Synthesis and Direct Sampling of Single-Cycle Light Transients by Electron Tunneling in a Nanodevice

Abstract

The generation and direct time-domain sampling of ultrashort and ultra-broadband laser pulses are at the forefront of time-resolved spectroscopy and attosecond science. Although high-energy (>1 μJ) single-cycle laser pulses at low repetition rates (∼kHz) can be generated by many techniques like spectral broadening and field synthesis and characterized using nonlinear optical techniques, realizing such capabilities for low-energy (<1 nJ) and high-repetition-rate (∼80 MHz) laser pulses is more challenging. Here, we demonstrate the generation and direct sampling of carrier-envelope-phase (CEP)-stable, single-cycle optical pulses (∼1.1 octave bandwidth) at a very high repetition rate (∼80 MHz) by realizing a three-channel light-field-synthesizer spanning the visible and near-infrared frequency range. The electric fields of the ultra-broadband single-cycle laser pulses were directly sampled in an on-chip nanodevice. We show that electron tunneling currents measured as a function of the delay between two slightly carrier-frequency-shifted (<1 kHz) laser pulses in the nanodevice enable ultra-broadband sampling of electric fields of the laser pulses. The demonstrated synthesis and direct measurement of single-cycle light fields at high repetition rates pave the way for broad applications in near-field ultrafast spectroscopies and on-chip light-wave electronics.

Efficient and Continuous Carrier-Envelope Phase Control for Terahertz Lightwave-Driven Scanning Probe Microscopy

“…Coherent control of ultrafast electromagnetic waveforms is crucial to understanding and manipulating fundamental carrier dynamics. Single-cycle laser pulses have become an established tool to control transport and tunneling processes with extreme precision and high time resolution. − At the same time, nanoscale spectroscopic probes have united subpicosecond time and atomic spatial resolution, enabling the investigation of carrier dynamics in atomic and molecular systems. , On the forefront of these technological advancements, the terahertz (THz) lightwave-driven scanning tunneling microscope (THz-STM) opened up new horizons to study electronic, − vibronic, , and excitonic , dynamics at unprecedented resolution. The low frequency and off-resonant character of THz pulses can easily reach the regime of field-driven tunneling, where the electric field acts as a transient voltage pulse across a conductive nanojunction with negligible thermal impact .…”