Response Of Long Focal Length Optical Systems To Thermal Shock

1980 ◽  
Vol 19 (2) ◽  
Author(s):  
Joseph M. Geary
Keyword(s):  
Thermal Shock ◽  
Focal Length ◽  
Optical Systems

Universal method for determining the focal length of optical systems by moire deflectometry

1988 ◽  
Vol 27 (8) ◽  
pp. 1383 ◽  
Author(s):  
Eliezer Keren ◽  
Kathi M. Kreske ◽  
Oded Kafri
Keyword(s):  
Focal Length ◽  
Optical Systems ◽  
Universal Method ◽  
Moiré Deflectometry

Comparison of Design and Spatial Stability of Two Kinds of Optical Systems for Stereoscopic Mapping Camera

2013 ◽  
Vol 760-762 ◽  
pp. 368-372
Author(s):  
Tian Jin Tang ◽  
Wei Jun Gao
Keyword(s):  
Optical System ◽  
Linear Array ◽  
Focal Length ◽  
Optical Systems ◽  
Modulation Transfer ◽  
Working Temperature ◽  
Edge Field ◽  
Performance Requirements ◽  
And Performance ◽  
Structure Layout

To achieve a certain precision when mapping in accord with a particular proportion or scale with stereo mapping camera, the change of chief ray height of the edge field due to the fluctuation of working temperature is required to be within the range of microns, and at the meantime the size and structure layout of three-linear array stereo mapping camera are determined directly by the configuration of optical system. Based on the requirements of refractive optical system with long focal length, academic calculation and actual optical designs based on two typical configurations for stereoscopic mapping camera are made,the actual working temperature and performance requirements are also taken into consideration, the results including the modulation transfer function, distortion and stability comparison are also given.

Meniscus Shape and Optical Performance of a MEMS-Based Liquid Micro-Lens System

2008 ◽  
Author(s):  
Shong-Leih Lee ◽  
Chao-Fu Yang
Keyword(s):  
Electric Field ◽  
Laplace Equation ◽  
Focal Length ◽  
Optical Systems ◽  
Lens System ◽  
Meniscus Shape ◽  
Optical Aberration ◽  
Numerical Result ◽  
Micro Lens ◽  
Back Focal Length

It is very difficult to fabricate tunable optical systems having an aperture below 1000 micrometers with the conventional means on macroscopic scale. Krogmann et al. (J. Opt. A: Pure Appl. Opt. vol. 8, 2006, pp. S330-S336) presented a MEMS-based tunable liquid micro-lens system with an aperture of 300 micrometers. The system exhibited a tuning range of back focal length between 2.3 mm and infinity by using the electrowetting effect to change the contact angle of the meniscus shape on silicon with a voltage of 0−45V. However, a serious optical aberration was found in their lens system. In the present study, a numerical simulation is performed for this same physical configuration by solving the Young-Laplace equation on the interface of the lens liquid and the surrounding liquid. The resulting meniscus shape produces a back focal length that agrees with the experimental observation excellently. To eliminate the optical aberration, an electric field is applied on the system. The electric field alters the Young-Laplace equation and thus changes the meniscus shape and the quality of the lens system. The numerical result shows that the optical aberration of the lens system can be essentially eliminated when a proper electric field is applied.

scholarly journals Metasurface Spiral Focusing Generators with Tunable Orbital Angular Momentum Based on Slab Silicon Nitride Waveguide and Vanadium Dioxide (VO2)

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1864
Author(s):  
Li Chen ◽  
Lin Zhao ◽  
Yuan Hao ◽  
Wenyi Liu ◽  
Yi Wu ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Vanadium Dioxide ◽  
Communication Systems ◽  
High Speed ◽  
Focal Length ◽  
Polarized Light ◽  
Optical Systems ◽  
Gaussian Beams ◽  
The Impact

The metasurface spiral focusing (MSF) generator has gained attention in high-speed optical communications due to its spatial orthogonality. However, previous MSF generators only can generate a single orbital angular momentum (OAM) mode for one polarized light. Here, a MSF generator with tunable OAM is proposed and it has the ability to transform linearly polarized light (LPL), circularly polarized light or Gaussian beams into vortex beams which can carry tunable OAM at near-infrared wavelength by controlling the phase transition of vanadium dioxide (VO2). Utilizing this MSF generator, the beams can be focused on several wavelength-sized rings with efficiency as high as 76%, 32% when VO2 are in the insulating phase and in the metallic phase, respectively. Moreover, we reveal the relationship between the reflective focal length and transmissive focal length, and the latter is 2.3 times of the former. We further demonstrate the impact of Gaussian beams with different waist sizes on MSF generators: the increase in waist size produces the enhancement in spiral focusing efficiency and the decrease in size of focal ring. The MSF generator we proposed will be applicable to a variety of integrated compact optical systems, such as optical communication systems and optical trapping systems.

Regionally different optical systems in the compound eye of the water-flea Polyphemus (Cladocera, Crustacea)

1983 ◽  
Vol 217 (1207) ◽  
pp. 163-175 ◽  
Keyword(s):  
Regional Differences ◽  
Compound Eye ◽  
Focal Length ◽  
Complex Refractive Index ◽  
Optical Design ◽  
Optical Systems ◽  
Refractive Index Gradient ◽  
Water Flea ◽  
Central Type ◽  
Index Gradient

Polyphemus pediculus (L.) is a small (1 mm long) predatory crustacean that lives in bodies of standing freshwater. It has a single fused compound eye, which occupies most of its head. The eye comprises 130 ommatidia with five distinct types of crystalline cones. Four of these cone types were found to focus light by means of gradient index optics (lens cylinders). The edge ommatidia differ by having the focus displaced below the distal rhabdom tip. This was found to be correlated with their special type of rhabdom, which is characterized by its short, broad shape and the absence of a palisade. The central-type crystalline cone, contributing to a zone of acute vision, is functionally different from the other four cone types. The focusing on the rhabdom tip is in this case achieved by a prism, inside the cone, corrected for optical aberration with a complex refractive index gradient. The prism is interpreted as a way of compressing a long focal length into a short optical system, i. e. to enable high resolution in spite of the small size of the eye. Extreme regional differences in interommatidial angles were found to be the main reason for the different optical design between central and peripheral ommatidia.

A Comparison of Two Different Approaches to Camera Calibration in LSDM Photogrammetric Systems

2014 ◽  
Author(s):  
Ou Bai ◽  
Fiorenzo Franceschini ◽  
Maurizio Galetto ◽  
Luca Mastrogiacomo ◽  
Domenico A. Maisano
Keyword(s):  
Camera Calibration ◽  
Large Scale ◽  
Focal Length ◽  
Calibration Procedure ◽  
Optical Systems ◽  
Multiple Cameras ◽  
Dimensional Metrology ◽  
Distortion Parameters ◽  
Length Distortion

Large Scale Dimensional Metrology (LSDM) is a branch of metrology that deals with the measurement of objects with dimensions in the order of several meters. Optical systems, relying on the use of multiple cameras and photogrammetric techniques, are among the most used instruments in this field. These systems require a preliminary calibration procedure to determine some essential parameters, such as camera positions and orientations, focal length, distortion parameters, etc. A structured comparison between two different approaches to camera calibration is herein discussed.

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