Questions tagged [hologram]

"Hologram" has evolved in meaning over the past 40 years. To Gabor it meant a diffractive "whole picture" recorded by optical interference. Today its meaning very loosely includes much more: HOE's, any image with diffractive effects, and even practically any 3D image regardless of how it works. But the preferred meaning is "a pattern recorded via wave interference", with "wave" being light, sound, radio, or quantum mechanical particles.

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Hologram Questions

How does a hologram create parallax, compared to a photograph? If a hologram's purpose is to reproduce the light field, what part of that field creates parallax (angle, magnitude or position)?
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Mirascope Holograms

So I just realised that 3d hologram fan projectors are now a thing, and the quality looks quite good (search Ashata 3d hologram fan projector). However, an inherent problem with them is that the image ...
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Information in Holograms

I was reading about Holograms, and I read something to the effect of the following statement - "In a hologram, any part of the hologram with sufficient size contains the whole of the stored ...
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What is the term for the simple, label/sticker like holograms?

From my everyday experience I can say that there are 2 types of holograms. One is the simple type that one can find on the important papers, paper money, as excise marks on the alcoholic beverages, as ...
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Is there any practical way we can verify Bob and Alice, Whitehole and Leonard Susskind's famous Hologram theories?

Alice and Bob analogy near Blackhole is a well known hypothetical theory that says suppose Alice and Bob are in a spacecraft near the Supermassive Blackhole located at the center of the Milkyway ...
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Possibility of Star Wars style holograms [closed]

We’ve all probably seen those neat little hologram projectors in franchises like Star Wars, are holograms on the level we see them in Star Wars possible? If so, what are some approaches to this type ...
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Can an optical phased array be used to create free-floating holograms?

Frustratingly, most sources I've found about optical phased arrays only state that they can be used for "holograms" but do not explain what that means. Can optical phased arrays be used for "Star ...
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Calculating maximum allowable velocity of an object during holography

I am working through some questions in preparation for an upcoming exam and the following has me doubting myself: An experiment takes $x$ seconds to create a hologram of an object using $\lambda$ nm ...
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Holographic “lens” - controlling light diffraction angles with silver halide film

I'm trying to develop a way to control the "exit angle" (diffraction angle) of a monochromatic light source. For example: taking a laser; spreading the beam; and directing the light at a piece of ...
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Holographic planetarium

Discussing the possibility of building a planetary with some colleagues, we started wondering about the theoretical idea of a planetarium dome based on a multichannel CGH able to show the sky of ...
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Holograms and Entanglement: Does recording an entangled signal in a hologram “observe” the entangled state?

Suppose I have two photons $A$ and $B$, which are entangled. As I have had it explained to me, entanglement works more or less as follows: I observe or measure $A$, and find $A=S_a$, where $S_a$ ...
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Are holograms in midair physically possible? [duplicate]

Is it possible for holograms, as in 3D projections of light in midair, to exist? Consider this image. If a projector, placed in the same position as the gray circle in the first image, were to ...
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Is it possible to make full-colour Holography using three lasers and three separate holograms?

Holograms need monochromatic coherent light sources like lasers so that the reference light can interfere with the light scattered by the object. Illuminating the holograms, the stored interference ...
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Holographic magnification and the requirement of single wavelength coherent reference wave

How is holographic magnification for different wavelength reference beams consistent with the requirement of illuminating the hologram with light with wavelength same as the reference beam? If we ...
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Where can I learn about holograms?

I want to learn about holograms. I have zero knowledge of how they work. How can I start? I tried using Google but I cannot decide where to and how to start. Can you suggest any good sites for this ...
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Can Young's double slit experiment be considered a holographic setup?

As described in his landmark paper on holography, "A new microscopic principle", Denis Gabor sent coherent light through a transparent plate with some black letters on it. The light that was ...
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Can single photons make a hologram over time

INTRO. In the parallel slit experiment, single photons ejected from the source at different times still seem to interfere to make a fringe pattern, which in a sufficientliy long exposure time becomes ...
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Sampling theorem for in-line digital holography

In digital holography, the image sensor must have a sufficient pixel density. The book New Techniques in Digital Holography by Pascal Picart and others, the following condition is given: ...
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How do self-developing holographic plates work?

Litiholo started working on self-developing plates in mid-2004 and managed to achieve its goal and started selling these no-fuss self-developing hologram kits that produce pretty good results. ...
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How can 2D flat holograms be considered holograms?

When I think of a hologram I imagine this where you shine a beam of laser light onto a holographic film to reproduce an object beam and see a virtual image of an object that can be viewed from many ...
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Can we see “imaginary” light beams?

When a reference beam, R, interferes with an object beam, O, the interference pattern is captured by a holographic plate. When reconstructing the image, the reference beam is incident on the ...
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What happens when a reference beam passes through a holographic plate?

Here is my understanding of how holograms work: A holographic plate captures the interference pattern between a reference beam and an object beam. When reconstructing the hologram, the reference beam ...
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How much can we infer internal structure from a hologram?

How much can we infer internal structure eg of an arbitrary object, like a sphere or cell, from a holographic interference pattern on its surface?
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Magnification in Holographic Microscopy

The book "Introduction to Optics" by Frank, Leno, and Leno Pedrotti, Ed 3, makes the claim that It can be shown that if the reconstructing light of wavelength $\lambda_r$ is longer than the ...
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What is the bright spot in reflective digital holographic microscopy and how to remove it?

