Detection of free-running electric signals up to 75 GHz using a femtosecond-pulse laser

A passively mode-locked Ti:sapphire laser is utilized to sample free-running microwave signals in time domain by photoconductive detection with a high sensitivity. The repetition frequency of the pulsed laser is locked to the free-running microwave signal by electronically controlled adjustment of the laser cavity length. A pump probe detection scheme allows absolute time scaling. The system's main application is the probing of electrical field distributions on free-running microwave circuits in the near and the far field.<
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