Single-cycle Optical Pulses and Isolated Attosecond Pulse Generation.

摘要

The MIT Single-Cycle Pulse and Isolated Attosecond Pulse Generation Program enabled to demonstrate, for the first time, a novel pulse synthesis technology based on ultrabroadband multi-color OPCPAs and explore the generation and control of isolated attosecond XUV pulses using the synthesized pulses. We developed several relevant ultrafast laser technologies and attosecond measurement systems, such as picosecond cryo-cooled Yb:YAG pump laser amplifiers, 2D and 4DSI pulse characterization techniques, optical balanced cross-correlator, CEP-jitter measurement apparatus, adiabatic DFG technique for high-energy broadband seeding, and a FROG-CRAB setup for attosecond XUV pulse characterization. Experimental demonstration of HHG with the 2.1 m source shows cutoff extension in Ar to 160 eV and promises the feasibility of coherent control of the HHG process with the synthesized sub- cycle electric-field transients after a further upgrade of the 800-nm OPCPA to the mJ level, as supported by our theoretical study. Since the scaling of energy and pulse duration is clearly possible by using higher-energy OPCPA pump lasers and/or by coherently adding different-color OPCPA systems, we believe that the high-energy pulse synthesis technology demonstrated under this grant has opened up a new high-energy ultrafast laser technology that is especially suited to attosecond and strong-field science.