Speaker
Description
In ultra-thin media, the phase-matching condition for nonlinear optical processes, such as four-wave mixing (FWM), relaxes. We characterize the resulting broadband biphoton states by stimulated emission tomography and present progress towards photon pair generation in ultra-thin carbon nanotube films. Our 200 nm thick single-walled carbon nanotube film (much smaller than the pump wavelength of around 810 nm) imposes energy conservation as the only requirement in the nonlinear interaction. The absence of phase-matching entails that the photon pairs are highly entangled in frequency and separable in all other degrees of freedom.
Using stimulated emission tomography we characterize the joint spectral intensity of the generated biphoton state. We keep the pump wavelength constant and stimulate the FWM process with different wavelengths. The measured spectral width of the state extends over more than 50 THz. This result shows the potential to generate photon pairs with broadband entanglement with application in particular in the field of quantum communication, such as demonstration of entanglement distribution.
