Title: The Net Gain Bandwidth Broadening in Yb-doped Laser Materials-A Breakthrough in Obtaining High-energy Pulses of Extremely Short Duration. Applicants.Abstract: Since Yb-based laser materials were established as an alternative to Ti-Sapphire for ultrafast laser development in the late 1990s, tremendous progress has been made in generating ultrashort pulses with record-high energies or average powers. Although the Yb femtosecond oscillator architectures with 30-100 fs pulse durations have advanced significantly in the past three decades, the pulse durations of conventional Yb chirped pulse amplification (CPA) systems have been limited to the 180-350 fs range. We demonstrate experimentally and theoretically a net bandwidth increase in a CPA system based on a single disordered Yb:CaYAlO4 crystal.Pulse duration of record 97 fs at 1038 nm with an energy of 2.7 mJ at 1 kHz is obtained straight from a single-crystal CPA system without additional spectral broadening or pulse shaping techniques. Furthermore, we demonstrated that by incorporating simple nonlinear spectral broadening in thin CaF2 plates and a prism post compressor [4], we achieved 58 fs. We will also discuss a wide range of applications, particularly in the area of developing new advanced transient spectroscopy techniques for the analysis of fast processes in quantum systems (PV-materials, optical metamaterials, and powder samples).About the Speaker: PhD in Physics (including Quantum Electronics and Nonlinear Optics) at the physics department at Sofia University "St. Kl. Ohridski" in 1994. In 2003, he acquired the academic permanent position of associate professor in physics of wave processes at SU "St. Kl. Ohridski". Since 2015, he has held research Pprofessor appointment at; University of Information Technology, Mechanics and Optics (ITMO), Sankt Petersburg within the framework of the Russian academic excellence project "5-100". Since December 2016, he has been elected by the Academic Council of Sofia University as a representative of Sofia University in the Center for Competence in Bio-Nanophotonics. John Atanasoff (JAC BNP ). Since 2017, he has held the position of president of the directors' board of the(JAC BNP http://bionano-bg.eu. He has over 30 years of professional experience in the quantum electronics field and its interdisciplinary applications in various research and academic institutions, including: Technical University Munich, Germany; Boston College, Boston, USA; Northwestern University, Evanston (Chicago), USA; ITMO, St. Petersburg; Max Born Institute, Berlin, Germany; and others. Research is in a relatively broad field known as the physics of ultra-fast optical processes and technologies, including both the generation of ultra-short pulses in various spectral regions (UV, VIS, NIR, and Mid-IR) and their use for Ultrafast Laser Spectroscopy and Nonlinear Optical Phenomena. An additional area of interest is the development of specific laser sources (Solid-State Laser Engineering) and methods for new multidisciplinary applications in Medicine and Material Science. Author of more than 100 research publications. Principle investigator (PI) of more than 17 government- and privately-funded grant projects Over the past 10 years, he has established two new laboratories for advanced experimental research at SU: "Laser Physics and Applications laboratory" (https://buchvarov.phys.uni-sofia.bg/layout.php?page=news ) and Ultrafast Laser Spectroscopy laboratory. Currently he is the research coordinator of the national research infrastructure roadmap project HEPHESTUS: Extreme Mid-IR and Coherent X-rays Light as a Lab Infrastructure; and Principal Investigator of the Bulgarian team of the EU project, Programme EU.1.2., Excellence Science- Future and Emerging Technologies (FET) Open, Metasurfaces for ultrafast light structuring.Virtual Location URL: https://ucf.zoom.us/j/91655162571?from=addon

Title: The Net Gain Bandwidth Broadening in Yb-doped Laser Materials-A Breakthrough in Obtaining High-energy Pulses of Extremely Short Duration. Applicants.Abstract: Since Yb-based laser materials were established as an alternative to Ti-Sapphire for ultrafast laser development in the late 1990s, tremendous progress has been made in generating ultrashort pulses with record-high energies or average powers. Although the Yb femtosecond oscillator architectures with 30-100 fs pulse durations have advanced significantly in the past three decades, the pulse durations of conventional Yb chirped pulse amplification (CPA) systems have been limited to the 180-350 fs range. We demonstrate experimentally and theoretically a net bandwidth increase in a CPA system based on a single disordered Yb:CaYAlO4 crystal.Pulse duration of record 97 fs at 1038 nm with an energy of 2.7 mJ at 1 kHz is obtained straight from a single-crystal CPA system without additional spectral broadening or pulse shaping techniques. Furthermore, we demonstrated that by incorporating simple nonlinear spectral broadening in thin CaF2 plates and a prism post compressor [4], we achieved 58 fs. We will also discuss a wide range of applications, particularly in the area of developing new advanced transient spectroscopy techniques for the analysis of fast processes in quantum systems (PV-materials, optical metamaterials, and powder samples).About the Speaker: PhD in Physics (including Quantum Electronics and Nonlinear Optics) at the physics department at Sofia University "St. Kl. Ohridski" in 1994. In 2003, he acquired the academic permanent position of associate professor in physics of wave processes at SU "St. Kl. Ohridski". Since 2015, he has held research Pprofessor appointment at; University of Information Technology, Mechanics and Optics (ITMO), Sankt Petersburg within the framework of the Russian academic excellence project "5-100". Since December 2016, he has been elected by the Academic Council of Sofia University as a representative of Sofia University in the Center for Competence in Bio-Nanophotonics. John Atanasoff (JAC BNP ). Since 2017, he has held the position of president of the directors' board of the(JAC BNP http://bionano-bg.eu. He has over 30 years of professional experience in the quantum electronics field and its interdisciplinary applications in various research and academic institutions, including: Technical University Munich, Germany; Boston College, Boston, USA; Northwestern University, Evanston (Chicago), USA; ITMO, St. Petersburg; Max Born Institute, Berlin, Germany; and others. Research is in a relatively broad field known as the physics of ultra-fast optical processes and technologies, including both the generation of ultra-short pulses in various spectral regions (UV, VIS, NIR, and Mid-IR) and their use for Ultrafast Laser Spectroscopy and Nonlinear Optical Phenomena. An additional area of interest is the development of specific laser sources (Solid-State Laser Engineering) and methods for new multidisciplinary applications in Medicine and Material Science. Author of more than 100 research publications. Principle investigator (PI) of more than 17 government- and privately-funded grant projects Over the past 10 years, he has established two new laboratories for advanced experimental research at SU: "Laser Physics and Applications laboratory" (https://buchvarov.phys.uni-sofia.bg/layout.php?page=news ) and Ultrafast Laser Spectroscopy laboratory. Currently he is the research coordinator of the national research infrastructure roadmap project HEPHESTUS: Extreme Mid-IR and Coherent X-rays Light as a Lab Infrastructure; and Principal Investigator of the Bulgarian team of the EU project, Programme EU.1.2., Excellence Science- Future and Emerging Technologies (FET) Open, Metasurfaces for ultrafast light structuring.Virtual Location URL: https://ucf.zoom.us/j/91655162571?from=addon