Optical zoom system is a key element in many optical devices such as cameras and video cameras. It is a long-term goal to realize miniaturization of optical zoom system and increase the zoom ratio of the system. In this paper, a three-liquid self-zoom lens is developed, which has the self-zoom function under the action of applied voltage. Therefore, the lens element itself can be used as a simple optical zoom system. The self-zoom function of the system is verified by the Gaussian optical theory and Zemax simulation. The results show that the focal length range of the system is 378-424 mm, and the zoom ratio is 1.217, which achieves the expected target and has a certain reference value for the research of optical zoom systems.

In order to realize the analysis of the initial value of the variable focal power lens(VFPLs) for the zoom system, the aberration of the VFPLs for the zoom system is analyzed. The primary aberration of the zoom system is determined according to the aperture angle of the beam and the height of the object. The relation between the shape parameters and the magnification of the zoom system is analyzed by using the theory of thin transparent image difference, and the initial value of the zoom system is determined by using the minimum value of spherical aberration and coma. The results show that the calculation equation of the magnification and shape parameters of the zoom system can reach the requirements of determining the initial value of the VFPLs in the zoom system, and it is simple, fast and reliable, which provides a reference for further computer correction of the aberration of the zoom system.

In order to improve the preparation quality of monolayer (ML) tungsten selenide (WSe2). We improve the traditional chemical vapor deposition (CVD) method. ML WSe2 film is prepared by introducing a trolley to construct a growth method that can regulate the deposition area, precisely control the growth time, and achieve rapid temperature reduction. Optical microscope and atomic force microscope are used to characterize the size, fluorescence intensity and morphology of the prepared materials, which proved that a high-quality ML WSe2 film is successfully prepared by the push-pull trolley method. The large-area, high-quality, single-layer WSe2 film can be stably prepared by the trolley based method, which provides an important basis for its future application in the information, energy, and biology frontier fields.

It is well known that femtosecond laser filamentation can be initiated by ultrashort laser pulses in condensed media. The supercontinuum generation was studied with the generated white light ranging from 400 to 950 nm in nanoparticle-doped water. We summarized the motion of the generated bubbles. The velocity of the bubble reached 0.16 m/s, and it means that the water flow can also reach the corresponding speed. This could be a potential technique for microfluidic chip fabrications.

The determination of moisture content in potato leaves using spectral technique was studied in this paper. Spectral signatures of one hundred and ten fresh potato leaves in the wavelengths of 900-2100 nm were acquired by the spectral device. Then, the moisture content was measured by the drying method.The near-infrared reflection spectrum information was corrected by the Savitzky-Golay (SG) smoothing, multiplicative scatter correction (MSC) and standard normal variable (SNV) correction. The quantitative relationship between spectral information and moisture was built by partial least squares regression (PLSR) and BP neural network respectively. The effective wavelength was identified by regression coefficients (RC) and corrected by three pretreatment methods. Then the PLSR and BP neural network models were built respectively. The results showed that for full wavelengths-based models, MSC-BP model performed the best with the coefficient of determination (R2) of 0.9791 and the root mean square error (RMSE) of 0.3723 in the prediction. For selected wavelengths-based models, it was the SG-BP model that obtained the optimal result. The R2 value was 0.965 8 and the RMSE value was 0.475 9 in the prediction. This experiment verified that the prediction results of the model established by combining the characteristic band with BP neural network were not different from those of the model established by the whole band, so it could greatly reduce the computation and improve the efficiency.

At present, there is a problem of uneven brightness of the out-coupling grating of the holographic waveguide display system in the field of AR. In this paper, a holographic grating with a diffractive efficiency gradient is designed and fabricated to further improve the brightness uniformity of out-coupling grating in the display optical path. Based on theoretical analysis and discussion, this paper proposes a scheme of moving the shutter to realize the change of the exposure time of the holographic plate by divisional region, so that the diffraction efficiency of the obtained holographic grating has a gradual characteristicThe final experimental results are studied and analyzed. The results show that the uniformity of the exit pupil brightness of the coupled grating in the system increases from 28.57% to 57.14%. Therefore, the photographic optical path and exposure method of the holographic optical element used in this paper can effectively improve the uniformity of the exit pupil brightness of the holographic waveguide coupling out grating.

The visual odometry uses visual cues to estimate the pose parameters of the camera motion and localize an agent. Existing visual odometry employs a complex process including feature extraction, feature matching/tracking, and motion estimation. The processing is complicated. This paper presents an end-to-end monocular visual odometry by using convolution neural network (CNN). The method modifies a classification CNN into a sequential inter-frame variation CNN. In virtue of the deep learning technique, the method extracts the global inter-frame variation feature of video images, and outputs pose parameters through three full-connection convolution layers. It has been tested in the public KITTI database. The experimental results show the proposed Deep-CNN-VO model can estimate the motion trajectory of the camera and the feasibility of the method is proved. On the basis of simplifying the complex model, the accuracy is improved compared with the traditional visual odometry system.

