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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Beating the Diffraction Limit with NSOM

I am trying to understand exactly why we can beat the diffraction limit when using near-field scanning optical microscopy (NSOM). For those who aren't familiar with NSOM, check out this article: ...
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80 views

Can the insertion of impurities (doping) influence optical properties of ZnS?

I am currently trying to simulate a scintillator system with silver doped zinc sulfide (ZnS:Ag). To simulate the propagation of photons inside the crystal accurately, optical properties like index of ...
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63 views

A Circle of light

I'm working on a project that refers to optics. the question says when a laser beam is aimed to a wire ( perpendicular to the surface ), a circle of light then will be seen on a the surface. I ...
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39 views

Light absorption for different liquid

when I was working on a cylindrical glassy bottle that filled with water, I found that the initial light intensity is less than the final light intensity. (It's clear but I experiment this) This is ...
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59 views

What happens if light is trapped between two points?

The image can explain my question In the image light is clearly trapped.Even if the mirror absorbs energy the light is continously being added, will there be enough force to break the mirror?
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70 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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24 views

Fresnel coefficient

I dont think I have enough backgrounds for optics. I am sorry for asking this elementary question. I am reading a paper Phyc Rev A, Vol 59 # 6, 1999 they introduces discontinuity matrix ...
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1answer
33 views

Can virtual reality goggles have focal point 20 feet away?

Can virtual reality goggles have focal point 20 feet away? I read that eye strain from computer screens occurs if the eyes spend too much time looking at a screen that is too close. The 20-20-20 ...
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1answer
58 views

James Bond and the invisible car [closed]

For a seminar paper with the topic "Illusion of Invisibility in the James Bond movies" I have to investigate, whether the invisible car from "die another day" is (at least from a theoretical point of ...
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1answer
22 views

Why does light reflected on water tends to 'smear' in the vertical direction? [duplicate]

I have noticed that in city lights reflected on the water are very often smeared more in the vertical direction (relative to the reflecting plane I presume), than in the horizontal direction. See, for ...
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2answers
391 views

Finding the illuminance from a triangular light source

Since most light sources in games are point-like, it's pretty difficult to approximate area light sources with point sources. As triangles are a universal form to represent 3D models (thus area light ...
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1answer
771 views

Why does the chief ray not bend like other rays at the optical axis but goes straight?

1 pg In this picture the chief ray is not bending which is going through the optical axis. It passes straight while other rays from the same object are refracted because they change the medium.
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3answers
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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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35 views

Non resonant modes in cavity

I have a simple question. Suppose we have a laser with a cavity such that the frequency of the light that the laser emits does not match with any longitudinal modes allowed by the cavity. In ...
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32 views

Is it possible to implement the reversed dispersion of a white light beam and how?

The dispersion of white light beam while passing through a triangular prism is well known. Considering the reversibility of optical path, it should be possible to reverse the experiment. How can ...
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1answer
3k views

What is the difference between the words transparent and translucent?

Merriam Webster defines transparent as: Having the property of transmitting light without appreciable scattering so that bodies lying beyond are seen clearly. And translucent as: ...
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1answer
90 views

Michelson interferometry - is a compensator plate necessary?

I am studying the Michelson interferometer shown in figure 2 (similar design shown below) of the AMRITA vlabs tutorial. There it is stated that Since the reflecting surface of the beam splitter ...
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1answer
57 views

How reflective are typical mirrors in the visible part of the spectrum?

I was wanting to perhaps grow some plants using grow lights. For the sake of efficiency, however, I would like to use some mirrors to reflect this light, ie, keep less of it from uselessly ...
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2answers
126 views

Resolving power of a microscope?

I was reading up on the resolution of a microscope. I read (in some lecture notes) that the size of the limiting spot size is $1.22 \lambda f/W$. But that the smallest resolvable feature has a size ...
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1answer
64 views

Spatial coherence of SLED light (width of active region?)

As far as I know, super-luminescent diodes (a.k.a. SLEDs) have a very similar structure to laser diodes, except that the front faces of the active region are tilted to prevent the sort of reflections ...
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How to calculate desired light path in continuous medium with gradient refraction index

See the Figure below. $O:(0,0)$ is the disk center of light source $\odot{O}$ with radius $3$. Then the profile light rays of disk $O$ from the view point $B:(-14,0)$ is defined by segments $DB$ ...
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56 views

Higher order multipolar second harmonic generation in centrosymmetric materials

As is pointed in this question, second harmonic generation is forbidden in the bulk of the materials possessing centrosymmetry. In some papers it is said that in the dipolar approximation the SHG ...
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1answer
153 views

Alternate young double slit experiment

What will happen in young's double slit experiment, when instead of screen I put a black screen with a hole and a second screen behind the black one. Will it still form interference pattern albeit a ...
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1answer
54 views

Textbook Problem: Fiber Coupling Spheres

I am reading the book Fundamentals of Photonics. I try to solve problems at the end of chapter 1, but I got stuck on two problems. Tiny glass ball are often used as lenses to couple light into and ...
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2answers
133 views

Imaginary number for extinction coefficient in complex refractive index

In complex refractive index on a material, $n=n'+ ik$, the imaginary part $k$ is physical meaning, as it shows absorption in the material but it is an imaginary. How we measure an imaginary values in ...
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1answer
35 views

What will happen if I transmit 850nm signal through a 1300nm optical fiber? [closed]

