Optics is the study of light, and its interaction with matter. It includes topics such as imaging systems, fiber optics, lasers, quantum optics, and more.

learn more… | top users | synonyms

1
vote
3answers
72 views

Derivation of the group velocity

I know that the group velocity of a light pulse is defined as $$\begin{split}v_g&=v_p\left(1+\frac{\lambda}{n}\frac{dn}{d\lambda}\right)\\ ...
0
votes
0answers
57 views

Cherenkov Luminescence Imaging, Cherenkov radiation,

Is it possible to see glowing from Thin Layer chromatography (TLC silica gel on Aluminium) when we image it by IVIS spectrum (no radioactive source)?
0
votes
1answer
34 views

Sphere, silver reflector, refraction questions

A sphere with its back silvered can act as a retroreflector. When a fine beam of light is directed to the sphere as shown, it is refracted at the front surface, and focused on the rear interior ...
-2
votes
1answer
34 views

Tricky Optics Questions, shifting lenses [closed]

A candle is placed at a fixed distance in front of a wall. A lens is inserted and moved slowly between them. At two particular positions, sharp images are formed on the wall. The heights of the images ...
0
votes
1answer
82 views

Given is an object which is cyan when illuminated with white light. What is the perceived colour of the object when illuminated with yellow light?

I know the perceived colour of an object depends on which wavelengths of the incoming light are reflected and not absorbed, which lead me to believe that it is impossible to be red or yellow... I ...
0
votes
1answer
54 views

Interference of light waves question

We were recently asked to solve a question in class which goes as follows: In a modified Young's double slit experiment, a monochromatic uniform and parallel light beam of wavelength $6000$ ...
3
votes
2answers
54 views

Optics to correct focal distance across a plane

I have a laser beam which is focused to a point at a certain distance. I'm then going to use a galvanometer to scan that beam across a plane. Obviously, as the beam scans across the plane, the ...
2
votes
1answer
68 views

Would the moon be brighter if it were completely spherical?

I remember reading Galileo's 'Dialogue Concerning the Two Chief World Systems' where Salviati and Sagredo explain how the moon would be almost entirely dark if it were a perfect sphere but after ...
3
votes
1answer
25 views

Why is a notch filter required for Raman Spectroscopy?

It is my understanding that Raman Spectroscopy uses a notch filter (or sometimes an edge filter) to remove the light from the laser, so only the relevant Raman bands are present. However, if this is ...
-1
votes
3answers
54 views

What physical properties can't be predicted based on index of refraction? [closed]

If I tell you the real and imaginary parts of the index of refraction for all frequencies, name a property that can't be predicted based on that information. If you're assuming this is a gas, specify ...
3
votes
0answers
25 views

Where do rays that are not marginal or principal get stopped?

The picture is from an MIT lecture but the concepts are explained in many optical texts. The chief/principal rays go through the center of the aperture stop, hit the edge of the field stop, and the ...
0
votes
1answer
26 views

I want to use the complex susceptibility to prove that E dot J is independent of the real part

As stated above, I want to use $\chi$=$\chi'$-i$\chi''$ to prove that E$\cdot$J is related to $\chi''$ and independent of $\chi'$. I need to do this using a monochromatic field ...
0
votes
0answers
39 views

Finding the appropriate fitting function for a coherence length measurement

I'm studying Coherent Optics in Experimental Physics, and I intend to determine the coherence length of a two beam interference. To do that, I used an He-Ne laser, a Michelson interferometer and a ...
0
votes
1answer
59 views

What is time badwidth product for pulses with GDD?

For a gaussian pulse the time bandwidth product is dwdt = 0.4. What is the time-bandwidth product for chirped pulse with group delay dispersion (GDD) added only ?
0
votes
0answers
29 views

How to determine Irradiance (W/m^2) at surface due to LED luminous intensity (mcd)

Thanks in advance for the help, I do not think this is a duplicate questions although there are some related discussions. While I'm mainly interested in the generic solution, my specific question ...
1
vote
2answers
45 views

Covering half of a lens [duplicate]

What happens to the image of an object kept before a lens if the upper half of lens is covered by an opaque coating? I understand that the full image will be formed and only the intensity of the ...
2
votes
1answer
36 views

Spectroscopy, interferometry and …?

