Fabrication of ZnO-QDs for a wavelength conversion film using a dressed photon

Tadashi Kawazoe

Takuya Kadowaki, Tadashi Kawazoe, Motoichi Ohtsu

Wance Wang, Dhruv Fomra, Amit Agrawal +2 more

Transparent conductive oxides (TCO) enable confinement of charge-sensitive ions and Rydberg atoms proximal to dielectric structures including waveguides and photon detectors. However, optical loss precludes the use of TCOs within high-finesse optical micro-resonators. Here we characterize a ZnO-based TCO that markedly reduces optical absorption. At 1650\text{ nm} we observe a 22,000 finesse in a Fabry-Pérot optical cavity coated with a 30\text{ nm} ZnO layer. This is a 5000 times reduction relative to indium tin oxide (ITO) at this wavelength. The same ZnO film exhibits 0.01\text{ \ensuremathΩ\ensuremath{\cdot}cm} surface resistivity at DC. We anticipate a step change in cavity-QED systems incorporating ultra-low loss TCOs like ZnO.

Tanaka Naohiro, Tadashi Kawazoe, Wataru Nomura +1 more

Saniya Shinde, Maximilian A. Weissflog, Shaun Lung +7 more

Entangled photon pairs play a major role in various modern technologies such as quantum imaging, communication, and computing. Conventional photon-pair sources are often based on spontaneous parametric down-conversion in bulk nonlinear crystals. Recent advances have also shown entangled photon-pairs from transition metal dichalcogenide thin-films, however, these materials are not widely available and are not compatible with existing fabrication capabilities. We present a new thin-film lithium niobate source of polarization-entangled photon pairs at the telecom wavelength that requires no additional optical elements for entanglement generation and allows for easy application using the existing lithium niobate fabrication technologies. We demonstrate tunable entanglement generation using the three-fold rotational crystal symmetry of lithium niobate, allowing the generation of different maximally entangled Bell states or completely separable states depending on the polarization of the pump beam.

I. I. Popov, Н. С. Вашурин, Путилин Сергей Эдуардович +3 more

A femtosecond stimulated photon echo is detected for the first time in thin semiconductor films with thicknesses of 100, 800, and 2400 nm. It is established that relaxation time T 1 varies with ZnO film thickness, taking values of 0.96, 2.96, and 4.312 ps at thicknesses of 2400, 800, and 100 nm, respectively. For ZnO/Si+/Si− trilayer films, the relaxation time is T 1 = 12.73 ps.