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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2answers
105 views

A simple question [closed]

This is a simple question but it seems to me that both the explanations are acceptable. Let say the least distance of least distinguished vision is 25 cm. An object is placed 12.5 cm in front of a ...
1
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1answer
103 views

Input parameters for the reconstruction algorithm in Digital Holography

I've been browsing some Digital Holography papers these days, and have come across this fundamental question. When you reconstruct the complex amplitude for the object image, you use e.g. Fresnel ...
1
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0answers
58 views

Conceptual way of understanding what material 'does' at critical angle

I would like a conceptual way of understanding how a material behaves at the critical angle. So why does it all reflect? I can see why it reflects in the maths, but conceptually, it doesn't make ...
2
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2answers
269 views

Change of hue near shadows

My brother is an artist and he told me his paintings look more natural when he slightly change the hue (color) of the surface near the transition between shadow and light. Here's three examples: (1) ...
2
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3answers
568 views

Unpolarized light vs. randomly rotating polarized light?

I am confused with physical picture about unpolarized light. Is unpolarized light very fast rotating polarized light? or co-existing state of two orthogonal polarization? (or something else?) If ...
3
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1answer
276 views

computing wavefront deviations for off-axis mirrors

Suppose you have two off-axis aligned mirrors which are nearly planar, with small deformations such that a wavefront at plane $P_I$ at distance $-D$ from the mirrors, is refocused at distance $D$ at ...
4
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3answers
2k views

Transmittance of glass

Glass has low transmittance for infrared light. Does glass reflect or absorb infrared light? Greenhouses are able to reflect infrared as I understand it.
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0answers
275 views

Cylindrical lens aberration fixed by roll

I have two cylindrical lenses essentially forming a beam expander. The problem that I am having is that I am seeing a very strange aberration. The image becomes "squashed". Cylindrical lenses only ...
7
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1answer
521 views

Huygens wave theory not applicable to lasers or parallel beams of light?

According to Huygens wave theory, every point on a wavefront acts as a secondary source of waves. Using this principle we can never have pretty narrow parallel beams of light right? Like lasers? ...
5
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2answers
3k views

Optimal slit width in Young's double slit experiment

I'm trying to do Young's double slit experiment at home. Note that I don't have a laser, only a torch. I could get a bulb or use a candle though, if it helps I built the slits by cutting into a ...
2
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2answers
2k views

Why do powers of lenses get added?

In our physics class, we were told that a power of a lens is defined as the reciprocal of its focal length. Also, the powers of multiple lenses get added up. But I didn't understand why this is. I ...
2
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2answers
247 views

How far can you scatter light using a prism?

If I were to scatter light how far do you think it will disperse and what prism is the most effectively scatters light?
2
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1answer
448 views

time constant for typical fluorescent lights

For a typical flourescent light available in the United States on a a standard 120V 60Hz line, is there information available on the decay time of the light? For example, if I am running the light a ...
0
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2answers
79 views

Brewster angle with diffraction propagation?

Diffraction theory is scalar. How you deal with beam propagation in fourier optics that is sensitive to the to the polarization? If I have linearly polarized gaussian beam incident on glass surface, ...
2
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1answer
259 views

Distinction between Larmor frequency and Rabi frequency

Wikipedia said "In the context of a nuclear magnetic resonance experiment, the Rabi frequency is the nutation frequency of a sample's net nuclear magnetization vector about a radiofrequency field. ...
2
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3answers
239 views

Four questions on color

First, I apologize for being a mathematician and having no scientific background in physics. The following questions on color came up in a discussion at lunch and I would be very happy to get some ...
2
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1answer
754 views

Compound microscope vs astronomical telescope

In compound microscope, we take such an objective lens which has small focal length. While in astronomical telescope, we take such an objective lens which has large focal length. Why don't we use ...
1
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0answers
305 views

How to calculate the helicity of polarized light?

At first, I used to think that only circular polarized light has non-zero helicity, linear polarized light has zero helicity, because the linear polarization can be seperated as the superposition of ...
1
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1answer
433 views

How mirror equation can explain farsightedness correction?

I have a friend who has just show me his medical prescription for hyperopia (farsightedness) correction and he needs glasses with 4,25 diopters for that, which seemed to be weird for me because I had ...
5
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3answers
587 views

Why does light diffract only through slits?

We can see diffraction of light if we allow light to pass through a slit, but why doesn't diffraction occur if we obstruct light using some other object, say a block? Why are shadows formed? Why ...
3
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1answer
415 views

electric field of unpolarized light after reflect?

Reflection and transmission (Fresnel equation) of polarized light are treated in many optics or electromagnetism books. If $E_s$ and $E_p$ is incident electric field with s-polarization and ...
1
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1answer
3k views

Radius of curvature of lens: Newtons Ring method vs spherometer

I have to do an experiment to find out the radius of curvature of a lens using the Newtons ring method given that you know the wavelength of the monochromatic light used in the experiment. What the ...
2
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1answer
194 views

Why does a stack of transparencies appear white when a single sheet is clear?

My daughter and I found a box of old transparencies (clear plastic sheets) and something struck me as odd: even though each transparency is clear, the whole stack of transparencies looks whitish - why ...
1
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1answer
43 views

Full refraction in fibre optics

Well in a problem I had to calculate the maximum amount of "reflections" in a glass fibre optic pipe (index of refraction = 1.3, width of 20 micrometer and length of 1 meter). I am a bit blocked on ...
1
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1answer
1k views

Magnifying factors of multiple lenses (closely packed)

Well the following question I really struggle to find an answer A thin lens creates an image of an object with magnification -3. A second identical lens is positioned very close to the first ...
8
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0answers
233 views

Suntan: UV absorption vs daytime

I guess that these questions were being asked by many people on the Northern Hemisphere during this summer (and other summers) and someone may give a nice, coherent answer. The general question is how ...
2
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1answer
747 views

Why does a white object lit by a blue light cast an orange shadow?

