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.

learn more… | top users | synonyms

1
vote
1answer
32 views

How to treat partially polarized light with Jones vectors?

I have to calculate the degree of s-polarization (perpendicular) of a transmitted unpolarised light ray when it goes through a glass plate ($n=1.5$) at Brewster's angle (Brewster's window). ...
0
votes
1answer
34 views

How to convert candela into joule?

How to convert candela into joule? What equation can we use? Is this site useful? http://en.wikipedia.org/wiki/Photometry_%28optics%29
25
votes
3answers
2k views

How does light speed up after coming out of a glass slab?

As I learned today in School, my teacher told me that when light enters a Glass Slab it slows down due to the change in density and it speeds up as it goes out of the Glass Slab. This causes a lateral ...
3
votes
0answers
18 views

What does it mean for a Fresnel lens to have two finite conjugates?

I'm in a situation where I need to reverse engineer a product that my company already manufactures and sells, but it wasdesigned too long ago for anyone to remember. It uses a Fresnel lens with the ...
2
votes
3answers
36 views

Do infrared lamps provide more heat than incandescent lamps?

Infrared lamps seem to be used in situations where you want to produce heat without producing (as much) light. But incandescent bulbs also produce heat. Why not just use incandescent bulbs? My ...
1
vote
3answers
49 views

Does polarization remove any of the fields completely?

A light is made up of electric and magnetic fields oriented perpendicular to each other. Can polarization lead to the removal of any of the fields completely?
1
vote
1answer
45 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 ...
0
votes
1answer
31 views

How does airborne laser system deflect the laser beam?

In the Airborne Laser system, the laser beam is directed from the nose of a Boeing airplane towards the target. In this system, the angle of laser beam with respect to airplane body can be changed at ...
2
votes
1answer
83 views

Mode groups in an optical fiber

I know what modes in an optical fiber mean but what are exactly mode groups in an optical fiber? From what I read until now, I have the impression that modes that have close propagation constants ...
3
votes
2answers
179 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 ...
7
votes
0answers
52 views

How would a fractal refract light?

A fanciful Pink Floyd reference has led me to wonder what white light passing through an object with an infinitely complex surface would do. Would it exit from a single chaotically-chosen point on the ...
2
votes
1answer
68 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 ...
0
votes
2answers
49 views

Solution of one dimensional wave equation by variable separation method

When solving the One dimensional wave equation by variable separable method, we equate left-hand side and right-hand side to a constant which is negative in nature. Why has the constant be only ...
0
votes
0answers
15 views

Filtering UV Light to Visible Light [closed]

I'm wondering if it is physically possible to filter UV light from 400nm to 100nm so that UV light is in the visible range. If we had a UV screen over a visible range screen, could there be two ...
2
votes
4answers
217 views

Is it feasible to detect light emitted from planet earth 2,000 years ago by reflection from an object situated 1000 light years away?

The possibility though remote, is intriguing as we may be able in the future to actually "see" our own planet's history. Though sounding science fiction, if we are able to detect bodies in space that ...
5
votes
6answers
4k views

Is it possible to witness a circular rainbow?

What conditions would make it possible to see a naturally occurring fully 360° circular rainbow? Would it even be possible?
0
votes
2answers
109 views

Light-Matter Interaction and 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 ...
1
vote
2answers
150 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) - ...
1
vote
1answer
52 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 ...
1
vote
2answers
75 views

What does amplitude in wavelength of light physically mean?What oscilates with time in photon?

Like amplitude in wavelength of water waves signify the displacement of water particles about their mean position.
2
votes
1answer
51 views

Does irregular reflection form images?

In one of my test papers at school, we had a true-false question which said "Irregular reflection can form an image." I marked it true, however I was not given any marks for the question. I asked my ...
0
votes
2answers
31 views

How are different wavelength components collected by the same detector in a spectrometer?

Let's think, we have a detector array (128x1 and each CMOS detector responds 400 to 1000 nm TSL1401CL that way, each detector has 4.6875 nm interval). Then, basically in a spectrometer a prism reflect ...
8
votes
6answers
3k views

Why does a laser beam diverge?

I was wondering why a laser beam diverges. If all the photons are in the same direction, I would imagine that it would stay that way over a long distance. I am aware that a perfectly collimated beam ...
0
votes
1answer
52 views

Resolving power of ultra-telescopes

Assuming we could create and orbit optical telescopes of arbitrary size, perhaps starting with (say) inflatables or active membrane of 100m diameter what kind of resolution in imaging extra-solar ...
1
vote
0answers
31 views

Why is responsivity quoted as a figure of merit?

Lately I have been investigating the physics literature on proposed photosensitive electronic devices made of graphene. Often I see responsivity values quoted as if they suppossed to impress, and ...
-1
votes
1answer
38 views
2
votes
1answer
12 views

How to propagate a (tilted) gaussian beam through a telecentric f-theta-lens

My questions has two parts: First of all let's assume I have a gaussian beam and I send it through a telecentric f-$\theta$-lens (e.g. http://specialoptics.com/products/scanning_confocal.html) with ...
0
votes
1answer
22 views

Intensity for Single-Slit Interference Pattern

In the derivation for the equation for the relative intensity of a single-slit interference pattern in my textbook, there is an assumption that I find a bit fishy. I know this equation works, so it ...
0
votes
2answers
223 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 ...
0
votes
1answer
31 views

Fresnel lens/kinoform: How to model diffraction at the edges of zones?

