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.

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addition of two lenses with a finite separation in between

Suppose there are two lenses with focal length $f_1$ and $f_2$ respectively. The effective focal length $f$ when they are combined is $1/f=1/f_1+1/f_2$, but this formula assumes the separation between ...
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1answer
49 views

Calculating angle of min deviation of prism [closed]

Two rays incident with angle 40 and 60 on one face of equilateral triangular prism the angle of deviation are equal .find angle of minimum deviation?
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1answer
37 views

Apparent depth is supposed to be independent of viewing angle but this seems inconsistent with critical angle diffraction

When rays from the object at some depth are draw so as to be incident at the critical angle (or some angle just lower) the ray is refracted along the surface. Retracing this line would give you an ...
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1answer
90 views

How far apart can the slits be in a double-slit experiment using direct sunlight?

In a normal double slit experiment, I'm told that sunlight doesn't produce a visible interference pattern because there is no stable phase relationship between the two slits. However, sunlight ...
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1answer
27 views

Reflection and angle of refraction

Does the angle of refraction depend on the properties of the material if the angle of the incidence is the same for two different materials? Say I shed light on a surface with angle $ \theta $ and ...
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1answer
53 views

Unpolarized wave, $\Delta\varphi =\Delta \varphi(t)$?

I have seen a unpolarized wave defined in a number of places (e.g. here) as a wave such that: \begin{align} E_x&=E_0 \cos(kz-\omega t) \\ E_y&=E_0 \cos(kz-\omega t+\varphi) \end{align} Where $\...
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2answers
47 views

Introducing a phase, what changes?

This question is related to: Mach-Zehnder interferometer and the Fresnel-Arago laws Let us say we have unpolarised wave taking the form: $$\psi=\psi_0 e^{i(kx-\omega t)+i\phi(t)}$$ Where $\phi$ ...
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18 views

Mach-Zehnder interferometer and the Fresnel-Arago laws

I have been reading this paper on a mathematical treatment of the Fresnel-Argo laws. In the paper they essentially they take the electric field: $$E_i=E_i(t)$$ and introduce a phase factor, $e^{-i\...
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1answer
38 views

Why is the wavelength of light proportional to the minimum angle of resolution?

E.g. why does the minimum angle of resolution increase as wavelength increases?
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9 views

Why long range ordering and higher order rotational symmetry leads to dense K-space ?

In case of Quasicrystals Why long range ordering and higher-order rotational symmetry leads to dense K-space ? And high rotational symmetry include modification in discrete spectral feature to ...
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1answer
43 views

Sech laser pulse time-bandwidth product calculation

Find the time bandwidth product for a $\operatorname{sech}$ shaped pulse. Attempt: I know that the time bandwidth product $\Delta t \Delta \omega$ for a $\operatorname{sech}$ shaped pulse must be $...
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30 views

Structured light, infinite focus

Im interested in projecting a static image across a room that stays focused over a wide range of distances from the projector, without re-adjustment, for a structured light setup. ie, the target may ...
3
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3answers
104 views

How can unpolarised light be produced from 2 beams with orthogonal polarisation?

Say I have 2 beams of equal intensity with orthogonal polarisation. Is there a way, using linear polarizers, half and quarter waveplates , to combine those two beams in such a way that they produce an ...
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1answer
787 views

Reflection of light rays

A set of light rays emitted from a point of an orange hits a smooth and flat surface. My question is: The angles of incidence are different, light rays are reflected towards different directions, why ...
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1answer
55 views

Laser resonator analytic formula for sum of modes

For a sum of N modes in a resonator with identical phases, find an analytic formula for the pulse shape in the limit of many modes. Use the analytic expression for the sum of a geometric series. ...
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1answer
40 views

Laser resonator modes

For a resonator, plot the intensity as a function of time for (i) when the modes have identical phases, and (ii) when the modes have random phases. Attempt Here is the equation for intensity (p. ...
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0answers
52 views

Why does a fan blade appear to spin backwards when spun really fast?

This a phenomenon which I notice everyday but never really took an interest in. Why does a fan (or any other rotary object), when spinning really fast, 'appear' to slow down, upto a certain rpm, then ...
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1answer
49 views

What is the divergence of a beam from the output of a laser?

