Questions tagged [microscopy]

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16 views

How to minimize beam walk off during quarter wave plate roration

I am currently building a laser scanning microscope setup. I need to focus the laser on my sample and also place a quarter-wave plate right before the sample so I can control the polarization of the ...
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1answer
82 views

Why is resolution half the wavelength?

My biology textbook says: The general rule is that the limit of resolution is about one half the wavelength of the radiation used to view the specimen. This means anything smaller than half the ...
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2answers
35 views

Can microscope lenses be non-spherical?

Most lenses are spherical, but... Are there elliptical, parabolic or hyperbolic microscope lenses? (I asked a similar question, about telescopes, on Astronomy S.E.; I hope this is not considered '...
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Question about time-resolved Kerr rotation microscopy

I think i have a dumb question. In the experiment mentioned above and depicted in the picture bellow (i'm studying it theoretically), they use two light beans one called pump and the other probe . My ...
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2k views

Why no proton microscopes? Proton diffraction; or proton scattering experiments? Proton crystallography?

I am asking a (relatively) 'low-energy' question here, not about things like the Large Hadron Collider... There are tons of articles everywhere, including such places as Wikipedia and ScienceDirect, ...
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9 views

Measurement of particle thickness on Scanning Electron Microscopy

I have a material (powder) that is likely to be crystalline and forms plate-like particles. Observed by SEM, I can clearly see the plates stacked on each other. It seems that during sample preparation,...
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2answers
35 views

Reflected light microscope semi-transparent mirror

When a light microscope is used in the reflected mode there is a semi-transparent mirror angled at 45 degrees that reflects a portion of the light onto the sample. The sample in turn reflects the ...
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3 views

What is the relationship of inelastic mean free paths and EPES?

In the literature, they calculate inelastic mean free path of electrons by EPES (elastic peak electron spectroscopy) measurements? How these two are related? Why one can calculate inelastic ...
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1answer
27 views

Why can't we image an insulating meterial with an SEM?

I know that insulating materials are difficult to measure for insulating materials because there are charging. The effect is a drift or a moving micrograph. Why does charging cause a drift in the ...
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1answer
19 views

Position dependent $y$ channel reading in lock-in in a photocurrent microscope setup

I am currently building a scanning photocurrent measurement setup. It basically focuses a CW laser down to $50\ um$ size on the sample and scan the laser beam over the sample (a metal) and record the ...
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17 views

Resolution of microscopy techniques

I am writing a popular physics article about microscopy techniques, where I would like to rank the techniques by their resolution, which also necessitates explaining why we do not always use the ...
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1answer
22 views

Applications of nanomechanics

What are applications of nanomechanics beyond its use in atomic force microscopy? The question is specifically about the existing applications rather than the potential/future ones (which are quite a ...
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146 views

How to calculate spot size of a laser focused through a microscope objective

I am trying to figure out how to approximate the spot size of a laser beam that is focused using a microscope objective where the size of the laser beam is smaller than the diameter of the objective. ...
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1answer
31 views

Imaging with two lenses: what if the distance between the lenses is not 2f?

A $4F$-configuration is usually utilized for imaging with $2$ lenses. An object is placed in the focus of the first lens ($f_{1}$), then the second lens is located at a distance $f_{1}+f_{2}$ from the ...
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36 views

Is it possible to scan matter on an atomic level?

is it possible to develop a model of a piece of ordinary matter and scan it to develop a model of what kind of elements are in the matter? Similar to an MRI scan? If it's not possible, why? What ...
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18 views

Influence in Beaker Electroscope

In WDemtröder's book Electrodynamics and Optics there is an experiment, which involves: a) charging a conducting cup by touching the inner cup wall with a charged ball b) charging a conducting cup ...
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28 views

Optical Microscope change in color of image

Is it possible for the numerical aperture to change the color of the image of an optical microscope? The first image is an image with 50x magnification, using a .95 NA. The second image is an image ...
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3answers
316 views

Why viruses cannot be seen?

With the coronavirus pandemic, a lot of websites are publishing articles about viruses. In particular, I've seen some of these stating that viruses cannot be seen because they are so tiny they cannot ...
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1answer
40 views

How to determine the particles size measurement error in SEM images

I have a question that bothered me last time. I did some scanning electron microscope (SEM) on my sample which is basically array of nanopillars . My goal is to determine the pillars diameter ...
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1answer
21 views

In phase contrast microscopy, how does the phase difference between the diffracted light and the background light come to be?

Phase contrast microscopy works by exploiting the phase difference between two paths of light which pass through a probe point of a specimen: One path, the "background" path, is the path the light ...
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Are confocal microscopy and f-number based on the same principles?

We use a small pinhole in confocal microscopy to block out-of-focus rays, much like having a high f-number (small aperture) in a normal camera. Are the two related? And does one ever tune the pinhole ...
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1answer
91 views

How can a picture of a virus be taken when they are not even 300 nm (wavelength of blue light) long?

We cannot take photos of protons because they are not at least the size of the wavelength that registers into visible light. I see photos of Coronavirus in the news everywhere where there is a clear ...
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18 views

Lensing effects from electric charge in electron microscopy

Are there any lensing effects from the electric charge in electron microscopy? For example, positive charge acting as a divergent lens or negative charge a convergent lens?
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1answer
22 views

Macroscopic averaging validity (e.g. density)

When dealing with macroscopic scales, it is common to introduce continuous functions (such as density) which model the behaviour of the underlying microscopic matter. However, I still can't understand ...
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20 views

Simple microscope but tangling doubt!

