Design and analysis of ultrashort femtosecond laser amplifiers

Doğan, Ersin
This thesis presents a compact femtosecond laser amplifier design for optical preamplifiers and power amplifiers consist of theoretical perspective, simulations to analyze and optimize beam performance. The propagation through optical media is simulated for every optical component such as mirrors and nonlinear crystal separately and suggested realignment of these components required increasing amplifier performance. Finally Gaussian beam propagation and aberration compensation has been conducted.


Development of a compact time-domain terahertz spectrometer using photoconductive antenna detection method
Güngör Erözbek, Ümmügül; Altan, Hakan; Department of Physics (2009)
In this thesis, we describe the development of a time-domain terahertz (THz) spectrometer driven by two different laser sources: an Er-doped femtosecond fiber laser and a mode-locked Ti:Sapphire laser. The resulting THz electromagnetic radiation was generated and detected using photoconductive antenna detection methods in both systems. In these experiments we characterized the THz power output for both the fiber laser driven system and the Ti:Sapphire laser driven system. Emphasis is given throughout this t...
Non-linear optical properties of two dimensional quantum well structures
Ağanoğlu, Ruzin; Tomak, Mehmet; Department of Physics (2006)
In this work optical properties of two dimensional quantum well structures are studied. Variational calculation of the eigenstates in an isolated quantum well structure with and without the external electrical field is presented. At weak fields a quadratic Stark shift is found whose magnitude depends strongly on the finite well depth. It is observed that under external electrical field, the asymmetries due to lack of inversion symmetry leads to higher order nonlinear optical effects such as second order opt...
Performance of M-ary pulse position modulation for aeronautical uplink communications in an atmospheric turbulent medium
Ata, Yalcin; Baykal, Yahya; Gokce, Muhsin Caner (The Optical Society, 2019-10-01)
This paper discusses the bit-error-rate (BER) performance of an aeronautical uplink optical wireless communication system (OWCS) when a Gaussian beam is employed and the M-ary pulse position modulation technique is used in an atmospheric turbulent medium. Weak turbulence conditions and log-normal distribution are utilized. The Gaussian beam is assumed to propagate on a slant path, the transmitter being ground-based, and the airborne receiver is on-axis positioned. Variations of BER are obtained against the ...
Advanced Design of Schottky Photodiodes in Bulk CMOS for High Speed Optical Receivers
Orsel, Ogulcan Emre; Erdil, Mertcan; Kocaman, Serdar (Institute of Electrical and Electronics Engineers (IEEE), 2020-02-01)
This paper provides theoretical insight on how circular Schottky photodiodes in bulk CMOS can be optimized for certain integrated receiver applications. An optimal photodiode size is analytically demonstrated and the effects of a metal plate reflector are simulated using a transfer-matrix method, both for frontside and backside illumination. Finally, a distributed circuit model is presented, which deviates from the classical lumped model for large photodiodes or sheet resistances. The presented methodologie...
Design and Analysis of Nanoantenna Arrays for Imaging and Sensing Applications at Optical Frequencies
Isiklar, Goktug; Cetin, Isa Can; Algun, Mustafa; Ergül, Özgür Salih (2019-01-01)
We present computational analysis of nanoantenna arrays for imaging and sensing applications at optical frequencies. Arrays of metallic nanoantennas are considered in an accurate simulation environment based on surface integral equations and the multilevel fast multipole algorithm developed for plasmonic structures. Near-zone responses of the designed arrays to nearby nanoparticles are investigated in detail to demonstrate the feasibility of detection. We show that both metallic and dielectric nanoparticles...
Citation Formats
E. Doğan, “Design and analysis of ultrashort femtosecond laser amplifiers,” M.S. - Master of Science, Middle East Technical University, 2006.