Optical Axis Parallel Research Articles

Online Optical Axis Parallelism Measurement Method for Continuous Zoom Camera Based on High-Precision Spot Center Positioning Algorithm

Ensuring precise alignment of the optical axis is critical for achieving high-quality imaging in continuous zoom cameras. However, existing methods for measuring optical axis parallelism often lack accuracy and fail to assess parallelism across the entire focal range. This study introduces an online measurement method designed to address these limitations by incorporating two enhancements. First, image processing methodologies enable sub-pixel-level extraction of the spot center, achieved through improved morphological processing and the incorporation of an edge tracing algorithm. Second, measurement software developed using Qt Creator can output real-time data on optical axis parallelism across the full focal range post-measurement. This software features a multi-threaded architecture that facilitates the concurrent execution of image acquisition, data processing, and serial communication. Experimental results derived from simulations and real data indicate that the maximum average error in extracting the center of the spot is 0.13 pixels. The proposed system provides critical data for optical axis calibration during camera adjustment and inspection.

WITHDRAWN: Measurement and calibration of optical instruments based on metrological calibration method and artificial neural network

At present, compared with foreign advanced optical instrument technology, the detection rate and accuracy of Chinese optical instrument system are relatively low. Therefore, it is necessary to update and discuss the measurement and calibration of existing optical instruments. The objective of this paper is to design a new calibration method by combining the traditional measurement calibration method with computer technology. This paper first studied the artificial neural network related knowledge. Then, the measurement parameters of the optical instrument are determined from three aspects: spectral resolution, optical axis magnification and optical axis parallelism measurement error. Then, based on the artificial neural network model and the measurement parameters of optical instruments, the measurement and calibration model of optical instruments is constructed, the measurement and calibration process of optical instruments is analyzed, and the systematic research method is obtained. The system model is combined with the spectral phase recovery method to complete the optical instrument testing and calibration experiments. Finally, the calibration results are tested with the center of mass method. By analyzing the experimental results of this measurement and calibration, it can be seen that updating the measurement and metrological calibration method of optical instruments can improve precision of optical instruments, and improve the application efficiency of optical instruments and promote the development of optical industry. So that, in this paper, the artificial neural network technology is introduced into the field of optical instrument testing as to achieve the calibration of optical instruments. Data AvailabilityData will be made available on request.

Orientation-Controlled Anisotropy in Single Crystals of Quasi-1D BaTiS3

Low-dimensional materials with chain-like (one-dimensional) or layered (twodimensional) structures are of significant interest due to their anisotropic electrical, optical, thermal properties. One material with chain-like structure, BaTiS3 (BTS), was recently shown to possess giant in-plane optical anisotropy and glass-like thermal conductivity. To understand the origin of these effects, it is necessary to fully characterize the optical, thermal, and electronic anisotropy of BTS. To this end, BTS crystals with different orientations (aand c-axis orientations) were grown by chemical vapor transport. X-ray absorption spectroscopy (XAS) was used to characterize the local structure and electronic anisotropy of BTS. Fourier transform infrared (FTIR) reflection/transmission spectra show a large inplane optical anisotropy in the a-oriented crystals, while the c-axis oriented crystals were nearly isotropic in-plane. BTS platelet crystals are promising uniaxial materials for IR optics with their optic axis parallel to the c-axis. The thermal conductivity measurements revealed a thermal anisotropy of ~4.5 between the c- and a-axis. Time-domain Brillouin scattering showed that the longitudinal sound speed along the two axes is nearly the same suggesting that the thermal anisotropy is a result of different phonon scattering rates.

