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

learn more… | top users | synonyms (1)

0
votes
0answers
132 views

Image formed by a Prism

A series of questions that came in my mind after I saw a question So here it goes first the questions that have made me confused : 1) How image is formed by the prism? 2) When we take different ...
0
votes
2answers
64 views

Are these reflected rays really parallel?

I have read that if an object is placed on the focus of a concave mirror (assume that the object is a vertical line placed on the focus), then the image will be formed at infinity. Here’s a diagram. ...
1
vote
1answer
44 views

pinhole in projector screen

Consider a conventional slide projector projecting a properly focussed static image from a photographic slide onto a conventional screen, with a second screen placed a short distance behind that one. ...
1
vote
1answer
30 views

Do all thermal radiators have the same surface brightness?

Imagine I heat a piece of metal to 1000K. It will be red hot and will emit black body radiation corresponding to this temperature. But what about the brightness? Assuming the bulk is opaque, does it ...
18
votes
1answer
518 views

Do light waves precisely follow null geodesic paths in General Relativity?

In special relativity one may show that a plane wave solution of Maxwell's equations (in a vacuum), of the form $A^a=C^a\mathrm{e}^{\mathrm{i}\psi}$ has the following properties: The normal ...
1
vote
1answer
459 views

Rayleigh-Plateau instability and optic [closed]

Let a liquid jet fall onto a surface. If the contact point is illuminated by a lase beam, rings of light around the jet can be observed . (pic.1) and we know it that the reason of this phenomenon is ...
2
votes
2answers
148 views

Experiment to find the circle of least confusion (optics)

I want to conduct an experiment where the circle of least confusion (wiki ref) occurs for a lens. Suppose that I shine white light onto the lens and I know the lens EFL is lets say 100 mm, in order to ...
3
votes
1answer
51 views

100x magnifying optics system for short laser pulse

I am now designing an experiment that consists of a 400 nm short pulse (~300 fs). In the experiment, we need to magnify the transverse profile of the pulse by 100x. That's the problem. I was ...
0
votes
0answers
36 views

Balance lens tilt aberration

Given a doublet (singlet in reference figure), if the rays enter at an angle with respect to the origin axis, we would see a shift of focal length for blue and red. A known optical jitter How could ...
-3
votes
1answer
106 views

Combination of mirror and lenses [closed]

I am a keen learner of physics, but I am unable to solve problems involving lenses and mirrors together. please can anybody tell me the method to solve these problems? for instance let us take a ...
1
vote
2answers
48 views

Let's suppose I am to display the letter R on mirror as well water , will I get the same images?

As far as my practical experience goes both look quiet the same when an image of any object is formed on them, yet I wanted to be ascertained is there any actual visible differences between both the ...
0
votes
1answer
33 views

Encoding multiple images in 1 beam

I am doing some research involving geometric optics. I need to reduce an image in size so it fits a rotating mirror we are using. I came up with the idea of projecting the focal plane on the mirror, ...
1
vote
0answers
15 views

Why to use the sign convention while solving problems as the mirror-formula itself is derived using the sign convention? [duplicate]

When we derive the mirror equation of concave mirror, i.e.,$\frac{1}{u}+\frac{1}{v}=\frac{1}{f},$ we've already used the sign conventions. Then why to use the sign conventions again while solving a ...
0
votes
0answers
82 views

Velocity of image formed by a spherical mirror in Y axis

If an object is moving with velocity $v_0$ along the positive Y axis in front of a convex mirror of focal length $f$ at a horizontal distance $u$ from the mirror's pole, what will be the velocity of ...
3
votes
1answer
407 views

Why doesn't a backward wave exist? [duplicate]

Huygens principle says every point of wavefront emit wavelet in all directions. Then why does a back ward wave not exist? Can any expert tell real answer? On different sites I get different and ...
1
vote
0answers
40 views

