The entrance pupil of an on-axis stigmatic singlet lens

2020 ◽  
Author(s):  
Rafael Guillermo Gonzalez Acuña ◽  
Julio C. Gutiérrez-Vega
Keyword(s):  
Entrance Pupil

ON OPTIMUM PUPIL FIELDS WITH MAXIMUM ELECTRIC FIELD COMPONENT IN FOCUS

2010 ◽  
Vol 19 (01) ◽  
pp. 189-201
Author(s):  
H. P. URBACH ◽  
S. F. PEREIRA ◽  
D. J. BROER
Keyword(s):  
Electric Field ◽  
Field Component ◽  
Optical Axis ◽  
Focal Point ◽  
Longitudinal Component ◽  
Electric Field Component ◽  
Incident Power ◽  
Entrance Pupil ◽  
Maximum Electric Field ◽  
High Na Lens

The field in the entrance pupil of a high NA lens can be optimized such that, for given incident power, the electric field component in a given direction in the focal point is maximum. If the field component is chosen parallel to the optical axis, the longitudinal component is maximized and it is found that the optimum longitudinal component is narrower than the Airy spot. We discuss how this can be used to obtain higher resolution in photolithography when a resist is used that is sensitive to only the longitudinal component. We describe a proposition for realizing such resist.

scholarly journals Pupillary axis of a heterocentric astigmatic eye

2013 ◽  
Vol 72 (1) ◽  
Author(s):  
W. F. Harris
Keyword(s):  
Anterior Chamber ◽  
Contact Lens ◽  
Line Of Sight ◽  
Compound System ◽  
Linear Optics ◽  
Optical Instrument ◽  
Entrance Pupil ◽  
Naked Eye ◽  
Straight Line

The pupillary axis of the eye is a clinically useful concept usually defined as the line through the centre of the entrance pupil that is perpendicular to the cornea. However if the cornea is astigmaticthen, strictly speaking, the entrance pupil is blurred and the pupillary axis is not well defined.  A modified definition is offered in this paper: the pupillary axis is the infinite straight line containing the incident segment of the ray that passes through the centre of the (actual) pupil and is perpendicular to the first surface of the eye.  The definition holds for the naked eye and for an eye with an implant in the anterior chamber.  It also holds for the com-pound system of eye and optical instrument such as a contact lens in front of it if the first surface is interpreted as the first surface of the compound system and the pupil as the limiting aperture of the compound system.  Linear optics is applied to obtain a formula for the position and inclination of the pupillary axis at incidence onto the system; the refracting surfaces may be heterocentric and astigmatic.  The formula allows one to examine the sensitivity of the pupillary axis to displacement of the pupil and any other changes in the anterior eye.  Strictly the pupillary axis depends on the frequency of light but examples show that the dependence is probably negligible.  The vectorized generalization of what is sometimes called angle lambda is easily calculated from the inclination of the pupillary axis and the line of sight. (S Afr Optom 2013 72(1) 3-10)

PROTECTION AGAINST UNAUTHORIZED ACCESS TO INFORMATION CIRCULATING IN WIRELESS INFRARED CHANNELS OF DATA TRANSMISSION

2020 ◽  
pp. 511-518
Author(s):  
Александр Вильямович Бабурин ◽  
Лариса Александровна Глущенко ◽  
Борис Николаевич Добряков ◽  
Григорий Александрович Остапенко ◽  
Андрей Петрович Преображенский
Keyword(s):  
Data Transmission ◽  
Transmission Channel ◽  
Access To Information ◽  
Optoelectronic System ◽  
Pseudorandom Sequences ◽  
Entrance Pupil ◽  
Unauthorized Access ◽  
Window Opening ◽  
Modern Level ◽  
Wireless Infrared

