Optical non-linearities at the few photon scale

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PHYSICAL REVIEW LETTERS

Optical Nonlinearity for Few-Photon Pulses on a Quantum Dot-Pillar Cavity Device

V. Loo, C. Arnold, O. Gazzano, A. Lemaître, I. Sagnes, O. Krebs, P. Voisin, P. Senellart, and L. Lanco
Phys. Rev. Lett. 109, 166806

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.109.166806

DOI:http://dx.doi.org/10.1103/PhysRevLett.109.166806

 

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The quantum optical transition of a single quantum dot can be saturated with just one photon. This open the possibility to implement quantum logic gates sending two photons to interact on the quantum dot. However, in the absence of good coupling between the quantum dot and the incident laser beam, such gate would be very inefficient.

Here we insert the quantum dot in a pillar cavity and we take advantage of the good coupling of the pillar cavity mode to the external optical field to demonstrate optical non-linearities for few photons incident on the device.

Measurements performed under continuous wave excitation demonstrate a near-unity input-coupling efficiency is obtained: 95% of the photons sent on the device interact with the QD.

Under pulsed excitation, we demonstratea record nonlinearity threshold at 8 incident photons per pulse.