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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Calculating the Poynting vector

Why is the equation $S=...=\frac{1}{\mu_0 c}E_0^2=\epsilon_0 c E_0^2$ accurate? Shouldn't it be $\epsilon_0 c^2 E_0^2$ instead, since $c=\frac{1}{\mu_0 \epsilon_0}$...
5
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1answer
317 views

How does one align a laser using two adjustable mirrors?

Suppose we would like to get a laser beam to pass through a particular point in space in a particular direction. At our disposal we have a laser, two adjustable mirrors (can rotate up/down and ...
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3answers
147 views

Capturing a light beam

For a given container made of an extremely reflective surface, is it possible to shine a beam of light in, and with no 'fiddling' (i.e. closing the hole, tilting the object) to contain the beam for an ...
2
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3answers
331 views

When does the wagon-wheel effect occur?

Sometimes you see a video of a fan or a propeller spinning very fast, and the apparent rotation is distorted. The fan can appear to be moving in the opposite direction of rotation, or even stationary. ...
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1answer
304 views

Microtops sunphotometer sun target optics

For atmospheric radiation observations, a portable piece of equipment such as the Microtops sunphotometer (pictured below) is useful. Image source: Solar Light However, while I can borrow this ...
2
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2answers
387 views

Law of reflection for a moving mirror

An elementary fact that people learn about mirrors is the law of reflection, that the angle of incidence of a light beam striking the mirror (as measured with respect to a normal) equals the angle of ...
2
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1answer
895 views

How does reflection of light at normal incidence angle happen?

I was wondering few scenarios pertaining about reflection of light at a normal incidence angle (perpendicular to the mirror) in that case how can a wave-of-light reflect of? As the reflected waves ...
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1answer
111 views

Length of Focal Spot Along the Optic Axis

I am currently attempting a physics question on optics. A Fresnel Zone Plate has overall radius a and contains N half-period zones. The odd-numbered zones are open but the even -numbered zones are ...
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1answer
58 views

Limitations of (non-lightfield) near-eye displays

The answer to Is it possible to blur an image in such way that a person with sight problems could see it sharp? suggest that you cannot present a "counter blurred" out-of-focus image such that it ...
5
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4answers
184 views

Possibility of making an experiment in a classroom to simulate DNA diffraction

I am a TA in a structural chemistry class. The professor want me to show students how Watson and Crick determined the structure of DNA from X-ray diffraction results of DNA crystals. The professor ...
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1answer
935 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
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2answers
280 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). ...
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3answers
3k 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 ...
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0answers
90 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 ...
10
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1answer
292 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 ...
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1answer
182 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 ...
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0answers
72 views

Simple thermodynamic proof that light from a source cannot be focused to heat an object above the source's temperature

I was thinking about the question in the title. I found the following thread, and some of the answers are making my head spin! Is it possible to focus the radiation from a black body to make ...
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2answers
253 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 ...
2
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3answers
132 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?
2
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3answers
580 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.
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3answers
5k 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 ...
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2answers
86 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 ...
3
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1answer
232 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 ...
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1answer
233 views

Resolving power of ultra-telescopes [duplicate]

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 ...
3
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1answer
82 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 ...
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1answer
875 views

Ways to measure the focal length of a convex lens with only natural sun light [closed]

What are the common ways to measure the focal length of a convex lens with only natural sun light?
3
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1answer
153 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 ...
2
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1answer
177 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 ...
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3answers
167 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 ...
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0answers
84 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 ...
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3answers
400 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. ...
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0answers
37 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
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2answers
367 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 ...
5
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4answers
227 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 ...
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1answer
479 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 ...
0
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1answer
82 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 ...
7
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3answers
3k 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)
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1answer
93 views

diffraction grating

Can I design a diffraction grating that has only two orders of diffraction, with the second one has a zero intensity? So the first order of diffraction would be bright and the weak light from far ...
2
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4answers
4k views

Spectrometer vs. Spectrophotometer

I have been researching about the difference of a spectrometer and a spectrophotometer. They both sound the same. What is the difference?
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0answers
114 views

If we increase the aperture of a telescope and decrease its magnification, can it be harmful to the eyes?

The full moon is the brightest object in the night sky. I believe that if we increase the aperture of the objective, and decrease the magnification of the telescope, it might concentrate a dangerous ...
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3answers
4k views

Does light change phase on refraction?

I have seen a lot about when light undergoes a phase change when it is reflected. But does it undergo a phase change when refracted and if so why and if not why not?
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2answers
200 views

Gaussian beam modelling, location of the beam waist?

In reference to the specifications of a laser diode below: http://www.thorlabs.de/thorcat/11900/L780P010-SpecSheet.pdf I wish to be able to model it as a gaussian laser beam. I understand there is a ...
0
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0answers
48 views

Transparent vs Insulator

Being transparent, can I say that glass is a better insulator than wood. (Reason: In GLASS visible light(lower energy)is not able to excite the electrons in it,so just pass away to other ...
0
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1answer
107 views

Total internal reflection for perpendicular incidence

Are there any materials, which give total internal reflection for perpendicular incidence? Here, by this phenomena I mean: no absorption (including for evanescent propagation inside), finite ...
1
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1answer
193 views

Lens surrounded by two different materials?

If have a material refractive index $n_1$ then a lens refractive index $n_2$ then another material on the other side of the lens (but in contract with the lens) refractive index $n_3$. How do I find ...
0
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1answer
148 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 ...
2
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0answers
29 views

What property of medium is directly related to light propagation speed in that medium? [duplicate]

Refractive index is used to calculate phase velocity of light in medium, other than vacuum. Recently I had a discussion with somebody claiming that light is slower due to magnetic field of atoms. I ...
1
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1answer
96 views

Understanding camera lens and sensor compatibility

When a lens is specified not just by its focal length, but also the sensor format for which it is intended, what compatibility limits does that place on the sensors it can be used with? For example, ...
3
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4answers
90 views

Wave interference

Visualizing the double slit experiment, there are light lines and dark lines. The dark lines I understand are caused by the interference cancelling waves. What I don't understand is where the energy ...
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0answers
108 views

Diffraction of a thin mirror

I have a question about a particular case of light diffraction. A laser light collides into a "hairline" mirror (I mean a straight line mirror that halves the wavelength dimension), see the image ...