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
2answers
47 views

Measuring image distance of a virtual image

How to a measure image distance of a virtual image without calculation? It is impossible? To measure it, we must have a real image to measure the image distance with a screen and a ruler. I saw it ...
5
votes
1answer
63 views

Long, blurry reflections in wet road [duplicate]

When driving on a wet highway at night, any surface emitting or reflecting light will have a reflection right under it that is blurry and seems to stretch to infinity. This is not exactly what I am ...
1
vote
1answer
23 views

difference between plasmonic wave plates and usual wave plates

plasmonic waveplates are constructed using the generation of surface plasmons. Is there any difference between these plasmonic wave plates and the usual wave plates used in optics, besides the ...
3
votes
2answers
71 views

Decoherence of a Coherent Beam

If retarding films (i.e. wave plates) can retard the electric components of light (based on the films thickness) without affecting it's direction, couldn't I use a retarding film of randomly varying ...
1
vote
0answers
98 views

Is it possible for someone traveling at the speed of light to see at all? [closed]

I know that the speed of light is the same for all observers regardless of your speed, But this question is really worth thinking about. If someone let's say managed to reach the speed of light, ...
1
vote
0answers
46 views

Can anybody explain about phase shift and phase spectrum terms in case of multidimensional signal?

I know about phase of a 1D signal, but when I move into higher dimensions like 2D or 3D etc, it becomes headache to grasp the concept. What do the terms "phase shift" and "phase spectrum" mean in ...
1
vote
1answer
32 views

Polarization and Reflection [duplicate]

The polarization is a property of waves that can oscillate with more than one orientation. Given this, when the light is reflected from a surface, does the reflection change the property/orientation ...
1
vote
1answer
46 views

Why Image is not enlarged if we keep convex lens first and concave lens at last?

Well After successfully getting some concave and convex lens I started observing. At first I saw that if we keep concave lens near to your eye and just after x distance away if we keep convex lens we ...
2
votes
1answer
43 views

How much UV is reflected by glass?

On a sunny day, how much of the Sun's UV is reflected by windows? I suppose this boils down to what are the refractive indices of common window glasses, so that one might solve the Fresnel equations. ...
0
votes
0answers
20 views

Is polarization a meaningful notion for an EM mode in a close cavity?

For a generic close cavity, I suspect that all the modes are non-degenerate? Therefore, in each mode, at each point, the E field has a definite direction, and consequently, it is meaningless to say a ...
2
votes
2answers
51 views

Is the photon truly not absorbed in Raman scattering?

In reading about Raman Scattering, I was thinking while reading it "okay, incident photo absorbed by molecule, molecule goes to higher energy vibrational state, molecule re-emits photon with either ...
1
vote
1answer
37 views

Plane Mirror as the Screen in Young's experient

If I place a plane mirror instead of the screen in the Young's double slit experiment, what will I see? Will the bands appear on the mirror face?
3
votes
0answers
46 views

3D movie optics mathematics

I get the idea that we use two polarized light sources and a parallax rendered film such that the objects seem to resemble true parallax in our eyes once it passes through the polarized glasses, but ...
1
vote
1answer
76 views

Propagating higher order Hermite Gaussian modes. What are complex amplitude coefficients?

I've been tasked with writing a code (in MatLab, but I'm currently using Mathematica because I don't know MatLab %\ ...) to simulate the propagation of a Gaussian beam. I don't really know anything ...
0
votes
1answer
31 views

hexagonal patterns when we look at bright light or sun

when we look at bright light or sun, we many a times hexagonal patterns are observed. these are easily observed when we click their images. why all this happens? is all this is just a lens flare or is ...
1
vote
0answers
33 views

coherent length measurement of a monochromatic laser source

i need to learn about how to measure coherent length of a monochromatic laser source.I know that I can use michelson interferometer or spectrometry.For laser which has long coherent length michelson ...
1
vote
1answer
36 views

Position dependent refractive index [duplicate]

How to determine the angle of refraction when the medium has position dependent refraction index? Lets say that the angle of incidence on the glassy slab is $\theta_1$ and the ray goes through the ...
1
vote
0answers
36 views

Rayleigh scattering equation for optical frequencies

I would like to know if there is an empirical/generic equation for Rayleigh scattering at optical frequencies in the atmosphere, similar to the Mie scattering model from Kim and Kruse which states ...
1
vote
0answers
33 views

Disadvantages of viewing a diffraction grating at larger order?

