Questions tagged [geometric-optics]

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

Filter by
Sorted by
Tagged with
0 votes
0 answers
5 views

How is a complete image of a distant object formed with an obstruction in the line of sight?

Can anyone please link to or sketch a diagram demonstrating how a complete (and clear) image can be formed of a distant celestial object with a central obstruction blocking part of the line of sight ...
flextempers's user avatar
0 votes
0 answers
12 views

How do you derive the formula's for equivalent focal length and back principle plane for 2 thin lenses separated by a distance?

I've found online that the formula for the effective focal length of 2 lenses separated by a distance is: $$ \frac 1f=\frac 1{f_1}+\frac 1{f_2}-\frac d{f_1f_2}. $$ However, I'd like to know how this ...
Max Wang's user avatar
  • 101
1 vote
0 answers
83 views

Why does Lens made of Two Materials form only Two Images?

I was solving a test this morning and came across this question. Now by intuition, I know that there should be only two images formed. Rays shall converge through the upper section of the lens to form ...
Schrödinger's Cat's user avatar
0 votes
0 answers
27 views

Proof for law of reflection with geometry only [closed]

I aim to prove, using pure geometry, that the path of light from point A to B, reflecting off a plane mirror, is minimized when the angle of incidence equals reflection. I am trying to use the method ...
user395979's user avatar
0 votes
0 answers
9 views

Input Parameter Location for 3x3 Beam Trace Matrix for Misaligned Optical System

I'm trying to use a 3x3 beam transfer matrix from "Generalized Beam Matrices: Gaussian Beam Propagation in Misaligned Complex Optical Systems" by Anthony A. Tovar and Lee W. Casperson https:...
JoeMama's user avatar
0 votes
0 answers
27 views

Multiple lens configuration thickness and distances

Struggling to understand where I should measure lens thickness and distance between lenses from. I've attached an example multiple lens setup. For determining individual lenses thickness is it simply ...
user94863's user avatar
0 votes
1 answer
32 views

Michelson interferometer but with 1 arm

If we design a setup similar to Michelson Interferometer but with one mirror only. So, there is an angle between the 2 rays to the detector. Will we get an interference pattern on the screen?
Wael Khatib's user avatar
0 votes
0 answers
16 views

Printing 2d fresnel zone plate

Recently my teacher asked me to create a Fresnel zone plate (Fresnel lens to be accurate). I wanted to print it using a laser printer with a resolution of 1200*1200 dpi. I know that i should block ...
Mohammad Ali Shojaie's user avatar
2 votes
1 answer
193 views

Lenses and missing reflection

I am wondering why reflected rays are not considered with lenses. If a ray strikes a surface, another is reflected off that striking point; however, this is not added when studying lenses, only ...
DisD's user avatar
  • 23
0 votes
0 answers
15 views

Final image formation in these 2 cases:

Can someone please explain simply how we determine how many times we have to consider reflection and refraction to obtain final image. Example a: Here they only considered refraction twice to obtain ...
Alex Aboda's user avatar
0 votes
1 answer
72 views

Keplerian telescope with parabolic mirrors

Is it possible to arrange two off axis parabolic mirrors (OPAs) to transform the emitted rays of a point source into a collimated beam, as in the figure below? That is, similar to a Keplerian ...
tush's user avatar
  • 195
0 votes
0 answers
31 views

Dispersion of light without deviation

Why do we have dispersive angle in dispersion without deviation if there is no deviation from the original path?
Anusha's user avatar
  • 3
0 votes
2 answers
49 views

Using Fermat's principle to derive the Cartesian paraboloid

I am self-studying Optics by Pedrotti and I'm on the subject of geometric optics, specifically ideal Cartesian surfaces. These are reflecting or refracting surfaces that form perfect images. I was ...
nwsteg's user avatar
  • 260
0 votes
0 answers
28 views

Efficiency of light collection of a lens

I am trying to calculate the theoretical imaging performance of a scintillator & camera combination, (scintillator is a plane that emits optical light under X-ray exposure). My question is I found ...
bbbeenn32's user avatar
3 votes
1 answer
49 views

Why is there no "parabolic abberation" in lenses?

I am trying to understand what an "ideal" lens would look like. Spherical surfaces are not correct, as these produce spherical aberration. This article here, is really useful. It 'derives' ...
AccidentalTaylorExpansion's user avatar
0 votes
2 answers
46 views

Can any mirror arrangement give an optical advantage?