Two-dimensional (2D) transition-metal dichalcogenides have attracted much attention because of its small size and direct band gap properties, which can be used as an excellent luminescent medium in micro-nano optical structures. The 2D materials based micro-nano structure, such as optical microcavity and micro-nano sensor, are always obtained by the transferring method. However, contaminations and damage to the materials are hard to be avoided during material transfer, which will greatly affect the functionality of the structure. Direct growth of the 2D material on the micro/nano structure can solve this problem. WSe2 is deposited directly on the surface of 6 μm-diameter SiO2 sphere cavities by chemical vapor deposition (CVD) method, the compositional characterization of the materials on the microspheres proved that WSe2 was grown on the microspheres, and it was proved that it is feasible to deposit two-dimensional materials on the curved surface by chemical vapor deposition. This 2D material based cavity is expected to be good candidates in high-performance optical sensors and light source devices. It also provides a basis for in-depth study of the exciton characteristics of two-dimensional materials in the high-strain condition induced by curved surface.

In this paper, we built the optical systems of three age-related human eye models, including the Navarro, the Atchison and the Zapata-Díaz models using the Zemax software, and analyzed the changes of image quality at different ages and different accommodation status. Simulations included retinal image quality evaluations at both 3 mm and 5 mm entrance pupil diameters (EPDs). Accommodation amplitudes ranging from 0.5 D to 2 D were measured in the Navarro and Zapata-Díaz models. Image quality worsens with age or EPD in all the age-related eye models. Besides of the good imaging quality, the Atchison model eye is also consistent with clinical results. Navarro model performs better during accommodation. The results of this study can be valuable for the eye model selection in the field of optometry.

Single-walled carbon nanotubes are a new generation of transparent conductive materials. They have many special optical, electrical, and mechanical properties and can be widely used in many fields. In this paper, single-walled carbon nanotubes were prepared by arc method and further integrated with polymethyl methacrylate (PMMA) tubular waveguides. The terahertz transmission spectral characteristics of single-walled carbon nanotubes based on tubular waveguides were experimentally and simulated. The results show that single-walled carbon nanotubes can enhance the terahertz resonance of a tubular waveguide and increase the resonance extinction ratio effectively. Graphene and carbon black have little effect on the terahertz transmission spectrum of the tubular waveguide. Single-wall carbon nanotube-assisted integrated devices can be widely used in future terahertz science and technology.

Near-infrared spectroscopy was used to study the mixed solution of transgenic oil/non-transgenic oil. The acquired original spectra were pretreated with multiple scattering correction (MSC), first-order derivative (FD), moving window smoothing (MWS) and savitzky-golay smoothing first-order derivative (SG1). The effects of different pretreatment methods on the discriminant analysis of transgenic oil/non-transgenic oil support vector machine (SVM) modeling were compared. The model after MSC pretreated has the best prediction effect, and the accuracy rate is 91.6%. In order to further improve the accuracy and stability of the model, the successive projections algorithm (SPA) is used to select the characteristic band. We input the 15 feature wavelengths after SPA selection into the SVM, and the prediction accuracy is 98.3%. The experimental results show that the near-infrared transmission spectrum combined with stoichiometry can achieve rapid and non-destructive detection of transgenic oil/non-transgenic oil, not only suitable for the identification of pure genetically modified oils, but also for the identification of non-transgenic oils that are mixed with genetically modified oils.

Two-photon (2P) stimulated emission depletion (STED) composite microscope has the potential to be widely used in clinical diagnosis of neurological diseases and brain science research. In this paper, based on the research of multi wavelengths selection, multi beams combination, key technical indexes testing research, the integrated development of composite microscopy prototype system and composite imaging are completed. The composite microscope can image the fluorescent labeled samples, which has the functions of red-green two-color fluorescence imaging, 2P green fluorescence imaging and STED super-resolution green fluorescence imaging. In terms of index, the imaging depth is 700 μm, and the resolution of STED imaging is better than 60 nm.

Aiming at the problems of limited measurement range, low accuracy and Abbe error in multi-degree-of-freedom measurement technology, a large-travel, high-precision, traceable, four- degree-of-freedom simultaneous measurement of heterodyne interferometry was proposed. The miniaturized 532 nm solid-state laser with iodine frequency stability was used, and the optical fiber coupling technology was used to spatially separate the dual-frequency light. Differential wavefront sensing technology realized the simultaneous detection of displacement, pitch and yaw, and wedge prisms are used to measure the change in straightness. The measuring instrument can suppress the non-linear error caused by dual-frequency optical aliasing, and realize the measurement with a travel range of 6 m, a displacement resolution of 0.13 nm, a pitch and yaw angle resolution of 0.026 μrad, and a straightness resolution of 14.88 nm. The measurement results are traceable.

In order to improve the ranging accuracy, the internal timing module of the laser rangefinder is studied. The factors affecting the ranging accuracy of the laser rangefinder are analyzed. An external delay chain chip is used as the delay line to design and make a timing generator based on the field programmable gate array (FPGA) development board. The test results show that the designed timing generator can achieve 11 ps timing resolution and a maximum data rate of 600 Mbit/s, which has achieved the expected target.