Diffraction through an aperture gives a half-angle divergence of $1.22\lambda/a$ where a is the aperture diameter. The half-angle divergence of a Gaussian beam is $\lambda/\pi w_0$ where $w_0$ is the $...
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1answer
46 views

Why does melted agarose in solution appear fully transparent, but become opaque when polymerized?

Agarose gels (hydrogels) are commonly used in molecular biology for electrophoresis of DNA. When a solution of hot agarose is poured, the material is clear: When a gel forms, the material ...
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2answers
48 views

Proportion of photons passing through three polarizers

I've started recently reading book "Quantum Computing, A Gentle Introduction". After each chapter there are exercises for self study. For some of them there are answers, for some not. So far I've been ...
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4answers
2k views

Same photon or different photon?

Consider a typical optical focusing system: A small light source, then a collimating lens, then a focussing lens, and then a detector (e.g. CCD). Assume that source intensity is so low that only one ...
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1answer
39 views

Photon absorption in a medium - basic principle?

I am trying to understand the basic physics of photon absorption in a medium. Take the example of oxygenated hemoglobin (red curve). Clearly at different frequencies/energies relatively more or less ...
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6answers
2k views

Light's inverse square law: Does it require a minimum distance from the source?

Does the inverse square law begin to take effect the moment light leaves its source? For example, does light's intensity decrease, i.e. does the area in which the photons might land increase, at a few ...
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1answer
29 views

Actual spot size = geometric spot size + diffraction spot size?

I read in [1] that for a camera obscura the total spot diameter is equal to the diameter of the spot produced concerning geometric optics only plus the diameter of the spot concerning only diffraction....
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4answers
109 views

Intensity fluctuations at the output of a single mode fiber coupled to a He Ne laser

I have coupled a Thorlabs HNL050L-EC - HeNe, 632.8 nm, 5 mW, Polarized Laser to a 2 meter long single mode fiber patch chord using a Thorlabs F230-FC-B aspheric lens. While I am certainly able to ...
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0answers
62 views

Breakdown of Snell [closed]

I have reason to believe the following: If we are using an accurately formed thin prism, with an apical angle of let's say 2 degrees, and direct a monochromatic source beam thru a slit onto the ...
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0answers
14 views

How does the area of illumination affect the numerical aperture / optical resolution of an optical system?

I have been reading an optics paper in which they designed a microscope with the following setup. A light source passes through a small pinhole, illuminates a sample, which then forms a diffraction ...
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1answer
49 views

Calculating the diameter of Jupiter through an image

I took an image of Jupiter through my 8" Dobsonian Telescope, attaching a DSLR and a 1.25" Barlow Lens where the eyepiece goes, as shown in this video: https://www.youtube.com/watch?v=reFxoF3XoaU ...
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2answers
59 views

Can AMO physics be applicable for space travel? [closed]

I know it sounds very stupid question. I am a Ph.D student currently working on the AMO physics (Quantum Optics). I recently saw articles about the Spacex, and I thought it is really amazing, and ...
17
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3answers
368 views

Why don't the colors in an oil slick change as I walk past?

After it rains, I often see bands of color on the asphalt roads. This is usually explained as an thin film interference. Wikipedia has a picture of it which looks by inspection to be the same ...
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2answers
44 views

How does change in medium affect object distance/image distance?

Say,we have a container filled with a liquid of refractive index $7/5$ upto a height up $H$. There exists a plane glass mirror at the bottom of the container. Now if a fish were placed at a height of ...
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1answer
30 views

Michleson Interferometer fringe shift

I have a problem with interferometer fringe shift. I am learning it from my physics book. In the book, it is written, "As the L1 (Displacement of moveable mirror) is changed, the pattern of ...
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0answers
20 views

Binocular vs. monocular field of view in head-up displays

I've been reading about head-up displays in Wiki: Head-up display and understand that it works such that an image from an LCD screen (automotive) or from a cathode ray tube (aviation) is projected to ...
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3answers
134 views

Why can't incoherent light be collimated as well as laser light (e.g. in a laser pointer)?