I'm trying to see tiny movements in a membrane using a laser spot that shines on it, and looking at the reflected spot. I was wondering if it is possible for any plane mirror arrangement to give me ...
Rishab Navaneet's user avatar
1 vote
1 answer
63 views

Snell's Law- Extraordinary ray

I applied the snell's law to find the angle of refraction of the Ordinary and Extraordinary ray. And I got the correct answer 3.51. But I know my approach to the question is wrong because I applied ...
Akshat Shrivastava's user avatar
4 votes
1 answer
65 views

About the focal length and $f\#$ of spectrometers

Suppose I image light into the entrance slit of a spectrometer (actually a monochromator). The spectrometer is schematically shown below. On the spectrometer's specs sheet, it is said that it has a ...
tush's user avatar
  • 195
0 votes
1 answer
41 views

Reflection from a spherical surface

I am self-studying Optics by Pedrotti and I'm stuck on the algebra for an example of spherical reflection. We have a point source at O that reflects off a spherical surface and creates a virtual image ...
nwsteg's user avatar
  • 260
0 votes
1 answer
55 views

How would a lens mirror work?

Say you have a convex lens with one of the sides completely coated with a mirror like substance, effectively rendering one side into a mirror. How would this lens work? Would the usual formulas like $\...
WilliamHarvey's user avatar
1 vote
1 answer
114 views

What is the use of $4f$ lens system for imaging?

Almost all the imaging experiments use $4f$ lens combination for imaging. What I don't understand is what is there a need for this combination. From my understanding, we can just use a convex lens. ...
QuantumOscillator's user avatar
0 votes
0 answers
43 views

If a white light is incident on a thin prism, that means all colors have the same incident angle

If a white light is incident on a face of a thin prism, then all colors have the same incident angle. A dispersion occurs in the prism, but only the ray of one color will be parallel to the base of ...
Jack's user avatar
  • 803
0 votes
1 answer
73 views

What shape should the lens be so that it collects all the rays at one point?

I want to understand what shape a biconvex lens should be so that it collects all the rays at one point (without spherical aberration). So I want to get the equation of the lens shape depending on the ...
Mikhail's user avatar
  • 11
0 votes
1 answer
37 views

Magnification of closely packed thin lenses, or of closely packed lens and mirror

I was taught how to calculate the equivalent foci in both the cases. And since the formulae resemble the simple mirror and lens maker formulae, teacher said that this system is behaving like a single ...
Gautam's user avatar
  • 39
1 vote
2 answers
189 views

How does 2f-2f lens configuration work?

Say I want to image a shape which is cut out on an Aluminium sheet. If I am passing a laser through the object in a setup like the image below. What I don't understand is why is there a need of ...
QuantumOscillator's user avatar
0 votes
1 answer
31 views

Perceived visual size of non-zero-sized collimated light source

Posting as a follow-up to my previous question where I modelled the system in question incorrectly, and therefore the question now completely changes with the physical model corrected. Suppose I have ...
DELTA12's user avatar
  • 135
0 votes
1 answer
42 views

Perceived visual size of collimated image

Suppose I have a light source which reflects off a collimating curved mirror into the eye. Knowing the size (d) of the final collimated beam focused at infinity, how can I determine the perceived ...
DELTA12's user avatar
  • 135
2 votes
1 answer
58 views

Is the ray model appropriate only for spherical/planar waves?

In ray optics, light propagation is modeled using rays, i.e., curves that are perpendicular to the wavefront. In general, rays can be curved; however, if the medium is homogeneous, it follows that the ...
mathslover's user avatar
1 vote
1 answer
77 views

How does rotating a beam splitter (cube) affect the output angles?

Normally, you would want to place a beam splitter at 45 degrees with respect to the input beam. This way, it splits the light 50/50 and the output beams are aligned for sure. Like this: Now, I want ...
AccidentalTaylorExpansion's user avatar
0 votes
1 answer
29 views

Working principle of Shack-Hartmann Wavefront Sensor

(Image source: https://www.thorlabs.de/newgrouppage9.cfm?objectgroup_id=5287) In the Shack-Hartmann wavefront sensor, the local slope of the incident beam's wavefront is measured as a displacement of ...
Ogiad's user avatar
  • 1
0 votes
0 answers
46 views

Silvering of lenses and their focal length

For a silvered biconvex lens the equivalent power is give by $P_{eqv.}=P_{lens}+P_{mirror}+P_{lens}$. Here we put power of lens as negative since it behaves as a concave mirror overall. Reasoning for ...
Physics Kota's user avatar
2 votes
0 answers
34 views

Why doesn't a lens after a diffraction grating affect the optical path difference?

When observing interference fringes one often uses a lens after the diffraction grating to focus the fringes on a screen like this: At first sight, one might think that after the lens the path ...
Julia's user avatar
  • 1,682
0 votes
0 answers
43 views

Two-qutrit preparation using linear optics

How can I prepare a two-qutrit product state (let's say $\frac{1}{\sqrt{2}}|0\rangle|0+2\rangle$ using optics? Do I need a BBO crystal (as I know BBO crystal produces an entangled state), or can I use ...
PAB's user avatar
  • 1
1 vote
0 answers
27 views

How does a Circular Light Source create Shadows with Darker Edges Sometimes?

