# Tagged Questions

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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### Does this expression $\frac{\lambda^2}{4\pi \sin^2{\alpha}}(1-\cos({\frac{2\pi b}{\lambda}\sin{\alpha}}))$ have a special name?

I am currently doing fourier transforms and during my calculation I came across this result: $$\frac{\lambda^2}{4\pi \sin^2{\alpha}}(1-\cos({\frac{2\pi b}{\lambda}\sin{\alpha}}))$$ Letting ...
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### Help to find a simple setup for optical surface topography

I'm looking for some help from someone expert in optics to create an inteferometry based setup to map the surface of a small object. This is for a small lab project so I'm not looking for a really ...
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### Why does the critical angle for refraction exist?

When light moves from a medium with a high refraction index to a medium with a low refractory index (water to vacuum), that there exists a "critical angle" at which no more refraction occurs. What is ...
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### Find the axial resolution achieved for confocal microscope [on hold]

Relevant equations F-number is f/d x0 = 1.2λ(fnumber) The attempt at a solution Fnumber1 = 0.2 Fnumber2 = 0.6 x01 = 180nm x02 = 540nm These values seem large for depth resolution, is this ...
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### Does the direction of propagation of the natural light is perpendicular to the direction of electric and magnetic field making up natural light? [on hold]

I know that the direction of propagation of the wave(light) is perpendicular to the direction of electric and magnetic field in the situation of plane waves. And I want to know the relation between ...
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### Lens design for a photodiode (using OSLO) [on hold]

I’m trying to design a simple plano-convex lens in OSLO (edu version) for a photo-diode that has a rectangular sensitive area of ~7 mm2. The photodiode is used as receiver in an IR sensor, which has ...
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### Is there any limit to distance between two waves when used in Huygens principle?

when I used Huygens principle to determine the spherical wavuefront of radius $R/2$ created by reflection from a spherical concave lens of radius $R$, I got amazingly different results for different ...
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### Bandwidth of laser pulses

I am working on a practice test for my optics class. The professor does not provide the solutions for the test. I was just wondering if someone could tell me if I am doing this correctly because it ...
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### Right lens for my laser [on hold]

I want to know if there is a way to find out size of lens(radius, it has to be sphere), when i know focal distance(120cm) and refractive index(1.7), for 2cm(diameter) laser ligting on it?
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### Confused regarding sign convention of silvered plano convex lens

I'm totally confused while finding the sign convention of a silvered plano convex lens. I know that equivalent power of such a system can be found by adding the power of the mirror and twice the power ...
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### Why does Feynman say that Huygens' principle is not correct for optics?

I am reading Feynman's famous paper Space-Time Approach to Non-Relativistic Quantum Mechanics, and in section 7 he says: Actually, Huygens' principle is not correct in optics. It is replaced by ...
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### About ray diagram in concave mirror [closed]

When I make a ray diagram of a concave mirror with the following details focal length (f) : -3 unit Object distance (u) : -2 unit Object height (h) : 2 unit ...
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### optical communication related project [closed]

Could anyone suggest me some good projects related to optical communication? I am a Bachelor of technology student. I have to submit a project related to optics.
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### Are there any CO2-Laser notch filters? [closed]

I'm searching for a notch (band-stop) filter (like [1]) for a 10.6 $\mu$m CO$_2$-Laser and I have yet to find one. Is there some physical reason such filters don't exist or is there just no demand? ...
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### How can I simulate two fluorophores with a reticle?

Fluorophores typically emit in an incoherent fashion. I thought I could simulate two fluorophores (e.g. single molecule fluors) with a reticle. My concept was to make two small holes in a chrome ...
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### In a double slit experiment, fringe separation is constant. However in a diffraction grating fringe separation is not constant. Why is this?

Can you explain this as simply as you can? I am currently in high school and I've been wondering why? Correct me if my question is wrong, and if my assumption in my question is wrong, would you help ...
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### Are there Non-conformal maps encountered in Physics?

We always encounter Conformal maps in Physics, may be they are easier to study, but are there Non-Conformal transformations encountered in Physics anywhere? if they are encountered, where are they ...
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### How does refraction work? [closed]

https://www.youtube.com/watch?v=YW8KuMtVpug&feature=iv&src_vid=CiHN0ZWE5bk&annotation_id=annotation_187211 Start the above video at 8:15. How does the phase velocity affect the apparent ...
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### differences between the real image and virtual image [duplicate]

which image can be seen by us and photographed simultaneously - real or virtual. I don't understand the major difference between the two.
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### Why aren't all objects transparent?

I know that for an object to be transparent, visible light must go through it undisturbed. In other words, if the light energy is sufficiently high to excite one of the electrons in the material, ...
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### Simulation software for wave optics

I am using COMSOL multiphysics Optics module for wave optics simulations and I am wondering if there is better simulation software for wave optics simulations (no multiphysics needed). Like software ...
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### What is the formula for light emission from a point source in scattering media?

I'm trying to model the light output emitting from a point source somewhere in R3, and impinging on a fiber optic at distance r, that may be angled relative to the point source at some angle $\theta$. ...
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### How to collimate a wide-field from a classical Cassegrain telescope?

I have a 0.25 degree field-of-view Cassegrain telescope (see below) that I'm trying to collimate, i.e. make the diverging beam afocal, not collimate in the sense of aligning M1-M2. I can do this with ...
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### Would optical signal processing still suffer from slew rate?

