Cheng Teng

Analysis of Optical Readout Sensitivity for Uncooled Infrared Detector

An optical readout uncooled infrared detector, employing a substrate-free focal plane array with pitch size 60 ?m, is established. The reflector deformation induced by the stress mismatching of the bi-layer structure is discussed and, in turn, a universal solution to determine both the optical readout sensitivity and the optimal filter position is found. By applying this solution, the optical readout sensitivity for the ideal plane reflector could theoretically increase by 80% as compared with the conventional operation, and the sensitivity loss caused by the reflector deformation can also be reduced to a reasonable level.

Electron Beam Lithographic Pixelated Micropolarizer Array for Real-Time Phase Measurement

Pixelated micropolarizer arrays (PMAs) have recently been used as key components to achieve real-time phase measurement. PMA fabrication by electron beam lithography and inductively coupled plasma-reactive ion etching is proposed in this work. A 320 × 240 aluminum PMA with 7.4 μm pitch is successfully fabricated by the proposed technique. The period of the grating is 140 nm, and the polarization directions of each of the 2 × 2 units are 0°, 45°, 90°, and 135°. The scanning electron microscopy and optical microscopy results show that the PMA has a good surface characteristic and polarization performances. When the PMA is applied to phase-shifting interferometry, four fringe patterns of different polarization directions are obtained from only one single frame image, and then the object wave phase is calculated in real time.

Accelerating Generalized Polygon Beams and Their Propagation

Accelerating beams with intensity cusps and exotic topological properties are drawing increasing attention as they have extensive uses in many intriguing fields. We investigate the structural features of accelerating polygon beams, show their generalized mathematical form theoretically, and discuss the even-numbered polygon beams. Furthermore, we also carry out the experiment and observe the intensity evolution during their propagation.

Real-time dynamic phase measurement based on pixelated micropolarizer array

Real-time phase-shifting interferometry based on pixelated micropolarizer array (PMA) has recently been used to achieve real-time phase measurement, and the requirement of vibration resistance is greatly reduced. In this paper, a 320×240 Aluminum PMA with 7.4 μm pitch is successfully fabricated by the electron beam lithography (EBL). The period of the grating is 140nm, and the polarization directions of each 2×2 units are 0°, 45°, 90°, and 135°. The PMA is integrated to the CCD sensor to achieve real-time phase measurement. Four fringe patterns of different polarization directions are obtained from only one single frame image by linear interpolation method, and then the object wave phase is calculated in real-time. Moreover, dynamic phase caused by temperature change is obtained in real-time, which verify the feasibility of this method in real-time dynamic phase measurement.

Research of Infrared Imaging at Atmospheric Pressure Using a Substrate-Free Focal Plane Array

An equivalent circuit model to the substrate-free focal plane array (FPA) is established. Using this fast and effective model, the performance of infrared (IR) imaging at atmospheric pressure is investigated and it is found that the substrate-free FPA has the ability of IR imaging at atmospheric pressure, whereas it has a slightly degraded noise equivalent temperature difference (NETD) as compared with IR imaging under a high vacuum. This feature is also identified experimentally by a substrate-free FPA with pixel size of 50 × 50 μm2. The NETDs are measured to be 160 mK at 10−2 Pa pressure and 1.08 K at atmospheric pressure.