Ultrafast Optical Generation of Coherent Bright and Dark Surface Phonon Polaritons in Nanowires

Pierre-Adrien Mante,Jesper Wallentin,Daniel Finkelstein Shapiro,Arkady Yartsev,Sebastian Lehmann,Magnus T Borgström,Kayin Lee

doi:10.1021/acsphotonics.0c00537

Pierre-Adrien Mante, Jesper Wallentin + Show 5 more

Open Access

https://doi.org/10.1021/acsphotonics.0c00537

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Abstract

The coherence of polaritons plays a fundamental role in numerous recent experimental observations, from strong coupling to Bose-Einstein condensation, but accessing the coherence of polaritons is a difficult task due to the high energy of plasmons and excitons. However, surface phonon polaritons offer similar promises at much lower energy. Here, we demonstrate the possibility to use visible ultrafast lasers to generate and time resolve coherent surface phonon polaritons in nanowires. We show that these modes are generated through the ultrafast screening of the surface depletion field. By comparing experiments and FDTD simulations, we show that this method allows the simultaneous generation of dark and bright mode. Our observations open the way to deeper investigations of the role of coherence in the rich polariton physics.

Highlights

The subwavelength confinement and enhanced electric field created by plasmons allow precise sensing and enhanced light−matter interaction
Our work offers a novel platform for the study of the dynamics of processes involving SPhPs, from radiative heat transfer[15] to strong coupling.[23−26] This experimental approach will permit the study of the rich physics of polaritons in the time domain, including the manipulation of quantum information and coherent energy transfer.[6,28−30]
We extract a coherence lifetime in air of 4.02 ± 0.13, 2.20 ± 0.03, and 0.81 ± 0.018 ps for M, transverse quadrupole (TQ), and transverse dipole (TD), respectively. These values correspond to quality factors of 115, 67, and 25, respectively. These values must be compared to what is achieved in noble metal, where the quality-factor of plasmon resonances reaches at best 20− 40.18 they are of similar order of magnitude to what has been previously reported in InP nanowires.[22]

Summary

Introduction

The subwavelength confinement and enhanced electric field created by plasmons allow precise sensing and enhanced light−matter interaction. We first review the different mechanisms for the generation and detection of coherent vibrations by light pulses in polar semiconductors in the presence of a surface field.

Results

Conclusion