In electronics, analog signal processing/computation suffers from parasitic capacitance which leads to slew rate—which is the maximum change of voltage allowed, so handling super-high frequency ...
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### How to estimate function from PDF and covariance? [closed]

I've added a picture of what I want to compute. In the nomenclature of the picture, I want to compute a realization of y(x) given the known distributions and constants. Let's say y(x), random ...
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### Is radar-style 'pulse coding' (stretch, amplify, interact, and then compress) used in the optical domain?

Chirped Pulse Amplification (CPA) is an optics technique for producing short laser pulses at intensities which are high enough that the gain medium would destroy itself through nonlinear phenomena ...
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### Calculating lens parameters

I have a very bright LED light and I'd like to make this light focus so it forms around 5mm thick strong line (height can be arbitrary) on on an object about 150 mm away. I used a cylindrical lens ...
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### White Laser Light

I have heard that recently researchers have developed white laser light by combining semiconductor laser sources of different colors. However, I have heard that before these lasers become a practical ...
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### Why paraxial rays are used for image construction?

I teach physics to high schoolers. Some days ago I read the following optics question in a physics book. Q. Why paraxial rays are used to study ray optics? The answer given in the book is ...
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### Aquarium/refractive indices/detector

Quick question: I'm currently fiddling around with this homework of mine and I seem to be lacking some basic optics knowledge apparently. An aquarium is filled with a fluid as seen in the figure ...
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### ray tracing through a stack of flat plates

Say I want to trace rays in 3 dimensions through a stack of flat plates of various refractive indices. My rays have canonical coordinates {Q,P}. The plates are normal to the z axis, all the rays start ...
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### Is it possible build a telescope on a field of mirrors?

Is it possible build a telescope on a "field of mirrors" like the image below? I mean, an energy plant on day time and a telescope in the night Maybe the mirrors are not enough polished but the ...
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### Gaussian beam with its waist lying on medium boundary

For $z<0$ the medium is air and for $z<0$ the medium has refractive index $n$ The waist lies on the $z=0$ plane with radius $W_0$. What is the solution in the medium? I take the distribution ...
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### How does the power-series expansion of the spectral phase describe chromatic dispersion?

I don't understand how the spectral phase (the phase in the frequency domain) describes dispersion.
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### Can Incoherent Polarization Beam Combining be Used to Produce Polarized Light?

I know that different beams can be incoherently combined to produce high power laser sources. But as far as I know these resultant beams are not polarized. But what if you combined several lasers with ...
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### How fast would you have to run to create a mirror image?

So I was watching The Flash and in the most recent episode he runs so fast that he is able to create a mirror image of himself so that it looks like there is more of him than there actually is. So I ...
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### Dispersion in ultrafast lasers

In mode-locked Ti:sapphire lasers, positive dispersion is caused mainly by the crystal. A prism pair placed in the laser resonator can compensate for some of the dispersion by introducing negative ...
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### The squeezed-displaced-thermal state [closed]

I wonder whether the following squeezed-displaced-thermal state has any applications in the related fields. I would be grateful if anyone could make some comments.
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### How can a slowed light ray bend?

If light is traveling through air, it slows down and ends up bending. But how? If I'm running straight, and I get slowed down, shouldn't I still be running straight?
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### Fraunhofer diffraction at circular aperture - integration of bessel function

I'm trying to understand the calculation here: http://en.wikipedia.org/wiki/Fraunhofer_diffraction_(mathematics)#Circular_aperture for the solution by integration, but I plain and simple fail to see ...
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### Interference of light in a dielectric mirror

Here it is mentioned that for dielectric mirrors (mirrors designed to reflect a specific wavelength of light) "there is a 180-degree difference in phase shift at a low-to-high index boundary, compared ...
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### Is an iPad screen an Optical Prism?

One day, I noticed that sometimes, when there is an iPad right below a light, such as a chandelier, when viewed from an angle, one can see what looks like a spectra of colors. Is the iPad screen ...
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### I have some questions about reproducing Young's double slit experiment

I want to reproduce Young's double slit experiment for a school project. For the slits I am thinking making cuts in aluminium foil or maybe do something with pencil leads like this instructable ...
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### Is Snell's Law valid even for on any curved surfaces?

Proof of Snell's Law can also done by using Fermat's principle of least time on plane surfaces. Can we prove the same result for any curved surfaces ?
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### Calculating propagation time along the path of a photon

In this paper $\tau(t) := \int_{t}^{t_d}ds$ is defined as "the propagation time between the detection time, $t_d$, and $t$, as incrementally measured by a set of local observers along the light path". ...
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### Hollow metallic waveguides versus optical waveguides versus cables

In almost every physics program, you learn about electricity, electromagnetism, photonics, ... Within the electricity course, you learn about transporting electric energy as electrons through cables. ...
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### Refractive index of prism

The formula for the refractive index of a prism is: $$\mu = \frac{\sin (\frac{A + D_m}{2})}{\sin (A/2)}$$ However, this requires me to find out the angle of minimum deviation ($D_m$). This would ...
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### Which coefficients are needed to numerically obtain transmission spectrum?

I'm using Omnisim program. I would like to obtain transmission spectrum of certain material so I have created two polynomials: one representing real refraction coefficient and one representing ...
I want to understand why, theoretically, the central bright fringe has maximum brightness/intensity. And where does the formula $I=I_0\left(\frac{\sin B/2}{B/2}\right)^2$ come from? My book says it is ...