ABSTRACT
Optically induced ultrafast switching of single photons is demonstrated by rotating the photon polarization via the Kerr effect in a commercially available single-mode fiber. A switching efficiency of 97% is achieved with a â¼1.7 ps switching time and signal-to-noise ratio of â¼800. Preservation of the single-photon properties is confirmed by measuring no significant increase in the second-order autocorrelation function g(2)(0). These values are attained with only nanojoule-level pump energies that are produced by a laser oscillator with 80 MHz repetition rate. The results highlight a simple device capable of both high-bandwidth operations and preservation of single-photon properties for applications in photonic quantum processing and ultrafast time-gating or switching.
ABSTRACT
Photon pair sources have wide ranging applications in a variety of quantum photonic experiments and protocols. Many of these protocols require well controlled spectral correlations between the two output photons. However, due to low cross-sections, measuring the joint spectral properties of photon pair sources has historically been a challenging and time-consuming task. Here, we present an approach for the real-time measurement of the joint spectral properties of a fiber-based four wave mixing source. We seed the four wave mixing process using a broadband chirped pulse, studying the stimulated process to extract information regarding the spontaneous process. In addition, we compare stimulated emission measurements with the spontaneous process to confirm the technique's validity. Joint spectral measurements have taken many hours historically and several minutes with recent techniques. Here, measurements have been demonstrated in 5-30 s depending on resolution, offering substantial improvement. Additional benefits of this approach include flexible resolution, large measurement bandwidth, and reduced experimental overhead.
ABSTRACT
Quantum photonics offers much promise for the development of new technologies. The ability to control the interaction of light and matter at the level of single quantum excitations is a prerequisite for the construction of potentially powerful devices. Here we use the rotational levels of a room temperature ensemble of hydrogen molecules to couple two distinct optical modes at the single photon level using femtosecond pulses with 2 THz bandwidth. We observe photon correlations that violate a Cauchy-Schwarz inequality, thereby verifying the creation of a nonclassical state. This work demonstrates the rich potential of molecules for use in ultrafast quantum photonic devices.
