The subfield of optics in which light propagation is approximated in terms of rays. It mainly includes reflection and refraction on surfaces.

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A beam of light, traveling around a planet

Some time ago, I happened to have found one problem: The refractive index of the planet's atmosphere decreases with height above the surface under the following law: $$n=n_0-\alpha h$$ ...
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2answers
43 views

does the positon of the virtual image change when I change position?

I placed a box in front of a plane mirror I looked at the image and smudged a bit of Vaseline on the mirror as a mark to indicate where I thought where the virtual image was. After that, I ...
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1answer
39 views

Optical signal filters

Are there any optical filters which filter the signal's frequency and not based on the wavelength of the light? So what I mean is, if I have a modulated/pulsating light signal riding on a large DC ...
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35 views

What is a good textbook to learn how to ray trace light through an optics system in 3d?

I can do 2d problems easily, but I need to learn more to do a 3D ray trace. Can you guys point me towards a textbook? I'm having trouble dealing with the normal and incident rays in 3D
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32 views

Highly diminished image of an Object placed at Infinity

Consider an object at infinity. The rays coming from it are parallel to each other. Let one of the parallel rays pass through the focus $F_1$ of a thin lens, and let a second ray pass through the ...
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57 views

Distance between Newton's Rings fringes is does not seem linear

On the outer edges of Newton Ring patterns, the fringes are really close together, and much more uneven. Also, the spacing does not seem to decrease linearly at all as you move from the center. Why is ...
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35 views

Measuring parallaxes from the moon

If one were to measure star parallaxes from the moon, what (if any) changes would you have to make compared to someone making the calculation from earth? What about on another planet in our solar ...
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14 views

Obtain scale factor by coordinates from the camera projections

I have a following optical system: 3 cams (left and top, which is orthogonal to the left, and right, which is parallel to the left and orthogonal to the top) and the 2 cubes in the 3D-space with ...
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8 views

How to create crystalographic orientation map from indexed Kikuchi bands?

Can somebody explain a detailed procedure, of producing orientation maps? I need to implement this into a software. Right now im able to transform EBSD pattern to probabilistic Hough space, get lines ...
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24 views

Is there a way to calculate how a point source would be imaged in a system with spherical aberration?

I want to create a picture like this for the system I am building. (Source: WP page on spherical aberration) Can someone point me towards a book were I can learn to calculate this pattern on an ...
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1answer
40 views

Determinant of ray transfer matrix

Quick question on the wikipedia entry for the ray transfer matrix, which is defined : where $x$ is the distance of a point from the optical axis and $\theta$ the angle that the beam profile at that ...
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28 views

Ray tracing in a inhomogeneous media

If I have an optical transparent slab with refractive index $n$ depending on the distance $x$ from the surface of the slab, the refractive index can be described by: $$n(x)=f(x)$$ where $f(x)$ is a ...
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70 views

Ion Optics: Electric and Magnetic field. A comparison with Light Optics

When we compare ion optics with light optics, normally we consider electric field. For example Snell's law. $n_1\sin\theta_1$=$n_2\sin\theta_2$. When an electron move from one electric potential to ...
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409 views

Will a prism widen a monochromatic beam?

The representation of the experiment which demonstrates that white light consists of many colors, invariably shows that the beam of white light is broadened inside the prism and is some what more ...
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1answer
50 views

Phase and amplitude information of an image

By applying Fourier Transform to an image we can get its magnitude as well as phase spectrum. A magnitude spectrum describes how various frequencies are attenuated and accentuated in that image but ...
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1answer
54 views

Does sign convention in geometric optics fail to explain the cases of image formation by virtual objects?

Here is an example of Cassegrain telescope: Parallel rays from a distant object get reflected by the concave mirror forming an image at its focus behind the convex mirror. This image acts as a virtual ...
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44 views

Surfaces that refract, but do not reflect

I know there exists surfaces that only reflect light (mirrors), but are there surfaces that only refract light? If so, how does that happen?
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55 views

Image formation at surface of water

Consider a lake full of water which has an object immersed in it. Now, if an observer was at the surface at a sufficient distance so that the light ray from the object is internally reflected, should ...
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reflection at intersection of 2 mirrors

Consider 2 mirrors which intersect at an angle. If we draw a light ray intersecting the mirrors at their point of intersection, how will it reflect? What will be the normal at that point?
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Why Least Distance of Distinct Vision is treated as image distance in the lens equation.

Least distance of distinct vision is the minimum object's distance that is able to produce a distinct image on the retina. Yet, it is treated as image's distance while applying lens equation. Say, ...
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33 views

Reflection vs indices of refraction [closed]

A magician during a show makes a glass lens with refractive index 1.47 disappear in a trough of liquid. What is the refractive index of the liquid? Could anyone please demonstrate with a ray diagram?
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60 views

Blonde hair looking green at certain angle

I have a friend who has blonde hair. And when look at an oblique angle, there's a tinge of light green in her hair. I've heard that the copper ion in pool water can make blonde hair green, but her ...
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28 views

size of an image formed by a concave mirror

a short linear object of length b lies along the axis of a concave mirror of focal length f at a distance u from the mirror.what is the size of the image? what i have done so far: since the ...
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91 views

Calculation of error in focal length? [closed]

$u=-10cm$ $v=10cm$ Using the formula the focal length is 5 cm. But how do I get the fractional error in focal length when neither $\Delta u$ nor $\Delta v$ are specified? The options given are ...
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38 views

Beamsplitter and Dielectric Mirror

Among two optical components. One is a Nd:YAG Laser 50/50 Beamsplitter and the second one is a Dielectric Mirror see pictures. Both of them almost looks like the same. If the specification is not ...
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2answers
66 views

Plano-convex lenses

When the spherical side of a planoconvex lens is towards the source we will see reduced aberrations normally we use it for the beam collimation. When we use two planoconvex lenses configuration why we ...
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166 views

Can't virtual images be put on a screen?

