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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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 ...
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2answers
425 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 ...
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1answer
164 views

Why are mediums always represented as straight and parallel lines in Ray optics?

I have been reading Ray Optics lately and I always see that the interface between mediums are always represented as Straight lines in ray diagrams. There is no mention that they are considering an ...
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1answer
53 views

Inside a spherical mirror

imagine standing inside a sphere composed entirely of mirror surface; what does this look like? inside is lit by an invisible light source if each point encounters a reflection of itself, what is ...
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11 views

Why would longer distance between collimated lenses improve coupling efficiency?

Im coupling 1550nm output from a single-mode lensed optical fiber to a standard SMF using a pair of collimating lenses, matched to the NA of the respective fibers. However, I find that by increasing ...
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1answer
77 views

Can QED explain this or do I have revert to the classical model of light?

I want to know can QED can explain this image,like why there are someplaces with low light (shadows) like behind the chair, and why there are some places that are bright(rest of the floor). I know ...
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2answers
484 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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0answers
17 views

How can line be parallel to Pricipal Axis after following Paraxial Ray Approximation?

I Studied In my previous Standards that Light Parallel to principal axis passes through focus always in Concave Mirror. But Now In one Book I read that there is a condition which should be followed ...
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1answer
26 views

What is Retracing in context of this Question?

My textbook Question is Two Mirrors are inclined at an acute angle theta.Light ray is incident parallel to one of the mirrors. Light will start retracing its path after third reflection if angle ...
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1answer
42 views

How second image is brightest here?

One of my Textbook's Multiple Choice Question is- A Thick plane mirror shows a number of images of the filament of an electric bulb. Of these, the brightest image is the- First Second Last Fourth ...
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8answers
3k views

Is it possible to make glasses that make everything brighter, but do not magnify or focus?

Corrective glasses are usually intended to help focus light on your retina. Supposing I had good vision already, but simply wanted more light, could I make glasses that would send more light into my ...
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1answer
36 views

Determining path of light through a nanolens

In the case of light passing through stacked liquids, we can use a ray approximation of the path of light to determine the path taken through each layer of liquid using Snell's law. From all the ...
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0answers
54 views

Re-reflecting in HUD optics

Simple HUD optics design can be described with below image. (source : http://www.mikesflightdeck.com/hud/head_up_displays.html) As you can see, if combiner and colimating lens(after fold mirror) ...
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4answers
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0answers
49 views

False sunset and false sunrise time estimation

False sunset and false sunrise are described . Here is a sample day rise and set time according to AccuWheather site and calculated value of sunrise and sunset in my country. Could you please help ...
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2answers
153 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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1answer
31 views

Geometry confusion with incident E field

My geometry is very rusty and I'm having trouble understanding why for the incident E field the X component is multiplied by cos and the -Z component is multiplied by sin instead of the other way ...
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0answers
15 views

Chief ray in two thin lenses optical system [duplicate]

I have an optical system made by two thin lenses with a stop between them. How can I find the chief ray in this optical system? Obviously I find a parameteric method assuming: $f_1:$ focal length of ...
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2answers
83 views

Is it possible to build an optical system that increases the perceived surface brightness?

So is it possbile to build a system from lenses and mirrors that can make faint gas nebulas brighter or can be used as nightvision? If you increase the size of the aperture of a telescope it will ...
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0answers
27 views

Rayleigh Criterion and Resolvability

If I want to resolve two close but different wavelengths $\lambda_{1}$ and $\lambda_{2}$ to the second order in my experiment using a grating of spacing $d$, is the size of the grating ($D = Nd$) I ...
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19answers
70k 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?
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1answer
22 views

Why does some light escape when in a fiber taper?

I am working with fiber tapers and i noticed that some light escapes from the tapering region and i am quite curious. I am using a 500 micron plastic optical fiber and i managed to stretch the ...
2
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1answer
58 views

If I wear contact lens and spectacles of same power, is it same wearing thick spectacles of twice the lens power?

Assume I have a contact lens of power -1 and a spectacles of +1. Will they cancel out their effect? is it same as my normal eye sight?
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1answer
42 views

combination of mirror and lens [closed]

a convex lens forms a real image of a point object at a distance of 50 cm from convex lens. a concave lens is placed 10 cm behind convex lens on image side. on placing a plane mirror on the image side ...
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3answers
954 views

reflection at intersection of two 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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2answers
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How do a microscope's optics expose defects in the user's 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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2answers
4k views

Bi-convex vs. plano-convex lenses

As I understand, less spherical aberration is obtained when a collimated beam is focused with a plano-convex lens as opposed to a biconvex lens. What would be a situation when a bi-convex lens should ...
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1answer
36 views

Position dependent refractive index [duplicate]

How to determine the angle of refraction when the medium has position dependent refraction index? Lets say that the angle of incidence on the glassy slab is $\theta_1$ and the ray goes through the ...
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1answer
79 views

Determining the path of a light ray

Let's consider a ray in the plane $xy$. Let the refractive index be defined in any point of the plane with the function $n(x,y)$. In time $t=0$ the ray is located in coordinates $(x_0, y_0)$ and its ...
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3answers
3k views

Why Does Passing Light Through a Slit Make it Coherent?

Related: Why incoherent source of waves have to be passed though a single slit for double slit interference pattern to occur? If you have a an incoherent light source, why does passing it through a ...
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3answers
5k 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 ...
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1answer
47 views

How is angle measured by telescope in spectrometer is twice the prism angle [closed]

While measuring the angle of the prism with the help of telescope in a spectrometer (see figure below), the observed angle is twice the angle of the prism. Can someone prove it geometrically? Edit : ...
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1answer
61 views

Why the image is being formed at the surface?

Last week I encountered a very cool optical phenomenon. A photo was sandwiched between the two glass plate to make the paperweight. The cool part is the picture seems to have been pasted on the top ...
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0answers
51 views

How does light manage to change its course at the boundary of two media of different optical densities?

This is a conceptual question. I already know the law of refraction but I need something like an idea of the Physical process from both particle and wave theory standpoints. Why does a ray of light ...
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0answers
47 views

About Powell lens

I am a Post graduation student and I am doing a project on the conversion of a Gaussian beam into a flat top beam using optical components. I have found that the best component to do the same is a ...
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0answers
21 views

Is the focal length of a thin convex lens always less than the radius of curvature?

For a convex lens, would the focal length always be less than the radius of curvature? How does the focal length vary as a function of the refractive index of the lens and the radius of curvature?
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0answers
46 views

Rayleigh length determination for Laguerre-Gaussian Modes

Recently I have measured the Rayleigh length of a Gaussian electron beam probe in a scanning electron microscope, using the function: $$w(z) = w_0 \times \sqrt{1 + (z/z_r)^2}$$ Where $w$ is beam ...
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0answers
49 views

geometric ray tracing

I'm using matlab for tracing rays in 3D through an optical system. I have a 3D prism which its yz cross section is a parabola, and its xz cross section is flat. It has non negligible thickness. I know ...
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1answer
186 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?
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1answer
88 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
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1answer
125 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 ...
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1answer
115 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 ...
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1answer
69 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 ...
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0answers
26 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 ...
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1answer
47 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.
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0answers
131 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 $DB$ ...
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0answers
81 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 ...
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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 ...
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2answers
10k 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) ...
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1answer
69 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 ...