MODE-LOCKING OF LASERS zyxwvutsrqponmlkjihgfedcbaZ P. W. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA SMITH, M. A. DUGUAY, and E. P. IPPEN zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQ Bell Telephone Laboratories. Holmdel and Murray Hill, New Jersey zyxwvutsrqponmlkjihgfedcbaZYX CONTENTS HISTORICAL INTRODUCTION MODES IN LASER RESONATOFU TYPES OF MODE-LOCKING A. Longitudinal M ode- locking B. Transverse M ode- locking C. Simultaneous Longitudinal and Transverse Mode- locking TECHNIQUES OF MODE-LOCKING 131 A. Selj4ocking 131 B. Internal M odulation 135 C. Saturable Absorbers 135, D. Other Methods of Producing Mode-locking 142 MODE-LOCKING OF SOME SPECIFIC LASER SYSTEMS 143 A. 6328 A Helium-Neon Gas Lasers 143 B. Neodymium : Glass Lasers 149 C. Carbon Dioxide Gas Lasers 157 D. Dye Lasers 160 MEASUREMENT OF PICOSECOND PULSE DURATIONS A. Introduction B. Two-photon Fluorescence C. Second Harmonic Generation D. Other Methods 107 109 115 121 121 125 128 174 174 178 187 190