## 2021年  14卷  第6期

2021, 14(6): 1305-1316. doi: 10.37188/CO.2021-0135

2021, 14(6): 1317-1326. doi: 10.37188/CO.2021-0067

2021, 14(6): 1327-1340. doi: 10.37188/CO.2021-0075

In order to reduce the manufacturing cost of the narrow-bandwidth Metamaterial Absorber (MA) and broaden its application field, a dual-wavelength dielectric narrow-bandwidth MA, composed of Au substrate, SiO2 dielectric layer and Si dielectric asymmetric grating, is designed based on the finite-difference time-domain method using dielectric materials. It is found by simulation that the proposed narrow-bandwidth MA has ultra-high absorption efficiency at λ1 = 1.20852 μm and λ2 = 1.23821 μm, and the FWHM is only 0.735 nm and 0.077 nm, respectively. The main principle that MA achieves the narrow-bandwidth absorption at λ1 is mainly due to the formation of Fabry-Pérot (FP) cavity resonance in the SiO2 layer, while the narrow-bandwidth absorption of MA at λ2 is mainly due to the guided mode resonance effect of the incident light in the asymmetric grating. The theoretical calculations show that the absorption characteristics can be affected more significantly by changing the structural parameters of the MA.

2021, 14(6): 1341-1347. doi: 10.37188/CO.2021-0013

2021, 14(6): 1348-1354. doi: 10.37188/CO.2021-0107

2021, 14(6): 1355-1361. doi: 10.37188/CO.2021-0054

2021, 14(6): 1362-1367. doi: 10.37188/CO.2021-0103

2021, 14(6): 1368-1377. doi: 10.37188/CO.2021-0051

2021, 14(6): 1378-1386. doi: 10.37188/CO.2021-0064

2021, 14(6): 1387-1394. doi: 10.37188/CO.2021-0128

2021, 14(6): 1395-1399. doi: 10.37188/CO.2021-0077

2021, 14(6): 1400-1409. doi: 10.37188/CO.2021-0105

2021, 14(6): 1410-1416. doi: 10.37188/CO.2021-0065

2021, 14(6): 1417-1425. doi: 10.37188/CO.2021-0078

2021, 14(6): 1426-1434. doi: 10.37188/CO.2021-0045

2021, 14(6): 1435-1450. doi: 10.37188/CO.2021-0087

An initial construction satisfying aberration balance and multi-constraint control is essential for the design of an off-axis multi-reflective optical system with minimal aberration. In this paper, a mathematical model for calculating the initial structure of off-axis multi-reflective is established based on the grouping design method combining spatial ray tracing and aberration correction, and an improved Particle Swarm Optimization (PSO) is proposed to solve the initial structure problem of an off-axis multi-reflective optical system. The PSO of natural selection with shrinkage factor is applied to improve calculation accuracy and design efficiency, so as to obtain the initial structure of the off-axis multi-reflection optical system. In the last part of this paper, taking an Extreme UltraViolet (EUV) lithography projection objective with six-mirror reflective aspheric mirrors as an example, the reliability and effectiveness of this method are verified. A 0.33 numerical aperture EUV lithographic objective with wave-front error better than 1/80λ (λ=13.5 nm) RMS is achieved.

2021, 14(6): 1451-1458. doi: 10.37188/CO.2020-0190

2021, 14(6): 1459-1467. doi: 10.37188/CO.2021-0073

2021, 14(6): 1468-1475. doi: 10.37188/CO.2020-0221

2021, 14(6): 1476-1485. doi: 10.37188/CO.2021-0052

2021, 14(6): 1486-1494. doi: 10.37188/CO.2021-0040

2021, 14(6): 1495-1503. doi: 10.37188/CO.2019-0255