Spatial Characterization Of Two-Photon States - GAP-Optique
Spatial Characterization Of Two-Photon States - GAP-Optique
Spatial Characterization Of Two-Photon States - GAP-Optique
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1.4. The mode function in matrix form<br />
and allows to solve some of those integrals analytically. For instance, the mode<br />
function normalization requires six integrals over the modulus square of the<br />
mode function. As appendix B shows, the matrix notation provides a way to<br />
calculate the normalization constant analytically,<br />
<br />
dx exp<br />
<br />
− 1<br />
2 xt <br />
(2A)x<br />
and thus the normalized mode function reads<br />
=<br />
Φ(qs, Ωs, qi, Ωi) = [det(2A)]1/4<br />
(2π) 3/2<br />
(2π) 3<br />
, (1.38)<br />
[det(2A)] 1/2<br />
<br />
exp − 1<br />
2 xt <br />
Ax . (1.39)<br />
In the same way, many other integrals over the mode function can be solved<br />
analytically using the matrix representation of the mode function.<br />
Conclusion<br />
The two-photon mode function can be written in a matrix form after a series<br />
of approximations. The matrix notation makes it possible to calculate several<br />
features of the down-conversion photons analytically, and reduces the numerical<br />
calculation time of others.<br />
The next chapter describes the different correlations in the two-photon state<br />
using the purity as a correlation indicator. The use of the approximate mode<br />
function in matrix notation makes it possible to find an analytical expression<br />
for the purity, and to study the effect of the different parameters on it.<br />
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