We demonstrate the existence of two types of dark gap solitary waves-the dark gap solitons and the dark gap soliton clusters-in Bose-Einstein condensates trapped in a bichromatic optical superlattice with cubic-quintic nonlinearities. The background of these dark soliton families is different from the one in a common monochromatic linear lattice; namely, the background in our model is composed of two types of Gaussian-like pulses, whereas in the monochromatic linear lattice, it is composed of only one type of Gaussian-like pulses. Such a special background of dark soliton families is convenient for the manipulation of solitons by the parameters of bichromatic and chemical potentials.
View Article and Find Full Text PDFWe present a single-shot wavelength-multiplexing technique for off-axis digital holography based on a spectral filter. Only a spectral filter is inserted between beam splitter and mirror in reflection off-axis digital holography (RODH). The spectral filter can transmit a well-defined wavelength band of light, while reject other unwanted radiation.
View Article and Find Full Text PDFNanomaterials (Basel)
August 2021
We propose a hyperbolic metamaterial-based surface plasmon resonance (HMM-SPR) sensor by composing a few pairs of alternating silver (Ag) and zinc oxide (ZnO) layers. Aiming to achieve the best design for the sensor, the dependence of the sensitivity on the incidence angle, the thickness of the alternating layer and the metal filling fraction are explored comprehensively. We find that the proposed HMM-SPR sensor achieves an average sensitivity of 34,800 nm per refractive index unit (RIU) and a figure of merit (FOM) of 470.
View Article and Find Full Text PDFWe present a simple and effective compensation method for the off-axis tilt in common-path digital holographic microscopy (CPDHM) by introducing a rotating operation on the hologram. The proposed method mainly requires a digital reference hologram (DRH), which is a rotated version of the original one; it is assumed to be easy to obtain by rotating the specimen's hologram 180°. In this way, the off-axis tilt could be removed by subtracting the retrieved phase of DRH from the retrieved phase of the original hologram, but without any complex spectrum centering judgment, fitting procedures, or prior knowledge of the system.
View Article and Find Full Text PDFIn a digital holographic microscopy (DHM) system, different microscope objectives (MOs) will introduce different phase distortions and thus lead to measurement errors. To address this problem, we present a simple and flexible method to compensate all phase distortions by introducing an electrically tunable lens (ETL) in the reference arm for a DHM system with multiple MOs. By exactly controlling the external currents of the ETL, we can change the reference wave front to match the wave front introduced by different MOs without complex alignment or additional numerical postprocessing manipulations.
View Article and Find Full Text PDFFringe projection 3D microcopy (FP-3DM) plays an increasingly important role in micro manufacturing and measurement. In recent decades, research on FP-3DM has made considerable progress. Nevertheless, some disadvantages arising from the limited depth of field, local specular reflection and occlusion still exist and need to be further addressed.
View Article and Find Full Text PDFIn phase-measuring profilometry, the lens distortion of commercial projectors may introduce additional bending carrier phase and thus lead to measurement errors. To address this problem, this paper presents an adaptive fringe projection technique in which the carrier phase in the projected fringe patterns is modified according to the projector distortion. After projecting these adaptive fringe patterns, the bending carrier phase induced by the projector distortion is eliminated.
View Article and Find Full Text PDFTo increase the measurement range of 3D microscopy, Scheimpflug adjustment, in which the imaging plane is tilted with respect to the telecentric lens plane, is often employed. However, the inclined imaging plane will introduce certain distortion to the captured image, which further affects the accuracy of the 3D reconstruction result. In this paper, a distortion model was derived based on the geometric optics theory.
View Article and Find Full Text PDF