Lock-in amplifier up to 530 MHz with phase and amplitude demodulation

The development and characterization of a heterodyne radio-frequency lock-in amplifier operating in the frequencies range from 118 MHz to 530 MHz is reported. Synchronous demodulation, achieved at an intermediate frequency of 10 MHz, is achieved by means of a high-speed and high-accuracy sample and hold device. Both amplitude and phase demodulation can be performed with a maximum output signal bandwidth of 1 MHz. This device was mainly developed for applications in the fields of ultra-high-resolution spectroscopy and of laser frequency stabilization.