My textbook (NCERT optics Class 12 pg 339) on simple convex lens microscope says, The idea is to get an erect, magnified and virtual image of the object at a distance so that it can be viewed ...
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25 views

Collection efficiency of a confocal microscope vs. numeric aperture

Setup I am trying to estimate the collection efficiency of a fiber-based confocal microscope depending on the numerical aperture (NA) and diameter of the gaussian beam used for illumination and ...
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20 views

How are Kikuchi Lines formed?

I know how a Kikuchi line can be produced, but I don't understand why the defect line would be darker than the surrounding environment. Does the line destructively interfere with electrons in that ...
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1answer
41 views

Microscope: relation between numearical aperture and working distance

I am looking for help in understanding the relation between the numercial aperture and the working distance of a microscope objective. I've searched for many hours but couldn't find any paper / book ...
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1answer
32 views

Specific applications of the various modes of optical microscopy [closed]

My question is primarily about reflected and transmitted light microscopy, and the BF and DF modes in both. I am aware of the basic working principles, to state it down briefly: Transmitted light ...
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1answer
130 views

Can you please explain me phenomenon of reflection at subatomic level? [duplicate]

When we see atoms under an electron microscope, what exactly are we seeing? I mean, these spheres that we know as atoms are electron clouds and that is what we are seeing, am I right? https://www....
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1answer
725 views

Can we use a telescope as a microscope and vice versa? [duplicate]

I got this question after I leant about microscopes and telescopes from my textbook. In a simplified compound microscope, the objective has a smaller aperture and a smaller focal length compared to ...
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3answers
213 views

What x20 x40 x100 magnification means?

I want to buy a biologic microscope for fiber analysis, thus I need to see details of a fiber of around 20μm. Could you please explain what "x20" magnification means? I understand that it will not ...
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18 views

Compound microscope

From where does the formula $L*D/f*fe$ for magnification of compund microscope derived? Where L is length of microscope D is distinct vision f is focal length of objective lens fe is focal length ...
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1answer
81 views

Changing hot-filament SEM electron source into field-emission one

MOTIVATION: The resolution of scanning electron microscope (SEM) images is limited by multiple factors, one of them being relatively low electron-beam current density emitted by cheap tungsten ...
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1answer
53 views

bombarding Electrons into the nucleus!

Recently, in a workshop on Electron microscopy, our professor asked us a question over the backscattering of electron. his question goes like this "Why doesn't this electron falls straight into the ...
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1answer
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What do you see in 'A Boy and His Atom'

A boy and his atom is a short movie by IBM animated by actually moving atoms around and using a scanning tunneling microscope to display the result. When I first saw this picture I was fascinated ...
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1answer
86 views

Why do we need an objective lens in a scanning electron microscope?

I've been studying scanning electron microscopes quite a bit but can't seem to get my head around why we need objective lenses. On paper I don't see a reason, if we would want to focus the electron ...
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207 views

Difference between electrostatic lens and electromagnetic lens

Imagine an electron-beam in a scanning electron microscope. From what I've gathered usually electro static fields are used to accelerate the electrons to a desired speed. At the same time electro-...
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32 views

Does the Rayleigh formula apply to electron microscopes or only light microscopes?

I am asked to determine the resolving power of both a TEM (transmission electron microscope) and a SEM (scanning electron microscope) and given the Rayleigh formula below. $$\mathrm{Resolution}=\...
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62 views

Why does carbon nanotubes look “furry” in scanning electron microscopy?

In scanning electron microscopy images, carbon nanotubes looks quite different from the schematic hexagonal structured tubes which usually describes them. How come they are all bent and "furry"?
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1answer
35 views

When using a microscope, why do we need to send waves through a specimen to see it?

I was curious about microscopes and I looked up how they work. The article I read(https://www.explainthatstuff.com/electronmicroscopes.html)mentioned that waves are passed through a specimen to see it....
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How to minimize the aberration by aligning the objective and the eyepiece when setting up a microscopic system

I set up a microscopic system, which consists of a 1-micron pinhole as the target, an objective, an eyepiece lens and a CCD camera. However, the image I obtained contains some kind of aberration. The ...
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344 views

Infinity Corrected Microscope vs. $4f$ imaging system

This questions concerns three types of microscope systems and the differences between them. Let me lay out my understanding of these three types of systems. I am imagining imaging with a camera so ...
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28 views

What magnification would an optical microscope need to see the 1000-200μm scale?

I would like to see the actual crystals in silicon and germanium wafers when I etch them, is this feasible with an optical microscope and if so what magnification would I need?
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1answer
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Atomic Force Microscopy - Lateral vs. Depth Resolution

I'm trying to gain a better understanding of Atomic Force Microscopy, specifically the relationship between its lateral and depth resolution. I've seen a variety of metrics on the two, but in general,...
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1answer
117 views

Average power and power density in microscopy

In a microscopy experiment, usually the power density at sample is reported like XX MW/cm^2 . Is this the power at the objective focal spot. Can it be calculated if we have the info like objective ...
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26 views

spot size in a microscopy experiment

How does a laser spot looks like under a high Numerical Aperture objective. I am attaching the profile I am getting in my case. Just wondering how can I calculate my spot diameter or point spread ...
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1answer
16 views

Ways to limit interaction volume in a SEM without changing e-beam energy (spot size)

All I can find online is that the interaction volume of a scanning electron microscope is affected by e-beam energy, angle of penetration, and sample composition. Are those really the only things that ...
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1answer
744 views

Determining the refractive index of a glass slab using a travelling microscope

In this practical video of finding the refractive index, the reading is being taken by placing the travelling microscope perpendicular to the slab. But I've learned in another video(Frame Shot) if you ...
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1answer
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TIRF mycroscopy with intermediate layer of different refraction index

I`m currently experimenting with through the lens TIRF microscopy in which an additional layer is used between the glass and the sample. This 10-30 μm layer has a higher refraction index than my ...