Published in Optical Engineering
An approach for measuring fast oscillations of an absolute value of interferometer optical path difference (OPD) has been developed. The principles of frequency-scanning interferometry are utilized for the registration of the interferometer spectral function from which the OPD is calculated. The proposed approach enables one to capture the absolute...
Published in Optical Engineering
Based on the tunable electrical and optical properties of graphene, we propose a tunable dual-band graphene-based metamaterial terahertz (THz) absorber. It successively consists of two layers of graphene-ring arrays and a metal ground plate separated by two dielectric layers. Simulation results indicate that either of the absorber’s two absorption ...
Published in Optical Engineering
Equivalence theory is commonly used by photographers in order to obtain equivalent photographs from cameras based on different sensor formats. A complete mathematical proof of equivalence theory that is valid for compound photographic lenses with any chosen pupil magnification is presented. An expression for a correction to the conventional equival...
Published in Optical Engineering
Shadow moiré fringes have a complex intensity distribution, which makes the existing arcsine function or arccosine function that is used in random phase-shift extraction algorithms unstable in applications. We propose a high-precision algorithm to determine the random phase shift in a robust way. The idea consists of constructing three consecutive ...
Published in Optical Engineering
A temperature compensated three-directional double-loop strain sensor is proposed. A normal fiber Bragg grating (FBG) sensor is surface glued on double-loop titanium alloy substrate, which can improve measurement range of the sensor. The three-directional sensor is made up of three double-loop sensors in three directions so that a two-dimensional s...
Published in Optical Engineering
Recently, it has become necessary to detect cracks in structures such as buildings and bridges. Phase-shifting digital holography is one valuable method that can be used to measure the strain distribution on the surface of an object. However, to simplify the optical measurement setup, more compact equipment is required. An interferometric trigger m...
Published in Optical Engineering
The laser is an important component of the resonator fiber-optic gyroscope (RFOG) and the optical noise of the laser severely limits the performance of the RFOG system. The mathematical model which presents the effect of the intensity noise on the RFOG is established. In order to verify the correctness of the model, an acousto-optic modulator is in...
Published in Optical Engineering
An in-line optical fiber Mach–Zehnder interferometric (MZI) sensor is proposed and experimentally demonstrated for magnetic field measurement. The fabrication mechanism of the optical fiber microstructures by CO2 laser is described in detail. The sensor with symmetrical structure is fabricated by splicing a 7-mm length of seven-core fiber and two f...
Published in Optical Engineering
Based on creep-induced deformation of a polyvinyl chloride (PVC) gel in an electric field, a Fresnel zone plate (FZP) is fabricated. The employed electrode is constructed with a series of concentric zones, and the soft PVC gel coated on the electrode forms a flat membrane. By applying a DC voltage to the electrode, electrons are injected to the PVC...
Published in Optical Engineering
The characterization of SiGe diode-connected heterojunction bipolar transistors (HBTs) through measurements of two-circuit configurations is presented. Characterization is done to understand the behavior of these diodes for near-infrared detecting applications at room temperature and 77 K. The two configurations that are considered differ; the firs...
