Degradation mechanism of SESAMs under intense ultrashort pulses in modelocked VECSELs

Sadhvikas Addamane, Darryl Shima, Alexandre Laurain, Hsiu Ting Chan, Ganesh Balakrishnan, Jerome V. Moloney

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations


Mode-locked VECSELs using SESAMs are a relatively less complex and cost-effective alternative to state-of-the-art ultrafast lasers based on solid-state or fiber lasers. VECSELs have seen considerable progress in device performance in terms of pulse width and peak power in the recent years. However, it appears that the combination of high power and short pulses can cause some irreversible damage to the SESAM. The degradation mechanism, which can lead to a reduction of the VECSEL output power over time, is not fully understood and deserves to be investigated and alleviated in order to achieve stable mode-locking over long periods of time. It is particularly important for VECSEL systems meant to be commercialized, needing long term operation with a long product lifetime. Here, we investigate the performance and robustness of a SESAM-modelocked VECSEL system under intense pulse intensity excitation. The effect of the degradation on the VECSEL performance is investigated using the SESAM in a VECSEL cavity supporting ultrashort pulses, while the degradation mechanism was investigated by exciting the SESAMs with an external femtosecond laser source. The decay of the photoluminescence (PL) and reflectivity under high excitation was monitored and the damaged samples were further analyzed using a thorough Transmission Electron Microscopy (TEM) analysis. It is found that the major contribution to the degradation is the field intensity and that the compositional damage is confined to the DBR region of the SESAM.

Original languageEnglish (US)
Title of host publicationVertical External Cavity Surface Emitting Lasers (VECSELs) VIII
EditorsJuan L. Chilla
ISBN (Electronic)9781510615151
StatePublished - 2018
EventVertical External Cavity Surface Emitting Lasers (VECSELs) VIII 2018 - San Francisco, United States
Duration: Jan 29 2018Jan 30 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherVertical External Cavity Surface Emitting Lasers (VECSELs) VIII 2018
Country/TerritoryUnited States
CitySan Francisco


  • Saturable absorbers
  • TEM
  • degradation mechanism

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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