Integrating fault tolerance algorithm and circularly polarized ellipsometer for point-of-care applications

Abstract

A circularly polarized ellipsometer was developed to enable real-time measurements of the optical properties of materials. Using a four photo-detector quadrature configuration, a phase modulated ellipsometer was substantially miniaturized which has the ability to achieve a high precision detection limit. With a proven angular resolution of 0.0001 deg achieved by controlling the relative positions of a triangular prism, a paraboloidal and a spherical mirror pair, this new ellipsometer possesses a higher resolution than traditional complex mechanically controlled configurations. Moreover, the addition of an algorithm, FTA (fault tolerance algorithm) was adopted to compensate for the imperfections of the opto-mechanical system which can decrease system measurement reliability. This newly developed system requires only one millisecond or less to complete the measurement task without having to adopt any other modulation approach. The resolution achieved can be as high as 4x10(-7) RIU (refractive index unit) which is highly competitive when compared with other commercially available instruments. Our experimental results agreed well with the simulation data which confirms that our quadrature-based circularly polarized ellipsometer with FTA is an effective tool for precise detection of the optical properties of thin films. It also has the potential to be used to monitor the refractive index change of molecules in liquids.

Integrating SPR-ellipsometry and electrochemical measurements for performance evaluation of label-free thiophene-based biosensor

“…The system measurement reliability was increased by a fault tolerance algorithm. The system phase detection sensitivity was verified to be 8.2×10 -6 (1⁄RIU) where p-polarized light change was found to be within the linear region [10,11]. In the electrochemistry measurement part of this system, cyclic voltammetry (CV) and impedance measurements were carried out in a conventional three-electrode configuration after incorporating into OBMorph.…”

The Applications of the Heterodyne Interferoemetry

“…There are many methods [9][10][11][12][31][32][33][34][35][36][37][38][39][40] can determine those factors, most popular method is ellipsometer [9][10][11][12]. Recently, these factors can be obtained by heterodyne interferometer.…”

“…Optical interferometry is widely used in many precision measurements such as displacement [1,2], vibration [3,4], surface roughness [5,6], and optical properties [7][8][9][10][11][12][13][14] of the object. For example, holographic interferomter [1][2][3] can be used to measure the surface topography of the rigid object.…”

“…That means the refractive index of the testing sample will be limit by the hemisphere prism installed in the refractometer. The ellipsometer [9][10][11][12] is widely used to measure the thickness and refractive index of film or bulk materials. Typically, the optical components of ellipsometer included polarizer, compensator, sample, and analyzer.…”

Circularly polarized light detector based on ferromagnet/semiconductor junctions

“…As exemplified by the chiral resolution in synthetic chemistry 7) , circularly polarized ellipsometry-based tomography 8,9) , and quantum optical computing and information processing 3,10,11) , CP photons play an important role in some of the optic and photonic applications. It is expected that a monolithic-type detector of CP photons, together with a monolithic-type CP light emitters 12) , would simplify and miniaturize the detection and generation apparatus for circular polarization, and would lead us to the study of new applications: one of such examples is the in-situ detection of optical isomers in a micro-channel, as shown schematically in Fig.…”