Цель исследования состоит в разработке методов защиты от несанкционированного доступа информации, циркулирующей в беспроводных ИК-каналах передачи данных. Показаны возможные способы несанкционированного доступа к каналу передачи данных от ИК-клавиатуры к компьютеру. Основной способ несанкционированного доступа к ИК-каналу передачи данных - это регистрация диффузно-отраженного от элементов интерьера излучения. Проведены теоретические оценки, подтверждающие возможность получения информации, циркулирующей в беспроводных ИК-каналах передачи данных при несанкционированном доступе. Рассмотрен типичный случай распространения излучения в помещении при использовании ИК-канала передачи данных при несанкционированном доступе. Неуполномоченный наблюдатель может регистрировать через оконный проем диффузно-отраженное излучение, используя специальную оптико-электронную систему. Для расчетов были приняты типовые фотометрические характеристики интерьера помещения и предельно достижимые на современном уровне техники характеристики фотоприемных устройств. Размер диаметра входного зрачка оптической системы принят не слишком большим из того соображения, что он не должен привлекать внимание (служить демаскирующим признаком). Предложен метод защиты информации, циркулирующей в беспроводных ИК-каналах передачи данных, основанный на формировании засветочных помех. Приведены схемы формирования засветочных помех. Для помехи может быть использовано диффузно-отраженной излучение или специально сформированное излучение, направленное на оконный проем помещения. The purpose of the research is to develop methods of protection against unauthorized access to information circulating in wireless infrared channels of data transmission. Possible ways of unauthorized access to the data transmission channel from the IR keyboard to the computer are shown. The main method of unauthorized access to the IR data transmission channel is the registration of radiation diffusely reflected from interior elements. Theoretical estimates have been carried out confirming the possibility of obtaining information circulating in wireless infrared channels of data transmission under unauthorized access. A typical case of propagation of radiation in room when using an IR data transmission channel with unauthorized access to information is considerd. An unauthorized observer can register diffusely reflected radiation through a window opening using a special optoelectronic system. For the calculations, the standard photometric characteristics of the interior of the room and the maximum achievable at the modern level of technology characteristics of photodetectors were taken. The size of the diameter of the entrance pupil of the optical system is taken not too large for the reason that optoelectronic system should not attract attention (serve as a unmasking feature). The method for protecting of information ciculating in optical wireless channels of data transmission, based on the formation of optical intentional noise, is proposed. It provides a brief overview of methods for generating pseudorandom sequences, wich can serv as a basis for the formation of an illumination noise channel. For optical intentional noise can be used diffusely reflected radiation or specially formed radiation, directed at the window opening of the room.

High-precision Shack-Hartmann wavefront sensing with a multi-focal diffraction Taiji-lenslet array

Laser Physics ◽  
2021 ◽  
Vol 31 (12) ◽  
pp. 125401
Author(s):  
Yaling Yang ◽  
Yanli Zhang ◽  
Junyong Zhang ◽  
You Li ◽  
Dean Liu
Keyword(s):  
Large Scale ◽  
Measurement Accuracy ◽  
Laser Beams ◽  
Diffractive Lens ◽  
Wavefront Sensors ◽  
Entrance Pupil ◽  
Optical Elements ◽  
Lenslet Array ◽  
Location Algorithm ◽  
Detection Instrument

Abstract A Hartmann wavefront sensor is a type of wavefront detection instrument that has been widely used in various fields. Traditional Hartmann wavefront sensors usually comprise a monofocal refraction lenslet array to segment the wavefront at the entrance pupil. Each wavelet is focused at the focal plane along the projection of the lenslet, forming the foci array. Unlike the multifocal self-interference Taiji-lenslet array, a type of multifocal diffraction Taiji-lenslet array was proposed in this study to improve the measurement accuracy using the weighted centroid location algorithm of these multifocal spots, where the latter is more easily designed than the former. An optical experiment was implemented using the multifocal diffraction Taiji-lenslet array to verify its effectiveness. As a type of diffractive lens, a large-aperture Taiji-lenslet array can be easily fabricated via lithography, which has great potential for application in the measurement of large-scale laser beams and optical elements.

Design of two channel panoramic annular optical system with entrance pupil preposition

2019 ◽  
Vol 48 (6) ◽  
pp. 618001
Author(s):  
黄蕴涵 Huang Yunhan ◽  
付跃刚 Fu Yuegang ◽  
刘智颖 Liu Zhiying
Keyword(s):  
Optical System ◽  
Entrance Pupil

scholarly journals Catadioptric Optical System Design of 15-Magnitude Star Sensor with Large Entrance Pupil Diameter

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5501
Author(s):  
Yang Bai ◽  
Jianlin Li ◽  
Rongwei Zha ◽  
Ying Wang ◽  
Guangzhi Lei
Keyword(s):  
Optical System ◽  
Attitude Control ◽  
Pupil Diameter ◽  
Focal Length ◽  
Field Of View ◽  
Star Sensor ◽  
Spherical Lens ◽  
Entrance Pupil ◽  
Secondary Mirror ◽  
Entrance Pupil Diameter

The optical system is one of the core components for star sensors, whose imaging quality directly influences the performance of star sensors for star detection, thereby determining the attitude control accuracy of spacecrafts. Here, we report a new type of optical system with a catadioptric structure and a large entrance pupil diameter for a 15-magnitude star sensor. It consists of an improved Cassegrain system (R-C system), an aperture correction spherical lens group and a field of view correction spherical lens group. By embedding the secondary mirror of the R-C system into the output surface of the negative spherical lens of the aperture correction spherical lens group, the blocking of incident light is eliminated from the secondary mirror holder. After the structure optimization, the catadioptric optical system (COS) had a spectral range of 450 nm–950 nm, an entrance pupil diameter of 250 mm, a half-diagonal field of view of 1.4° and a focal length of 390 mm. By using theoretical calculations and experimental measurements, it was verified that the COS, with the ability to correct astigmatism, lateral color and distortion, can fulfill the detection of 15-magnitude dark stars.

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