An advanced lifetime measurement method by square wave excitation and lock-in amplifier

Achieving the radiation decay rate with high accuracy is crucial for all light emitters and absorbers. Therefore, a wide variety of measurement approaches have been developed for the measurement of radiation decay rate. Herein, we introduce a method to measure the decay rate with a common photoluminescence intensity setup without any modification. The square wave created by simply turning the output of the laser on and off is used as the excitation waveform, and a lock-in amplifier is used to gather the detected signal, making it a cost-effective way. Moreover, the constructed method can be used in a wide range of frequencies, detection voltages, and lifetimes. Finally, we applied the derived method to measure the photoluminescence lifetime of the first excited state of erbium ions in upconverting erbium-ytterbium silicate samples. (paper)