Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany.
Department of Engineering Physics, Polytechnique Montréal, Montréal, H3T 1J4, Canada.
Phys Rev Lett. 2019 Feb 8;122(5):053604. doi: 10.1103/PhysRevLett.122.053604.
We study spectral properties of quantum radiation of ultimately short duration. In particular, we introduce a continuous multimode squeezing operator for the description of subcycle pulses of entangled photons generated by coherent-field driving in a thin nonlinear crystal with second-order susceptibility. We find the ultrabroadband spectra of the emitted quantum radiation perturbatively in the strength of the driving field. They can be related to the spectra expected in an Unruh-Davies experiment with a finite time of acceleration. In the time domain, we describe the corresponding behavior of the normally ordered electric field variance.
我们研究了具有极短持续时间的量子辐射的光谱特性。具体来说，我们引入了一个连续多模压缩算符，用于描述由相干场驱动在具有二阶介电常数的薄非线性晶体中产生的纠缠光子的亚周期脉冲。我们在驱动场的强度下对发射量子辐射的超宽带光谱进行了微扰计算。这些光谱可以与在具有有限加速时间的 Unruh-Davies 实验中预期的光谱相关联。在时域中，我们描述了相应的正则序电场方差的行为。