I want to make convex lens of focal length 40mm [closed]

i have set of negative meniscus lenses power ranging from -0.5 to -15D made from material whose refractive index is 1.586 please tell how to make a biconvex lens of focal length 40mm
0
votes
0answers
30 views

Effect of introducing lens on Fringe width

Suppose I have a light source of wavelength 400 nm. The slits are placed at a distance 1 mm apart. The distance between the slit plane and the screen is 50 cm. So that makes the fringe width, $\beta ...
0
votes
0answers
33 views

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 ...
2
votes
0answers
44 views

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 ...
0
votes
0answers
192 views

A small object faces the convex spherical glass window of a small water tank, find the final image?

I was hoping you guys could look over my solution to this question. A small object faces the convex spherical glass window of a small water tank. The radius of curvature of the window is 5cm. The ...
0
votes
0answers
47 views

Trapping force in optical tweezer

I am reading a paper on theory of optical tweezers in ray optics regime by A. Ashkin. For reference "click here". It is given that Gradient force $F_g$ is directed perpendicular to the light ray and ...
1
vote
0answers
25 views

Method of Transformed Impedances

So I am taking an advanced optics class at the moment, using the book Lasers and Electro-Optics by Chris Davis. At one point, while explaining the concept of impedance, he mentions something called ...
3
votes
4answers
194 views

Shining a laser onto a mirror

Theoretically, if I shined a laser at a mirror at an angle of 0 degrees so that the light was perfectly reflected back to the light source, then I should not be able to see the light because it is not ...
0
votes
1answer
43 views

Ray optics : Circular mirror with reflecting surface on the inside

A light ray enters through an infintely small hole and gets reflected as shown. After how many reflections will it emerge out again? (It can come out in any orientation). Will it emerge out for any ...
3
votes
2answers
75 views

What makes a lens a lens?

I am asking about the way that a convex lens works. All the lenses I have ever seen were solid glass or solid plastic. If I have a convex sheet of clear glass or of clear plastic, shaped into a ...
1
vote
0answers
58 views

Source of a parabolic wavefront

The Huygens-Fresnel diffraction integral has been formulated for incident spherical waves. A source of a spherical wave is kind of intuitive, since the perpendicular rays of the sphere converge into a ...
1
vote
2answers
58 views

Can we trap living cells in optical tweezers?

I read that optical tweezers work on the principle of radiation pressure caused due to momentum change of incident light due to refraction from a spherical object. For refraction to happen the object ...
1
vote
1answer
152 views

Path of a light ray in a medium of varying refractive index [closed]

How do we get the equation for the path of a light ray in a medium of varying refractive index. I can draw a rough sketch, but don't know how do we get the exact curve. I encountered this while ...
5
votes
4answers
306 views

Infinite total internal reflection

Suppose that I have a block of some transparent material, glass, for instance, with a certain index of refraction. Suppose that the transparent material is placed in air or in any other transparent ...
1
vote
0answers
84 views

Why isn't the magnifying power in a compound microscope zero when image is formed at infinity?

I think, in a compound microscope, angular magnification and lateral(or linear) magnification is given by the same formula for both image at infinity and near point(D) And the formula is ...
1
vote
0answers
54 views

Optimization of transfer matrix method for quarter wave stack

Does anyone have any tips for Matlab optimization algorithms to use with a 2x2 Transfer Matrix Method Program? I have written a Matlab function that takes a series of refractive index values and ...
2
votes
1answer
69 views

Why does in the definition of 'optical path', only spatial phase change is taken into consideration & not that of time?

In Concepts of Physics by H.C.Verma, I got the definition of optical path. However, one thing that I couldn't understand is why only the spatial phase change is considered in its definition. As he ...
3
votes
2answers
255 views

How does Huygens Principle incorporate the unidirectional property of a traveling wave?

