April 26, 2019

Julia Yeomans

Dense Active Matter

April 12, 2019 Nanocolloquium

Prof. Sergei K. Turitsyn

Nonlinear world of commercial photonic systems

    EventDr. Işınsu Baylam

Graphene-based nanomaterials and their use as saturable absorbers to generate femtosecond pulses from solid-state lasers

Graphene has emerged as an alternative saturable absorber to other semiconductors due to its nearly constant broadband absorption of 2.3%. It has been shown that graphene and graphene-based nanomaterials can be used as efficient saturable absorbers to generate ultrashort pulses from lasers operating in the near- and mid-infrared. However, the 2.3% absorption of the monolayer graphene introduces operational challenges to the lasers with low gains. To obviate such challenges, the Fermi level position of the graphene can be varied to control the amount of absorption at the desired wavelength. For this purpose, chemically- or  electrostatically-doped novel graphene architectures with reduced optical insertion losses can be used to optimize the power performance of the femtosecond lasers. In this talk, the use of carbon-based saturable absorbers to generate ultrashort pulses from solid-state lasers will be presented and their current drawbacks will be discussed. This will be followed by the overview of the possible approaches, which have been demonstrated to shift the Fermi level of graphene to control the amount of absorption at the desired wavelength. At this point, the voltage-controlled graphene-based supercapacitor architectures proposed by our groups will be demonstrated and the femtosecond pulse generation results obtained with these devices will be discussed

Bilkent-osa

About The Speaker

OSA-Isinsu-Baylam

Dr. Işınsu Baylam received her BS degree in Physics from Bilkent University in 2010, MS, and PhD degrees in Physics from Koç University in 2012 and 2017. During her MS and PhD studies, she focused on the development of ultrafast, near- and mid-infrared solid-state lasers, graphenebased nanomaterials and their use as saturable absorbers to generate femtosecond pulses from solid-state lasers. She currently works as a doctoral researcher at Koç University Surface Science and Technology Center (KUYTAM) and she supervises the Ultrafast Laser Spectroscopy Laboratory located at KUYTAM. Her research interests include near- and mid-infrared solid-state lasers, ultrafast laser spectroscopy, and laser-based microfabrication. She is a member of the Optical Society (OSA) and the International Society for Optics and Photonics (SPIE). During her OSA and SPIE student memberships, she received “Outstanding Student Oral Presentation Award” in both 2015 and 2016 Advanced Solid-State Lasers Conferences in Berlin, Germany and in Boston MA, USA. She also received “Newport Research Excellence Award” in 2013 SPIE Photonics West Conference, San Francisco CA, USA. She has been selected to serve as an Ambassador of the OSA and she was recently selected as one of the participants of the 69th Lindau Nobel Laureate Meeting.