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
2answers
322 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 ...
1
vote
1answer
99 views

Apparent depth and virtual image position

Why does the virtual image appear right on top of the object and not a little to the right, for example? Is it explained by some formula or just symmetry of the geometry?
1
vote
1answer
25 views

Refraction of light marching band analogy

When trying to understand the refraction of light when it hits a slower medium, lots of people seem to be enlightened by the 'marching band' or 'marching soldiers' analogy, which 'explains' that when ...
5
votes
1answer
74 views

Options to correct rectangular laser beam profile?

We recently switched to a 405 nm laser diode which has a terrible beam profile -- it is a well-defined rectangle with an aspect ratio of about 10:1. The image below shows the collimated beam which ...
0
votes
1answer
65 views

Reflection in a cylindrical mirror

Suppose I have a completely cylindrical surface which is silvered on the inside. I want to know what type of reflection takes place when an object is placed inside the ring. Does infinite reflections ...
0
votes
1answer
37 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 ...
1
vote
0answers
21 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 ...
2
votes
2answers
385 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 ...
1
vote
1answer
31 views

Can a virtual image created by a mirror have position in front of the mirror?

I dont think so, because then the rays will intersect and the image will be real. Please let me know if you know a case in which a virtual image is formed in front of the mirror.
4
votes
0answers
88 views

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 $DB$ ...
2
votes
0answers
19 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 ...
9
votes
3answers
1k views

How many times can light revolve around a black hole?

Take a light ray approaching a black hole from infinity which goes out again to infinity. What is the maximum finite rotation it can describe? (I know it can loop around indefinitely in the ...
4
votes
2answers
9k views

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) ...
3
votes
1answer
61 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 ...
1
vote
0answers
30 views

Microscopy: aperture matching and Huygen's principle

I have repeatedly read that the maximum spatial resolution of a microscope occurs when the aperture of the objective and condenser are the same. However, I don't understand why. The resolution is ...
2
votes
2answers
64 views

Examples in which the light maximizes the optical path length

I posted a similar question about geodesics on Math.SE. Many sources (Wikibooks for instance) claim that the light could maximize the optical path length in some cases. But I don't think it's actually ...
3
votes
1answer
58 views

Why grating is an essential part of a monochromator?

From looking at these two images, it appears that the dispersed "rays" of the reflected light could be manipulated just as well if the reflecting mirror would be turned to a fixed angle. So why is ...
1
vote
2answers
113 views

light ray undergoing total internal reflection thrice inside a prism

Can it ever be possible that a light ray going inside a triangular prism of refractive index n having refracting angle A undergo total internal reflection thrice before emerging out? Note:I know it ...
5
votes
3answers
4k views

Software for geometrical optics

Is there any good software for construction optical path's in geometrical optics. More specifically I want features like: draw $k \in \mathbb{N}$ objects $K_1,\dots,K_n$ with indices of refraction ...
0
votes
1answer
55 views

geometrical optics

I doing an experiment now. My structure has 700nm periodicity. The surface of the unit structure is sloped at 45 degrees from the normal incidence angle. My laser is 500 nm. I can expect there ...
2
votes
1answer
121 views

Huygens' Principle During Reflection: comparing wavelets from before reflection with wavelets from during reflection

I was recently reviewing geometric optics, during which I read about Huygens' Principle and how it could be used to prove the Law of Reflection from the "light is a wave" viewpoint. I'll quote what I ...
1
vote
0answers
3 views

Hildring - Influence of vertical temperature gradient on light beam curvature

In special atmospheric condition it is possible to see coastline that normally is behind the horizon. It is apparently lifted to become visible. In Scandinavian the phenomenon is called 'hildring', a ...
1
vote
1answer
57 views

Can a polarizing beam splitter cube be used to replace two polarizers?

I have a design for a setup to look at the light reflecting off the back of the human retina. I would like to remove any specular reflection that occurs at the cornea. At the moment the idea is to use ...
0
votes
1answer
85 views

What does the equation of a refracted ray trace mean?

I am doing a ray trace to a refracted vector. I read in some PDF files that: vector($\mathbf{t}$) is the refracted ray, vector($\mathbf{i}$) is the incident ray, the angle $\theta_t$ is the refraction ...
3
votes
3answers
67 views

How to improve the visibility of light without increasing the brightness?

I am not sure whether or not this is the right SE site to post this question on but I'm sure someone will inform me of my mistake soon enough if it is wrong. Basically I am an Electronic Engineer and ...
2
votes
1answer
60 views

Problem with Beam Splitter Refraction

I made a beam splitter for a simple test, as shown in the images below: This was my expected ray trace: But it instead refracted light like this: Why did the splitter cause light to ...
3
votes
1answer
56 views

What are the common points between physical optics and geometric optics? [closed]

I am trying to write a paper about light, I want to discuss the two way of studying light, the physical/wave optics and the geometric/ray optics, but I want to write a general introduction about them, ...
1
vote
2answers
71 views

how to trace light after refraction by a camera lens?

