Browsing by Author "Haakestad, Magnus Willum"
Now showing items 1-8 of 8
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250-MHz synchronously pumped optical parametric oscillator at 2.25–2.6 μm and 4.1–4.9 μm
Coluccelli, Nicola; Fonnum, Helge; Haakestad, Magnus Willum; Gambetta, Alessio; Gatti, Davide; Marangoni, Marco; Laporta, Paolo; Galzerano, Gianluca (2012)A compact and versatile femtosecond mid-IR source is presented, based on an optical parametric oscillator (OPO) synchronously pumped by a commercial 250-MHz Er:fiber laser. The mid-IR spectrum can be tuned in the range ... -
Intracavity molecular spectroscopy in the mid-IR using ultra-broadband optical parametric oscillator
Haakestad, Magnus Willum; Lamour, Tobias P.; Leindecker, Nick; Marandi, Alireza; Vodopyanov, Konstantin L. (2013)We have performed intracavity molecular spectroscopy of water vapor, isotopic carbon dioxide, methane, acetylene, carbon monoxide, formaldehyde and other gases using broadband mid-IR sync-pumped OPO sources (PPLN-based OPO ... -
Intracavity trace molecular detection with a broadband mid-IR frequency comb source
Haakestad, Magnus Willum; Lamour, Tobias P.; Leindecker, Nick; Marandi, Alireza; Vodopyanov, Konstantin L. (2013)Ultrasensitive detection of methane, isotopic carbon dioxide, carbon monoxide, formaldehyde, acetylene, and ethylene is performed in the spectral range 2.5–5 μm using intracavity spectroscopy in broadband optical parametric ... -
Inverse scattering of dispersive stratified structures
Skaar, Johannes; Haakestad, Magnus Willum (2012)We consider the inverse-scattering problem of retrieving the structural parameters of a stratified medium consisting of dispersive materials, given knowledge of the complex reflection coefficient in a finite frequency ... -
Mid-infrared source with 0.2 J pulse energy based on nonlinear conversion of Q-switched pulses in ZnGeP2
Haakestad, Magnus Willum; Fonnum, Helge; Lippert, Espen (2014)Mid-infrared (3–5 μm) pulses with high energy are produced using nonlinear conversion in a ZnGeP2-based master oscillator-power amplifier, pumped by a Q-switched cryogenic Ho:YLF oscillator. The master oscillator is based ... -
Reciprocity and the scattering matrix of waveguide modes
Svendsen, Guro Kristin; Haakestad, Magnus Willum; Skaar, Johannes (2013)The implications of the Lorentz reciprocity theorem for a scatterer connected to waveguides with arbitrary modes, including degenerate, evanescent, and complex modes, are discussed. In general it turns out that a matrix ... -
Robust Identification of Concealed Dangerous Substances by Spectral Correlation of Terahertz Transmission Images
Rheenen, Arthur Dirk van; Haakestad, Magnus Willum (2015)Terahertz (THz) images containing spectral information in each pixel are recorded in transmission mode using a fiber-coupled time-domain spectroscopy system. The images are acquired by mounting a sample holder on an x-y ... -
Robust identification of concealed dangerous substances using THz imaging spectroscopy
Nystad, Helle Emilia; Haakestad, Magnus Willum; Rheenen, Arthur Dirk van (2015)False alarm rates must be kept sufficiently low if a method to detect and identify objects or substances is to be implemented in real life applications. This is also true when trying to detect and identify dangerous ...