Renormalization of the electron g factor in the degenerate two-dimensional electron gas of ZnSe- and CdTe-based quantum wells

The effective electron $g$ factor, ${g}_{\text{eff}}$, is measured in a two-dimensional electron gas (2DEG) in modulation-doped ZnSe- and CdTe-based quantum wells by means of time-resolved pump-probe Kerr rotation. The measurements are performed in magnetic fields applied in the Voigt geometry, i.e., normal to the optical axis parallel to the quantum well plane, in the field range $0.05--6$ T at temperatures $1.8--50\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. The ${g}_{\text{eff}}$ absolute value considerably increases with increasing electron density ${n}_{e}$. ${g}_{\text{eff}}$ changes in the ZnSe-based QWs from $+1.1$ to $+1.9$ in the ${n}_{e}$ range $3\ifmmode\times\else\texttimes\fi{}{10}^{10}\ensuremath{-}1.4\ifmmode\times\else\texttimes\fi{}{10}^{12}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$ and in the CdTe-based QWs from $\ensuremath{-}1.55$ down to $\ensuremath{-}1.76$ in the ${n}_{e}$ range $5\ifmmode\times\else\texttimes\fi{}{10}^{9}\ensuremath{-}3\ifmmode\times\else\texttimes\fi{}{10}^{11}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$. The modification of ${g}_{\text{eff}}$ reduces with increasing magnetic field, increasing temperature of lattice and 2DEG, the latter achieved by a higher photoexcitation density. A theoretical model is developed that considers the renormalization of the spin-orbit coupling constant of the two-dimensional electrons by the electron-electron interaction and takes into account corrections to the electron-electron interaction in the Hubbard form. The model results are in good agreement with experimental data.

Efficient framework for the examination of the field of view sensitivity of a field-widened birefringent interferometer.

An efficient approach is presented that allows the field of view sensitivities of a field-widened birefringent interferometer constructed from several stacked birefringent slabs to be examined. The approach utilizes a Jones matrix framework that is valid for birefringent slabs that have their optic axis parallel to the surface of the slab. It neglects Fresnel effects and multiple reflections, but accounts for birefringent splitting and does not neglect higher-order angular effects. The simplified approach allows the angular sensitivity of the optical path difference near the field-widened configuration to be examined in the presence of misalignment and mismatches between the components. Understanding these effects is critical to developing wide-field interferometers that can be utilized for imaging purposes. Here, we present the developed framework and apply it to examine the field of view effects of a three-element field-widened static birefringent interferometer that is being developed for the measurement of upper atmospheric winds. We examine the sensitivity of the device to rotational misalignment, mismatches, and wavelength shifts. Comparisons among the modeled interference fringes, output from Zemax optical design software, and lab observations are used to validate the approach. It is also shown that the approach accurately simulates parasitic fringes associated with unwanted coupling between extraordinary and ordinary waves at the interfaces.

The consistent of laser pointing and theodolite tracking

The distance between the laser optical axis and the tracking optical axis of the theodolite (axis shift) and the parallelism error of the optical axis cause the tracking position of the theodolite to be inconsistent with the laser pointing position.The analysis of the influence of off-axis and parallelism errors shows that a large amount of shift and parallelism errors will lead to inconsistencies between the laser pointing and the theodolite tracking pointing, which in turn leads to an increase in the blind zone of the laser ranging, a decrease in the operating distance and the accuracy of target positioning. A dynamic correction method for laser pointing based on bias tracking is proposed. By keeping the target always at the center of the laser beam and keeping the laser ranging position consistent with the theodolite tracking and locking position, it effectively solves the effect of laser edge energy drop on the operating distance. For a certain type of theodolite, the blind spot of the target can be reduced from 1 km to 82 m. At the same time, in view of the problem that the bias tracking algorithm needs the initial distance of the target to start the bias tracking, a one-dimensional search method for the target with unknown initial distance is proposed, which greatly improves the search efficiency of the target with unknown initial distance. The method in this paper solves the problem of the consistency between the tracking position of the theodolite and the pointing position of the laser, and greatly reduces the limitation on the shift and parallelism of the laser optical axis and the theodolite tracking optical axis

Plasmon Polaritons with Uniquely Long Free Path

It is shown that the free path of plasmon polaritons propagating along the interface between a metal and a crystal may be greatly increased (up to several orders of magnitude) by the choice of a certain crystal orientation that provides complete delocalization of the polaritons. As an example, a theory is developed for the interface between a metal and a uniaxial crystal with its optical axis parallel to the interface, both considered as semi-infinite media.