I was reading this blog post: http://ianstormtaylor.com/design-tip-never-use-black/ Which phenomenon explains this: But I must have been thinking the same thing, because one of those days in art ...
4
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1answer
103 views

Is diffraction through an aperture similar to diffraction by a plane of atoms?

I'm asking because I have a problem asking me what the diffraction pattern would be if instead of spherical atoms I'd have triangular atoms. I can't find anything about this in my X-ray diffraction ...
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0answers
111 views

C Method for Diffraction grating

Alright, so I am trying to find the efficiencies of a coated diffraction grating through the method in this paper. This is through a change of coordinate system. So I went through and derived all of ...
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0answers
140 views

Determing aperture size for space-based-solar-power laser transmitter

I have hit a bit of a roadblock in my simulation. In the equation I require the aperture size for the laser source. $$I_a ≈ \frac{\lambda d}{A}$$ $I_a$ = aperture atop the atmosphere ($m$) ...
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0answers
26 views

What are physical effects that could be employed to emulate this system?

This is a simple system consisting of a tree of numbers such as ((1 2 (3 4)) (2 6) 1 6) and a rule of application, that states that a tree A applied to B is a copy ...
2
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1answer
331 views

Diffraction Gratings

Is it possible to use the sawtooth shape diffraction grating instead of rectangular grating if yes then which parameters will affect at the output ? Secondly, what is special in blaze grating ...
1
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2answers
82 views

Ultrafast Lasers

Is the main idea of femtosecond or attosecond lasers is to achieve the high energy or do we have any other parameters achieved by ultra-fast lasers ?
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0answers
31 views

Optics of a rotated spectacle lens [duplicate]

I have just discovered that if I rotate my left spectacle lens about the vertical axis by 10 degrees in one direction, the vision in that eye becomes much crisper. Note that the sphere and cylinder ...
3
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1answer
305 views

Rayleigh scattering in three dimensions

How does the Rayleigh scattering intensity depend on the polarization angle of the incident, linearly polarized light, and the observation angle in three dimensions?
4
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1answer
170 views

Light entering in a 0° angle, is there any reflection?

Is there any reflection of light that enters a new medium at a 0° angle, if the electric field is such, that it is completely in the plane of the double layer?
4
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2answers
342 views

What is the meaning of “CW” in LASER?

I am reading a user's manual, and the word appears here. At first, I think "CW" means "center wave". But later, I find that the meaning of "CW" is "continuous wave". It makes me confused. ...
5
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1answer
124 views

Why does static electricity not make a charged body reflective?

If mirrors work by deflecting photons by free electrons in surface layer of mirror, so it could be possible to take a glass pane and provide it with extra free electrons by giving it massive static ...
4
votes
2answers
297 views

Shape of the rainbow

I have watched Walter Lewin's lecture(http://www.youtube.com/watch?v=6QVbE_tU2sA) which was about the rainbows. But there is still a question bothering me. I understood the first part of the ...
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0answers
65 views

Is there spatial data loss in light passing through transparent crystal?

There is perfect parallelepipedal bar made of transparent crystal with cubic lattice floating in vacuum. Faces of parallelepiped are parallel to lattice axis. There is image, forming checkerboard ...
1
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1answer
103 views

Is there any optical phenomenon can't be explained without magnetic field?

Almost all optical phenomenon can be explained considering a fluctuating electric field. Is there any optical phenomenon which can't be explained without considering two fluctuating fields, electric ...
1
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1answer
5k views

Minimum height of mirror required to view image

I wanted to know the minimum height of mirror required to be able to view a complete image of a person. I considered the following setup: $HF$ is the person in question. $H$ denotes the head, $F$ ...
1
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1answer
99 views

Vibrations after polarization of light

When we polarize a light, do we get electric vibrations, magnetic vibrations or the mixture of both. If both, then how can both electric and magnetic vibrations occur in single plane because ...
51
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6answers
11k views

Why are most metals gray/silver?

Why do most metals (iron, tin, aluminum, lead, zinc, tungsten, nickel, etc.) appear silver or gray in color? (What atomic characteristics determine the color?) What makes copper and gold have ...
4
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3answers
242 views

Fourier transform of two pulses of light

I have laser beam path that fires two pulses of light in a gaussian distribution, so the intensity graph over time is two identical gaussians separated by a distance $t_0$. In other words, a gaussian ...
7
votes
2answers
1k views

Slowing down light in an opaque crystal for a whole minute

I just read about a team of physicists at the University of Darmstadt, Germany, that managed to completely slow down a beam of light that traveled through an opaque crystal (article here). How is it ...
0
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4answers
687 views

Blocking an IR camera [closed]

What kind of material would be best to block an IR camera? Would Silicon work? (e.g the Silicon typically used in iPhone cases) Rather than covering the object/subject, I'm interested in fully ...
3
votes
0answers
373 views

Pockels effect/Kerr effect

In Pockels electro-optic effect, change in Electric field produces change in refractive index/ birefringence. Moreover this effect becomes electric field squared in the case of Kerr effect. If we ...
14
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1answer
253 views

GHz rate single photon counting

The fluorescent lifetimes of molecules used in biological applications tend to be in the sub-ns to a few ns timescale (let's say 0.8-4). The most direct methods to measure lifetimes typically involve ...
3
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1answer
67 views

Silicon Laser and Laser mirrors

If I will place Silicon as the active medium to create a Silicon Laser. Why I cannot achieve Lasing ? secondly, why do we always consider Laser mirrors in an standing position along the optical axis ...