一种新型的两镜三反射光学系统设计

 结合反射系统中双反射和三反射各自的优缺点,提出一种特殊的两镜三反光学系统,给出其初始结构的确定方法。对其结构优化过程中,在系统次镜后加平面反射镜,将系统进行折轴处理,然后在折轴反射镜后加透镜来校正剩余像差。该系统初始结构中两反射镜组成的是一个无焦系统,在主镜发生2次反射后成像。分析该初始系统的缺陷,对补偿该缺陷并使其成像质量达到衍射极限的后续补偿系统进行了设计。应用该方法设计了焦距f=5000mm,F数均为5,全视场角分别为0.4°和1°的2个系统,从像质评价结果可以看出,系统成像质量接近衍射极限,具有长焦距、小尺寸等特点。     

紧凑型长焦距平行光管的设计

设计一台用于CCD相机外场测试标定的超小体积、长焦距、高像质的平行光管,结构形式采用全反射离轴两镜式。设计的平行光管焦距1 2000 mm,有效口径400 mm,在线视场30 mm30 mm范围内波像差优于/20@6328 nm。光路经过多次折转后,平行光管外形尺寸小于1 000 mm600 mm500 mm,总质量小于60 kg。经分析计算,平行光管的环境适应性较好,能够满足被检相机正常发射场测试使用需求。     

大孔径长焦距摄远物镜光学系统设计

对于长焦距摄远光学系统,大相对孔径意味着成像亮度更加优秀,但是也伴随着孔径边缘像差变差而难以校正的难题。利用折反系统减小光学系统总长,采用反射结构为基础,搭配前后两组校正镜构成光学系统,设计出大相对孔径,总长较短的摄远光学系统。光学系统工作波段为可见光波段,焦距1 000 mm,F数2.1,摄远比0.52,光学总长远小于焦距,遮拦比45%,全视场MTF在空间频率80 lp/mm处大于0.3,像面直径11 mm。该光学系统镜片全部采用球面镜,光学系统由2片反射镜和7片透射镜组成,结构紧凑,成像质量好。对摄远物镜进行公差分析,得出该设计公差较宽松。     

Corrected mirror systems with double reflection

We propose objectives consisting of two mirrors with central holes for passage of a light beam. The optical layout ensures multiple reflection of rays from both mirrors. We consider several approaches to calculating the design parameters for which three and four aberrations do not occur. The objectives can be used in optical devices operating in the UV and IR regions of the spectrum. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 267–270, March–April, 2007.     

近红外成像光学系统设计

为了明确近红外成像光学系统对杂散光的抑制能力,设计了一个光谱为0.75 m ~1 m,焦距12.002 mm,F/1.8,视场1515的光学系统,其结构为改进型的双高斯结构。实验结果表明:设计的光学系统的各视场光斑在艾瑞斑内,焦移量最大为4.9 m,球差约为1 m,垂轴像差最大为3 m,MTF接近衍射极限。对设计的光学系统进行了杂散光评估和杂散光抑制,得到了杂散光抑制前后的点源透射比。分析结果表明:与未加遮光罩相比,加入遮光罩的光学系统PST值下降了76.6%~87.5%。     

A double-gap planar magnetic lens

An analytical model and equations for describing the field of a planar magnetic lens with two concentric nonmagnetic gaps are developed. It is demonstrated that the “half-width” of the magnetic field of the lens can be controlled by varying independently the currents in the excitation coils of the two gaps. This makes it possible to control the focal length and the spherical aberration of the lens. It is shown that when oppositely directed currents are used in the excitation coils, a planar magnetic lens that does not rotate the image can be obtained. Zh. Tekh. Fiz. 69, 133–134 (August 1999)     

Use of multimode cavities with equidistant spectrum for increasing the energy accumulation rate of particles in linear supercolliders

We propose a new accelerating structure for teraelectronvolt linear electron–positron colliders [1–4]. The structure is based on acceleration of a sequence of particle bunches (accelerated beam) by means of a periodic system of quasioptical cavities. Each cavity is operated at several eigenmodes with equidistant frequencies which are excited by a drive beam bunched with the same spatial period as the accelerated beam. The accelerating field represents a time-periodic sequence of narrow peaks separated by wide intervals of a field close to zero. This makes it possible to significantly decrease the effective time of exposure of the structure surface by ultrahigh microwave fields compared with the single-frequency structure. To maximize filling of the structure by accelerating-field regions and minimize ohmic losses, we suggest using a set of modes with a nonzero number of longitudinal variations strictly proportional to the frequencies of these modes. Such modes are able to provide long effective interaction of the total microwave field with a bunch of particles passing across the cavity. In this way, the acceleration gradient averaged over the structure length can be increased. A variant of the accelerating structure which is based on two-mirror cavities with small curvature of the mirrors is proposed. Such cavities can provide approximate frequency equidistance of a large number of modes with nonzero longitudinal variations.     

