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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Focusing laser & off-axis illumination & diffraction limit

I've thought I had a good understanding how resolution enhancement tricks works for projection lithography, until I tried to understand if it's possible to get sub-diffraction performance for focused ...
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163 views

Reflected optical rotation of polarised light

Assume polarised light travels through an optically active medium (e.g. water with lots of sugar) with the specific angle $\alpha_s$ of depth $d$ at which end it is reflected (so in total it travels ...
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Compound lenses and virtual images

Ok so I have this problem where I have a system of two lenses. All I know is that the distance between the object and the first lens is 30cm, the distance between the object and the final image is ...
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Virtual images in (plane) mirrors?

The following image is taken from teaching physics lecture Was man aus virtuellen Bildern lernen kann (in German): Now the cited paper claims that the left hand side is the correct picture to ...
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2k views

How to determine divergence of a LED source from a single biconvex lens

I'm trying to determine the divergence angle of light from a single lens that is completely illuminated by a high power LED. Most optics textbooks only deal with imaging optics and I'm having a hard ...
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What does Lijun Wang's experiment about supraluminal speed of light in a medium mean?

This is a summary from Physics World of the paper: L J Wang et al. 2000 Nature 406 277-- "Wang and colleagues begin by using a third continuous-wave laser to confirm that there are two peaks in the ...
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95 views

Spherical mirror ray diagram question

why does a ray, parallel to the principle axis, intersect the principal axis at half the radius of curvature, i.e. focus? EDIT I was taught that in a spherical concave mirror, the rays parallel to ...
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414 views

Sign convention for mirror and lens formulas

I have just started learning optics at school and my teacher derived the lens and mirror formulas. While doing so, she applied the sign convention for u,v and f and arrived at the final expression. ...
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445 views

Does optical fiber preserve the angles of incoming light?

I am reading up on optical fibers and there's one thing I haven't understood yet: Does an optical fiber preserve the angles of incoming light? For example, if we light two LEDs in front of an ...
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176 views

How does light pass through rough glass?

Light incident on a rough surface will be diffuse after passing it. Angular intensity depends on the grinding of the glass surface. I'm trying to find information about the scattering indicatrix of ...
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201 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 ...
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124 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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567 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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430 views

Question about Rayleigh scattering

To quote from Wikipedia on elastic scattering, "In this scattering process, the energy (and therefore the wavelength) of the incident photon is conserved and only its direction is changed." How does ...
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How to find the principal point in an image?

I need to find the principal point in an image. Its a point where the principal axis intersects the image sensor. Due to misalignment this point is not at the center of image always(or image sensor). ...
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8k views

refractive index of air in dependence of temperature

What is the exact dependence of the refractive index of air and the temperature? Is there a theoretical derivation of it?
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565 views

In interferometry, what is the origin of the name “Airy function”?

In interferometry (specifically, in the domain of Fabry-Perot cavities), the function $$f(\phi) = \frac{1}{1 + F \sin^2 \phi}$$ , which describes the shape of the resonant structure of the cavity, is ...
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206 views

Will overlapping two different beams of coherent light cause interference?

I have two laser beams with same polarization running parallel to each other. Will they interfere? If yes, then what are the conditions (perpendicular distance etc) and how can I observe the ...
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324 views

Inverse Fourier Transform Of K-space Image…what is the object space scale?

Checked around a buch and could not find any help. But I needed help with: Understanding that if I get the Inverse FT of K-space data, what is the scaling on the X-space (object space) resultant ...
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353 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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How can some optical microscopes measure height differences of different sample planes with nanometer accuracy?

I could use last week an optical microscope, didn't seem special in any way, 50x magnification, image viewable per a CCD camera on a computer screen besides through the ocular. But the software of ...
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225 views

Filter out polarized light

Unpolarized light enters the polarizer and gets polarized at one certain angle. If we place an analyzer behind the polarizer and align them, we observe that all light is transmitted. If we rotate the ...
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193 views

On the optics of high-resolution surveillance drones

In this youtube video (which is an except from a documentation I believe) a DARPA development for a high-resolution surveillance camera is presented. This question is regarding the optics that are ...
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294 views

Do wide-angle videos make the first-person view seem slower than perceived in real life?

I considered posting this on other SE sites such as Audio-Video Production and Photography, but I didn't feel I'd get the definitive, fact-based (rather than experience-based) answer I'm seeking. ...
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How does the grid on the microwave oven window prevent microwave radiation from coming out?

If I look through the microwave window I can see through, which means visible radiation can get out. We know also that there is a mesh on the microwave window which prevents microwave from coming out. ...
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Adaptive Optics Capability in the Visible Range

Telescopes with adaptive optics (AO) have been in use for several decades. To my knowledge, the lowest wavelengths utilized are in the near-infrared. It's known that Fried parameters are smaller for ...
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373 views

Effect of a wavefront deformation on the far-field diffraction pattern of a TEM00

By performing Matlab simulations on a TEM00 mode (approximated by a gaussian intensity profile with a flat wavefront), I got the impression that applying wavefront deformations (such as a single ...
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394 views

How to adjust feather touch focuser for collimation?

