Optically trapped and controlled microapertures for studies of spatial coherence in an arbitrary light field

2007 ◽  
Vol 90 (26) ◽  
pp. 261101
Author(s):  
W. M. Lee ◽  
K. Dholakia
Keyword(s):  
Light Field ◽  
Spatial Coherence ◽  
Optically Trapped

scholarly journals Controlled levitation of nanostructured thin films for sun-powered near-space flight

2021 ◽  
Vol 7 (7) ◽  
pp. eabe1127
Author(s):  
Mohsen Azadi ◽  
George A. Popov ◽  
Zhipeng Lu ◽  
Andy G. Eskenazi ◽  
Avery Ji Won Bang ◽  
...  
Keyword(s):  
Space Flight ◽  
Light Field ◽  
Vacuum Chamber ◽  
Low Cost ◽  
Nanostructured Surface ◽  
Near Space ◽  
Recoil Force ◽  
Long Duration ◽  
Gas Molecules ◽  
Optically Trapped

We report light-driven levitation of macroscopic polymer films with nanostructured surface as candidates for long-duration near-space flight. We levitated centimeter-scale disks made of commercial 0.5-micron-thick mylar film coated with carbon nanotubes on one side. When illuminated with light intensity comparable to natural sunlight, the polymer disk heats up and interacts with incident gas molecules differently on the top and bottom sides, producing a net recoil force. We observed the levitation of 6-mm-diameter disks in a vacuum chamber at pressures between 10 and 30 Pa. Moreover, we controlled the flight of the disks using a shaped light field that optically trapped the levitating disks. Our experimentally validated theoretical model predicts that the lift forces can be many times the weight of the films, allowing payloads of up to 10 milligrams for sunlight-powered low-cost microflyers at altitudes of 50 to 100 km.

Diffraction technique for measuring the spatial coherence function of a nonstationary light field

1986 ◽  
Vol 29 (10) ◽  
pp. 892-896
Author(s):  
A. V. Ivanov ◽  
V. P. Kandidov ◽  
D. P. Krindach ◽  
V. N. Sokolov
Keyword(s):  
Light Field ◽  
Coherence Function ◽  
Spatial Coherence ◽  
Spatial Coherence Function

Longitudinal pure spatial coherence of a light field with wide frequency and angular spectra

2005 ◽  
Vol 30 (3) ◽  
pp. 224 ◽  
Author(s):  
Vladimir Ryabukho ◽  
Dmitry Lyakin ◽  
Mikhail Lobachev
Keyword(s):  
Light Field ◽  
Spatial Coherence

Longitudinal purely spatial coherence of a light field

2006 ◽  
Vol 100 (5) ◽  
pp. 724-733 ◽  
Author(s):  
V. P. Ryabukho ◽  
D. V. Lyakin ◽  
V. V. Lychagov
Keyword(s):  
Light Field ◽  
Spatial Coherence

Quanitative aspects of electron diffraction using electron holography

1995 ◽  
Vol 53 ◽  
pp. 616-617
Author(s):  
E. Völkl ◽  
L.F. Allard ◽  
B. Frost ◽  
T.A. Nolan
Keyword(s):  
Electron Beam ◽  
Electron Diffraction ◽  
Software Package ◽  
Spatial Coherence ◽  
Electron Holography ◽  
Image Intensity ◽  
Interference Fringes ◽  
Complex Image ◽  
The Difference ◽  
Recorded Image

Off-axis electron holography has the well known ability to preserve the complex image wave within the final, recorded image. This final image described by I(x,y) = I(r) contains contributions from the image intensity of the elastically scattered electrons IeI (r) = |A(r) exp (iΦ(r)) |, the contributions from the inelastically scattered electrons IineI (r), and the complex image wave Ψ = A(r) exp(iΦ(r)) as:(1) I(r) = IeI (r) + Iinel (r) + μ A(r) cos(2π Δk r + Φ(r))where the constant μ describes the contrast of the interference fringes which are related to the spatial coherence of the electron beam, and Φk is the resulting vector of the difference of the wavefront vectors of the two overlaping beams. Using a software package like HoloWorks, the complex image wave Ψ can be extracted.

The Impact of Light Polarisation on Light Field of Scenes with Multiple Reflections

2020 ◽  
pp. 108-115 ◽  
Author(s):  
Vladimir P. Budak ◽  
Anton V. Grimaylo
Keyword(s):  
Mathematical Model ◽  
Light Field ◽  
Global Illumination ◽  
Multiple Reflections ◽  
Software Environment ◽  
The Monte Carlo Method ◽  
Mueller Matrices ◽  
Volume Integration ◽  
The Impact

The article describes the role of polarisation in calculation of multiple reflections. A mathematical model of multiple reflections based on the Stokes vector for beam description and Mueller matrices for description of surface properties is presented. On the basis of this model, the global illumination equation is generalised for the polarisation case and is resolved into volume integration. This allows us to obtain an expression for the Monte Carlo method local estimates and to use them for evaluation of light distribution in the scene with consideration of polarisation. The obtained mathematical model was implemented in the software environment using the example of a scene with its surfaces having both diffuse and regular components of reflection. The results presented in the article show that the calculation difference may reach 30 % when polarisation is taken into consideration as compared to standard modelling.

Reconstruction of Smoke based on Light Field Consistency

2016 ◽  
Vol 136 (12) ◽  
pp. 522-531
Author(s):  
Yuta Ideguchi ◽  
Yuki Uranishi ◽  
Shunsuke Yoshimoto ◽  
Yoshihiro Kuroda ◽  
Masataka Imura ◽  
...  
Keyword(s):  
Light Field

Full-parallax spherical light field display using mirror array

2018 ◽  
Vol 2018 (4) ◽  
pp. 142-1-142-5
Author(s):  
Hiroaki Yano ◽  
Tomohiro Yendo
Keyword(s):  
Light Field
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