Amplified Spontaneous emission from optical fibers containing anisotropic morphology CdSe/CdS quantum dots under CW excitation

TL;DR

This paper demonstrates amplified spontaneous emission from fibers containing tunable CdSe/CdS quantum dots under continuous wave excitation, highlighting their potential as versatile gain media for fiber lasers beyond rare-earth materials.

Contribution

It reports the synthesis of asymmetric CdSe/CdS quantum dots with demonstrated optical gain and their integration into fibers to produce ASE at room temperature using CW pumping.

Findings

Quantum dots show efficient optical gain under CW excitation.

ASE observed in fibers containing quantum dots at room temperature.

Emission stability achieved by controlling QD concentration.

Abstract

Fibers lasers is a field which is typically dominated by rare earth ions as gain material in the core of a silica optical waveguide. Due to their specific emission wavelengths, rare-earth doped fiber lasers are available only at few pre-defined wavelengths. However, Quantum Dots (QDs) are materials, which shows tunable emission with change in size and composition. Due to such tunability, QDs seem to be promising candidates for obtaining fiber lasers at a spectrum of wavelengths which are not possible using rare earth ions. To replace rare earth ions with QDs, it is of paramount importance that QDs show signatures of optical gain. Here, we report synthesis of asymmetric pod-shaped CdSe/CdS QDs, which demonstrate efficient gain through pumping. The intrinsic gain properties of the QDs have been evaluated through Transient Absorption Spectroscopy. Later, the exquisite QDs are used to fabricate specialty fibers from which ASE has been obtained by using CW laser pump at Room Temperatur. Finally, Stability of the emission signal has been by studying photobleaching and controlling the concentration of the QDs.