L. J. Wang’s research while affiliated with Duke University and other places

... In the ideal case represented by the model studied here, this ratio would be zero, but in a real experiment a value less than unity is enough to identify the quantum nature of correlations characterizing the DCE [38,39]. The emerging picture would be different if initially the system is set in an excited state of the phonon operators, say due to a small not axisymmetric perturbation. ...

Reference:

The Dynamical Casimir Effect in quasi-one-dimensional Bose condensates: the breathing ring

... In the previous section, we presented the status of recent quantum optics calculations as an extension of earlier semi- classical treatment of n-point correlation functions in which the amplitudes are classical c-numbers (e.g., Wang et al. 1989), and summarized their specific predictions of flux measurement sensitivity comparison between two methods. Despite the theoretical consensus among the three most recent papers on the subject (Zmuidzinas 2015; Lieu & Kibble 2015;Nair & Tsang 2015), there has not been any deliberate experimental verification of their predictions. ...

Reference:

Photon Flux and Bunching Noise from Measurement of the Shot Noise Variance

... ⌽ SHG and ⌽ DC are also real, and they possess certain symmetries. [14][15][16] From Eqs. (12) and (13) and the Heisenberg equation of motion, ...

Reference:

Photon antibunching in downconverted light

... Individually, the resulting signal and idler fields thus generated would have random or undefined phases, preventing first-order interference between the signal (or idler) fields. However, if one seeds the idler mode in both crystals with the same light field, it induces stimulated emission of phase-locked signal fields, allowing first-order coherence and interference between the signal fields of both crystals 108 . This scheme was used for imaging in Ref. 109 . ...

Reference:

Advances in quantum imaging

... After this point, there are two main design formats that can be followed. The first one to be described is passive quenching [6], the second is active quenching. Passive quenching is much simpler than active quenching , which is a plus for the designer, however this comes with several drawbacks of which the most important are speed and flexibility. ...

Reference:

Review of tradeoffs for quenched avalanche photodiode sensors for imaging turbid media

... The nonlinear optical process of parametric downconversion (PDC) has been extensively employed to generate quantum states of light structured in the transverse spatial degrees of freedom [1]. In the classical regime, the same process can be operated in the stimulated emission mode (StimPDC) [2,3], providing a convenient platform for the design of quantum optical schemes [4][5][6], and for the study of the interplay between the spatial structures of the interacting light fields in the parametric process [7][8][9][10][11]. In the same way, parametric upconversion plays an important role in a wide variety of applications in quantum and classical optical schemes, as, for instance, frequency conversion of squeezed light fields [12,13] and imaging with visible and invisible light [14,15]. ...

Reference:

Observation of a triangular-lattice pattern in nonlinear wave mixing with optical vortices

... However, there exists quantum entanglement for quantum fields. The strong quantum correlations between two entangled fields can lead to disappearance of interference in one field from the distinguishability of the other [5,6] and recovery of interference by erasure of this distinguishability through projection measurement [2,3]. Moreover, it is even possible to remotely manipulate the coherence property of one field by controlling the other entangled field [7]. ...

Reference:

Temporal coherence in an unbalanced SU(1,1) interferometer

... In the first decade after the experiment by Zou-Wang-Mandel experiment in 1991, a manifold of theoretical and experimental investigations have been reported. A few notable and exciting results contain the following: Studies of the interference's time delays and coherence times demonstrated elegantly the fundamental importance of information in quantum mechanics [17][18][19][20][21][22][23]. Unlike quantum erasure experiments, where information is deleted to observe interference, in the ZWM experiment, the whichway information is never born. ...

Reference:

Quantum Indistinguishability by Path Identity: The awakening of a sleeping beauty

... This means the bias may reach the operation point before all trapped carriers escape from trap states. The operation speed or bitrate of passively quenched detectors is limited by the RC time constant where R is the quenching resistor ranging from 100 K Ohms to megaohms [19]. The bitrate could, in principle, be increased by reducing the load resistance, leading to a smaller quenching time constant [20]. ...

Reference:

Single photon avalanche detectors: Prospects of new quenching and gain mechanisms

... This phase is an example of geometric phases, which appear also in quantum systems [2,3] and in many branches of physics [4], and plays a central role, e.g., in the Aharonov-Bohm and quantum Hall effects [5,6]. In optics, several experimental demonstrations of the geometric phase have been performed [7][8][9]. It has been shown to appear when the propagation direction of a light beam is slowly changed (spin-redirection phase) [10], with single photons [11,12], surface plasmon polaritons [13], metasurfaces [14][15][16], and in spatial [17][18][19] and temporal [20] interference of electromagnetic beams. ...

Reference:

Pancharatnam’s connection and geometric phase of partially polarized light