Search

Aiming at the method of indoor calibration of a transmission visibility meter has not been established; a new calibration method by measuring the luminous transmittance of attenuator piece was established. Based on the high homogeneity stability lighting and the multi-spectral transmittance analysis technique, a calibration system of the transmission visibility meter by measuring the luminous transmittance of the attenuator piece was designed. The experiment was designed by measuring the luminous transmittance with the range of 0.2–99.2% of a series of calibrated attenuators and the visibility in the range of 40 m to 20 km, then the luminous transmittance errors, the meteorological optical range (MOR) errors and their uncertainty were obtained. The result showed that the luminous transmission error was within ±0.18%, which satisfied the calibration requirement for transmission visibility meter transmittance; the MOR calibration error met the accuracy requirements of the International Civil Aviation Organisation for visibility measurement; this work will have guiding significance in establishing a calibration procedure for the transmission visibility meter.

In traditional faint starlight simulators, stray light interference prevents the accurate magnitude simulation of weak stars. In this study, we propose a method to optimise the parameters of the optical engine to suppress stray light. The results from a simulated model of the system’s point source transmittance (PST) and incident off-axis and azimuth angles show the optimised design to have a PST value that is nearly five times higher than that of a traditional system. The performance of the optimised system was evaluated using the detector’s signal-to-noise ratio (SNR) and magnitude. Moreover, polarisation aberration was used to derive the optimised index, and experimental results show the optimised simulation error of the new system to be less than 0.1 Mi, thus confirming the accuracy of our theoretical research.

An optical engine (OE) for stellar simulation systems with low extinction ratios (ERs) is proposed. This engine combines two orthogonal polarizers with a non-polarizing beam splitter to suppress the leakage of dark silicon-based liquid crystals (LCOS) in traditional systems. In this paper, a method to calculate the ER based on vector ray tracing is used. The new optical engine (OE) is demonstrated to have lower ERs than traditional systems. The calculations show that the maximum ER is 5 × 10−5 in the range of ± 8 ° , which is much lower than the ERs of traditional optical engines of 2.5 × 10−2 . It reduces the ER by three orders of magnitude. The experimental results show that the new OE improves the ERs by 92.68% compared with the traditional system.

The optical engine (OE) is the core component of a projection optical system. The extinction ratio (EO) directly affects imaging contrast. A three-dimensional EO calculation and analysis method, based on traditional EO theory, is proposed to obtain the optimal incidence angle range and solve the problem of ignoring the oblique incidence’s influence on the EO’s existing research process. The method is simulated and verified by LightTools. Results show that, when the incident azimuth half angle is less than 4.7 ∘ , and the spatial half angle is less than 180 ∘ , the EO is 0.016, distribution is uniform, and the stray light is effectively suppressed.

Aiming at lower irradiation uniformity of the traditional solar simulator,an optical integrator is designed which can effectively improve the irradiation uniformity of sun simulator.The composition and working principle of optical integrator is introduced,optical optimization design technology of optical integrator is described,optical and mechanical structure of the optical integrator is designed reasonably,and the ansys software is used for thermal analysis of the machine structure.Finally,lightTools software is used to be simulating for solar simulator.The results show that: after using the optical integrator,irradiation non uniformity of the sun simulator is markedly improved,irradiation non uniformity in 60 mm range is less than ±1%,and in(60~200) mm is less than ±2%,instability is better than ±1%/h,which agree with the test data and can meet the requirements of high-precision.

A diode-pumped high-power continuous-wave (cw) dual-wavelength Yb:CaNb2O6 lasers at 1003 nm and 1038 nm is reported. By using an end-pumped structure and employing a 978 nm diode-laser as the pump source. As a result, the total output power of 803 mW dual-wavelength lasers at 1003 nm and 1038 nm is obtained at an incident pump power of 17.8 W. Furthermore, intracavity sum-frequency mixing at 1003 and 1038 nm was then realized in a LBO crystal to reach the green range. We obtained a total cw output power of 94 mW at 510 nm.

To satisfy meteorological observation and measurement needs, the general composition and optical system of a high precision solar simulator is designed to the calibration requirements for high precision solar radiation meters. Given the light source characteristics of the solar simulator, an ellipsoid convergent lens is employed so as to enhance the energy utilization ratio of the light source; the optical integrator and the collimator are optimized in design with the aid of Zemax software, resulting in improved irradiation uniformity and output beam alignment. The test results suggest that, at a working distance of 1000 mm and with an effective irradiation aperture of O60 mm, the solar simulator generates an irradiance of up to 1222 W/m2 and the irradiation nonuniformity is 0.83%, satisfying the requirements for meteorological observation and measurement.

To solve the bottleneck caused by the fact that solar simulators are unable to simulate a solar collimation angle of 32′ and an irradiance of one solar constant at the same time, we designed a new type of optical system for solar simulators. Five major design aspects of the optical system are addressed: the hybrid condenser, collimation lens, field stop, optimization of the optical integrator and the effects on the non-uniformity when the projector lens is defocused. The results show that the solar simulator described in this paper can realize a solar angle of 32′ and an irradiance of one solar constant. Meanwhile, the non-uniformity is less than ±1.34% when the irradiation area has a diameter that is no more than 100 mm and in the 100–300 mm diameter range is less than ±3.8%.

In order to improve simulation precision of solar simulator, this paper researched general design scheme of optical system. First of all, this paper discussed optimization techniques for focusing system, optical integrator, collimating system, and which aberrations influenced the uniformity of optical integrator; Secondly, analysis of defocus effect for integrator projector lens and put forward optimal defocus distance formula, then using ZEMAX to design collimating optical system, and simulated the system in LightTools; Finally, tested solar simulator, the results show that: it can simulated one solar constant, irradiation range reached Φ200mm, working distance is 1000mm, irradiation non uniformity in 60mm range is less than ±1%, and in (60-200) mm is less than ± 2%, instability is better than ± 1%/h.