If you are using a diffraction grating as a spectrometer you are likely to use high order, because you have a better resolution (as a result of larger dispersion??). But are there any disadvantage? I ...
3
votes
1answer
99 views

Why infrared light waves is visible through camera? [duplicate]

For example We know that some television manufacturers have the limited IR-based remotes which cannot be seen by our eyes directly but while playing when I just put my camera in front of my TV remote ...
1
vote
1answer
89 views

How do I convert lux to lumens

Overview... I'm a novice in the very basics of light physics and calculation between various units. I'm sure this is a very simple problem to those who know the process. And, before we continue, this ...
12
votes
2answers
3k views

Is true black possible?

Black is the absence of light because it absorbs light, but when we create black paint or black objects, light is always reflected, either in all directions in matte or smoothly in shiny black ...
5
votes
0answers
70 views

What's the size of the smallest possible CCD/CMOS pixel size?

For a given wavelength $\lambda$, is there a limit on the size of the sensor pixel, regardless of the optical equipment attached to the sensor?
6
votes
0answers
132 views

Why can I turn light red or blue by holding my finger up to it?

This is a difficult phenomenon to explain. Imagine you have an opaque object partially covering a very bright light source, for example, an object held up against the sky. The left hand diagram is ...
1
vote
3answers
131 views

Is the output of a laser pointer polarized or not?

How to verify it? Is a laser necessarily polarized? I have a laser pointer with wavelength 532nm in hand.
0
votes
1answer
35 views

Optical spectrometer

I am new on optical spectrometer, my particular interest is the spectrometer in which the deflection is produced by diffraction in a diffraction grating. But I can not find a good schematic and the ...
0
votes
0answers
28 views

Magneto Optical Kerr Effects

I have a few questions on MOKE setup. Firstly, why is calibration of the coils necessary? Is it to get a relationship between the voltage and the Magnetic field? Secondly, why do we have to normalise ...
2
votes
0answers
32 views

How accurately do Airy discs need to be superimposed in an optical interferometer to create fringes?

In an astronomical optical interferometer, what is the largest amount of error in the alignment of the Airy disks of point source star images from different arms of the interferometer that will still ...
7
votes
1answer
161 views

Viewing computer screen through 3D glasses, why the asymmetry?

I have 3D glasses made up of plastic. First case: When I hold front side of the 3D glasses (by this I mean that side on which light falls) in front of a computer screen, light coming from screen is ...
2
votes
0answers
46 views

How to deal with coma and oblique spherical aberration in a Czerny Turner configuration?

I am modelling my own spectrometer using Zemax when all of a sudden I've been told that: even if you manage to optimize the angles or positions of the grating and the mirrors, you won't get ...
1
vote
1answer
34 views

Apparent motion in a convex mirror

Why is it that if we look at the image of a person running with a constant velocity, in a convex mirror (for instance the rear view mirror of a car), the man's velocity seems to be accelerated?
3
votes
0answers
65 views

Is refraction of light a thermodynamic process?

Is refraction of light a thermodynamic process? Can it be explained by conservation of energy? If so, does temperature has an effect on refraction of light?
4
votes
1answer
135 views

Why don't extraordinary rays follow Snell's law?

I understand that ordinary ray (O-ray) and extra-ordinary ray (e-ray) have different refractive indices. This should mean O-ray and e-ray move with different velocities in a substance and they should ...
3
votes
1answer
120 views

What are the purposes of slits inside a spectrometer (Czerny-Turner)?

I am building a Raman spectrometer with a Czerny Turner configuration (with RamanPi). Why does the light source (A) appear to be converging into the entrance slit (B)? When a sample is excited by ...
1
vote
0answers
49 views

In the photon picture, how can light slow down and yet not be absorbed? [duplicate]

Many materials, such as glass, are transparent over some wavelength interval. In the photon picture, as far as I understand it, this is because there are no allowed transitions corresponding to the ...
0
votes
2answers
42 views

Would obstacles cause light diffraction if it has the same refractive index as the surrounding material?

