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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Is near point defined for a myopic eye and far point defined for a hypermetropic eye?

I learnt about far Point of a myopic eye and near point of a hypermetropic eye. But I am confused about the above question. And if near point is defined for a myopic eye and far point defined for a ...
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3answers
130 views

Do we have a deeper understanding of Fermat's Principle?

Fermat's principle says that light travels between two points along the path that requires least time as compared to other nearby paths. But why this is so? Why can't light follow other paths? How ...
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1answer
74 views

Minimum glare from reflected sunlight [closed]

I'm studying for the IB Physics HL exam, and I came across a question neither my physics teacher or I can solve. It has a diagram like so: The text of the question is this: A person wearing ...
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1answer
31 views

In geometric optics we treat light as a collection of particles?

I've been reading the book "Geometric Mechancis" by Darryl Holm and the in the first chapter he treats geometric optics. There the author talks about light rays and those light rays looks like ...
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1answer
30 views

What blurs the swimming pool

Mystery of the swimming pool With eyes above water, I can see the bottom of the pool very clearly, almost as if the water wasn't there. Refraction at the water level shifts the grout lines between ...
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1answer
33 views

Laser: Looking for name for optical component

I'm currently planning a laser setup in which I want to send a (1mW) laser into the environment using a commercial scanning unit (made of two galvanometers). I would like to measure the reflectivity ...
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1answer
24 views

Transmission of light, sub-wavelength apertures, and cut-off frequencies

I was hoping someone could please explain how the transmission of light through a sub-wavelength aperture in a metal film, at a particular wavelength, changes when the aperture is: i) above cut-off ...
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1answer
41 views

Can someone please explain extraordinary optical transmission (EOT)?

Can someone please explain extraordinary optical transmission (EOT)? I'm hoping someone can describe the physical process by which light is transmitted through a periodic metal hole array which is ...
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what is meant by stationary optical path length or what does it mean when one says the time taen by light is rither maximum or minimhm or stationary? [duplicate]

I have not been able to understand what is meant by stationary optical path length and extremum i.e. either maximum or minimum or stationary time taken by light in fermat's principle.sir,would you ...
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25 views

Optical path length and extremum time taken in Fermat's principle [duplicate]

Could someone please explain what is meant by stationary optical path length and extremum time taken in Fermat's principle?
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1answer
56 views

Question about lens maker's formula

I am trying to follow the derivation of lens maker's formula from the textbook "University Physics", p.1133 ...
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1answer
36 views

Refraction of white light through a glass slab: what does it actually look like?

When a collimated beam of white light enters a rectangular prism, it develops slightly coloured edges due to the dispersive refraction of the glass: each ray in the beam is displaced differently ...
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2answers
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What is so good about diffractive optics?

What's so ingenious in diffractive lenses? To my naive eye they seem to be just Fresnel lenses with smaller features. What makes it so magic and why all the fuss about it?
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56 views

Is circular masking a laser beam an acceptable way to get the beam diameter you require?

I am wondering what are the down sides to just masking a laser to get the beam diameter you require? For example if you have a collimated eliptical beam of say 2mm width and 4mm height, but you ...
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1answer
32 views

Maxwell Stress Tensor at material boundaries

I am trying to grasp the meaning of the Maxwell Stress tensor $T_i^j$ at material boundaries. Concretely, I am trying to calculate the force between two waveguides. The results are given in an article ...
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1answer
23 views

Does the order in which light comes into a rectangular prism affect its dispersion?

I read about how when light comes out of a rectangular prism, there are violet and red fringes on either side of the light spectrum. The website didn't give the specifics in this subject, so I am not ...
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2answers
6k views

How does Newton's 2-prism experiment help to explain why light does not get dispersed into 7-colors in a parallel glass slab?

In a real parallel glass slide(with two prisms imagined to be touching each other to form a parallel glass slide), The ray of light should pass through the Z in between without any dispersion or ...
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1answer
236 views

Increasing the efficiency of solar cell systems

As far as I know, there are currently two main approaches to utilising solar radiation for maximum energy conversion to electricity. These are either direct conversion to electricity, using ...
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69 views

Rings of light around water

There's a question I want to ask. The question says : Let a liquid jet fall onto a surface. If the contact point is illuminated by a laser beam, rings of light around the jet can be observed (see ...
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1answer
26 views

Why, in Chroma key composting, green colour is used? [closed]

In movie shootings, we observe that the Chroma Key Composting method is used very widely. Why do they only use dark green colour, what not some other like white, blue etc,
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0answers
27 views

How to design a grating coupler to produce surface plasmon-polaritons (SPPs) at a desired frequency?

Following on from this question, which I found very useful on the topic, I was wondering how you would use the equation $\beta = k sin \theta \pm \nu g$ to fabricate a grating coupler to generate SPPs ...
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1answer
48 views

Different colors and Metamerism

Given the following graphs: They describe the response for two different colors . In addition that both colors are metamerism. My question is why? how can I prove it? Thanks
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3answers
1k views

Exciting Surface Plasmon-Polaritons with Grating Coupling

I'm very new the topic of SPPs and have been trying to understand this particular method of exciting surface plasmons using a 1D periodic grating of grooves, with distance $a$ between each groove. If ...
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0answers
14 views

How to apply contrast sensitivity function to an image?

I would like to apply contrast sensitivity function (CSF) to an image. My idea is to do the Fourier tranform of the image and then do the filtering in the frequency domain by applying the CSF. However ...
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3answers
540 views

Is there a way to increase the speed of light itself?