I was reading French's Vibrations & Waves where he discusses Huygens-Frensel Principle. The principle talks about how secondary sources give rise to secondary wavelets to form the displaced ...
1
vote
1answer
36 views

Experiment to test flatness of prism

I have a Prism glued to a prism plate. Let's say the method of using optical glue is good enough, and minimal human error is tolerated. What experiment would be a good to check if the prism is not ...
1
vote
0answers
88 views

In Fermat's Principle of Least Time, how do we know that light is able to reach the end point? [duplicate]

From my understanding of Fermat's Principle, you decide a start point and an end point for a light ray to travel between, and the light 'chooses' whichever path takes the least time (or technically ...
0
votes
1answer
217 views

How to calculate the diameter of a thin lense?

A photo produced with a single thin lense is provided. Only based on the photo I should calculate the diameter of the lense. The photo shows a ruler in the foreground and a point source of light in ...
0
votes
1answer
752 views

Way of measuring thickness of a glass [closed]

Imagine you have a laser pointer and a glass. You don't know the refractive index of the glass and you just have Wavelength of laser! How can you measure the thickness of glass? (I have some idea but ...
2
votes
2answers
140 views

What is really a light ray? [duplicate]

I've been studying geometric optics and I'm still a little confused with this idea of light ray. In the book I'm studying everything is being done starting from Fermat's principle which states that ...
39
votes
5answers
5k views

If a lens focuses all incoming light to a point, how do we get 2D images?

How do lenses produce 2-dimensional images, if a lens bends all incoming rays of light to intersect at the focal point? Shouldn't this produce a single dot of light on a screen placed at the focal ...
4
votes
3answers
2k views

Calculating light's lateral shift in a glass slab

I have tried to compute light's lateral shift after passing through a glass slab In terms of the incidence angle $\theta_1$, the slab thickness $d$ and the refraction index $n$, I have found that ...
1
vote
2answers
91 views

How can one prove the equation for a system of lenses? [closed]

Let's say we have a system of 2 lenses which are placed in a non-negligible distance $L$ from eachother. How can I prove without using geometrical construction and principal planes that $$\frac 1f ...
1
vote
1answer
70 views

In geometric optics we treat light as a collection of particles?

I've been reading the book "Geometric Mechancis" by Darryl Holm and the in the first chapter he treats geometric optics. There the author talks about light rays and those light rays looks like ...
0
votes
2answers
28 views

Principle of fibre optic cable coating

I was reading about fibre optic cables and it was mentioned that ,the individual "light pipes" are coated with a material whose refractive index is less than that of that of the glass. My question is ...
1
vote
1answer
662 views

Question about lens maker's formula

I am trying to follow the derivation of lens maker's formula from the textbook "University Physics", p.1133 ...
2
votes
2answers
70 views

How to estimate if an image is in focus

I am building a test measurement (optics) to look a rectangular slit opening (1mm x 15 microns). The slit opening is illuminated by a white LED and using a microscope objective to magnify it to 10X on ...
0
votes
1answer
55 views

What's the difference between two types of diaphragms?

What's the principal difference between aperture iris diaphragm and field iris diaphragm?
0
votes
1answer
45 views

Does “converge” mean intersecting and producing image when we are taking about convex lenses?

After reading the chapter on convex lens, I saw several places where "converge" is used. In the very beginning of the chapter, my book says "converging lenses bring light together". So I thought ...
0
votes
3answers
175 views

What is the total internal reflection?

From what I read, it sounds like when a light ray passes from one medium to the other, if the critical angle is reached so that the refractive ray is at 90 degree with the normal, the light ray does ...
1
vote
5answers
1k views

Why does an image form at the intersection of light rays?

If image is simply what we see, then why, when light rays bend in the atmosphere, enabling us to see the sun, is there no intersection of rays? The concept is strange. I can not relate it to ...
0
votes
0answers
120 views

When to use lateral magnification vs angular magnification?

What is the essential difference between lateral and angular magnification (like why do we need to use both and when do we use which)? Also, is there a relationship between the two magnifications?