Submonolayer Quantum-Dot Based Saturable Absorber for Femtosecond Pulse Generation

• Published in: Journal of electronic materials Vol. 50; no. 5; pp. 2710 - 2715
• Main Authors: Addamane, S. J., Laurain, A., Baker, C. W., Rotter, T. J., Watt, J., Reno, J. L., Balakrishnan, G., Moloney, J. V.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2021; Springer Nature B.V; Springer
• Subjects: Absorbers; Characterization and Evaluation of Materials; Chemistry and Materials Science; Electronics and Microelectronics; femtosecond pulse; Femtosecond pulses; Indium gallium arsenides; Instrumentation; Material Science; MATERIALS SCIENCE; modelocked laser; Optical and Electronic Materials; Original Research Article; Quantum dots; Quantum wells; saturable absorber; Solid state lasers; Solid State Physics; submonolayer quantum dot; Surface emitting lasers; ultrafast laser; submonolayer quantum dot; ultrafast laser; saturable absorber; Femtosecond pulse; modelocked laser
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-021-08795-x

Semiconductor saturable absorber mirrors (SESAMs) enable passive modelocking of several ultrafast solid-state lasers. Conventionally, SESAMs in the 1-µm wavelength range have employed InGaAs quantum wells (QWs) as absorbers. We demonstrate here a SESAM based on InAs/GaAs submonolayer quantum dots (SML QDs) capable of generating femtosecond pulses by passively modelocking a vertical-external-cavity surface-emitting laser (VECSEL). Structural measurements are carried out to verify the quality and composition of the QDs. Modelocking experiments with a VECSEL and the QD SESAM in a ring cavity configuration yield pulses as short as 185 fs at 1025 nm. Compared to a traditional QW absorber, SML QD SESAMs exhibit ~ 25% faster recovery times. This also translates to slower power degradation rates or higher damage thresholds in SML QD SESAMs.