Der-Chin Su | PubMed Health

PubMed2003

Interferometric optical sensor for measuring glucose concentration.

With a specially designed probe, the phase difference between s andp polarization of light reflected under surface-plasmon resonance is measured by use of a common-path heterodyne interferometer. For specific ratios of phase difference to glucose concentration, the glucose concentration can be estimated as a function of the measured phase data. A prototype was set up to demonstrate the feasibility of this sensor, which was experimentally tested in the range 40-500 mg/dl with a small quantity of solution and had a measurement resolution of 1.41 mg/dl at 25 degrees C.

Feasibility Studies↗

PubMed2002

Method for determining the optical axis and (n(e), n(o)) of a birefringent crystal.

There is a phase difference between s and p polarizations when a circularly polarized heterodyne light beam is reflected from a birefringent crystal. It can be measured accurately with a common-path heterodyne interferometric technique. We have derived an equation that describes the relationship between the phase differences and n(e), n(o), and alpha. Two groups of solutions for (n(e), n(o)) can be obtained from this equation by the phase measurements performed at three incident angles under moderate conditions. Each group consists of three pairs of solutions for (ne), n(o)). Finally, by justifying with physical conditions, we obtained the correct solution for (n(e), n(o)). Azimuth angle alpha of the birefringent crystal optical axis can also be determined. And the feasibility of this method is demonstrated.

Journal Article↗