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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14 views
Problem in angle measurement [migrated]
From the above picture we can prove easily $ CF = XF$ because CFX is a isosceles triangle. Now if we move the point X more near near P, it will give the same results(I mean we will get again $ CF = ...
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16 views
Why is Erbium Doped Fiber Amplifier (EDFA) preferred over Erbium Doped Waveguide Amplifier (EDWA)?
Why is Erbium Doped Fiber Amplifier (EDFA) preferred over Erbium Doped Waveguide Amplifier (EDWA)?
The question has been asked from an engineering point of view, but obviously I would also be ...
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1answer
76 views
Calculate the distance between two points from iPhone Camera
I want to calculate the distance between two objects using an iPhone camera.
Suppose I'm standing with my iPhone 10 feet away from the objects. Now, I want to calculate the distance between those ...
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0answers
19 views
Specular intensity [closed]
Im currently studying for an exam and have been going through some past papers on the subject, however i have come across a question that has recursively come up each year and the notes on it are not ...
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1answer
32 views
Optical element fitting to Jones matrix
I need help with finding out which optical element is this.
I read about Jones matrix and vectors, but this is not one of the standards.
$$
\begin{pmatrix}
1 & i \\
-i & 1\end{pmatrix}
\cdot ...
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Lowest attenuation at 1550 nm for link lengths in 30-50 km range [closed]
Could someone point me to a reference that features the lowest-possible loss value (as of today) for transmission of light at ~1550 nm? In particular, the typical length of the optical link is in the ...
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0answers
17 views
Image formed by a spherical ball [closed]
There is an object on one end of a sphere and an image is formed on the other end. I am given the index of refraction,radius and the distance of the image from the center ball. How do I find the ...
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1answer
33 views
Photo of reflection in magnifying mirror shows normal magnification. Why?
I just took a picture of myself in one of those magnifying shaving mirrors and in the photo I am unmagnified! Why is this?
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1answer
18 views
Heat deposition at optical focus in a clear medium
This is an applied physics question for an engineering problem. The well known experiment we have all done--burn paper and wood with a magnifying glass and the sun's rays. My question is, if one were ...
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2answers
28 views
Penetration of light in the atmosphere
While I was considering an answer to this question, I wondered how much light that enters the atmosphere reaches the ground without colliding with air molecules—if any. I've taken a good bit of ...
2
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1answer
54 views
Manufacturing Fresnel Lenses with Sound
I understand fresnel lenses are manufactured using CNC machines. I was wondering, if it would be possible to use sound to vibrate liquid silicon and then fast cool it into the standard form of a ...
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1answer
63 views
Optics alignment of a confocal scanning microscope
I am facing a challenge in my project regarding optical alignment.
See the figure:
The challenge is with the vertical optical system alignment. I considered placing a mirror and check back if the ...
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16 views
What's the equations for spacial charge distribution in COMSOL? [migrated]
I am now using COMSOL (RF model) to simulate the optical response of a given object (say, a Au sphere) when experiencing the incident plane wave. I wish to get the spacial charge distribution of this ...
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36 views
Physical Optics [closed]
Monochromatic light is used to illuminate a pair of narrow slits 0.3 mm apart and the interference pattern is observed on a source 0.91 mm away. The second dark band appears 3.0 mm from the center. ...
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1answer
139 views
What's the physical significance of using fourier transform for diffraction?
I am studying some basic idea of diffraction and there mention in far field, the diffraction pattern could be understood by Fourier transform. But I just don't understand what's the physical fact for ...
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1answer
45 views
Reflection of a polarised beam
The past days I've been trying to understand how AutoFocus(AF) works on photographic cameras. There is a statement that says AF systems are polarisation sensitive. This means that they can only work ...
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Liquid crystal physics, uniaxial nematics, do director and optical axis point in the same direction?
question relates to the physics of liquid crystals(tried to add liquid-crystal or soft matter physics tag but couldn't find one). Uniaxial nematics are a type of LC. It's easy and convenient to ...
5
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1answer
42 views
Reflectivity of a glowing-hot metal surface
When a polished piece of metal (or steel in particular) is heated to incandescence, how do its reflective properties change?
Given a mirror-like surface, would the object temporarily cease to act ...
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2answers
51 views
Hyperopia, Far Sightedness
With hyperopia, the focal point is behind the retina, shouldn't this mean that the image is flipped on the retina itself from what is usual?
I must be drawing my ray diagrams wrong.
A little ...
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1answer
43 views
Optics, lenses and our eyes
When we view an image, is the focal point of our eye on our retina? Shouldn't that hurt?
Also, if that is how our eye works, then why don't lenses put the focal point their equivalent retina? I was ...
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2answers
69 views
Mirror image at relativistic speeds
Imagine moving parallel to the surface of a very large flat mirror at relativistic speeds. What would be the effect of viewing yourself in the mirror? At non-relativistic speeds your image would be ...
3
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2answers
82 views
Is there a way to create a flickering frequency to be dependent on speed of the person looking at it?
Is there a way to make a screen or a road sign flash at different rates, depending on the velocity of the observer looking at it?
I would like to achieve a state where two observers going at ...
2
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1answer
39 views
State emitting from an extended thermal source
This calculation is for a double slit experiment setup which is experiencing a far field radiation from an extended monochromatic thermal source. I assume the source is 1-D and it's length is $b$. ...
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27 views
Non reciprocal light propagation
In search for some explanation in why magneto-optical materials (like the one used in the Faraday rotator and, consequently, in the "optical diode") act in such a "strange" way, I saw that this kind ...