Consider the case of a Michelson 'Interferometer', from what I have read: If you measure the output as a function of mirror separation that's interferometry. If you measure the output as a function ...
2
votes
0answers
29 views

What is the shape of the MTF curve in coherent imaging?

For incoherent imaging, the shape of the diffraction-limited MTF curve would look roughly like a triangle, with normalized contrast starting at 1 for zero spatial frequency and decreasing to 0 at the ...
5
votes
1answer
81 views

Why are UV protective eyeware Orange?

Many industrial processes use uv as a curing agent. When one uses such a process, one must protect one's eyes from the radiation. Most uv protective gear I have seen is tinted orange? Does this ...
0
votes
0answers
24 views

Michelson Fringes

When using a Michelson Interferometer to view circular fringes (i.e with mirrors in exact perpendicular alignment and a relatively large difference in arm length) would fringes be observed using a ...
0
votes
0answers
17 views

Frequency combs measurment

How is a frequency comb actually used to measure something? For example: I don't know the length of my pen, so I take a ruler and measure it -- it reads 10 cm, so now I know my pen is 10 cm. From my ...
3
votes
1answer
80 views

Why purple seems so to similar to red? [duplicate]

Purple lights has the highest frequency among all visible lights, while the red lights is the least frequent one. However, purple seems to be a mix of red and blue to human eyes, why?
0
votes
2answers
81 views

How is focal length defined for a two lens system?

I have found the formula for the effective focal length $f$ of two thin lenses with focal lengths $f_1$ and $f_2$ separated by distance $d$ to be $\frac 1f=\frac 1{f_1}+\frac 1{f_2}-\frac d{f_1f_2}$. ...
3
votes
4answers
144 views

Capture the entire light field of a 3D scene and construct a virtual scene

I've been fascinated with light field cameras for quite a while. They are devices that can capture information about the light field emanating from a scene; that is, the intensity of light in a ...
0
votes
0answers
272 views

What is the physical meaning of magnifying power of a telescope?

So the following question was given in the JEE Mains 2016 conducted throughout India on 3rd April. An observer looks at a distant tree of height 10 m with a telescope of magnifying power of 20. To ...
3
votes
1answer
39 views

What causes damage to interference filters?

I am currently working on a UV detector meant to be mounted on a CubeSat satellite. To select the bandwidth, I consider using an interference filter placed between the detector and the source. ...
4
votes
1answer
62 views

What determines laser frequency?

I am studying Lasers and frequency combs - and am not quite understanding something. I understand the working principle of a laser, and thought the Laser output frequency is just the energy gap ...
0
votes
1answer
23 views

Thermal imaging

If we have thermal imaging camera and the sound is wave is produced and propagates in hot air can we see the electromagnetic emission of molecules producing pressure packets of sound wave?
3
votes
1answer
40 views

Femtosecond photography

My question regards comments made around the 9:23 minute mark in Ramesh Raskar's TED talk, "Imaging at a trillion frames per second". At this point in the talk, an image shows "light ripples" that ...
0
votes
0answers
33 views

Splitting an image in a lens into two sources?

Is it possible to project an image of light that passes into a lens onto two surfaces without affecting the image?
2
votes
1answer
55 views

Chance of distinguishing between many pure states

Helstrom has demonstrated that the maximum probability of any process correctly distinguishing between two pure states $|\psi_0\rangle$ and $|\psi_1\rangle$ is determined by their trace distance: ...
0
votes
0answers
37 views

How are optical lattices created, and how big can they be?

I am asking about the basic concept and the schematics of the laser configuration. How are atoms forced to stay in optical lattices? What lasers (power, wavelength, etc.) are used, and how are they ...
1
vote
0answers
59 views

Why does Light change color through Glass slab?

I shone a green laser light(~532 nm) through a glass slab and what I saw inside was that the light beam was now red. Imagine a regular refraction diagram but color the beam outside green and that on ...
0
votes
0answers
17 views

What does “Polarization Gradient Cooling” mean?