We prefer 1300nm optical fiber over 850nm optical fiber because later one is more efficient. So am selecting 1300nm optical fiber. But I want to know the possibility of using same cable to transmit ...
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1answer
107 views

Optical mode leakage through a layer of gold

The geometry of my semiconductor device is given below. The blue regions are gold, the grey ones - gallium arsenide (n-doped to $2.9 \times 10^{15} \mathrm{cm^{-3}}$). The dimensions are μm, i.e. it ...
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25 views

Black holes in a denser media

In Crown Glass, the speed of light is 1.52 times the speed of light in vacuum. Consider the following hypothetical situation: Hypothetical Situation If a black hole is surrounded by a giant crown ...
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1answer
18 views

Understanding Braggs x-ray diffraction and why light is treated as a single “ray/line”

I'm not familiar with optics. So my knowledge of treating light as single lines is almost completely foreign to me. Although I do know something about EM waves and Maxwells equations, so you can ...
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1answer
155 views

Solution of the wave equation [closed]

I am dealing with the solution of the wave equation in two different cases represented in figure by Case A and Case B. The two figures were obtained by shining a slab with an incident wave coming from ...
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31 views

Interpreting Seidel Aberration coefficients

I am trying to model a simple system in Zemax (though I think the question is general and is not limited to Zemax app), but the ray-tracing does not seem to be consistent with the analysis of the ...
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44 views

Far-sightedness problem

Let's consider BOB and HENA have far-sightedness problems, and they uses lenses to correct their vision. Somehow, they exchange their glasses; how then can we determine the closest object distance ...
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4answers
298 views

Sign convention in optics

Why is the sign convention used in the derivation of the lens formula and yet used again when it is applied in numerical problems? Won't the whole idea of sign convention be eliminated if it is used ...
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22 views

Radius of an image not in the image plane due to diffraction?

When viewing an image in the image plane the radius of the image (assuming it is circular) is given by the radius of the Airy disc. But let's say we are not viewing it in the image plane, but in ...
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68 views

Increase contrast on the image taken by CCD camera

I project a pattern on a reflecting object and I capture the reflected pattern (reflected via the object) using a CCD camera. However, the reflected pattern has a very low contrast (due to volume ...
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Optics of the eye - do we see Fourier transforms?

I've recently been learning about Fourier optics, specifically, that a thin lens can produce the Fourier transform of an object on a screen located in the focal plane. With this in mind, does the ...
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2answers
360 views

Why must an integrating sphere be a sphere?

Why must an integrating sphere be a sphere? Why can't it be an integrating cube? What is the difference? Could I use a cube to measure total illuminance like an integrating sphere does?
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4answers
1k views

Are telescopes with a concave lens useful for astronomy?

Are telescopes with a concave lens (instead of convex ones) ever useful for astronomy? And if so, where are they used? Do they ever affect resolving power?
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30 views

On unfocused images, their information content and possible restoration

So, when an image is out of focus the light of any given point of the object does not refocus exactly at one point on the screen, but is spread out around a region, such that the light of the image at ...
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1answer
30 views

Why is there no fluorescence background in CARS?

In CARS (coherent anti-Stokes Raman scattering), the detected signal is blue-shifted with respect to the excitation - how does this mean that there is no fluorescence or that the fluorescence can be ...
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1answer
42 views

How to calculate the colour a human eye sees when looking at a light spectrum?

I have to do a presentation about colourants in Chemistry class (grade 12, advanced) and want to write a program that calculates and visualizes the colours of some simple molecules. What I need is ...
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Scattering of strong non-resonant light by cesium vapor

can anybody provide good references (research papers, books,,reviews, recent...) about a VERY strong NON-resonant light scattering from a cesium atomic cloud/vapor? (The light should be capable of ...
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40 views

Why can one see the outline of a white sheet of paper kept on another white sheet of paper?

Why can you see the outline of an object of a color that is in front of another object of the same color.
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1answer
64 views

The lineshape of a 2D photonic crystal dispersion diagram

Using simulation software (CST Studio), I calculated the dispersion of the eigenmodes of a photonic crystal, that is frequency vs wavenumber for the desired propagation direction. I wonder what kind ...
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1answer
33 views

Resonant vs. Non-resonant Raman

What does it mean to say that the conventional Raman effect is non-resonant? And, how/why does resonant Raman give a stronger signal than the non-resonant type?
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72 views

Is possible carry light using a rectangular mirroned tube? [closed]

I'm newbie and I want know if Is possible to carry light using a rectangular mirroned tube and create a illumination system with this principle.? I think is possible using schemas with mirrored ...
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1answer
68 views

How is the imaginary part of angular frequency omega related to the imaginary part of the refractive index?

I'm trying to find the attenuation constant (leak rate) $\alpha$ from the imaginary part of the refractive index of a lossy material. I have the eigen frequency $\omega$ for my structure which has an ...
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2answers
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Why do things that are far away seem smaller?

As you see things that are far smaller, a funny question about this: Imagine there are many people in a row (all are same height) ...
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Diffraction from a single slit experiment and Heisenberg's uncertainty principle [duplicate]

Practically how to separated between Fraunhofer and Fresnel diffraction? Do all diffraction fringes from single slit have same peaks? Why?
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1answer
44 views

Is near point defined for a myopic eye and far point defined for a hypermetropic eye?

I learnt about far Point of a myopic eye and near point of a hypermetropic eye. But I am confused about the above question. And if near point is defined for a myopic eye and far point defined for a ...