Abstract:A tunable narrowband THz filter with a sub-wavelength array structure based on FDTD simulation is presented. Since the array structure is adjustable in the size range of 16μm to 160μm, its filtering frequency can be tunable in a wide range of 2.5THz to 20THz with a minimum bandwidth down to 0.04THz. With this filter, excellent narrowband filtering is achieved. In addition, the structure can change the THz wave polarization by changing the angle between itself and the THz wave. So it can achieve both narrowband filtering and polarization. Compared with the traditional structures, this structure has the features of simplicity and easy operation. It can improve the resolution of THz imaging systems and is of significance to the future research on THz imaging.

Abstract:Natural lightning is a global phenomenon. If a lightning mapper is onboard a geostationary satellite, it can be used to detect the location, time and strength of the lightning in a global area. Because the function and performance of such a mission are greatly different from those of other optical sensors for earth observation, its instrument should be designed on the basis of new theory and technology. The analysis of the spectral, temporal and spacial characteristics of natural lightning, the understanding of space lightning detection environment and the research on the interaction between natural lightning and its environment are very important for the design optimization of the instrument. For this reason, the design features of a lightning mapper for a geostationary satellite, including signal maximization, background subtraction and onboard data processing, are discussed.

Abstract:According to the make-up of optoelectronic payloads for shipborne Unmanned Aerial Vehicles (UAV), the specifications of optical, infrared and lidar payloads are discussed. Since an optoelectronic sensor is susceptible to the environment under the complicated sea surface atmospheric condition, a field test scheme of an optoelectronic payload for a shipborne UAV is designed. The test scheme includes coastal experiment front arrangement, design of static and dynamic test programs and subsequent processing of test data.

Abstract:The preamplifier circuit in a photoelectric detector can directly affect the signal-to-noise ratio (SNR) of a whole detection system. To improve the detection precision of weak photocurrent, a low noise preamplifier circuit for a photoelectric detector based on a photodiode (in photovoltaic mode) and an operational amplifier is designed. The instability in an I/V conversion circuit due to the parasitic parameters of the photodiode is overcome by using a lead correction method to compensate the phase shift caused by the junction capacitance of the photodiode and the input capacitance of the operational amplifier. Finally, the reasons for choosing the relevant parameters of the components such as photoelectric devices and preamplifiers in the design of this low noise photoelectric detection circuit are given.

Abstract:The composition uniformity of a HgCdTe bulk material used as liquid-phase epitaxial solution was studied. By optimizing the compound temperature, compound time, furnace swing frequency and quench process, the longitudinal composition uniformity of the HgCdTe bulk material was improved greatly. 28 epitaxial film samples were grown by using the HgCdTe bulk material compounded after the growth process was modified. They had a average composition uniformity of 0.95\% which met the fabrication requirement of the second generation infrared focal plane arrays.

Abstract:It is very important for a high performance infrared detection system to select an appropriate operating waveband. By comparing the operating waveband selection criteria of infrared detection systems with those of hyperspectral remote sensors, a waveband selection method based on working distance is proposed according to the detection principle and the hyperspectral classification. The simulation result shows that this method is feasible and can be used to calculate the desired operating waveband parameters effectively.

Abstract:The two-point algorithm is a linear correction method based on calibration data. Because of a narrow dynamic range and a poor accuracy, it is difficult for the algorithm to overcome the non-linearity and spatio-temporal drift of a detector in response. To remove the nonuniformity of the detector, a new algorithm which combines a polynomial fitting algorithm with a one-point algorithm is proposed after the two-point algorithm is analyzed. With this new algorithm, the variation of the coefficient of the detector with the environment is removed.

Abstract:An infrared human body temperature measurement system based on an ARM processor is proposed. The system consists of a MLX90615 high accuracy medical digital infrared sensor, an ultrasonic sensor, an environmental temperature sensor, a master CPU and other external circuits. The MLX90615 sensor collects the infrared radiation from a human forehead and sends it to the CPU. Through temperature and distance compensation, the forehead temperature value is converted to the corresponding body temperature and is displayed in a liquid crystal display. The experiment shows that compared with other systems, this infrared human body temperature measurement system has its functions of environmental temperature compensation and distance compensation. It can reduce the effect of environmental temperature and distance greatly and can be used to measure human body temperature accurately, quickly and contactlessly.

Abstract:A method and an apparatus for improving solar light absorption and energy storage of solar cells are designed. The V-A characteristics of a solar cell and the charging and discharging characteristics of a Farah capacitor are presented. The apparatus uses a concave mirror to achieve the absorption of solar light on both sides of a solar cell and uses a Farah capacitor to store the solar energy. Compared with the traditional apparatus using single-side solar cells and storage battery, this apparatus has the advantages of high absorption effciency, fast charging and large discharging current. It can be widely used in street and corridor lighting and other related fields.