I'm well versed with what "Polarization Gradient Cooling" refers to, as in how the process works and what the term refers to, but the term itself baffles me. What is a "Polarization Gradient"? The ...
3
votes
1answer
86 views

What exactly happens when total internal reflection takes place at a quantum level?

What happens when light interacts with the boundary between 2 mediums at a quantum level? Why is it totally reflected back when it is travelling from an optically denser to a less dense medium? How ...
0
votes
1answer
28 views

rare occurence of diffraction in light [closed]

My question is that how the diffraction is not a common phenomenon of light.Here the lunar eclispe also is on the same basis but the diffraction is only a feature of sound .how?
0
votes
0answers
19 views

Transmittance of yellow light through blue substance

I am performing an experiment in which I flash an LED-light through a substance with different opacities and do voltage measurements over a photoresistor on the other side. When I decrease the ...
0
votes
1answer
48 views

Point source behind a diffusing plate? [closed]

I am confused about the action of a diffusion plate in optics experiments (e.g. with the Michelson interferometer). Let us say we put a point source behind a diffusion plate, what will the set up ...
0
votes
1answer
35 views

Optics of stationary waves

could anybody tell me how it Works if it comes to stationary waves created on the surface of water jet and optics? there are some crests and troughs which work like lenses, but if you have water jet, ...
7
votes
1answer
350 views

What was Newton's own explanation of Newton's rings?

What was Newton's own explanation of Newton's rings? Newton advocated a corpuscular theory of light, but his rings would most conveniently be explained by a wave theory. How did he explain his own ...
0
votes
0answers
20 views

determine axial resolution in microscopy

I want to determine the axial resolution of a fluorescence microscope. As I understand, this is commonly done employing a thin fluorescent specimen and performing an axial scan. The axial resolution ...
1
vote
1answer
47 views

Could you use polarization filters to make a privacy screen?

I remember seeing that brusspup video where the polarization filter on the monitor was removed and put it in his glasses, causing only the wearer to see the screen. (, and) I was thinking, would ...
1
vote
1answer
36 views

Fresnel equations for perpendicular angle of entry [closed]

In many text books one finds for the fresnel coefficients for light perpendicular to the surface: $$r = \dfrac{n_1 - n_2}{n_1 + n_2}\quad\text{and} \quad t = \dfrac{2n_1}{n_1 + n_2}.$$ When I try to ...
15
votes
5answers
730 views

Why can a solution show optical rotation?

Why can a solution show optical rotation? A solution, as a liquid, is rotationally isotropic, right? So, even if the molecules are chiral, because of the random orientation of the molecules, shouldn't ...
5
votes
0answers
38 views

Can a naked eye see a single atom when it is resonantly driven by some laser beam? [duplicate]

Presumably, when the laser is strong enough, the fluorescence will be very strong too. So, is it possible to see a single atom with a naked eye?
0
votes
0answers
19 views

Analytical derivation of photonic bandstructure in photonic crystal

It seems the usual way to find the photonic bands of a photonic crystal is to setup the "master equation" $$\nabla\times\left(\frac{1}{\epsilon(\mathbf{r})}\nabla\times\mathbf{H}(\mathbf{r}) ...
1
vote
2answers
64 views

Convex lens with object at the focus

When the object is at the focus, the image will be formed at infinity. What exactly does this mean? What will it look like if you hold the entire apparatus at arms length? Will it be extremely ...
0
votes
0answers
21 views

On which factors does reflectance depend?

For my college physics project I'm planning to measure the change in reflectance of an object with respect to a factor (temperature, current going through, etc., not angle of incident, wavelength, ...
1
vote
2answers
81 views

view angle independant focal point

Is there any way to design a lens or system of lenses where I see the same part of the image below the lens, irrespective of direction from where I am viewing. In the image uploaded, there is a black ...
1
vote
1answer
54 views

How does one calculate how big something has to be, to be seen at a given distance? [closed]

Ignoring curvature of the Earth. How do I calculate the size an object would need to be in order to appear to be approx 1cm tall at a given distance?