基于干涉条纹的光轴平行性校准方法

基于干涉条纹的光轴平行性校准方法

Form and magnetic birefringence in undulated Permalloy/PET films.

We report the measurement of form and magnetic birefringence in Permalloy (Ni80Fe20) films grown on rippled Poly(Ethylene Terephthalate), PET, substrates. Prior to Permalloy deposition, Laser Induced Periodic Surface Structures (LIPSS) were generated on the polymeric substrate by a nanosecond laser beam, developing an ordered rippled nanostructure. Due to their high transparency factor, we could investigate the behavior of linear polarized light transmitting at normal incidence on Permalloy/PET sample. The results show the existence of an optical axis parallel to the ripples direction, which yields an strong form birefringence effect arising from the laser patterning. Concerning the Permalloy thin film, the study of its in-plane magnetization was carried out measuring the Voigt magnetooptical effect. The obtained data in our samples reveal the appearance of two different mechanisms to reverse the magnetization, as the external magnetic field is parallel or perpendicular to the ripples direction. Accordingly, the transmitted light shows a magnetic birefringence depending on the relative orientation between the ripple direction, i.e. the optical axis of the LIPSS, and the in-plane magnetization of the Permalloy film.

Calibration of focusing lens artifacts in a dual rotating-compensator Mueller matrix ellipsometer.

A focusing lens consisting of two or more elements is widely used in ellipsometers for spatial resolution. In a typical ellipsometer layout, a lens is placed before the sample to focus light emerging to the sample, and another after the sample to collect the scattered light from the sample. Accurately calibrating the artifacts of the focusing lens is of great importance. In this paper, a method to improve calibration accuracy is proposed. A general analytical model is deduced to describe the artifacts of the focusing lens. This model can be applied to a system model of a dual rotating-compensator Mueller matrix ellipsometer. By adding a uniaxial crystal to calibration samples, with its optical axis neither parallel nor perpendicular to the incident plane, we can better separate artifacts from the lens before and after the sample. The system model also includes depolarization effects due to a finite numerical aperture (NA) that is related to the focusing lens. Similar effects due to the finite spectral bandwidth are also considered. Our simulation's results have validated the proposed method.

Synthesis of full Poincaré beams by means of uniaxial crystals

A simple optical system is proposed to generate full-Poincaré beams (FPBs), i.e. beams presenting all possible states of (total) polarization across their transverse section. The method consists in focusing a uniformly polarized laser beam onto a uniaxial crystal having its optic axis parallel to the propagation axis of the impinging beam. A simple approximated model is used to obtain the analytical expression of the beam polarization at the output of the crystal. The output beam is then proved to be a FPB. By changing the polarization state of the input field, full-Poincaré beams are still obtained, but presenting different distributions of the polarization state across the beam section. Experimental results are reported, showing an excellent agreement with the theoretical predictions.

基于双五棱镜组件的大间距光轴平行性检测方法

基于双五棱镜组件的大间距光轴平行性检测方法

Intravital imaging of osteocytes in mouse calvaria using third harmonic generation microscopy.

Osteocytes are the most abundant cell in the bone, and have multiple functions including mechanosensing and regulation of bone remodeling activities. Since osteocytes are embedded in the bone matrix, their inaccessibility makes in vivo studies problematic. Therefore, a non-invasive technique with high spatial resolution is desired. The purpose of this study is to investigate the use of third harmonic generation (THG) microscopy as a noninvasive technique for high-resolution imaging of the lacunar-canalicular network (LCN) in live mice. By performing THG imaging in combination with two- and three-photon fluorescence microscopy, we show that THG signal is produced from the bone-interstitial fluid boundary of the lacuna, while the interstitial fluid-osteocyte cell boundary shows a weaker THG signal. Canaliculi are also readily visualized by THG imaging, with canaliculi oriented at small angles relative to the optical axis exhibiting stronger signal intensity compared to those oriented perpendicular to the optical axis (parallel to the image plane). By measuring forward- versus epi-detected THG signals in thinned versus thick bone samples ex vivo, we found that the epi-collected THG from the LCN of intact bone contains a superposition of backward-directed and backscattered forward-THG. As an example of a biological application, THG was used as a label-free imaging technique to study structural variations in the LCN of live mice deficient in both histone deacetylase 4 and 5 (HDAC4, HDAC5). Three-dimensional analyses were performed and revealed statistically significant differences between the HDAC4/5 double knockout and wild type mice in the number of osteocytes per volume and the number of canaliculi per lacunar surface area. These changes in osteocyte density and dendritic projections occurred without differences in lacunar size. This study demonstrates that THG microscopy imaging of the LCN in live mice enables quantitative analysis of osteocytes in animal models without the use of dyes or physical sectioning.