Why does a laser pointer contain a laser diode, and not just an LED? A laser pointer contains a laser diode, which essentially shines coherent light over a large angle, and a collimating lens, to ...
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0answers
39 views

how to solve this question? [closed]

This is the question in my text : A monochromatic light of wavelength $\mathrm{600 \times 10^{-9}m}$ is used in a Young's double slit experiment. One of the slit is covered by a transparent sheet ...
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1answer
41 views

How black body absorbs light?

I learn that black body absorbs light, but couldn't get the mechanism behind it. I wish I could get help.
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0answers
39 views

Amplitude of unpolarized EM wave after a polarizer

The amplitude of a linearly polarized wave after a polarizer is $$E_1 = E_0\cos(\theta)$$ and the intensity is $$I_1 = I_0\cos^2(\theta)$$ Now for unpolarized light, the time averaged amplitude is ...
4
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0answers
33 views

Quantify shade-off and halo effect in phase contrast microscopy

Shade-off and halo effect introduce distortion to phase contrast images. I am trying to utilize these features to write a program which could identify spherical cells from (positive) phase contrast ...
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2answers
51 views

Interference Pattern and dark lines

Two very narrow slits are spaced apart and are placed 35.0 cm from a screen. What is the distance between the first and second dark lines of the interference pattern when the slits are illuminated ...
23
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1answer
859 views

How can my window not scramble the image of my yard?

How can an image pass through a window if the atoms in the glass randomly emit photons in any direction? I've read that glass is transparent because the atoms don't readily adsorb visible light, so it ...
3
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1answer
40 views

Does the angle of incidence change the refractive index?

I've been told if you plot a graph using the sine of the angle of incidence and the sine of the angle of transmission it should follow a linear regression $y = ax + b$. However, if you use certain ...
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1answer
35 views

Tilted and Misaligned Items in Optical Schemes

My scientific advisor has said me to find correct and concrete ray matrices (ABCD (2x2) or ABCDEFGHI (3x3) or ABCDEFGHIJKL (4x4)) corresponding to tilted and misaligned optical elements such as: ...
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1answer
31 views

What is meant by the point-source response of eye or telescope?

I have heard that a source is called unresolved if it is much smaller in angular size than the point-source response of the eye or telescope observing it. What is the meaning of point-source response ...
2
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0answers
26 views

What is the relative importance of lens element quality in a multiple lens system? [closed]

I tried grinding a custom lens out of acrylic glass (diameter 20mm, focal length 30mm). Not very surprisingly, the result is a quite poor quality lens. I think it mostly suffers from geometry and ...
3
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1answer
26 views

Is perfectly diffuse reflection entropy maximizing?

Suppose that I shine light on a surface and none of it will be absorbed or transmitted, and the spectrum doesn't change (so that all that's left to determine is the power reflected from the surface as ...
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1answer
46 views

Application of Snell's law for an extraordinary wave?

I have read [1] that when the light enters a birefringent material with optical axis perpendicular to the plane of incidence that the angle of refraction of the extraordinary wave can be found by ...
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1answer
22 views

Why is second harmonic Intensity periodic in coherent length?

Solving for the intensity of second harmonic generation we get that intensity is $sinc^2(\pi/2*L/L_{coherent})$. How is calculated that the intensity is periodic in L_{coherent} (coherent length, L ...
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1answer
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What is the theoretical maximum data transmission rate of an optical laser at 400nm and at 800nm, with optimal pulse width? [closed]

I want to know what the highest possible data transfer is for visible light with regards to the frequency, disregarding noise. Using the shannon-hartley formula wasn't of much use, as it operates ...
2
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1answer
42 views

Does curving only the inner surface of a diving mask prevent blurred images?

Diving masks often have lenses built into the glass for divers who do not have perfect vision. The lenses in a diving mask faceplate often only have a curved surfaces on the inside glass. Why is this ...
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1answer
79 views

What is the difference between a white object and a mirror in terms of heat absorption?

Will a white object be cooler than a mirror when exposed to direct sunlight? Or will it be the other way around? If mirrors bounce all visible light and some of the other elements of electromagnetic ...