Apparently the plane mirror makes virtual images, and virtual images cannot be projected onto a screen. If you look below, it is? If the eye is basically a screen of rods and cones, then everything ...
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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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Difference between the increase in optical path due to refraction and that due to reflection

If we place two glass plates of refractive index n and each having thickness t,on the way of a light ray the increase in optical path becomes (S2P-S1P)=2(n-1)t due to refraction through them,and the ...
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227 views

Why do we need screen to see real images?

As we know that concave mirror forms a real image when object is placed beyond focal plane. This image can only be seen if a screen is kept at the point of intersection of rays(sharp image).If any ...
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81 views

Calculating the rainbow angle

I've read that the angle for viewing a Primary Rainbow is between 40-42 degrees. How would I go about showing this? How would I calculate that angle from scratch? I figured that Snell's Law and the ...
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1answer
104 views

Numerical aperture of a lens

Using a laser setup, I was asked to determine the aperture of a given lens and then use some geometrical arguments and compare the theoretical value from the manufacturer and the experimental value. ...
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41 views

How does a microscopes optics expose defects in the users vision?

I've got cataracts in both eyes. My vision is correctable to 20/30, so the cataracts are essentially a non-issue in daily living. But when I use a microscope, which I do daily, (binocular, zoom ...
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1answer
38 views

Refraction problem - limiting radius of observation

I solved this problem but I don't know if the solution is correct. Please, correct me if I'm wrong. There are two mediums, 1 and 2, with absolute refraction indexes $n_1$ < $n_2$, and an observer ...
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109 views

Magnification in compound microscope

I was studying about compound microscope here I don't see why we multiply linear magnification of objective with angular magnification of eyepiece. Shouldn't it be both angular or both linear? Can ...
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622 views

Fermat's principle to prove the law of reflection

Fermat's principle tells that a light ray will follow a path from point $A$ to point $B$ so that the optical path length of this path is an extremum over neighboring paths. I wanted to use this ...
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How much can a thin layer of hi-speed material within a low-speed volume block a wave due to total internal reflection?

Consider a block of isotropic material with compression wave velocity associated with it, $v_1$. Consider a thin flat layer of high compression wave velocity $v_2, v_2>v_1$ that is buried within ...
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39 views

Help me understand virtual images versus real images [duplicate]

Simple question; Is a virtual image that is produced by a lens always - in front of or in back of the lens?
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Determining a person's sight from his speech [closed]

Suppose we meet a person wearing glasses.Can we determine whether the person is short-sighted or long-sighted? However,due to courtesy,we are not allowed to ask him to try the glasses and in general ...
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2answers
104 views

Basic geometric optics question - how come we don't have to have exact focus to capture objects clearly?

The top frame of the image below shows an image formed on the screen (at right) of an object (pencil on the left) located at some distance $D$ from the lens. The lens focuses all the light rays ...
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269 views

Why do the passing objects' shadows run in the direction of the moving train?

While travelling in the train on the sunset, I have noticed the strange phenomenon. The shadows of the lonely trees and lampposts, that stay along the railroad, are moving on the wall in the same ...
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Find the position of the final image [duplicate]

I was going through Geometrical Optics and came across the following question in my textbook: Q. An object is placed $21$ cm in front of a concave mirror of radius of curvature $20$ cm. A glass slab ...
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1answer
759 views

Plano convex lens with one silvered surface

For the derivation of the focal length of a planoconvex lens with one surface silvered, we consider the phenomenon taking place in three steps: Refraction through first surface Reflection ...
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3answers
182 views

Is there any optical component that uniformizes the incoming light?

Is there any optical component in existence that uniformizes randomly pointing rays?
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2answers
107 views

Is it possible to focus the sun in such way?

Imagine the sliding part of the mirror is controlled by computer and opens on intervals. Is it possible to increase the power of the beam by making it bounce between the mirrors thus going through ...
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2answers
104 views

Why would the reflection of a lamp by a bowl look like a heart?

I have this bowl roughly the shape of a circular truncated cone, and the lamp shines on the bowl at an angle. The reflected lamp light hit the bottom of the bowl and created a light ring that looks ...
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2answers
52 views

Determine whether the light will reach certain points or not [closed]

I've got an interesting question which goes like that: suppose we have a long cylindrical rod made of a transparent material (see illustration below). A point source $O$ which sits on rod's axis emits ...
2
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2answers
518 views

Fresnel distance and Geometrical limit

I read about the geometrical limit of wave theory. The source from where I read had a slightly different explanation to provide than here(The more rigorous answer is too complicated for me to ...
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2answers
78 views

Are images of three-dimensional objects also three-dimensional?

Suppose that I produce an image of a dog using a converging lens. I can draw ray diagrams for the nose of the dog as well as the back leg. These are definitely longitudinal points, not transverse. ...
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What's the local law of propagation of disturbances

In Vladimir I. Arnold's Lectures on Partial Differential Equations, Chapter 3 Huygens' Principle in the Theory of Wave Propagation, which is devoted to the proof of Huygens principle (original one by ...