Wavelength conversion through plasmon-coupled surface states

TL;DR

This paper introduces a novel passive wavelength conversion method leveraging plasmon-coupled surface states and giant electric fields, achieving high efficiency without nonlinear optical processes, applicable across a broad spectrum.

Contribution

It demonstrates a new approach to wavelength conversion using surface states and surface plasmons, surpassing nonlinear optical methods in efficiency.

Findings

Achieved wavelength conversion from 1550 nm to terahertz with record-high efficiency.

Utilized surface states and plasmons to generate mixing products without nonlinear optics.

Demonstrated potential for broad-spectrum wavelength conversion from microwave to infrared.

Abstract

Surface states generally degrade semiconductor device performance by raising the charge injection barrier height, introducing localized trap states, inducing surface leakage current, and altering the electric potential. Therefore, there has been an endless effort to use various surface passivation treatments to suppress the undesirable impacts of the surface states. We show that the giant built-in electric field created by the surface states can be harnessed to enable passive wavelength conversion without utilizing any nonlinear optical phenomena. Photo-excited surface plasmons are coupled to the surface states to generate an electron gas, which is routed to a nanoantenna array through the giant electric field created by the surface states. The induced current on the nanoantennas, which contains mixing product of different optical frequency components, generates radiation at the beat frequencies of the incident photons. We utilize the unprecedented functionalities of plasmon-coupled surface states to demonstrate passive wavelength conversion of nanojoule optical pulses at a 1550 nm center wavelength to terahertz regime with record-high efficiencies that exceed nonlinear optical methods by 4-orders of magnitude. The presented scheme can be used for optical wavelength conversion to different parts of the electromagnetic spectrum ranging from microwave to infrared regimes by using appropriate optical beat frequencies.