分类： 光学 >> 光学设计与制造 提交时间： 2022-10-19 合作期刊: 《桂林电子科技大学学报》
摘要： 为了更好地选择一个合适的的辅助物镜,基于辅助物镜的工作原理,从理论推导和实验仿真两方面出发,对常见双胶合形式的辅助物镜进行了结构优化设计。根据设计要求,合理选择辅助物镜的初始结构,并从理论上推导了各类像差。基于初始结构和优化目标,利用光学设计软件OSLO对2种形式的辅助物镜进行了结构优化和像差分析。之后对于创新型双胶合-厚弯月型辅助物镜进行设计优化,以文献中相似透镜的结构参数为该设计的初始结构,利用OSLO光学软件及设计经验,对其进行结构优化、像差分析及矫正。对2种形式的辅助物镜进行对比分析的结果表明,2种结构形式的辅助物镜经过优化后,其参数均能满足设计要求,但双胶合-厚弯月型的辅助物镜更适用于大像面的光学系统。
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： High harmonic generation (HHG) from crystals in strong laser fields has been understood by the band theory of solid, which is based on the periodic boundary condition (PBC) of translational invariant. For systems having PBC of rotational invariant, in principles an analogous Bloch theorem can be developed and applied. Taking a ring-type cluster of cyclo[18]carbon as a representative, we theoretically suggest a quasi-band model and study its HHG by solving time-dependent Liouville-von Neumann equation. Under the irradiation of circularly polarized laser, explicit selection rules for left-handed and right-handed harmonics are observed, while in linearly polarized laser field, cyclo[18]carbon exhibits solid-like HHG originated from intra-band oscillations and inter-band transitions, which in turn is promising to optically detect the symmetry and geometry of controversial structures. In a sense, this work presents a connection linking the high harmonics of gases and solids.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： This paper proposes a novel and rapid calibration-free wavelength modulation spectroscopy algorithm based on even-order harmonics. The proposed algorithm, analytically deduced from Voigt line-shape function, only involves simple algebraic operations to describe the actual gas absorption spectra, thus eliminating the time-consuming simulations and line-shape fitting procedures adopted in traditional algorithms. Instead of acquiring the entirely scanned absorption line-shape, the proposed technique only requires extraction of the peak values of the harmonics. This characteristic significantly benefits gas diagnosis at elevated pressure and/or temperature, in which the entirely scanned absorption is very difficult to be obtained due to the broadened line-shapes. The proposed algorithm is validated by both numerical simulation and condition-controlled experiment, indicating millisecond-level calculation of gas parameters with the relative error less than 4% in the experiments.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Applicability and accuracy of traditional scanned-wavelength direct absorption spectroscopy (SDAS) diagnostic method is largely affected by combustion state such as temperature and pressure. To resolve this problem, an innovative baseline-free scanned-wavelength direct absorption spectroscopy (BF-SDAS) method is proposed in this work. This method does not need the zero-absorption regions for baseline fitting and can exclude the influence of baseline fitting error on the final result. It is especially suitable for the cases when the scanning range is too narrow or the absorption linewidth is too large to acquire the baseline. In this paper, the BF-SDAS is first derived and theoretically analyzed based on the Fourier analysis, and then the accuracy of this method is validated by measuring the concentration of H2O molecules in a static gas absorption cell at room temperature.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Yifei Zhang
Baoqing Zhang
Mingming Feng
Haotian Ling
Xijian Zhang
Yiming Wang
Xiaomu Wang
Qingpu Wang
Aimin Song
摘要： Extraordinary optical transmission (EOT) is a phenomenon of exceptional light transmission through a metallic film with hole arrays enhanced by surface plasmon (SP) resonance, which stimulates renewed research hotspots in metamaterials, subwavelength optics, and plasmonics. Below the frequency of the first order SP mode, f_pl0, the metallic film typically shows strong reflection and no EOT. Here, we report an unusual EOT phenomenon below fpl0, i.e., beyond the long-held spectral boundary of classic EOTs. It is induced by a novel bound surface state in a Fabry-Perot(F-P) cavity comprising a holey gold film and a silicon-air interface. By tailoring the cavity length, EOT phenomenon has been pushed deep into the sub-wavelength region by a factor of as large as 20%, and EOT frequency comb with cavity function has been achieved. Due to the enhanced slow-wave effect as the frequency approaches fpl0, the cavity induced EOT gradually merges with the first order SP EOT. Distinguishing from the classic EOT phenomenon, no transmission zero is found between these two EOTs, which dramatically broadens the EOT bandwidth by a factor of 10 at terahertz (THz) frequencies. Furthermore, the EOT transmittance is actively modulated with graphene, achieving a large modulation range from 0.5 to 0.25 under a sub-volt bias from -0.3 to 0.5 V at 500 GHz. To the best of the authors' knowledge, both the modulation range and the low bias are among the best for active EOT devices with graphene to date. Such a structure provides a new strategy for miniaturizing sensing devices, high-power sources, and broadband photonics as well as their active control in the THz regime.
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