利用恒星对天文观测系统光轴平行性检校

To satisfy the requirement of field measurement of optical axis parallelism for the ground- based astronomical observation system, a high-precision multi-optical axis parallel calibration system was put forward. For astronomical observation system which contains the imaging spectrometer, a star was used as a point source, and the star image and its spectrum was synchronous acquisition by using the astronomy tracking system. It was not easy to determine the center of field of view in spectral dimension of the imaging spectrometer, and the scheme takes advantage of control system of the equatorial and a small field of view of the imaging spectrometer, so the center of field of view in spectral dimension was calculated by fitting energy of scanning the target star with respect to the scanning position, then the bias of optical axis parallelism between the instrument was calculated by Gaussian fitting. Experimental results show that the standard uncertainty of this measurement can reach 1.52, and the optical measurement system structure is simple, so it meets the need of field optical axis parallel measurement with high precision and high speed between the imaging spectrometer and other imaging instrument.

Optical axis parallelism calibration system of large-scale multi-spectral multi-optical axis

Optical axis parallelism calibration system of large-scale multi-spectral multi-optical axis

Optical axis parallelism adjusting instrument for multichannel photoelectric system

Optical axis parallelism adjusting instrument for multichannel photoelectric system

Beam Propagation Method Calculating Attenuated Total Reflection Spectra to Excite Hybridized Surface Plasmon Polaritons.

Using the beam propagation method, an analytical expression of the reflection spectra of a Kretschmann configuration is derived in order to excite hybridized surface plasmonic polaritons (HSPPs). In this configuration, the cladding is a uniaxial dielectric with the optical axis parallel to the interface. The validity of the analytical expression is confirmed by a finite-difference time-domain algorithm and a reported experimental result, respectively. Based on this expression, the properties and the conditions for excitation of the HSPPs are discussed in detail, with regard to the strongly anisotropic cladding and the weakly anisotropic cladding.

Alignment of optical axis parallelism in multi-axis system

Alignment of optical axis parallelism in multi-axis system

Electro-optically Q-switched 946 nm laser of a composite Nd:YAG crystal

A depolarization phenomenon in an electro-optical crystal in a quasi-three-level 946 nm Nd:YAG laser is observed. A compensation of the thermal effects in electro-optical crystals is achieved by employing a quarter-wave plate, with one optical axis parallel to the laser polarization. This technique allows for the production of an electro-optically Q-switched 946 nm Nd:YAG laser at 1 kHz. A maximum output power of 350 mW at 1 kHz repetition frequency and 11 ns pulse duration are achieved with an output coupler of 10% transmission under the incident pump power of 11.1 W, corresponding to a peak power of ∼32 kW.

Comparative analysis of Dyakonov hybrid surface waves at dielectric–elliptic and dielectric–hyperbolic media interfaces

We comparatively investigate Dyakonov surface waves (DSWs) traveling along the plane interface between a dielectric isotropic medium and a lossless anisotropic uniaxial medium with the optic axis (OA) parallel to the interface, when the principal permittivities of the uniaxial medium are both positive (elliptic medium) and of opposite signs (hyperbolic medium). New insights concerning the DSWs are given by analyzing the behavior of the Poynting vector (PV) components. Thus, singularity points at which the PV of the DSW vanishes can exist at the dielectric–elliptic media interface. The range of angles with respect to the OA, which is determined both for the wave vector and the respective PV, can be larger for the DSWs at the dielectric–hyperbolic media interface. Extremely high values of the wave vector and the PV components of the DSWs can be attained at the dielectric–hyperbolic media interface.