Supercontinuum laser for broadband spectroscopy using upconversion

This thesis describes an experimentally based, and application oriented investigation of the possibilities offered by the combination of upconversion detection methods developed at DTU Fotonik with mid-infrared supercontinuum sources built at NKT Photonics. The first introductory chapter provides a brief overview of prior work in the field of upconversion detection and presents the motivations and goals of the Ph.D. project. Chapters 2 and 3 cover the relevant physics of upconversion detection and supercontinuum generation as support for subsequent discussions and analyses. These chapters also include construction notes and practical design aspects of pulsed upconversion setups using supercontinuum illumination. Chapter 4 focuses on the experimental work achieved during this project. The experiments are based on synchronous broadband upconversion of mid-infrared (MIR) pulses from a supercontinuum source and include both imaging and spectroscopy setups. The experimental results are presented in the order in which they were realized. The thesis is concluded in chapter 5 with a summary of the main results of this project followed by a discussion about the possible improvements that could be brought to synchronous pulsed upconversion in the future as well as its strong potential for many key applications.