Kazuki Nishijima

Carrier-envelope-phase stabilized chirped-pulse amplification system scalable to higher pulse energies

We have demonstrated a carrier-envelope phase (CEP) stabilized chirped-pulse amplification (CPA) system employing a grating-based pulse stretcher and compressor and a regenerative amplifier for the first time. In addition to stabilizing the carrier-envelope offset phase of a laser oscillator, a new pulse selection method referenced to the carrier-envelope offset beat signal was introduced. The pulse-selection method is more robust against the carrier-envelope offset phase fluctuations than a simple pulse-clock dividing method. We observed a stable fringe in a self-referencing spectrum interferometry of the amplified pulse, which implies that the CEP of amplified pulse is stabilized. We also measured the effect of the beam angle change on the CEP of amplified pulses. The result demonstrates that the CEP stabilized CPA is scalable to higher-pulse energies.

Route to design electric fields of optical pulses: A combination of a pulse shaper and a carrier-envelope-phase stabilized chirped-pulse amplifier system

We demonstrated active carrier-envelope-phase (CEP)-shift by utilizing a 4f-pulse-shaper in a CEP-stabilized chirped-pulse-amplification system. A combination of a pulse-shaper and CEP-stabilized pulses enables us to design electric fields, both the pulse envelope and the carrier-envelope relation.

Effect of Beam Pointing Shift on the Carrier-envelope Phase Measurement using Self-referencing Spectral Interferometry Method

We measured effects of beam pointing shift on the carrier-envelope phase measurement by self-referencing spectral interferometry method using hollow-core fibers or a sapphire plate for spectral broadening

Chirped-pulse amplification system providing electric-field-controlled optical pulses

We demonstrated control of full electric-field shapes of optical pulses by combining a carrier-envelope-phase stabilized chirped-pulse amplification system with a pulse-shaper that controls both the carrier-envelope phase and the pulse envelope.