Kyle Johnston

TL;DR: Nanofabricated structured targets of ZnO are used and varied the chemical composition of the sample to demonstrate that (modest) high harmonics can be generated as the light interacts with the target materials, and present the possibility of developing solid-state ultrafast optical devices.

Abstract: We demonstrate a novel method to measure the temporal electric field evolution of ultrashort laser pulses. Our technique is based on the detection of transient currents in air plasma. These directional currents result from subcycle ionization of air with a short pump pulse and the steering of the released electrons with the pulse to be sampled. We assess the validity of our approach by comparing it with different state-of-the-art laser-pulse characterization techniques. Notably, our method works in ambient air and facilitates a direct measurement of the field waveform, which can be viewed in real time on an oscilloscope in a similar way as a radio frequency signal.

TL;DR: In this paper, the authors demonstrate a method to measure the temporal evolution of electric fields with optical frequencies based on the detection of transient currents in air plasma, which can be viewed in real time on an oscilloscope in the exact same way as a radio frequency signal.

TL;DR: In this article, the authors explore new ways to control high-harmonic emission in semiconductors using nanofabrication and demonstrate prototype devices which simultaneously emit and focus harmonic radiation.

TL;DR: In this paper, the authors extend these novel approaches by nanoscale engineering of the solid targets and demonstrate that high harmonic generation in semiconductors can be tailored and controlled by modification of the local chemical composition or the microstructure.