Mode-Hopping Phenomena in the InGaN-Based Core–Shell Nanorod Array Collective Lasing

Research paper by Chia-Yen Huang, Tzu-Ying Tai, Jing-Jie Lin, Tsu-Chi Chang, Che-Yu Liu, Tien-Chang Lu, Yuh-Renn Wu, Hao-Chung Kuo

Indexed on: 22 Jun '18Published on: 19 Jun '18Published in: ACS Photonics


A two-dimensional monolithic InGaN-based core–shell nanorod array was excited under a varying temperature. We observed an abrupt dominant mode hopping from 3.29 to 3.41 eV in the collective lasing as the temperature decreased from T = 240 to 225 K. Photoluminescence under a near-threshold pumping density revealed the splitting of spontaneous emission between the core and the shell with a decreasing temperature. The bandgap evolution of GaN and InGaN showed opposite trends due to the interaction of temperature effects and bandgap renormalization effects. Theoretical simulation revealed the differences of gain spectra evolution between room temperature and low temperature due to the difference in the carrier dynamics. In the optically coupled nanorod array, the dominant lasing mode was not only determined by its structure, but also strongly influenced by external operating conditions. Rather than singular microcavity lasers, the coupled nanorod array demonstrated a broader parameter space for on-chip wavelength manipulation.

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