Generation of two types of nonclassical optical states using an optical parametric oscillator with a PPKTP crystal

As important members of nonclassical states of light,squeezed states and entangled states are basic resources for realizing quantummeasurements and constructing quantum information networks. We experimentally demonstrate that the two types of nonclassical optical states can be generated from anoptical parametric oscillator(OPO) involving a periodically poled KTiOPO4 crystal with a domain-inversion period of 51.7  μm, by changing thepolarization of the pump laser. When a vertically polarized 671  nm laser is used to pump theOPO, the intra-cavity frequency-down-conversion with type-0 quasi-phase matching is realized and the output optical beam is a quadrature amplitudesqueezed state of light at the wavelength of 1342  nm with the fluctuation of quadrature component of 3.17 dB below the quantum noise limit (QNL). If the pump laser is horizontally polarized, the condition of the type-II quasi-phase matching is satisfied and the output optical beam becomes Einstein-Podolsky-Rosen entangled state of light with c orrelation variances of both quadrature amplitude-sum and quadrature phase-difference of 2.2 dB below the corresponding QNL.

Source: Applied Physics Letters - November 28, 2016 Category: Physics Authors: Meiru Huo, Jiliang Qin, Zhihui Yan, Xiaojun Jia and Kunchi Peng Source Type: research