Raman laser from an optical resonator with a grafted single molecule monolayer

TL;DR

This paper demonstrates a surface-stimulated Raman scattering laser using an oriented monolayer on integrated microresonators, achieving low threshold power and high efficiency, advancing surface-based Raman laser technology.

Contribution

It introduces a novel surface Raman laser based on a grafted monolayer, combining surface chemistry with integrated photonics to enable stimulated Raman scattering at surfaces.

Findings

Achieved surface Raman lasing with a threshold of 200 microW.

Observed polarization dependence due to bond orientation.

Improved Raman lasing efficiency from ~5% to over 40%.

Abstract

Raman-based technologies have enabled many ground-breaking scientific discoveries related to surface science, single molecule chemistry and biology. For example, researchers have identified surface bound molecules by their Raman vibrational modes and demonstrated polarization-dependent Raman gain. However, a surface constrained Raman laser has yet to be demonstrated because of the challenges associated with achieving a sufficiently high photon population located at a surface to transition from spontaneous to stimulated Raman scattering. Here, advances in surface chemistry and in integrated photonics are combined to demonstrate lasing based on surface stimulated Raman scattering (SSRS). By creating an oriented, constrained Si-O-Si monolayer on the surface of integrated silica optical microresonators, the requisite conditions for SSRS are achieved with low threshold powers (200microW). The expected polarization-dependence of the SSRS due to the orientation of the Si-O-Si bond is observed. Due to the ordered monolayer, the Raman lasing efficiency is improved from ~5% to over 40%.