Non-degenerate polarization-entangled photon pair generation device and non-degenerate polarization-entangled photon pair generation method
A non-degenerate polarization-entangled photon pair generation device ( 1 ) that efficiently and easily generates non-degenerate polarization-entangled photon pairs includes: a quantum-entangled photon pair generator ( 2 ) including a single crystal in which periodically poled structures ( 3 a, 3 b ) having different periods are formed; and a light radiating unit ( 4 ) for entering light into the quantum-entangled photon pair generator ( 2 ) such that the light passes through the periodically poled structure ( 3 a ) and then through the periodically poled structure ( 3 b ). A period of the periodically poled structure ( 3 a ) is different from a period of the periodically poled structure ( 3 b ) such that a parabola indicative of a relation between an emission angle and a wavelength of a polarized photon emitted based on light incident on the periodically poled structure ( 3 a ) comes into contact with a parabola indicative of a relation between an emission angle and a wavelength of polarized photon emitted based on light incident on the periodically poled structure ( 3 b ), within an allowable range under a phase matching condition.
1. A non-degenerate polarization-entangled photon pair generation device comprising:
a quantum-entangled photon pair generator including a single crystal in which a first periodically poled structure having a first period and a second periodically poled structure having a second period that is different from the first period are formed; and
light radiating means for entering light into the single crystal such that the light passes through the first periodically poled structure and then through the second periodically poled structure.
2. The non-degenerate polarization-entangled photon pair generation device as set forth in claim 1 , wherein:
the first period of the first periodically poled structure is different from the second period of the second periodically poled structure such that a parabola indicative of a relation between an emission angle and a wavelength of a polarized photon emitted based on light incident on the first periodically poled structure comes into contact with a parabola indicative of a relation between an emission angle and a wavelength of polarized photon emitted based on light incident on the second periodically poled structure, within an allowable range under a phase matching condition.
3. The non-degenerate polarization-entangled photon pair generation device as set forth in claim 1 , wherein:
the single crystal is a lithium niobate crystal.
4. The non-degenerate polarization-entangled photon pair generation device as set forth in claim 1 , further comprising:
a third periodically poled structure that produces pump light,
the light radiating means entering the light into the third periodically poled structure such that the light passes through the third periodically poled structure, the first periodically poled structure, and the second periodically poled structure, in this order.
5. The non-degenerate polarization-entangled photon pair generation device as set forth in claim 4 , wherein:
the third periodically poled structure is formed in the single crystal.
6. A non-degenerate polarization-entangled photon pair generation method comprising the step of:
entering light into a single crystal in which a first periodically poled structure having a first period and a second periodically poled structure having a second period different from the first period are formed, in such a manner that the light passes through the first periodically poled structure and then through the second periodically poled structure.