We study the integration of plasmonic traps with microfluidic channels. Plasmonic traps are optical traps
that use the evanescent field generated by metallic nanostructures at their plasmon resonance to trap small
objects. Contrary to conventional - far-field - traps, plasmonic traps do not require complex optics, as the
trapping potential is solely determined by the near-field generated by the nanostructure. This work includes
the theoretical study of the trapping potential and its relation to the plasmon resonance; the fabrication of
plasmonic traps using electron-beam lithography; the integration with PDMS microchannels; and the
statistical analysis of small objects trapped in the structure.
Dual-wavelength optical low-coherent interferometry is proposed in this paper to measure the oxygen saturation in
human retinal blood vessel. Wavelength consideration is made from the standpoint of eye safety and system
sensitivity. Principle of oxygen saturation measurement based on dual-wavelength low-coherence interferometer is
thoroughly developed. Numerical simulation on interference signal versus oxygen saturation corresponding to the
oxygen sensitive wavelength and the isobestic wavelength is conducted.
Optical coherence tomography (OCT) has been developed not only for morphological imaging, but also for functional imaging. By combining Doppler velocimetry with optical sectioning capability of OCT, we developed one branch of functional OCT (F-OCT) termed optical Doppler tomography (ODT). This newly developed fiber-based F-OCT system can provide structural image and Doppler image simultaneously, and is ready for extension to another branch of F-OCT termed as polarization-sensitive OCT (PS-OCT). Measurements of in vivo human skin and fresh milk flowing inside capillary tube are presented to demonstrate the capability of the developed system.
A fiber-based polarization-sensitive optical coherence tomography system was described. The polarization modulator in this system was introduced in the reference arm rather than in the source arm, providing an increased power delivered from light source to sample. Based on angle preservation of Stokes vectors in the PS-OCT system, Stokes parameters of backscattered light measured at the detection arm were used to determine the phase retardation of birefringence samples as a function of depth. With the developed PS-OCT system, investigation on birefringence alternation of ligament under different physical condition was carried out.