We are working on reflective DHM and the system looks like the setup in figure 1. We are facing a severe problem of reflection in the system. Apart from the reference beam and object beam, there is ...
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How do holographic mirrors work?

I found this hologram on a book. Apart from the usual rainbow colors, it sported a convex mirror effect on it. Here, you can see my phone's reflection in the tiny circles. It would be ...
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How to Approximate the Maximum Diameter of a Particle in In-line Holography

The in-line, digital holographic system that I am designing is similar to this article, https://www.ncbi.nlm.nih.gov/pubmed/21460907, which images a range of particles present in clouds. I understand ...
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(Fresnel) diffraction in on-axis holography

In on-axis holography one can consider the plane wave from source the scattered wave from object (spherical if the object is a point) Then it is possible to model the transmission on the ...
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What's a tangible explanation of the angular spectrum in optics?

In order to understand image reconstruction from a diffraction pattern as applied in in-line holography, I'm reading Joseph Goodman's Introduction to Fourier Optics. Chapter 3.10 discusses the angular ...
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Holography versus Young's double slit

In order to see interference fringes in double slit one needs the two slits to be very close (1-2 wavelengths) even using highly coherent laser. But in Holography this condition apparently does not ...
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What type of LED to use with a 100 micrometer pinhole for in-line digital holography?

I want to set up an in-line digital holographic microscope that is similar to the one describe in the article, A Study of Digital In-Line Holographic Microscopy for Malaria Detection, which is they ...
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Setting Up In-line Digital Holography

I would like to set up an in-line digital holography system to image plankton samples. The set up consist of a laser that project through an objective which will transmit through a pinhole. In the ...
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Virtual and real in the case of hologram images?

Are the terms virtual and real applicable to hologram images? Is the hologram image real if the observer sees it in front of the photographic plate, so he could 'touch' it, and virtual if the observer ...
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What information is lost when you view only a piece of broken hologram?

When a hologram is broken into pieces, you can still see the whole object from any piece of them, but I am wondering what information is lost in each of them, does the hologram images look the same ...
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How does the holographic grating in a Near Eye Waveguide work?

I'm an electrical engineer who recently started working with these near eye optics like this one https://www.trulifeoptics.com/ It looks like a microscope slide but it's a waveguide that transports a ...
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How does a piston display work?

I was watching this video on how a Micromagnetic Piston Display works. After some research I can still not get my head around on how this display actually shows a holographic image. In my opinion, ...
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Are plasma holograms really 3D

After reading this article and watching the video attached in it, I wondered if a plasma hologram is really as three dimensional as they say. I would say the hologram is only three dimensional if you ...
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The need of the reference beam in Holography

For a project, we're investigating how a transmission hologram works. I understand how the process of making this hologram works, but I can't get my head around just one thing. Why would a ...
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Is it possible to project an image into the eye which appears to be on a focal plane above source, and is larger? [duplicate]

Is it possible to project an image into the eye, without wearing glasses or using a projection screen, which: Appears to be on a focal plane in front of rather than behind the source Appears larger ...
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Holography, what is difference in it and photography in detail and in concern with physical meaning? [closed]

I don't understand what new will we get by it, mean I know it will get phase difference and features like that but physically what will we get? And it's reconstruction of image method?
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How does making “pyramid hologram projectors using smartphones” work?

The basis of this question is this video, where a 3D hologram like effect is achieved using a 4 sided hollow pyramid. I don't know if this is holography in the usual sense. Can some one explain this ...
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Holography with object and reference waves with a slightly different wavelength

Recently I've been looking into holography, where one interferes the object wave with a reference wave and encodes their combined intensity on a transparency, so that if one then re illuminates the ...
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Drawing in the air with lasers Question

Are there two different lasers that can be invisible when not overlapping, but visible when overlapping? I desire to build a hologram-ish thing, but with lasers. The system would use many lasers that ...
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3D hologram without a requirement of screen [closed]

How can I project a 3D hologram outdoor without a screen? is it possible to do it? Basically I just want a hologram of a square shape or a cube in a field at daylight.
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Hologram without requirement of screens

I'm not much familiar with holograms and I've read a few articles on how holograms are made. I have a question that how does hologram get projected in air? If it were tyndall effect, then we could see ...
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Proof that fixed points of a null field are zero

Suppose we have a scalar field $V$ (which can be acoustic pressure, or a scalar electric potential) that is a solution of the wave equation $$\Box V(x,y,z,t) = 0$$ I am wondering if a fixed (non-...
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How does a DIY holographic display work?

I made a holographic display with this tutorial, but now I'm wondering if the 4 projections on each side of the pyramid do interfere with each other. Can you get just the same image if you only ...
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Hologram Breakdown

Why does a hologram when divided still maintain the total image of the subject? And one would imagine at the atomic scale when the hologram is separated to such a small set of atoms the total image ...
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How is the virtual image reconstructed from a hologram?

To make a hologram a film is exposed to an incident plane wave and wave from the object to record the interference pattern on the film. The principle is commonly explained in a way like that in p.1212 ...
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Blazed phase profile to generate laguerre gaussian beam

How to add blazed grating to a fork grating to achieve maximum diffraction efficiency in the first order while generating laguerre gaussian beam?