Diederichs C, Tignon J, Dasbach G, Ciuti C, Lemaître A, Bloch J, Roussignol Ph, Delalande C
Laboratoire Pierre Aigrain, Ecole Normale Supérieure, 24 rue Lhomond, F-75231 Paris Cedex 05, France.
Nature. 2006 Apr 13;440(7086):904-7. doi: 10.1038/nature04602.
Optical parametric oscillation is a nonlinear process that enables coherent generation of 'signal' and 'idler' waves, shifted in frequency from the pump wave. Efficient parametric conversion is the paradigm for the generation of twin or entangled photons for quantum optics applications such as quantum cryptography, or for the generation of new frequencies in spectral domains not accessible by existing devices. Rapid development in the field of quantum information requires monolithic, alignment-free sources that enable efficient coupling into optical fibres and possibly electrical injection. During the past decade, much effort has been devoted to the development of integrated devices for quantum information and to the realization of all-semiconductor parametric oscillators. Nevertheless, at present optical parametric oscillators typically rely on nonlinear crystals placed into complex external cavities, and pumped by powerful external lasers. Long interaction lengths are typically required and the phase mismatch between the parametric waves propagating at different velocities results in poor parametric conversion efficiencies. Here we report the demonstration of parametric oscillation in a monolithic semiconductor triple microcavity with signal, pump and idler waves propagating along the vertical direction of the nanostructure. Alternatively, signal and idler beams can also be collected at finite angles, allowing the generation of entangled photon pairs. The pump threshold intensity is low enough to envisage the realization of an all-semiconductor electrically pumped micro-parametric oscillator.
光学参量振荡是一种非线性过程，能够相干产生频率相对于泵浦波发生偏移的“信号”波和“闲频”波。高效参量转换是用于量子光学应用（如量子密码学）中产生孪生或纠缠光子，或在现有器件无法达到的光谱域中产生新频率的范例。量子信息领域的快速发展需要单片、免对准的光源，以实现高效耦合到光纤中并可能实现电注入。在过去十年中，人们致力于开发用于量子信息的集成器件以及实现全半导体参量振荡器。然而，目前光学参量振荡器通常依赖于置于复杂外腔中的非线性晶体，并由强大的外部激光器泵浦。通常需要较长的相互作用长度，并且以不同速度传播的参量波之间的相位失配会导致参量转换效率低下。在此，我们报告了在一种单片半导体三重微腔中实现参量振荡的演示，其中信号波、泵浦波和闲频波沿纳米结构的垂直方向传播。另外，信号光束和闲频光束也可以在有限角度收集，从而实现纠缠光子对的产生。泵浦阈值强度足够低，有望实现全半导体电泵浦微参量振荡器。
