International Journal of Optics and Photonics
نشریه انجمن اپتیک و فوتونیک ایران
IJOP
Basic Sciences
http://ijop.ir
1
admin
1735-8590
2538-4007
10.29252/ijop
1735-8590
en
jalali
1397
9
1
gregorian
2018
12
1
12
2
online
1
fulltext
en
The Impact of the Spectral Filter Bandwidth on the Spectral Entanglement and Indistinguishability of Photon Pairs of SPDC Process
عمومى
General
پژوهشي
Research
<p class="Abstract" style="text-align: justify;">In this paper, we have investigated the dependence of the spectral entanglement and indistinguishability of photon pairs produced by the spontaneous parametric down-conversion (SPDC) procedure on the bandwidth of spectral filters used in the detection setup. The SPDC is a three-wave mixing process which occurs in a nonlinear crystal and generates entangled photon pairs and utilizes as one of the most useful resources in a variety of fields such as quantum computation, quantum cryptography, and quantum communication. The amount of the spectral entanglement and the indistinguishability of photon pairs are the two critical characteristics of the photon pairs determining their potential applications. The degree of the spectral entanglement of a quantum system, i.e. photon pairs, is determined by the entanglement entropy which is a measure of the system disorder. First, we derive the eigenvalue equation of reduced density operator of the signal and the idler photons in terms of the bandwidth of spectral filters. Then, by numerically solving the eigenvalue equation, we calculate the Schmidt coefficients for different values of the bandwidth of spectral filters. Finally, by calculating the entropy operator one can obtain the dependence of spectral entanglement of the photon pairs on filter bandwidth. The amount of indistinguishability of the photon pairs is measured by the visibility of the HOM diagram. Since the whole spectral information of the photon pairs exists in their two-photon mode function, using this function and the presented model we calculate the amount of indistinguishability by obtaining the visibility of the HOM diagram for different values of the bandwidth of the spectral filters. In this way, the dependence of the indistinguishability of the photon pairs on this quantity is reported.</p>
Spontaneous Parametric Down-Conversion, Entanglement, Entangled Photon Pairs, Single Photon sources, Indistinguishability, entropy, reduced density operator.
119
128
http://ijop.ir/browse.php?a_code=A-10-580-1&slc_lang=en&sid=1
Ali
Mohammadi
a.mohammadi101@gmail.com
`10031947532846002362`

10031947532846002362
No
Laser & Plasma Research Institute
Atoosa Sadat
Arabanian
a_arabanian@sbu.ac.ir
`10031947532846002363`

10031947532846002363
Yes
Laser & Plasma Research Institute
Ali
Dalafi
a_dalafi@sbu.ac.ir
`10031947532846002364`

10031947532846002364
No
Laser & Plasma Research Institute