# What is Beam splitter: Definition and 31 Discussions

A beam splitter is an optical device that splits a beam of light in two. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding widespread application in fibre optic telecommunications.

View More On Wikipedia.org
1. ### I Commutation of Beam splitter operator with Displacement operator

I have a beam splitter operator (a†)b +(b†)a. Does it commute with exp(αâ†-α*â). Here a and â† are creation and lowering operator
2. ### I Use of the Beam Splitter Operator

Hello, I am a senior undergrad doing research in quantum optics, and I am trying to work out at the moment the output state of sending a coherent state through one input port and a squeezed vacuum state through the other, just to see what happens tbh. The problem I have constantly been running...
3. ### Beam Splitter Inputs and Commutting Modes

My thinking so far is that if the two different input mode operators of a beam splitter commute, but I can't really give any good reasoning behind it. I defined ##\hat{A} = \frac{i\pi}{4}\hat{a}_0^{\dagger}\hat{a}_1 ## and ##\hat{C} = \frac{-i\pi}{4}\hat{a}_0\hat{a}_1^{\dagger} ## and am...
4. ### Image position in an optical system?

I have an plano-convex lens with focal length 75 mm. The object is 325mm from the lens. a) Where is the location of the image after the lens? b) Where is the location of the image if an beamsplitter is placed after the lens? My solution, questions: a) a = 325 mm b = ? mm f = 75 mmm...
5. ### A Two Different Fock State Inputs into a Beam Splitter

Hello everyone, I am an undergraduate doing research in quantum optics, and my topic involves 50:50 beam splitters and studying entanglement for different input states. I came across a paper which I am using as a guide for now, but I wanted to derive a result they had and have been working on it...
6. ### Finding the unitary matrix for a beam splitter

Hello, I have some trouble understanding how to construct the matrix for the beam splitter (in a Mach-Zehnder interferometer). I started with deciding my input and output states for the photon. I then use Borns rule, which I have attached below: To get the following for the state space...
7. ### I Polarization and the beam splitter

When 2 identical photons are incident at the same time at the input channels of a 50:50 beam splitter, quantum interference causes the elimination of the both reflected and both transmitted outcomes ##\hat{a}_{1H}^{\dagger}\hat{a}_{2H}^{\dagger}|0\rangle_1|0\rangle_2 \ne...
8. ### I How to estimate total energy when dealing with beamsplitters

I'm having a brain freeze right now and I need some help. :frown: I have a 50/50 beamsplitter (non-polarizing) with 5% tolerance. Test measurement (with a laser at a certain wavelength) gave that I'm transmitting 5.36 units and reflecting 4.6 units (49.5 transmitted; 42.6% reflected). Units...
9. ### I How does the thickness of a beam splitter affect the phase shift produced?

I'm having trouble understanding the phase shift produced by a beam splitter. I seem to be finding conflicting information. I'm specifically looking to understand a 50/50 beam splitter where one side has a dielectric mirror, as shown in this figure from wikipedia: I understand the pi...
10. ### I How to create the operator of unknown beamsplitter

Hello everyone, I'm undergraduate and my project is an experiment in the field of quantum optics. For now, I have an Unknown beamsplitter in my lab and I want to calculate the operator of this beamsplitter in matrix form (this BS is not perfected equipment because the reflected beam is not...
11. ### I Beam splitter in an entanglement swapping experiment

I have a misunderstanding about the beam splitter in this experiment High fidelity entanglement swapping with fully independent sources Rainer Kaltenbaek, Robert Prevedel, Markus Aspelmeyer,Anton Zeilinger http://arxiv.org/pdf/0809.3991.pdf Part of the diagram is reproduced here Two photons...
12. ### B Beam splitter, one photon, one detector?

I would like to know the results of a few scenarios with a beam splitter. (1) You send a single photon through a half silvered mirror with a reflector at either side, as above, but instead of having two detectors, and a 50% chance of either going off, you just have one detector, and where...
13. ### B "Mysterious" beamsplitter cube

I'm using a non-polarizing beamsplitter cube in an experiment, but it's behaving in an unexpected way. I expected that, if a laser beam enters the cube from one side, ~50% of the beam passes through the cube in the same direction, while ~50% of the beam is reflected and exits the cube at a...
14. ### Rotate only H-Pol Component of Light beam by 90 degrees

Is there a single optical component that will do the following? Do nothing to the horizontally polarized input, but rotate the vertically polarized input by 90 degrees, so that both beams finally emerge with the same polarization? I am looking for a single element that will replace the...
15. ### I What is the name of the matrix decomposition with specific properties?

Hi everyone. There is the ##2\times 2## matrix ##B## $$B= \left[ \begin{array}{cc} B_{11} &B_{12} \\ B_{21}&B_{22} \end{array} \right],~B_{ij}\in \mathbb{C}$$ with property $$\vert B_{11}\vert^2 + \vert B_{12}\vert^2=1,$$ $$\vert B_{21}\vert^2 + \vert B_{22}\vert^2=1,$$...
16. ### What's the unitary matrix equivalent to a beam splitter?