Problem: There is a room where the light fixture is circular*. Shadows of objects in this room are darkest in the center and brighter toward the edges, except for my phone charger. Its shadow is ...
E Tam's user avatar
  • 95
0 votes
0 answers
23 views

Paraxial Spherical wave emanating from point source

I'm reading through chapter 5.3.1(Impulse response of a Positive lens), in Goodman's "Fourier Optics"(p.109). An object is placed a distance $z_1$ in front of a lens. If we place a point ...
Sammy Apsel's user avatar
-1 votes
1 answer
58 views

When does magnification not depend on distance of object? [closed]

Two thin lenses share a common optical axis. Their focal lengths are f1 = 20 cm, respectively and f2=50 cm. In front of the first lens at distance x>f1 there is an item. On the screen behind the ...
mathchad's user avatar
0 votes
0 answers
21 views

Is it preferable to say $v$ is " image distance " than to say " image position " in spherical mirror formula?

I was going through spherical mirror formula $1/v + 1/u = 1/f$ where $u$, $v$ and $f$ are named as object distance, image distance and focal length respectively. But while using this equation we do ...
Shinnaaan's user avatar
  • 1,219
0 votes
2 answers
99 views

Imaging and illumination plane in microscope

I've been delving into the intricacies of achieving Kohler illumination in microscopy, and the term 'illumination and image-forming rays' consistently surfaces. Most resources emphasize the ...
CoffeeBiscuit's user avatar
0 votes
1 answer
42 views

As we all know a convex lens doesn't exactly converge all rays parallel to it's axis on a single point. So I want to find one such figure

Writing a differential equation for such a figure is an uncomplicated task. It can be accomplished by using snell's law. But the resulting equation probably isn't solvable. I put it in wolfram alpha ...
Arpan Bajpai's user avatar
0 votes
0 answers
109 views

Why do projector condenser lenses focus light directly onto the projection lens?

I've seen diagrams for projectors where condenser lenses focus light directly onto the pupil of the projector lens, after going through the image source. Am I misunderstanding the diagram? If not, ...
Sohil Sathe's user avatar
1 vote
0 answers
42 views

What is the connection between Ray (Geometric) optics and Electromagnetic theory optics in fiber optics?

I am currently reading about fiber optics and wave propagation in fiber optics and encountered the following part of Gerd Keiser's Book : according to the diagram shown, its a general case when the ...
AbdAllah Talaat's user avatar
10 votes
2 answers
2k views

Is it possible to witness a rainbow while facing the sun?

We know that a rainbow occurs due to the refraction and reflection of light inside raindrops. We also know that inside spherical raindrops total internal reflection is not possible. So some light is ...
Al-Ahsan Abhro's user avatar
-1 votes
2 answers
269 views

Which distance to be used for object distance, in mirror formula? [closed]

I know that mirror formula is, $$\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$$ but there's a doubt in the following case, Here to solve the problem, what value should i put for u in mirror formula, u1 ( ...
Rohan Singh's user avatar
-1 votes
2 answers
199 views

A object viewed from a red glass would appear red colour? [closed]

Original Question: Explain, why in daylight an object appears red when seen through a red glass and black when seen through a blue glass? My understanding according to what is given in my textbook ...
Darshit Sharma's user avatar
2 votes
2 answers
120 views

Do Normal Incidence contradicts the definition of refraction?

Professor told our class that if someone wants to define refraction in words, it can be done as the following, The deviation of light from its path when it passes from one medium to another is called ...
user avatar
1 vote
0 answers
23 views

I need to figure out the length of a crystal to move a light beam [closed]

I need to figure out the length of a crystal to move a light beam shining through it. The height is known, and so is the refractive index of the crystal and its length. What I can't figure out is the ...
100xln2's user avatar
  • 119
0 votes
0 answers
27 views

Why the angle between incident ray and normal is 0° and not 180° if incident ray is directed perpendicular to "plane" of plane mirror?

Here the incident ray is normal to the plane of plane mirror, that is obvious but why everybody say that this ray is making an angle 0° with normal, why the angle is not 180° ? Are they relating it ...
user avatar
0 votes
0 answers
45 views

Can lasers really show microbes in water?

I used a 532 nm green laser and passed its beam through a water droplet. Can you explain me are these really microbes and if they are then how a laser is able to do so?
Akshat Parmar's user avatar
0 votes
1 answer
69 views

Inverse square law for non-point sources?

Assuming I have a light diffuser with an area A (approximately planar, not spherical) and measure the light intensity directly at the surface (23 mW/cm^2), how could I determine the intensity at ...
iwab's user avatar
  • 145
2 votes
0 answers
94 views

What is the exact reason of using sign convention to derive mirror formula & if it's done already then why sign convention is used again for problems

Today i studied about mirror formula, its derivation and sign convention used while deriving it, a question which i have is, why do i have to use sign convention while doing the derivation ? focal ...
user avatar

1
2 3 4 5
29