When light enters materials it slows down due to its refractive index (due to absorbing and re-emission of photons). But, is there a way to increase the speed of light itself? Can there be some ...
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1answer
83 views

Mechanism for visible light frequency mixing in storm clouds

So I know that when red and blue light (or the frequencies/wavelengths we percieve as such) hit our eyes with the correct proportions, our eyes and brains interpret that as the color purple. In ...
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73 views

Is the formula, for finding the distance between two slits, my books gives correct?

In my book'a section on Young's double-slit experiment, the formula, $d = m \lambda \sin\theta$, is given. In this equation $d$ is the distance between two slits, $\lambda$ is the wavelength of light ...
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109 views

Is this diagram, concerning Young's double slits, inaccurate?

"This diagram" : My question is whether those lines (interference) have to originate from a single point. The diagram used to demonstrate what $m$ (path difference) means, has two lines originating ...
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3answers
57 views

What is the total internal reflection?

From what I read, it sounds like when a light ray passes from one medium to the other, if the critical angle is reached so that the refractive ray is at 90 degree with the normal, the light ray does ...
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0answers
26 views

Does light accelerate when it meets a surface? [duplicate]

Does light accelerate when it meets a surface like mirror, we know that light changes path when it meets a surface like mirror.If light changes path,even if travelling at c,this means light has ...
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2answers
278 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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1answer
36 views

is copper a non-magnetic?

I'm working on an optics project that I'm using Fresnel Equation for Intensity. but I've got a question, is copper a non-magnetic ? You know because in Fresnel Equation, for non-magnetic materials ...
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21 views

What's the difference between two types of diaphragms?

What's the principal difference between aperture iris diaphragm and field iris diaphragm?
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20 views

Does “converge” mean intersecting and producing image when we are taking about convex lenses?

After reading the chapter on convex lens, I saw several places where "converge" is used. In the very beginning of the chapter, my book says "converging lenses bring light together". So I thought ...
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1answer
84 views

What is the frequency of the color black?

Our eyes don't see light; they detect vibrations in the 400-800 THz range that we call color. Since our eyes can detect the color we call black, what is its frequency?
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7answers
5k views

Why did high quality mirrors use aluminum coatings instead of silver?

I have two questions on mirrors. I’ve read that in the past quality mirrors were coated with silver but that today vacuum evaporated coatings of aluminum are the accepted standard. When I look at ...
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5answers
579 views

Why does an image form at the intersection of light rays?

If image is simply what we see, then why, when light rays bend in the atmosphere, enabling us to see the sun, is there no intersection of rays? The concept is strange. I can not relate it to ...
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2answers
17 views

How are aberration levels measured?

I was reading reading the paper: Predicting subjective judgment of best focus with objective image quality metrics when I come across this statement: Through-focus visual acuity (VA) was ...
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0answers
207 views

Is it possible to calculate the work function of a metal with basic lab equipment?

ive been given a problem in physics, its to prove if a lump of metal we have been given is real gold or not. one way to to do it would be to work out its density, which is fairly easy, mass/volume. ...
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4answers
413 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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2answers
1k views

Eliminating IR light reflection perceived by a steep viewing angle

I am having a problem with reflection on an acrylic surface, in the IR part of the spectrum. This reflection is interfering with an algorithm that looks at objects, as it makes two show up when only ...
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22 views

When to use lateral magnification vs angular magnification?

What is the essential difference between lateral and angular magnification (like why do we need to use both and when do we use which)? Also, is there a relationship between the two magnifications?
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2answers
3k views

Wavelength-dependent refractive index

I read in a book about optical fibers that the different spectral components of a light pulse transmitted in the fiber propagate with different velocities due to a wavelength dependent refractive ...
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0answers
67 views

General proof of formulas of geometric optics?

In most lf textbooks formulas of geometric optics like lens maker formula and base formula for that are proven (or rather verified from my point of view) by taking specific case (ray diagram) and ...
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1answer
26 views

Recreating an image from a photometer or similar light-detecting device?

I'm thinking if it is possible to recreate an image from data from this kind of device. It is known analog signals theoretically have infinite resolution, but since we use them in discrete systems ...
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35 views

Visible wavelengths of air fluorescence data - needed for school demo laser telephone design

I'm seeking information about fluorescence in visible wavelengths (390-700nm) of any of the main constituents of air ( $ N_2, O_2, CO_2, H_2O, CO, etc. $) that can be excited with a (hopefully ...
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2answers
53 views

Why is the index of refraction different for different wavelengths? [duplicate]

The index of refraction can be written as $$n=\frac{\lambda_v}{\lambda_m}$$ where $\lambda_v$ is the wavelength in a vacuum and $\lambda_m$ is the wavelength in the medium. I’ve been told that since ...
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2answers
115 views

Is the plane wave model always valid in reflection and transmission?

my question is related to another one I asked, but I foolishly made that question about several things (experiment, computation, theory) at once so it was confused. I was talking to my boss about ...
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51 views

Red light in the depths of the ocean

I've read that fish in the deep ocean tend to be red because it makes them look black for other fish, thus reducing their chance of being eaten. Why do they look black?
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51 views

Optics phenomenon with my glasses?

When I look through my glasses toward the extreme left, a very odd and intriguing phenomenon occurs: The border of everything I see is lined with a hazy blue lining on the left and a hazy yellow ...