I have a Starlight Instruments feather touch focuser for my Dobsonian telescope. While trying to collimate the secondary mirror with the focus all the way in, I noticed that my Howie Glatter laser ...
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69 views

Should I be concerned about spot corrosion on a telescope's primary mirror?

I am considering buying a telescope with a large primary mirror that is about seven years old - it has a small spot of corrosion on the mirror, that the owner says is stable. Should I be concerned ...
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217 views

What sets the resolution on analog film?

When taking a picture with old fashioned film what sets the resolution of the picture? Is it the wavelength, or the chemical makeup of the film?
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What is the specific meaning of “Fourier frequency” (as opposed to simply “frequency”)?

I've noticed that many journal articles (in optics) use the phrase "Fourier frequency" to describe, well, the frequency of something. Google scholar search for "Fourier frequency". Example: ...
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192 views

Impact of covering glass on lens performance

I've seen microscope lenses optimized for 0.17mm covering glass. I don't see what needs to be optimized here? As glass does not touch the lens (as in case of oil/water immersion) - it should just ...
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556 views

How does phase modulation conspire to eliminate power variations?

A purely phase-modulated signal has no power modulation. This is obvious enough if you look at the time series, but I'd like to "see" it in the frequency domain. In physical terms, if we take a ...
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62 views

How do mirrors look & behave atomically?

I was observing mirrors recently and I was thinking about how an mirror would look atomically. I was always used to looking at atoms as being colored that said, I was always concerned at how they ...
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153 views

Reconciling total internal reflection and the evanescent Wave

I understand that light is guided in a dielectric waveguide via total internal reflection. My question is regarding the origin of power contained in the evanescent field traveling along the direction ...
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38 views

How would the composition of the Venusian atmosphere visually affect the sunrise and sunset there?

The Venusian atmosphere is according to CalTech's webpage What is the atmosphere of Venus like? is 90 times heavier, than Earth's, containing predominantly carbon dioxide, some nitrogen, sulfuric acid ...
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120 views

Possibility for contact lenses that enhance the vibrancy of color

Would it be possible to develop oculars that would enhance the vibrancy of color? I know there are many digital filters to improve vibrancy, but are there physical devices able to produce the same ...
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402 views

Problem in Youngs double slit experiment

This is from Young Double slit experiment. But How to prove the the two $\theta$ are equal, I meant, how $\angle EAD= \angle PEC$? I see from the both triangle have $90^0$ but what about others?
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Diffraction pattern when wavelength tends to zero

While studying about Fresnel and Fraunhofer diffraction, I came across a statement which says that the fringes disappears and the image would take on the limiting shape of the aperture when wavelength ...
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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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346 views

Light scattering vs roughness

I've been searching for an answer to this question in professional circles for a while; now I'd like to ask here, to find out why the answer is not there :) In my optical modelling (computer ...
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41 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 ...
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double slit experiment with two opposite quarter waveplates

Consider the usual double slit experiment involving laser and a double slit and a screen. Now place in front of the left slit a quarter waveplate (let's call it QWP1) that changes a certain linear ...
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Future space-based telescope array

Radio-telescopes (e.g. the Very Large Array (VLA)) can simulate one gigantic dish by using separate smaller dishes. Q: Could such an array of optical telescopes potentially see an exoplanet at say 20 ...
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How does a 2D MEMS based optical cross-connect control its mirrors?

Concerning fiber optics, I'd like to know how a 2D MEMS based optical cross-connect is able to switch optical signals. I've read that these mirrors are controlled with electrical signals to be either ...
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56 views

Does a “reflected” hologram produce a caustic in the shape of the original object?

Imagine you make a transmission hologram, ala the standard picture. Now you take your photographic plate, and everywhere it is transparent, you put a thin reflective layer on, and everywhere it is ...
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701 views

How does a holographic object change perspective when the image is rotated?

Fundamentally i want to know: How do holograms work? The problem with that question is that normally you will end up with pages and pages talking about: a laser a beam splitter a diffuser the ...
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Efficiencies of Coupling Light into a Fiber

I am in AMO Physics and work a lot with optics. I just wanted to get an idea of what coupling efficiencies one "should" get in a "reasonable time"* by coupling light into a fiber using different ...
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221 views

what is the probability distribution for the angle of an approximate laserbeam

I'm trying to simulate the light distribution characteristics from a Gaussian laser beam, but having difficulty with the angular distribution. I need to generate a large number of points on an x/y ...
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436 views

Building an Afocal Zoom System with only one stage

Can you build an afocal zoom system with only one stage. It looks like you would have to use more than three lenses. You would probably have to have all but one of the lenses be fixed; but it might ...