Photon-Pair Generation from Chip-Scale Cs Atomic Vapor Cell

The realization of a narrowband photonic quantum source based on a chip-scale atomic device is considered essential in the practical development of photonic quantum information science and technology. In this study, we present the first step toward the development of a photon-pair source based on a microfabricated chip-scale Cs atomic vapor cell. Time-correlated photon pairs from the millimeter-scale Cs vapor cell are emitted via the spontaneous four-wave mixing process of the cascade-type 6S1/2–6P3/2–8S1/2 transition of 133Cs. The maximum normalized cross-correlation value between the signal and idler photons is measured as 622(8) under a weak pump power of 10 mW. Our photon source violates the Cauchy–Schwartz inequality by a factor of >105. We believe that our approach has very important applications in the context of realizing practical scalable quantum networks based on atom–photon interactions.

Monolithic Chip System with a Microfluidic Channel for In Situ Electron Microscopy of Liquids

Electron microscopy of enclosed liquid samples requires the thinnest possible membranes as enclosing windows as well as nanoscale liquid sample thickness to achieve the best possible resolution. Today liquid sample systems for transmission electron microscopy (TEM) are typically made from two sandwiched microchips with thin membranes. We report on a new microfabricated chip system based on a monolithic design that enables membrane geometry on the scale of a few micrometers. The design is intended to reduce membrane deflection when the system is under pressure, a microfluidic channel for improved flow geometry, and a better space angle for auxiliary detectors such as energy-dispersive X-ray spectroscopy. We explain the system design and fabrication and show the first successful TEM images of liquid samples in the chips.

On-Chip Cryopreservation of Living Cells

On-chip cryopreservation of biological cells under low-temperature environments has been successfully demonstrated using a microfabricated chip with an incubation microchamber and microfluidic channels. Microheaters are used as both the resistive heating elements and temperature sensors to control the temperature profile of microenvironment under the liquid nitrogen cooling process. A two-step, temperature-controlled, on-chip cryopreservation process is applied for yeast cells, and after the thawing process, 74% cell survival rate has been accomplished. The reference experiment conducted without using the temperature control results in 27% cell survival rate. As such, this technique could have potential applications in on-chip cryopreservation processes, including those for sperm, embryo, or future cryogenic-based, lab-on-a-chip applications.