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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Why is there a $\pi$ phase difference when light goes from a rarer medium to a denser medium? [duplicate]

I want the basic reason. I want the description of answer graphically also.
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36 views

How can there be a glitch in a live speech? [on hold]

There is a live speech being given by Obama but suddenly there is a glitch and he is in a different position and speaking differently. How could this be?
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2answers
65 views

Speed of light and distance

Our measure of distance (the meter) is defined in terms of how far light in a vacuum travels in a specific time. When light travels through another medium, we say it travels at a different speed. Why ...
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1answer
32 views

Drawing Ray diagrams

When drawing ray diagrams for concave mirrors, I was advised to : draw a ray that is parallel to the principle axis, the reflected ray will pass through the focus Draw a ray through the center (C), ...
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1answer
33 views

How to understand “the speed of propagation of the condition of constant phase”?

I still can't understand that the phase can be a constant until now. If the phase is constant, from the $$y(x,t) = a \times \sin(phase)$$ the shape of wave will be a line parallel to x-axis.But I ...
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1answer
66 views

Making fire using a filled water bottle

I have seen videos where a fire was started using a water bottle filled with water. I guess the bottle acts like a convex lens that converges light to a focal point to start a fire. But why does water ...
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23 views

Telescope Viewing problem [on hold]

2 months ago, my dad and I together bought a refractor telescope (danubia mars 66). Yesterday I woke up in the morning and saw Venus and Jupiter. I pointed my telescope towards them and I saw 4 ...
2
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1answer
76 views

Why aren't train headlights brighter? [on hold]

I suspect a valid scientific, physics answer for this question, because I'd venture that train, insurance companies would've calculated and contemplated this question. Yet the train headlights at ...
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2answers
34 views

Resolution of the Eye-Light Rays and Diffraction

Please look at the problem. The problem is solved for me. However, I don't understand why the angle alpha is considered to stay constant when the rays go through the lens. The ray along the distance s ...
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21 views

What are some good resources for learning photonics?

Including the generation, transmission, modulation, signal processing, amplification, and detection/sensing of light, I am interested in getting a good understanding of photonics. Does anyone have any ...
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1answer
37 views

Ray Tracing and Combination of Lenses [closed]

I was looking at this problem. Does the problem assume that the focal point of the divergent lens is right next to it? The answer is c, saying that the focus point will be further away: but that ...
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34 views

What is a good textbook to learn how to ray trace light through an optics system in 3d?

I can do 2d problems easily, but I need to learn more to do a 3D ray trace. Can you guys point me towards a textbook? I'm having trouble dealing with the normal and incident rays in 3D
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1answer
41 views

Why do we observe opposite motion of trees (nearer) and trees (distant) when seen from a moving frame? [duplicate]

If you are in a moving train or in a bus, what you observe is that the trees which are nearer to you move opposite to the direction of your motion. But the trees which are very far away from you, ...
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1answer
41 views

Some objects seem to have the same color whether the light that we perceive is emitted or reflected

Is color only a property of perception, considering these two examples: The glass used in a green traffic light looks green no matter how it is illuminated, either by a white light bulb behind it or ...
3
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1answer
27 views

Can a Chemical's Opacity be Deduced Mathematically?

all. I have tried Googling but have had no luck. My question is simple (although, I presume the answer is not): If one knows the chemical structure of, well, a chemical, could its optical properties ...
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1answer
24 views

Can a painting be used as a current generator via absorption of photons in the paint?

What happens to absorbed photons in a painting? Heat of course except for the free electrons. Could paint compounds (the dark, non-reflective) be embedded with reactive and conductive materials to ...
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1answer
27 views

Highly diminished image of an Object placed at Infinity

Consider an object at infinity. The rays coming from it are parallel to each other. Let one of the parallel rays pass through the focus $F_1$ of a thin lens, and let a second ray pass through the ...
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1answer
14 views

Calculate transparency from Beer-Lambert Law

I want to calculate a transparency parameter for a superposition of several volumes containing media using the Beer-Lambert Law, which states that $$I/I_0=exp(-\tau)$$ where $I$ is the transmitted ...
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2answers
53 views

How is photon time of flight/range over sub-millimeter distances measured?

I was reading a paper that described how the force a low-thrust torsion pendulum was measured. In it, the paper states a laser is bounced off a mirror and the displacement is "...based upon the beam ...
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4answers
871 views

Why are objects opaque?

I have been searching the internet for answers to this question, but haven't found a convincing one. I would appreciate any response. I understand why objects are opaque/black. For example when ...
3
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1answer
55 views

Optical absorption in multilayer structure

Assume a hypothetical 3 media/ 1 layer structure with the following indices of refraction: $$n_1 = 2, n_2 = 2+i0.5, n_3 = 1$$ where the thickness of the layer is 100 nm and wavelength = 1000 nm. ...
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1answer
35 views

Interferometer problem about periodic fringe patterns [closed]

Please,kindly help me; my teacher assigned me problem set, and she never went over anything about interferometers in class. Also, there is almost no information about about how to solve interferometer ...
2
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0answers
17 views

How absorption coefficient determines which material is used to make solar cells?

Does the knowledge of the material absorption coefficients aids engineers in determining which material to use in their solar cell designs? If yes, how?
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20 views

Refractive index variation with colors [duplicate]

To explain the spectrum formation in the prism, my teacher said that different colors have different speeds in a medium, so, refractive index is different for all. So, angle is different. But I don't ...
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2answers
501 views

If I reflect light from a projector using a mirror, then is the reflected image real or virtual?