I've seen various different matrices used to represent beam splitters, and am wondering which is the "right" one. Alternatively, are there various kinds of beam splitters but everyone just ambiguously calls them the same thing? The matrices I've seen are the...
17. ### How do you store (safe-keep) beam-splitters?

someone purchased cube beam splitter years ago, it was wrapped around in tracing paper, really delicately. I un-wrapped it , and used it for my experiment. Now, my experiment is done, and I don't know how to store it safely. If I leave it on the shelf carelessly, the beamsplitter will get...
18. ### Optics: Design of Beamsplitter Ge on KBr substrate

Hi there, I am making a beam splitter for an FTIR, but I do not know the anatomy of a beamsplitter of this type, does anybody have information on the design of these? I plan to order KBr crystal windows and apply the Ge coating myself using physical vapor deposition and assuring quality with a...
19. ### The Quantum Computer and beamsplitter

Dear fellows, please help me to imagine the physical working of a quantum computer (QC). I have read here ( http://www.cs.rice.edu/~taha/teaching/05F/210/news/2005_09_16.htm ) that the basic idea behind it is the phenomenon that you can find in the Mach–Zehnder interferometer But how come this...
20. ### Beam Splitter - Commutation relations

Hi guys, why does the following mean B is unitary? if we have two rotations such that; b1 = B11a1 + B12a2 b2 = B21a1 + B22a2 and the following commutator results are; [b1, b1(dagger)] = |B11|^2 + |B12|^2 --> 1 [b2, b2(dagger)] = |B21|^2 + |B22|^2 --> 1 [b1, b2(dagger)] =...
21. ### Beam Splitter Physics: |45>,-|45> State Output

If we have a beam splitter, and we fire two photons from either side towards it (both meeting and interfering at the same time): If the state of the photon coming in from the left is |45>, and the one coming in from the right is -|45>, would the output be: -i|45>(l)|45>(l) -...
22. ### Beam splitter with single photons

Homework Statement So we have a source (OP) that emits single photons of a constant wavelength and angular frequency. The photons hit a 50-50 beam splitter, and are then reflected in the mirrors. Where is says (L) ou (SP) (yay for studying in French!) there is a beam splitter. What I...
23. ### Single photons traversing a beam splitter

Hi! I'm not sure this is exactly the right subforum, but here goes: Homework Statement So we have a source (OP) that emits single photons of a constant wavelength and angular frequency. The photons hit a 50-50 beam splitter, and are then reflected in the mirrors. Where is says (L)...
24. ### Exploring Quantum Entanglement at a Beam Splitter

Okay, I have the following scenerio (attached picture). The inputs for path b and c are two photons. both photons aren't entangled with each other - they're entangled to other photons. Before the beam splitter there is a wave plate that converts the photon into the 45/135 basis. So what we...
25. ### Are Input Photons #2 and #3 Still Entangled After Going Through a Beam Splitter?

In regards to the attached image; If the input photons were, for input b = photon #2, and for input c = photon #3, where: photon #1 and #2, and #3 and #4 are entangled as |H>|V> + |V>|H>, for the outputs:|H>(b’)|H>(b’) - |V>(b’)|V>(b’) + |H>(c’)|H>(c’) - |V>(c’)|V>(c’) + H(b’)|V>(c’) -...
26. ### Cube beam splitter transmission and reflection ratio

Looking around at all the cheap surplus beam splitter cubes out there. I've found no description of how things would be expected to behave outside of the spectral bands for which they're designed. Leaving out the transmissivity of the glass itself, should I assume that when relative...
27. ### Beam splitter energy conservation

Hi, If we describe a beam splitter as follows: e^{ikx} -> \sqrt{T}e^{ikx} + \sqrt{R}e^{i\theta}e^{iky} e^{iky} -> \sqrt{T}e^{iky} + \sqrt{R}e^{i\theta'}e^{ikx} then \theta+\theta'=\pi is a condition to ensure conservation of energy according to my text. I tried working this out by taking...
28. ### How do the intensities change when using a polarization beam splitter?

Hi, let's assume a polarization beam splitter (PBS) that splits the unpolarized beam into two beams with opposite polarization states. The PBS has one input port and two output ports. 1) If input beam has an intensity I, what will be the intensity of beam at each output port...
29. ### Fiber optic based beam splitter

Hi, Does any of you know any commercially available fiber optic - beam splitter? It is very crucial for my experiment where I distribute an electromagnetic beam from one laser source (infrared) to two waveguides.. Since I am coupling using fibers, I require a fiber optic based beam...
30. A

### Beam Splitter: were is the power?

http://physics.nad.ru/img/bs1.gif Let us consider beamsplitter BS. 2 rays are incident on it as shown in figure. During reflection the waves are shifted by phase at pi. As a result I=0 in both directions. Where is the power lost?
31. ### Brian Green's Beam Splitter Experiments

Hi all, I read about the beam splitter experiments in Brian Green's most excellent book The Fabric of the Cosmos. I am obviously missing something and thought I'd ask here. Forgive me if I sound ignorant; I am well educated but lacking in advanced physics (although fairly mathematically...