IdealPhotonics' alkali photomultiplier tube (AMT) is a vacuum tube-type high-gain photodetector. It emits photoelectrons through an alkali metal (such as Na-K-Sb) photocathode, which are then amplified by multiple stages of dynodes to output a current signal (gain reaching 10⁶-10⁷ times). Its spectral response range depends on the photocathode material (e.g., Cs-Sb covering the ultraviolet-visible range), and its time response is in the picosecond range, making it suitable for extremely weak light detection, such as fluorescence spectroscopy and nuclear physics experiments. However, it requires a high-voltage power supply (kV level) and is susceptible to magnetic field interference.Ultra-high gain (10⁷ times) and picosecond-level time response are also available, but these are bulky and require light-shielded operation.