2-FREQUENCY INJECTION-SEEDED ND-YAG LASER

Dual longitudinal mode (DLM) operation of a Nd:YAG laser is achieved b y simultaneously injection seeding with two seed frequencies. We show that the relative energy in the two frequency components can be adjust ed by varying the relative seed power, and that they have excellent sp atial, angular, and temporal overlap. The result is a deeply modulated 1.06-mu m pulse with a modulation frequency that can be tuned from 18 5 MHz to at least 17 GHz in 185 MHz increments. In addition to the two seeded frequencies, weak sidebands are also observed in the output sp ectra. Their energy content is typically less than 1% of that of the s eeded modes. We discuss mechanisms which might cause them.