Ring-shaped spectra of parametric downconversion and entangled photons that never meet.
Ring-shaped spectra of parametric downconversion and entangled photons that never meet.
复制标题
参量下转换和永不相遇的纠缠光子的环形光谱。
作者：
K. Spasibko;D. Kopylov;T. Murzina;G. Leuchs;M. Chekhova
我们报告的观察一个不寻常的类型的参数下转换。当共线简并辐射处于群速度色散的反常范围内时，其光谱在角度和波长上都受到限制。从精确共线-简并相位匹配的失谐导致的波长-角谱的环形，这表明一种新的时空相干性和纠缠的光子对。通过在角度和波长上施加以特定方式变化的相位，可以获得纠缠光子对的有趣状态，其中两个光子永远不会在同一时间处于同一点。
We report on the observation of an unusual type of parametric downconversion. In the regime where collinear degenerate emission is in the anomalous range of group-velocity dispersion, its spectrum is restricted in both angle and wavelength. Detuning from exact collinear-degenerate phase-matching leads to a ring shape of the wavelength-angular spectrum, suggesting a new type of spatiotemporal coherence and entanglement of photon pairs. By imposing a phase varying in a specific way in both angle and wavelength, one can obtain an interesting state of an entangled photon pair, with the two photons being never at the same point at the same time.