DEVELOPMENT OF A MODE-LOCKED TI:SAPPHIRE LASER

ADVANCES IN THE DEVELOPMENT OF TUNABLE SOLID-STATE LASER MATERIALS FOR THE NEAR-INFRARED PROVIDES US WITH THE OPPORTUNITY TO DEVELOP A CLASS OF HIGH PERFORMANCE LASER SYSTEMS THAT OVER-COME THE LIMITATIONS OF PRESENTLY AVAILABLE DYE LASERS. IN PARTICULAR, THE BROADLY TUNABLE TI:AL(2)O(3) SYSTEM IS ATTRACTIVE AS A NEAR-INFRARED DYE LASER SUBSTITUTE THAT OPERATES FROM 680 NM TO 1000 NM WHEN AR(+)-ION LASER PUMPED. THE SUBJECT OF THIS PROPOSAL IS THE DEVELOPMENT OF A NOVEL MODE-LOCKING TECHNIQUE FOR THE TI:AL(2)O(3) LASER THAT WILL PROVIDE A SOURCE OF PICOSECOND/SUBPICOSECOND DURATION PULSES OVER THE ENTIRE LASER TUNING RANGE OF 680 NM TO 1000 NM. WE PROPOSE INTRODUCING A NONLINEAR REFLECTOR INTO A LOSS MODULATED CW MODELOCKED LASER. AN ANALOGY MAY BE DRAWN BETWEEN THE USE OF A SATURABLE OBSORBER IN HYBRID-MODELOCKING OF DYE LASERS AND THE USE OF THE NONLINEAR REFLECTOR FOR THE TIAL(2)O(3) LASER. THE SATURABLE ABSORBER IS A NONLINEAR ELEMENT WITH INCREASING TRANSMISSION AS A FUNCTION OF INCREASING INCIDENT INTENSITY. OUR NONLINEAR REFLECTOR IS A GERMANIUM OPTICAL FLAT WITH INCREASING REFLECTIVITY AS A FUNCTION OF INCREASING INCIDENT INTENSITY. BOTH NONLINEAR DEVICES ARE CAPABLE OF PROVIDING PULSE COMPRESSION IN A SUITABLE RESONATOR CONFIGURATION WITH A GAIN MEDIUM. THE NONLINEAR REFLECTOR THAT SHOULD PROVIDE US WITH A BROAD-BANDWIDTH INTRACAVITY PULSE COMPRESSION ELEMENT WITH SUPERIOR DURABILITY. SUCCESSFUL OPERATION WOULD PROVIDE THE PROOF OF CONCEPT NECESSARY FOR FURTHER DEVELOPMENT OF A SCIENTIFIC INSTRUMENT.