I would like to find the intensity distribution of light due to the diffraction at the edges of zones on Fresnel lenses or kinoforms. (That is, location of orders, heights of maxima, etc.) I can't ...
0
votes
3answers
49 views

Mirrors and the human eye

Not sure if this is a suitable question for this exchange. Me and a friend are debating what can be seen through a periscope consisting only of two 45 degree mirrors. My friend tells me that the ...
2
votes
3answers
10k views

3d holograms - How are they created?

How do 3d holograms work exactly? I read that there is a laser in use, but how are the multiple perspectives generated and how is the light trapped? in a certain area to create the effect? ...
3
votes
2answers
135 views

A mirror in the sky to look at past Earth

Earth reflects light from Sun into Space; are there any "mirror like" objects which reflect back to Earth this light? Has anyone been able to use this method to recover some information on how was the ...
3
votes
3answers
234 views

Optics - Faraday Rotator using waveplates

I'm trying to replicate the effect of a 45° Faraday rotator using a series of waveplates instead. I've encountered some difficulties using the jones matrix notation, the main book I'm using is: ...
1
vote
2answers
74 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 ...
0
votes
0answers
12 views

What curved, transparent media exists for full-motion holograms?

Looking to project light either on, or through, but not from, a transparent medium. So I'm thinking of half a hollow sphere with a surface thickness of 1/10th the radius of sphere. A clear curved ...
25
votes
4answers
2k views

What really cause light/photons to appear slower in media?

I know that if we solve the Maxwell equation, we will end up with the phase velocity of light being related to the permeability and the permittivity of the material. But this is not what I'm ...
1
vote
0answers
23 views

How to choose a type of a lens for a particular optical component?

With almost no experience in optics, I am trying to create a system that looks something like that: The idea is to be able to focus the parallel wide beam (shown in broken line between lens 214 and ...
0
votes
3answers
90 views

Is the kinetic energy of an electron always $1.6 \cdot 10^{-19}~\text{J}$?

I was doing the following problem. For $d$. They bizarrely added an extra step. They calculated the momentum of the electron to find the De Broglie wavelength using the kinetic energy relationship. ...
2
votes
2answers
2k 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 ...
5
votes
4answers
125 views

Light Polarizer and the Second Law of Thermodynamics

I have stumped myself with a thought experiment of my own devising. Suppose I take a beam of wholly depolarised, but otherwise plane wave light. Its von Neumann entropy per photon is $\log(2)$ nats ...
0
votes
2answers
189 views

Cylindrical Fresnel Lens Focus Problem

How to focus beam from the fresnel lens on a flat surface. In my case, instead of producing the light beam, I am receiving the light beam. So, the beam comes from the right and then focuses at a ...
1
vote
0answers
16 views

Fresnel equations of reflection applied to microparticles

I wanted to know if the Fresnel equations of reflection, as described here, can be used to calculate the reflectance on the interface of particles which have a diameter near the size of the wavelength ...
0
votes
2answers
28 views

Light intensity units in Beer-Lambert law

I have always found the Beer-Lambert law written in terms of light intensity, but what are the units of that light intensity? When related to light, some people talk about cd, or W/cm/cm... What are ...
0
votes
0answers
9 views

Photonic slab: 1D or 2D guide?

I have read several books that start talking about photonics wires by describing the slab guide first. Obviously, this kind of structure is a simplification of a 2D waveguide. My question is related ...
0
votes
1answer
65 views

Proving susceptibility in Lorentz Model satisy Kramers-Kronig relations [closed]

My instructor asked me to prove that the real and imaginary parts of the electric susceptibility derived from Lorentz Model satisfy the Kramers-Kronig relations using the residue theorem. The problem ...
10
votes
3answers
150 views

Optics: Derivation of $\vec\nabla{n} = \frac{d(n\hat{u})}{ds}$

I have been given this formula from optics here, with no background: $$\vec\nabla{n} = \frac{d(n\hat{u})}{ds}$$ Where $n$ is the refractive index and $\hat{u}$ is a unit vector tangent to the path ...
-1
votes
1answer
41 views

Lens's diameter [closed]

This question is asked in a famous competition in my country: "Approximately calculate the diameter of the lens which this picture is taken with.(for measurements consider lens as a flat object)" Can ...
0
votes
1answer
128 views

Stimulated emission direction

Place a sub-micron clump of crystal violet molecules in front of a multipixel detector. Raise the molecules to an electronically excited state with a beam of 590 nm light, illuminating from the side ...
7
votes
3answers
1k views

Can I calculate the size of a real object by just looking at the picture taken by a Camera?

Can I calculate the size of a real object by just looking at the picture taken by a Camera? (I think people do that) i dont understand how?(from physics point of view)