Spatial interference fringes in Hong-Ou-Mandel

In summary, HOM interference can be observed by slightly skewing the optics in a HOM setup and varying the phase difference between Beam-1 and Beam-2 across one of the detection planes. This interference can also be seen throughout the coincidence detection planes if the two incoming beams completely overlap on a quantum level. Typically, HOM interference is done with beams of down-converted light that come in pairs of photons that can overlap completely. By varying the light after the beamsplitter, HOM interference can be displayed over both spatially resolving detectors. Additionally, shifting one of the incoming beams into the beamsplitter or performing a spatially varying phase shift on one of the beams can also affect the number of coincidence counts and result in a
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Swamp Thing
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If we can slightly skew the optics in a HOM setup, so that the phase difference between Beam-1 and Beam-2 varies slowly across one of the detection planes, then would we see dark and bright regions in the cumulative pattern (assuming an array type i.e. spatially resolved detector) ??
 
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I think the HOM interference takes place at the beamsplitter well before the detectors.
That being said, if the two incoming beams completely overlap on a quantum level, then you'll see HOM interference throughout the coincidence detection planes.
Usually HOM interference id done with beams of down-converted light, because the light comes in pairs of photons which can completely overlap each other.

If you're varying the light after the beamsplitter, the light should display HOM interference regardless (i.e., a dip to near zero coincidence counts) over both spatially resolving detectors.

If you shift one of the incoming beams of light into the beam splitter, the photon-photon overlap will decrease, and the number of coincidence counts will rise.
If you perform a spatially varying phase shift on one of the incoming beams (say by a spatial light modulator), while keeping everything else aligned, then you should see a spatially varying HOM interference pattern with a pair of spatially resolving photon counting detectors, and the pattern you see will be an image of the pattern you put on the modulator.
 

1. What is the Hong-Ou-Mandel (HOM) effect?

The Hong-Ou-Mandel (HOM) effect is a phenomenon in quantum optics where two identical photons incident on a beam splitter can either interfere constructively or destructively, depending on their arrival time. This effect is a result of the indistinguishability of photons in quantum mechanics.

2. How does the HOM effect relate to spatial interference fringes?

The HOM effect can also be observed in the spatial domain, where the interference fringes are created by two overlapping beams of identical photons. These fringes are a result of the constructive and destructive interference of the photons, and their visibility is a measure of the degree of indistinguishability between the photons.

3. How are spatial interference fringes in HOM used in quantum information processing?

Spatial interference fringes in HOM are crucial in quantum information processing as they can be used to measure the degree of entanglement between two photons. The visibility of the fringes can be altered by manipulating the entanglement, making it a useful tool for quantum state engineering and quantum computing.

4. What are the applications of spatial interference fringes in HOM?

Spatial interference fringes in HOM have many applications in quantum optics, including quantum state engineering, quantum computing, quantum cryptography, and quantum metrology. They are also used in experiments to study the fundamental properties of photons and their behavior in quantum systems.

5. How can spatial interference fringes in HOM be experimentally observed?

To observe spatial interference fringes in HOM, a setup with a beam splitter, photon sources, and detectors is required. The photon sources must be identical and produce single photons with high indistinguishability. The visibility of the interference fringes can then be measured by varying the arrival time of the photons at the beam splitter and analyzing the output using detectors.

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