We report on the all-optical production of Bose-Einstein condensates in microgravity using a combination of grey molasses cooling, light-shift engineering and optical trapping in a painted potential. Forced evaporative cooling in a 3-m high Einstein elevator results in 4 × 10 4 condensed atoms every 13.5 s, with a temperature as low as 35 nK. In this system, the atomic cloud can expand in weightlessness for up to 400 ms, paving the way for atom interferometry experiments with extended interrogation times and studies of ultra-cold matter physics at low energies on ground or in Space.

We demonstrate how simultaneously operated 39K–87Rb interferometers exhibiting a high level of correlation can be used to make competitive tests of the university of free fall. This work provides an overview of our experimental apparatus and data analysis procedure, including a detailed study of systematic effects. With a total interrogation time of 2T=40 ms in a compact apparatus, we reach a statistical uncertainty on the measurement of the Eötvös parameter of 7.8×10−8 after 2.4×104 s of integration. The main limitations of our measurements arise from a combination of wavefront aberrations, the quadratic Zeeman effect in 39K, parasitic interferometers in 87Rb, and the velocity sensitivity of our detection system. These systematic errors limit the accuracy of our measurement to η=0.9(1.6)×10−6. We discuss prospects for improvements using ultracold atoms at extended interrogation times.

Due to its high transparency and low sheet resistance, indium tin oxide (ITO) has been the material of choice for transparent anodes in organic light-emitting diodes (OLEDs). Indium tin oxide, however, is a source of outcoupling loss due to waveguiding and reduced mechanical stability on flexible/stretchable substrates due to its brittle nature. We demonstrate that highly efficient ITO-free OLEDs can be achieved using high quality silver electrodes and horizontally aligned dipole emitters to avoid plasmonic losses. Using an ultrathin Ag/MPTMS anode and a partially aligned phosphorescent emitter, we demonstrate OLEDs with 30% EQE, luminous efficiency exceeding 130 lm/W, and low leakage current. In addition, we demonstrate OLEDs with an optimized structure showing a 36.1% outcoupling efficiency. Theoretical calculations show that our approach can yield up to 48.4% outcoupling efficiency for perfect horizontal alignment, which exceeds the maximum achievable with ITO. The combination of a silver anode and a horizontal phosphorescent emitter is promising for the future design of ultra-efficient flexible OLEDs.