I am in a great confusion about this question. In our school, we have been taught that: A real image is an image which can be obtained on a screen. It is always inverted. A virtual image is ...
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0answers
24 views

How can a semi-transparent object appear white? [duplicate]

Can an object appear opaque white to the eye and be transparent ; i.e. pass light through; In other words, is there any other way for an object to appear white, other then by scattering all the ...
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2answers
60 views

Modeling the free space propagation of laser beams using Fourier transforms

I am trying to model the propagation of a laser beam in free space. I have an initial field $E_{in}(x,z=0)$ (a Gaussian beam) and need to find the fields at other points on the optical axis $E(x,z=d)$ ...
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13 views

Obtain scale factor by coordinates from the camera projections

I have a following optical system: 3 cams (left and top, which is orthogonal to the left, and right, which is parallel to the left and orthogonal to the top) and the 2 cubes in the 3D-space with ...
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1answer
8 views

How to create crystalographic orientation map from indexed Kikuchi bands?

Can somebody explain a detailed procedure, of producing orientation maps? I need to implement this into a software. Right now im able to transform EBSD pattern to probabilistic Hough space, get lines ...
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1answer
24 views

Is there a way to calculate how a point source would be imaged in a system with spherical aberration?

I want to create a picture like this for the system I am building. (Source: WP page on spherical aberration) Can someone point me towards a book were I can learn to calculate this pattern on an ...
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2answers
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Why is the sun brighter in Australia compared to parts of Asia?

Background: I've lived in Philippines for several years, and visited other parts of Asia occasionally (Singapore, Indonesia, Hongkong). I just moved to Western Australia a few months ago and I ...
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2answers
2k views

Is it possible to 3D print a mirror to create a high quality telescope?

Is it possible to 3D print a mirror with todays available materials? If so, would there be a reduction in image quality?
2
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1answer
51 views

Why does the speed of the Electromagnetic wave in the material depend on the frequency of the wave where as they are constant in vacuum (freespace)? [duplicate]

I am confused on why would the propagation speed of any EM waves at ANY frequency is constant in the free space (vacuum) but they seem to disperse in any other materials as the propagation speed of EM ...
12
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1answer
468 views

Why is Huygens' principle only valid in an odd number of spatial dimensions?

Apparently Huygens' principle is only valid in an odd number of spatial dimensions: http://mathoverflow.net/a/5396/21349 Huygen's principle in curved spacetimes Why is this? [EDIT] This is ...
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2answers
80 views

How to calculate magnification

I have various magnifying glasses and I'm using them when I take macro photos with a phone or a camera. I want to group/label my magnifying glasses by their magnification power. And by magnification ...
3
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1answer
108 views
+50

Has anyone developed tunable notch filters in the visible RGB wavelengths which have very fast response times?

I am interested in whether the combination of a spectrometer and a tunable notch filter with notch frequencies at the visible red, green and blue wavelengths which have very fast response times could ...
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Optics - Derivation of Linear Magnification of Lens without Sign Convention [duplicate]

In some posts in this forum I've read that sign convention in optics is useful for making formula memorizing easier, and that we have to use sign convention again while applying the formulae to ...
2
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1answer
46 views

Reflection from multiple thin films: accounting for lost light due to small surface area

I have a problem similar to reflection of multiple thin films. I have light coming in from medium 1 and I want to find the total reflected intensity after being reflected inside 2 layers. However, I ...
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44 views

Rotating a Gaussian Beam

I need to see how the phase fronts of two gaussian beams interact when they intersect with each other. The two beams are tilted towards each other so that they intersect each other at their respective ...
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10 views

Transmission of porous membrane with vertical cylindrical pores

There is some porous dielectric membrane with strictly vertical cylindrical pores. I would like to find theoreticaly optical transmission spectra of this membrane, depending on the bulk material ...
2
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1answer
43 views

Fringe Pattern Brightness for Young's Double-slit experiment

Perhaps I have missed something in my notes, but I have noticed when looking at different sources that some textbooks/sites state that the fringe brightness for the young's experiment is the same for ...
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1answer
55 views

Does this photograph portray double muon impact with nanogold atoms?

1PHOTO 1: Macro-photograph of an NIH/FDA TEM of a nanogold dark stained biological sample projected onto Silver Halide (AgX) photographic gel paper. On June 10 I questioned if PHOTO 1 ...
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Output of a beamsplitter with photon number (Fock) state inputs

Given a beamsplitter drawn below, where $\hat{a}$ and $\hat{b}$ are input modal annihilation operators, transmissivity is $\tau\in[0,1]$, and output modal annihilation operators are ...
2
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1answer
25 views

Color in Different media

When a light wave passes from one medium to other, the wavelength of the light wave changes and the frequency remains constant. If then color of the light waves depends on changing wavelength or ...
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2answers
52 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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2answers
309 views

How would an X-ray mirror work?

I was wondering if light can be reflected how can someone reflect X-ray of what material does it need to be made of and is its design completely different to that of our original mirrors? Does this ...
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1answer
28 views

Trouble understanding phase matching equation

consider a 2nd order non linear optical material, i.e. a material in which it holds that $ P = \epsilon_0 E + 2dE^2$. In the Born approximation, the non linear contribution to the polarization density ...
2
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1answer
31 views

What happens if we use an optical fibre for light at a different wavelength than the one specified on the fibre?

Say the fibre is for 700 nm, and we shine light at 1064 nm into it. Would it change the mode? The polarisation? The beam shape (i.e. introducing ellipticity in the beam)?
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Understanding the mathematical formulation of the Faraday effect

The Faraday Effect is a magneto-optical effect which results in the polarisation of light being rotated I would really want to understand the theory of this, but I only have a basic EM knowledge, ...
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1answer
17 views

How to block coupling between adjacent waveguides?

I have a number of nonlinear waveguides, say six. I don't want coupling between specific two waveguides. Other than keeping them large distance away, what are the other possibilities to ensure no ...