Transformation of laser radiation by Gaussian apertures

The transformation of simple Gaussian light beams by lenses with a complex focal length is investigated in an approximation of paraxial optics. The results obtained are compared with the corresponding results of geometric optics into which they go over in limiting cases. A. N. Sevchenko Scientific-Research Institute of Physical Problems, 7, Kurchatov St., Minsk, 220064, Belarus. Translated, from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 4, pp. 471–478, July–August, 1997.     

大口径红外成像系统的光学设计

推导了以反射式两镜系统为主体的红外成像系统中满足光瞳匹配要求的转像透镜的高斯光学参量与两镜系统参量的关系式。当选定红外焦平面的冷屏直径及到焦面的距离后，转像透镜与两镜系统的高斯光学参量之间必须满足这个关系式，才能做到光瞳匹配，这就是冷屏为系统的出瞳．而入瞳是主反射镜的口径。消像差由主镜、副镜的非球面及转像透镜上的一个非球面承担。用实例计算验证了所推导出的公式的可靠性，红外系统的口径取为250mm，红外接收器的冷屏直径为5mm，冷屏到红外像面的距离为20mm。两镜系统主镜的曲率半径选定为-1000mm及-800mm两个值，两镜系统焦距为2000mm，1500mm及1000nm三个。共计算了六种结构参量不同的系统。     

Focal shift and focal switch of partially polarized Gaussian Schell-model beams passing through a system with the aperture and spherically aberrated lens separated

Based on the beam coherent-polarization (BCP) matrix approach and propagation law of partially coherent beams, the focal shift and focal switch of partially polarized Gaussian Schell-model (PGSM) beams passing through a system with the aperture and spherically aberrated lens separated is studied in detail. Our main attention is focused on the effect of spherical aberration and partial coherence on the focal shift and focal switch of PGSM beams. It is shown that for polarizer-free case there is no focal switch of PGSM beams, the focal shift of PGSM beams is closely related with spherical aberration coefficient C₄, auto-coherence length σ_a, truncation parameter δ and relative position s/f between the aperture and lens in general, and is independent of the cross-coherence length σ_c. After inserting a polarizer the focal switch can take place. Numerical calculation results are given to illustrate how the spherical aberration and partial coherence affect the focal shift and focal switch of PGSM beams.     

一种两镜五反光学系统设计

利用反射式光学系统宽光谱,无色差,纵向外形尺寸小等特点,提出一种采用两镜系统为原型的五反光学系统,实现了宽光谱（0.4 m~12 m）、长焦距(1.6 m)、小型化(总长85 mm)光学系统设计。2个反射面引入高次非球面,经像差平衡设计,像质达到使用要求。轴外视场激光能量经两镜五反系统聚焦后,激励光谱转换靶使之发出可见光 长波红外光谱,为光电装备的光轴调校提供模拟的无穷远目标。     

Design and energy analysis of interference imaging system with annular-aperture

An interference imaging system with annular aperture is presented having focal length of 6000 mm, aperture of 1000 mm, and ring width/semi-diameter of 0.2. The energy analyze is carried out to evaluate the optical performance of this system, and imaging restoration processing is also performed by the blind deconvolution algorithm with iteration number of 25. Results show that the quality is close to the diffraction limit and the weight has greatly reduced to 36% of the full-aperture system, which verifies the annular aperture system is a better choice for the space telescope with large-caliber and long focal length.     

用于红外焦平面的正方形孔径球面微透镜阵列研究

针对目前红外焦平面光敏阵列中存在的占空比小、光能利用率低的实际问题,展开了正方形孔径球面微透镜阵列制作及其与红外焦平面阵列集成应用的研究.本文从红外焦平面光敏阵列特点入手,对比分析了正方形孔径相比于传统圆形孔径微透镜阵列在光能利用上的优势.提出正方形孔径微透镜阵列激光直写变剂量曝光制作技术,建立光刻胶曝光数学模型和正方形球面微透镜面型函数,以此为基础,编制直写设备变剂量曝光控制软件;利用长春理工大的学复合坐标激光直写系统和等离子刻蚀机进行相关工艺实验,制作了阵列256×256、单元尺寸40×40 μm²、球面半径60 μm、单元间距1 μm的红外石英微透镜阵列;并将其与相应阵列的碲-镉-汞红外光敏阵列进行集成.结果表明:微透镜的占空比达到95%,红外焦平面光能利用率从原来的60%提高到90% 以上.由此得出结论:变剂量曝光制作微透镜技术是可行的,正方形孔径球面微透镜阵列代替圆形孔径微透镜阵列,对于提高红外探测器的灵敏度、信噪比、分辨率等性能具备明显优势.     

