# Waveform-sequencing for scanning tunneling microscopy based pump-probe spectroscopy and pulsed-ESR

## TL;DR

This paper introduces a simple waveform-sequencing method for STM systems that enables pump-probe spectroscopy and pulsed-ESR, achieving ~5 ns time resolution and broad applicability in spin-resonance and quantum experiments.

## Contribution

The authors develop a straightforward upgrade using waveform sequencing and relay switching to incorporate pump-probe and pulsed-ESR capabilities into existing STM systems.

## Key findings

- Achieved ~5 ns time resolution limited by electronics.
- Demonstrated cross-correlation of DC/DC and DC/RF pulses.
- Enabled advanced spin-resonance experiments with STM.

## Abstract

We present here the straightforward implementation of pump-probe methods into existing scanning tunneling microscopy (STM) systems. Our method uses the waveform-sequencing abilities of a standard arbitrary waveform generator (AWG) and a simple mechanical relay switch that either connects the regular STM control electronics or the AWG to the STM system. Our upgrade further enables pulsed-ESR excitation for advanced STM based spin-resonance experiments. We demonstrate the technical implementation, signal detection using a lock-in amplifier, and cross-correlation measurements of DC/DC and DC/RF pulses highlighting our ~5 ns time resolution, here limited by the speed of the available electronics. Our setup is highly versatile and can be extended to suit other needs of STM based investigations such as required in diverse mapping schemes or the coherent manipulation of qubits.

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Source: https://tomesphere.com/paper/1902.05609