Browsing NTNU Open by Author "Engan, Helge Emil"

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Acoustooptic characterization of a birefringent two-mode photonic crystal fiber

Haakestad, Magnus Willum; Engan, Helge Emil (Journal article; Peer reviewed, 2006)

The effect of axial variations in acoustooptic phase-mismatch coefficient of a two-mode birefringent photonic crystal fiber (PCF) is studied experimentally using two different methods. The first method is to determine axial ...
Heterodyne interferometer for absolute amplitude vibration measurements with femtometer sensitivity

Leirset, Erlend; Engan, Helge Emil; Aksnes, Astrid (Journal article; Peer reviewed, 2013)

A heterodyne interferometer for highly sensitive vibration measurements in the range 100kHz − 1.3GHz is presented. The interferometer measures absolute amplitude and phase. The signal processing of the setup is analyzed ...
Wide frequency range measurements of absolute phase and amplitude of vibrations in micro- and nanostructures by optical interferometry

Martinussen, Hanne; Aksnes, Astrid; Engan, Helge Emil (Journal article; Peer reviewed, 2007)

A heterodyne interferometer has been built in order to characterize vibrations on micro- and nanostructures. The interferometer offers the possibility of both absolute phase and high resolution absolute amplitude vibrational ...