Active mode locking of lasers by piezoelectrically induced diffraction modulation

摘要

A new amplitudehyphen;modulation modehyphen;locking technique is presented. Acoustic waves are generated directly on the faces of a resonant photoelastic medium. The created standing waves cause a highly efficient diffraction modulation of light. The modulation depth of standinghyphen;wave mode lockers is related to material and drive parameters and a figure of merit is introduced. With a lithium niobate crystal modulation depths over 10 are achieved at 1.054 mgr;m and 1 W of radio frequency power. Using this device for the active mode locking of a continuoushyphen;wave Nd:glass laser pulses as short as 3.8 ps are produced at a repetition rate of 66 MHz. Limitations of amplitudehyphen;modulation mode locking by standing acoustic waves are discussed.