I am a programmer and I am doing a camera simulation, I am stuck in a matter of how to know where arrives every ray of light after traveling through the lens and being refracted. Every point of the ...
1
vote
0answers
49 views

Does the anisotropic Fermat eikonal equation predict the extraordinary ray direction given by Poynting vector?

Does the anisotropic Fermat eikonal equation predict the extraordinary ray direction given by Poynting vector?
189
votes
18answers
65k views

A mirror flips left and right, but not up and down

Why is it that when you look in the mirror left and right directions appear flipped, but not the up and down?
56
votes
4answers
6k views

Is it possible to start fire using moonlight?

You can start fire by focusing the sunlight using the magnifying glass. I searched the web whether you can do the same using moonlight. And found this and this - the first two in Google search ...
1
vote
2answers
146 views

Why do we assume that rays from infinity are parallel?

If light rays are parallel to each other , if they are from infinity, they are not gonna make an image because they won't intersect with each other. So we are not gonna see the image. Does that means ...
104
votes
2answers
5k views

Why do sunbeams diverge even though the sun is much more than a few kilometers away?

Consider this picture of sun beams streaming onto the valley through the clouds. Given that the valley is only (at a guess) 3km wide, with simple trigonometry and the angles of the beams, this ...
1
vote
3answers
68 views

Does polarization remove any of the fields completely?

A light is made up of electric and magnetic fields oriented perpendicular to each other. Can polarization lead to the removal of any of the fields completely?
-1
votes
1answer
133 views
0
votes
2answers
63 views

Gaussian beam modelling, location of the beam waist?

In reference to the specifications of a laser diode below: http://www.thorlabs.de/thorcat/11900/L780P010-SpecSheet.pdf I wish to be able to model it as a gaussian laser beam. I understand there is a ...
1
vote
1answer
49 views

Does the distortion of an image depend on the location of the object with respect to the mirror?

A mobile phone lies along the principal axis of a concave mirror with its distorted image, as shown in Fig. How do we actually figure out the formation of such images? The answer says: "The image ...
2
votes
0answers
27 views

Ray tracing a three-way intersection

I've been studying ray tracing in media with linear velocity-depth functions. One of the key concepts I've come across is the ray parameter, and in particular the idea that the ray parameter is ...
0
votes
0answers
55 views

Gaze tracking with the pupil-glint response how does the geometry work?

I am struggling to understand the geometry behind the pupil glint response (see above) (With only one light source). I understand that you use the glint to find the corneal centre (Centre of corneal ...
0
votes
2answers
59 views

Object inside the eye

What will be the image seen to us if an object is placed in between the focus and pole of our eye lens ? I guess no image will be formed.
0
votes
0answers
23 views

Does dispersion take place in our eyes? [duplicate]

What do we see if a single ray of white light falls in to our eyes ? Doesn't it undergo dispersion ?
1
vote
0answers
30 views

how can a lens combination take virtual object to the second lens?

When two lenses are in combination. what logic is it to take the image of first lens (which is not formed in real) as a virtual object to the second lens ?
0
votes
0answers
99 views

Geometric optics question

This question appeared on this site Q17: here A concave mirror is broken into two parts and these parts are separated by a distance if 1 cm. The focal length of the mirror is 10 cm. Find the ...
1
vote
0answers
32 views

Using aluminium foil as a reflection for UV at 240nm [closed]

Will aluminium foil or sheeting reflect UV light at 240nm being used as a disinfection cell for bacteria in water.
1
vote
1answer
114 views

Issue on sign convention with optics

I have a problem understanding the sign conventions used in the equations that describe the imaging properties of mirrors - in particular, when and why should I use a positive or negative number for ...
2
votes
2answers
224 views

Interferometers and Earth's motion relative to the Aether

Why was the Michelson and not the Fabry-Perot interferometer used to detect the motion of Earth relative to the Aether? Maybe the Fabry-Perot was used but we all know that the most famous experiment ...
1
vote
1answer
45 views

Ray diagram of infinity well

An infinity well works on the principle that when two plane mirrors are placed in front of each other an infinite number of images are produced thus creating an illusion.I am a bit confused about it's ...
0
votes
0answers
24 views

What is the minimum bend radius of a square optical fiber on a microfluidic chip interface?

I want to make a microfluidic chip with colorimetry cuvettes with 100um square optical fibers coupled to the side of them. They should bend at a 90 degree angle to exit the side of the chip in a ...
3
votes
2answers
98 views

Why is there no dark band below a rainbow?

I've read articles about Descartes' theory of the rainbow and I can understand why there is a dark band of about 8 degrees (Alexander's band) between the primary and secondary bows: for all the water ...
2
votes
1answer
85 views

Good resource for geometric optics

I'm looking for a good resource (preferably a book) on geometric optics. I am thorough with the basics (the mirror formula, lensmaker's formula, thin lens formula, etc). What I want is something that ...