Search

An optical refractive index sensor with a metal-multilayer dielectric film structure based on Fano resonance (FR) is proposed to solve the low sensitivity of traditional surface plasmon resonance (SPR) sensors. The sensor’s performance can be optimized, and a plasmon-induced reflection (PIR) of incident light can also be achieved by adjusting the thickness of each layer. Through an innovative experimental design, the practical measurement phase sensitivity of the sensor based on FR is achieved for the first time, which provides a reference for subsequent theoretical research and experimental preparation. The wavelength sensitivity and the phase sensitivity can reach 345 nm/RIU and $4.00\times 10^{{5}\circ }$ /RIU, which experimentally proves that phase interrogation has higher sensitivity than traditional wavelength interrogation. The sensor can be a promising candidate for exploiting novel plasmonic sensors with ultrahigh sensitivity and resolution for biosensing applications. [ABSTRACT FROM AUTHOR]

Low frequency primary calibrations of condenser microphones are the basis of accurate measurement of low frequency sound and infrasound. Prior arts on the primary phase calibrations differ greatly, simultaneous primary amplitude and phase calibrations are rarely seen. Recently, two infrasonic sensitivity models of condenser microphones based on the pistonphone technique, for the vent immersed in sound field and outside are derived. The relevant models can explicitly characterize the influence of pistonphone, microphone and environment on the voltage output and sensitivity of the microphone. On this basis, simultaneous primary amplitude and phase calibration tests are evaluable. Based on adequate performance tests of the designed laser pistonphone, this paper carries out in-depth primary microphone calibrations. The calibrated infrasonic amplitude and phase sensitivities are in good agreement with theoretical results, thus proves their values to reveal and quantify the influence of various factors on the calibration results based on the pistonphone technique. [ABSTRACT FROM AUTHOR]

Magnetoelastic sensors for the detection of low-frequency and low-amplitude magnetic fields are in the focus of research for more than 30 years. In order to minimize the limit of detection (LOD) of such sensor systems, it is of high importance to understand and to be able to quantify the relevant noise sources. In this contribution, cantilever-type electromechanical and magnetoelastic resonators, respectively, are comprehensively investigated and mathematically described not only with regard to their phase sensitivity but especially to the extent of the sensor-intrinsic phase noise. Both measurements and calculations reveal that the fundamental LOD is limited by additive phase noise due to thermal-mechanical noise of the resonator, i.e. by thermally induced random vibrations of the cantilever, and by thermal-electrical noise of the piezoelectric material. However, due to losses in the magnetic material parametric flicker phase noise arises, limiting the overall performance. In particular, it is shown that the LOD is virtually independent of the magnetic sensitivity but is solely determined by the magnetic losses. Instead of the sensitivity, the magnetic losses, represented by the material’s effective complex permeability, should be considered as the most important parameter for the further improvement of such sensors in the future. This implication is not only valid for magnetoelastic cantilevers but also applies to any type of magnetoelastic resonator. [2020-0219] [ABSTRACT FROM AUTHOR]

We demonstrate the characterization of optical sources with high sensitivity, high temporal resolution, and phase sensitivity using linear optical sampling. Eye diagrams and constellation diagrams are reconstructed using the interference of the source under test with a train of sampling pulses. This concept is implemented using a waveguide optical hybrid, which splits and recombines the sources and adjusts the phase between the recombined signals to provide optimal detection. This diagnostic is used to characterize on-off keyed (OOK) waveforms at rates up to 640 Gb/s and various phase-shift keyed (PSK) signals at 10 and 40 Gb/s. [ABSTRACT FROM PUBLISHER]

Nonspecific surface binding of small protein molecules presents a major obstacle to surface biosensing techniques attempting to detect very low concentrations (< 1 pg/mm2) of large biological objects such as cells and bacteria. A new method for selective desensitization of a polarimetric waveguide interferometer eliminates the background noise from nonspecific surface binding. We demonstrate the ability to tune the phase sensitivity of a waveguide interferometer as a function of the distance of the biological or chemical analyte from the waveguide surface. This makes possible a sensor that has zero sensitivity at a particular distance where nonspecific surface binding occurs without significantly reducing the sensitivity to target larger biological species [ABSTRACT FROM PUBLISHER]

A novel method using cost-effective electronic equalizer is proposed to mitigate the impairment from timing misalignment (TM) between the pulse carver and data modulator in return-to-zero (RZ) and carrier-suppressed RZ systems. Simulations show that maximum likelihood sequence equalizer (MLSE) significantly reduces TM-induced power penalty and sampling phase sensitivity. Simultaneous mitigation of both TM-induced distortion and polarization-mode dispersion using a single MLSE is also demonstrated. [ABSTRACT FROM PUBLISHER]

We propose and experimentally demonstrate a novel fiber sensor array based on a Sagnac interferometer with very simple electronic signal processing. A stable quadrature phase bias was obtained using a phase modulator, and the polarization-induced signal fading was suppressed by using a depolarizer and a broad-band source. A phase sensitivity of about 4.0 μradrms/√Hz at 5 kHz was obtained using a two-sensor array [ABSTRACT FROM PUBLISHER]

An $X$ -band (8–12 GHz) dual channel microwave phase detector is investigated. This phase detector is based on measuring the output power by microelectromechanical systems sensors. The device is fabricated by GaAs monolithic microwave integrated circuit technology. Experiments show that this dual channel detector can detect a phase difference in entire cycle from −180° to +180°. Its frequency response reaches maximum at 9.6 GHz. By cascading a capacitive power sensor, the dynamic range of this system has been expanded up to 2 W and the phase sensitivity can reach to 58.91~\mu \text{V/deg} . [ABSTRACT FROM PUBLISHER]