偏轴两镜系统的设计

用解析方法求出消除中心视场球差、彗差及像散的偏轴两镜系统的结构及面形参数．根据解出的参数进行光线追迹，得到中心视场像斑尺寸在０．２″以内．要改善边缘视场的像质，需要在双曲率面镜上加高次项，并偏离解出的某些参数．对于Ｆ／１１左右的系统，可以得到±０．６°视场边缘有１．５″～１．９″的像斑角尺寸．这种系统的子午与弧矢焦距不等，相差在１％以内．     

Yield of singlet oxygen from optically pumped CCl<Subscript>4</Subscript> solution of fullerenes

Boiling occurs in a solution of oxygen and fullerenes in CCl₄ upon optical pumping of C₆₀ upon the fast appearance of incandescent fullerenes in cold solvent. Upon single-photon absorption, a spherical zone of the critical state of CCl₄ is formed within 5 ns (with a diameter of 22–25 nm, P _cr ∼ 45 atm, and T _cr ∼ 556 K). This spherical zone (gas-bubble nucleus) expands to a diameter of ∼100–400 nm for 2–5 ns. If the external pressure (natural or artificial) is rapidly released, the bubble accelerates and emerges into a vacuum chamber within 0.7–25 μs (the length of the passage is 0.1–5 cm depending on the construction of the singlet oxygen generator). We note that singlet oxygen appears 50 ns after the absorption of a photon by fullerene (i.e., inside of the almost formed gas bubble that only begins to emerge from the liquid to a low-pressure gas region).     

Focal switch of spherically aberrated Laguerre–Gaussian beams

Based on the Collins formula, we study the focal switch of spherically aberrated Laguerre–Gaussian (L–G) beams passing through an optical system with the aperture and lens separated. Our results demonstrate that the behavior of the focal switch of spherically aberrated L–G beams is generally dependent on the spherical aberration coefficient, truncation parameter, Fresnel number and mode indices. The spherical aberration affects the relative focal shift, critical position of the focal switch and the relative transition. We also illustrate that there exists a minimum in addition to a maximum in the truncation parameter. Only inside the region between the minimum and the maximum the focal switch effect can be expected. The region depends on the spherical aberration coefficient as well as the Fresnel number.     

利用联合付里叶变换谱干涉法测量透镜焦距

本文提出了采用联合付里叶变换频谱干涉法测量透镜焦距的方法。输入面上两个分布完全相同的图像经光学付里叶变换在频谱面上得到二者付里叶变换频谱的干涉条纹，通过测量干涉条纹的间距即可得到透镜的焦距。该方法装置简单、操作调整方便；易于采用实时空间光调制器、ＣＣＤ及微机实现快速自动测量，且具有较高的精度。文中进行了原理分析和实验验证。     

Formation of optical fields of stimulated Raman scattering with a resolution beyond the Abbe diffraction limit by spherical microlens cavities with whispering gallery modes: Near-field approximation

We consider a significant lowering of the threshold of stimulated Raman scattering in solid fused silica spherical microlenses cavities that is caused by an increase in the integral overlap factor of whispering gallery modes. The structure of focal regions of a microlens is shown to have the shape of honeycombs, forming a photonic crystal or a photonic nanojet. We show that, at comparatively small numerical apertures NA = 0.7–0.8, which correspond to hemispherical microlenses, a spherical microlens cavity exhibits the possibility of focusing laser radiation beyond the Abbe diffraction limit. This enables the possibility of wide practical applications of microspheres as a focusing element the resolving power of which exceeds the Abbe diffraction limit in the near field. The whispering-gallery-mode spherical microlens cavity makes it possible to perform laser generation with a duration of a coherent pulse in the subfemtosecond range and to form a subwavelength focal region of the near field. This ensures the possibility of detecting single molecules of a substance in the subwavelength range in the near field and can be used to increase the sensitivity of intracavity spectroscopy methods and as microlasers for excitation of molecules in metal molecular nanoswitches and semiconductor heterostructures. From an array of microlens cavities, metamaterials with a negative refractive index can be formed.     

Magnetized quark and strange quark matter in the spherical symmetric space–time admitting conformal motion

In this paper, we have examined magnetized quark and strange quark matter in the spherical symmetric space–time admitting one-parameter group of conformal motions. For this purpose, we have solved Einstein’s field equations for spherical symmetric space–time via conformal motions. Also, we have discussed the features of the obtained solutions.     

用于红外焦平面的正方形孔径球面微透镜阵列研究

针对目前红外焦平面光敏阵列中存在的占空比小、光能利用率低的实际问题,展开了正方形孔径球面微透镜阵列制作及其与红外焦平面阵列集成应用的研究.本文从红外焦平面光敏阵列特点入手,对比分析了正方形孔径相比于传统圆形孔径微透镜阵列在光能利用上的优势.提出正方形孔径微透镜阵列激光直写变剂量曝光制作技术,建立光刻胶曝光数学模型和正方形球面微透镜面型函数,以此为基础,编制直写设备变剂量曝光控制软件;利用长春理工大的学复合坐标激光直写系统和等离子刻蚀机进行相关工艺实验,制作了阵列256×256、单元尺寸40×40μm2、球面半径60μm、单元间距1μm的红外石英微透镜阵列;并将其与相应阵列的碲-镉-汞红外光敏阵列进行集成.结果表明:微透镜的占空比达到95%,红外焦平面光能利用率从原来的60%提高到90%以上.由此得出结论:变剂量曝光制作微透镜技术是可行的,正方形孔径球面微透镜阵列代替圆形孔径微透镜阵列,对于提高红外探测器的灵敏度、信噪比、分辨率等性能具备明显优势.