Ultra-fast adaptive optical micro-lens arrays based on stressed liquid crystals

Kurochkin, O.; Buluy, O.; Varshal, J.; Manevich, M.; Glushchenko, Anatoliy; West, John L.; Reznikov, Yuriy; Nazarenko, V. G.

doi:10.1063/1.5057393

Cited by 14 publications

(10 citation statements)

References 43 publications

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“…The internal structure of the composite can be tailored by manipulating, while printing, the particles with an electric or magnetic field. These systems can be used in applications like personalised hearing aids [19], lenses being flat with a micro-structure consisting of a gradient concentration of particles that bestow the functionality of their curved counterparts [20], piezoelectric or Hall effect sensors [21], and direction-specific thermally or electrically conductive composites [22]. The formation of structures of particles in external fields is well documented in the literature, e.g., the formation of strings in field direction [23,24], as well as the merging/thickening and percolation of particle chains [25,26].…”

Section: Introductionmentioning

confidence: 99%

Effect of matrix solidification on the structure formation in electromagnetic suspensions

2022

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For suspensions with electromagnetic particles exposed to an external field, we examine the effect of the solidification of the suspending medium on the formation of particle structures, representative of the curing of a photo-reactive resin during stereolithography. To that end, Brownian Dynamics (BD) simulations are examined in which the solidification of the suspending medium can be incorporated by increasing its viscosity in the course of time. For illustrative purposes, it is assumed that the viscosity function is known apriori in explicit and parametrized form, however, experimental data can be used as well. It is demonstrated that one can study the effects of the viscosity increase by a transformation of time, akin to the time–temperature superposition principle, but here also in the presence of thermal noise on the suspended particles. Therefore, instead of performing BD simulations with a continuously increasing viscosity (computationally inefficient), we advocate performing simulations at a constant (low) viscosity and subsequently transform time (nonlinearly) for re-interpretation of the simulation results. So doing, one can predict the formation of particle structures during on-going solidification of the suspending medium. In practice, the viscosity increase is so drastic that further evolution of the particle structure can be considered as arrested after the characteristic transition-time of the viscosity is reached. Semi-quantitative rules of thumb are formulated for the 3D-printing practitioner. Graphical Abstract

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Section: Introductionmentioning

confidence: 99%

Effect of matrix solidification on the structure formation in electromagnetic suspensions

2022

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“…Because the size of the microlens is far beyond the operating wavelength, there is no wavelength dependence, which is obviously different from the scheme for photonic crystals. A large number of reports in the literature described the application of MLAs onto the light extraction of OLEDs, − a single photon source, , super-resolution imaging, upconversion luminescence, and ultrafast adaptive optics . MLAs can be fabricated by methods such as thermal photoresist reflow, − laser direct writing, , inkjet droplets, , self-assembly method, − optical μ-printing technology, and nanoimprint lithography .…”

Section: Introductionmentioning

confidence: 99%

“…A large number of reports in the literature described the application of MLAs onto the light extraction of OLEDs, 16−21 a single photon source, 22,23 superresolution imaging, 24 upconversion luminescence, 25 fast adaptive optics. 26 MLAs can be fabricated by methods such as thermal photoresist reflow, 27−30 laser direct writing, 31,32 inkjet droplets, 33,34 self-assembly method, 35−38 optical μ-printing technology, 39 and nanoimprint lithography. 40 However, the research of MLAs for controlling scintillation luminescence is rare.…”

Section: Introductionmentioning

confidence: 99%

Directional Control and Enhancement of Light Output of Scintillators by Using Microlens Arrays

Yuan

Liu

Zhu

et al. 2020

ACS Appl. Mater. Interfaces

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Scintillators play an important role in the field of nuclear radiation detection, such as nuclear medical imaging, dark matter detection, nuclear physics experiments, and national security. However, the light extraction efficiency of a scintillator with a high refractive index is severely restricted because of the total internal reflection. In this paper, microlens arrays have been applied onto the surface of a cerium-doped lutetium−yttrium oxyorthosilicate scintillator to improve the light extraction efficiency and to control the directivity of the light output. Compared to that of a reference sample, a 3.26-fold enhancement with an emission angle of 45°has been obtained by using microlens arrays with optimal parameters. It was also found that the enhancement ratio can be affected by the refractive index of the microlens, the spacing of individual microlens. The control mechanism of microlens arrays is revealed by a combination of simulations and experiments. X-ray imaging characteristics exhibit an improved gray scale amplitude without any loss of the spatial resolution. The present results suggest that the application of microlens arrays to scintillators is beneficial to the field of nuclear radiation detection.

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“…Micro-sized water droplets have been widely used in multiple research fields, such as analytical chemistry [1], [2], precision engineering [3]- [7], biological sciences [8]- [12], etc. [13]- [17].…”

Section: Introductionmentioning

confidence: 99%

Novel Method to Simultaneously Adjust the Size and pH Value of Individual Microdroplets in Silicone Oil

Chen

Zhang

2019

IEEE Access

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In this paper, a strategy to modify each micro-droplet's volume and synchronously adjust its pH value as required based on the electrolysis reaction in silicone oil is demonstrated. A pair of platinum electrodes fixed onto the jaws of a vernier caliper was used to modify the micro-droplet's volume and adjust its pH value by simply adjusting the distance between the two electrodes. To get a micro-droplet with desirable volume and pH values, three models, the relationship between the droplet's volume and its diameter when the droplet was placed on a fluorinated ethylene propylene (FEP)-covered glass substrate, the relationship between the distance of the two electrodes and the size of the resulted micro-droplet, and the relationship between the pH value and the micro-droplet's consuming rate, were built through the least square method. In our experiments, a droplet (5% sodium chloride solution, 1.4 uL, pH = 7) could consume 98.9% of its initial volume and form a new droplet with a volume of 0.016 µL and pH of 12.2. In addition, to validate that this method is also suitable in the acid and alkaline solutions, 0.001 mol/L NaOH and H 2 SO 4 solutions were, respectively, operated using the same procedure. Both the volume and pH values could be controlled, which proved the potential application of our proposed method in analytical chemistry, precision engineering, and so on.

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Ultra-fast adaptive optical micro-lens arrays based on stressed liquid crystals

Cited by 14 publications

References 43 publications

Effect of matrix solidification on the structure formation in electromagnetic suspensions

Effect of matrix solidification on the structure formation in electromagnetic suspensions

Directional Control and Enhancement of Light Output of Scintillators by Using Microlens Arrays

Novel Method to Simultaneously Adjust the Size and pH Value of Individual Microdroplets in Silicone Oil

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