fast cool it into the standard form of a ...
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2answers
720 views

Optics alignment of a confocal scanning microscope

I am facing a challenge in my project regarding optical alignment. See the figure: The challenge is with the vertical optical system alignment. I considered placing a mirror and check back if the ...
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2answers
748 views

What's the physical significance of using fourier transform for diffraction?

I am studying some basic idea of diffraction and there mention in far field, the diffraction pattern could be understood by Fourier transform. But I just don't understand what's the physical fact for ...
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96 views

Reflection of a polarised beam

The past days I've been trying to understand how AutoFocus(AF) works on photographic cameras. There is a statement that says AF systems are polarisation sensitive. This means that they can only work ...