Restatement of title: Would an obstacle still cause diffraction of light if it has the same refractive index as the surrounding material?
2
votes
0answers
71 views

Why do spatial filters use microscope objectives, and not other types of lenses?

A spatial filter is a device to 'clean up' a laser beam with an irregular intensity profile, and create a smooth Gaussian profile at the output. It is usually said (e.g. here) that you need a ...
1
vote
1answer
27 views

How to convert the molar attenuation coefficient, ie. molar absorptivity, to heat capacity?

In spectroscopy techniques, such as infrared spectroscopy, light of a certain wavelength is absorbed. I see parallels to the concept of heat capacity, i.e. the heat necessary to change the temperature ...
0
votes
0answers
50 views

How to convert from transition dipole moments to oscillator strength?

I'm having some trouble converting from transition dipole moments (in atomic units) to oscillator strength. I've found the following equation in Modeling Molecular Photochemistry by Nick Turro, which ...
0
votes
0answers
24 views

Finite Value of Cross Section of (Scattering/Absorption) of Localized Surface Plasmon at Resonance

According to textbook written by Stefan A. Maier, ch.5, p.70, cross section of scattering and absorption are defined as: $$C_{sca}=\frac{8\pi}{3}k^4a^6 ...
0
votes
2answers
25 views

For a light of given frequency, what does the amount of refraction in a variable medium depends upon?

I want to know whether the amount of refraction of a given monochromatic light depends solely upon the density of the of the medium ( increase the density to increase the angle of refraction), or ...
3
votes
1answer
75 views

Does Fermat's principle of least time apply to sound waves?

I am reading Feynman's presentation of Fermat's Principle of Least Time, which explains the behavior of light; does it apply to waves in general? for example sound waves or waves on the surface of ...
0
votes
1answer
80 views

Determining the path of a light ray

Let's consider a ray in the plane $xy$. Let the refractive index be defined in any point of the plane with the function $n(x,y)$. In time $t=0$ the ray is located in coordinates $(x_0, y_0)$ and its ...
3
votes
1answer
445 views

why cant we use a pair of polarizer ( whose pass axis are oriented at 90 degrees ) to protect from entry of harmful radiation?

If a pair of polarizers can block EM waves passing through it, then can we use them for protecting against harmful radiation (in nuclear reactors and also in spaceships) in thermo flasks to ...
1
vote
0answers
36 views

473 nm light through a single mode fiber designed to operate between 1500 and 1600 nm

Can we send light with 473 nm through a single mode fiber designed to operate between 1500 to 1600 nm spectrum? The radius of the fiber core is 4.25 micrometer, NA=0.12 and the single-mode cut-off is ...
0
votes
1answer
51 views

How is angle measured by telescope in spectrometer is twice the prism angle [closed]

While measuring the angle of the prism with the help of telescope in a spectrometer (see figure below), the observed angle is twice the angle of the prism. Can someone prove it geometrically? Edit : ...
1
vote
0answers
30 views

Is my window's semi-transparency a consequence of elementary quantum mechanics? [duplicate]

Studying mathematical concepts of quantum mechanics, I have recently become familiar with the classical model of one-dimensional particle being scattered by a potential barrier. As a mathematician, I ...
1
vote
1answer
54 views

Why does radiance remain constant along rays of light through empty space?

In Radiometry, radiance (L) is defined as flux density per unit area per unit solid angle. If we move further along a ray, away from a point, shouldn't the radiance decrease? I am unable to grasp an ...
2
votes
0answers
30 views

Is there any review paper on spatial light modulator?

I need a review paper on the various types, principles and characterization of spatial light modulator. But it seems I could not find one. Any one has a good idea?
1
vote
1answer
18 views

Lens to optimize field of view through a tube

I have a tube of length L and radius R with L>>R. I want to place a lens in the tube such that I have the biggest field of view when I look through the tube. Is the correct answer just the obvious ...