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In this paper, we demonstrate a method of measuring the flexural elastic modulus of ceramics at an intermediate (~millimeter) scale at high temperatures. We used a picosecond laser to precisely cut microbeams from the location of interest in a bulk ceramic. They had a cross-section of approximately 100 μm × 300 μm and a length of ~1 cm. They were then tested in a thermal mechanical analyzer at room temperature, 500 °C, 800 °C, and 1100 °C using the four-point flexural testing method. We compared the elastic moduli of high-purity Al2O3 and AlN measured by our method with the reported values in the literature and found that the difference was less than 5% for both materials. This paper provides a new and accurate method of characterizing the high-temperature elastic modulus of miniature samples extracted from representative/selected areas of bulk materials. 

Metal halide perovskites represent a promising class of gain media for next‐generation nonepitaxial laser diodes. However, fully electrically pumped perovskite laser diodes have not been achieved yet. Herein, the use of sodium fluoride (NaF) is explored as an efficient additive in halide perovskite films to improve their optical and light amplification properties. The incorporation of NaF in perovskites leads to a remarkable threefold increase in light‐emitting intensity. The threshold of amplified spontaneous emission (ASE) by optical pumping is reduced by more than 20%, from ≈13.5 to 10.4 μJ cm⁻². Furthermore, the NaF‐modified perovskites exhibit stable ASE emission, even after exposure to 1.5 billion optical pulses, highlighting substantial improvements in the material's photostability. Finally, optically pumped ASE is observed from a full perovskite light‐emitting diode stack, including lossy metal electrodes. This work demonstrates significant progress toward the development of electrically pumped perovskite lasers.