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1answer
43 views
Apparent and real depth object in water [closed]
Did I get my formula right? Seems like the correct answer is $d_o = 1.33 \times d_i$ but I thought the formula I should use is $d_i = - \frac{n_2}{n_1} d_o$
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2answers
126 views
Physical explanation for why total internal reflection occurs
I have been trying to understand total internal reflection (and have read several posts on this site already). Mathematically, I feel that I understand how the evanescent wave decays exponentially as ...
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2answers
92 views
Keep the light beam in a closed room, is it possible? [duplicate]
I mean if I am in a room totally closed to light. If I switch on a torch for a second then switch it off. So will the inside of room be always bright?
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43 views
Is my textbook in error about this geometric optics relation?
Given a centered optical system (having an axis of rotational symmetry), let $H_1$ be the intersection of the optical axis and the "principal object plane" (I'm studying in French and have no idea how ...
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1answer
65 views
Infinite reflection of light and the conservation of energy / momentum
First off, I confess I'm no physicist, but I have been asking people with a more extensive knowledge this one question, without a definitive answer so far.
Basically, I'm playing around with the idea ...
4
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1answer
34 views
The weight of a cavity of radiation
A sealed cavity full of light weighs more than an empty one. So consider a cavity consisting of parallel mirrors, with a pair of beams bouncing between the mirrors. The question is whether that weight ...
3
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2answers
27 views
Concerning Scattering Intensity and Particle Concentration
I am trying to determine what governs my sensor output. I have an optical sensor that emits infrared radiation on a sample volume and gives me a voltage output from the scattering of (1 to 10 micron) ...
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119 views
Optimal telescope size?
Consider a diffraction-limited telescope with unobstructed aperture $D$. Such a scope is capable of yielding an angular resolution $\alpha$ that scales as $\lambda/D$, with $\lambda$ denoting the ...
2
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1answer
53 views
Why does the quantum eraser seem to violate energy and momentum conservation?
In the literature of the quantum eraser experiment it is argued that the change in statistics of the system from non-interference to interference is due to the erasing of "distinguishing information". ...
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1answer
183 views
Can a photon exhibit multiple frequencies?
Can a photon be a superposition of multiple frequency states? Kind of similar to how an electron can be a superposition of multiple spin states.
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Selectively visible laser beam with a controllable means
How can parts of a laser beam be made visible while others left invisible using something electronically controllable (for example, another laser beam crossing it, or a magnetic field, or heat, etc).
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2answers
160 views
Light Ray Reflection from concave mirror
Suppose a ray of light hits a concave mirror and is parallel to principle axis but far away from it such that it doesn't follow paraxial ray approximation. Will it pass through focus or between focus ...
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1answer
86 views
Why do focal lengths affect magnification?
For compound lenses, the image formed by first lens acts as the imaginaryobject for the second lens.
In telescopes, the objective lens projects an image on its focal point which works as the object ...
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2answers
62 views
Is light red shifted in optical tweezers?
This is a question I put to my supervisor during my PhD many years ago, and never really got a satisfactory answer to.
In an optical tweezers, assume that a beam of light is used to move a glass ...
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33 views
can you guys help me with image properties. how to do the calculations [closed]
A 10 cm tall perfume bottle is placed 100 cm in front of convex spherical mirror with a radius of curvature of 50 cm.
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1answer
56 views
Confusing mirror problem
A piece of thin spherical shell that has a radius of curvature of 106 cm is silvered on both sides. The concave side of the piece forms a real image 79.5 cm from the mirror. The piece is then turned ...
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1answer
69 views
Three polarizers, 45° apart
If light is passed through two polarizing filters before arriving at a target, and both of the filters are oriented at 90° to each other, then no light will be received at the target. If a third ...
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32 views
Determine the image properties by calculation [closed]
A 10 cm tall perfume bottle is placed 100 cm in front of a convex spherical mirror with a radius of curvature of 50 cm. Determine the image properties by calculation
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1answer
110 views
Young's double slit experiment viva question
My professor asked me (in my viva exam), "If, in the Fraunhofer single slit diffraction experiment, if we have 2 slits instead of one (at very short distances), What would happen?"
I answered with ...
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1answer
34 views
Can the choice of reflection angle for light can be derived from a minimality condition?
When the light hits on a surface, it reflects with the "same" angle as the one that hits the surface. I was wondering if this choice of angle can be explained by a minimality condition?
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26 views
Problem in geometrical optics [duplicate]
I was trying to solve a problem taken from an Physics Olympiad when I came across a curious and complex mathematical expression. I can not prove with what I know so far about mathematics, does could ...
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0answers
47 views
Trigonometry in the plane mirror [closed]
I was trying to solve a problem taken from an Physics Olympiad when I came across a curious and complex mathematical expression. I can not prove with what I know so far about mathematics, does could ...
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1answer
41 views
How can a Jones vector give linear polarization along an axis?
If we represent a Jones vector by two complex-valued exponentials, $J_1 = e^{i \phi_1}$ and $J_2 = e^{i \phi_2}$, how can this ever give a polarization along the x-axis? We write such a polarization ...
3
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1answer
81 views
How to create visible reflections in shallow water?
Assumption: The only lights I have are candle, table lamp, and sunlight.
What would I need to create visible reflection of an object in the shallow water contained in a 5 liter bucket? Is it even ...
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2answers
61 views
Speed and transparency of light
I have been puzzled with a fact that as an object moves faster, it ceases its property of opacity. I mean to say that as an object moves faster we can see right through it (more clearly than in a ...
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2answers
119 views
How does this trick with mirrors work?
Imagine two mirrors, set touching each other at right angles to one another. There is a 90 degree arc in which reflections can be seen, and a person standing in that arc can see himself reflected in ...
