Spectral effects of phosphor-based white light-emitting-diode (LED) in coherence scanning interferometry

• Main Author: Chong, Wee Keat
• Other Authors: Li Xiang Leon
• Format: Theses and Dissertations
• Language: English
• Published: 2014
• Subjects: DRNTU::Science::Physics::Optics and light
• Online Access: https://hdl.handle.net/10356/55377
• Institution: Nanyang Technological University

Phosphor-based white light emitting diode (LED) is made out of blue LED and yellow phosphor, so there are two peaks in its spectrum. Compared to prior works, the spectral effect has been either neglected or suppressed. Hence this research investigates the spectral effects of phosphor-based white LED in coherence scanning interferometry. Instead of suppressing or neglecting the spectral effect of phosphor-based white LED, this research work investigates the spectral effects of phosphor-based white LED with the aim to improve the usability and performance of coherence scanning interferometry: First, a signal modeling for coherence scanning interferometry which expresses the signal in elementary form is proposed. It is then followed by applying the proposed signal model to investigate and give a theoretical explanation of the spectral effects of phosphor-based white LED in coherence scanning interferometry. With the proposed theoretical explanation, the spectral effects are harnessed to improve the usability and performance of coherence scanning interferometry. We believe that the results reported in this thesis will draw further research in the spectral effects in coherence scanning interferometry and the associated spectral manipulations.