Investigation of laser speckle noise suppression by using polymer-stabilized liquid crystals within twisted nematic cell

Abstract

We propose a robust method to suppress laser speckle using a polymer-stabilized liquid crystal (PSLC) device with high initial transmittance. With applied voltage, a large modulation depth has been produced through light scattering because of the refractive index mismatch between the rotated nematic liquid crystals and the polymer networks. By using PSLCs with 5 wt % monomer, a speckle noise reduction rate of approximately 54.7% can be achieved with an applied voltage of 6 V. The lowest speckle contrast of approximately 0.025 with relatively high discrimination from the projected AF image has also been demonstrated through a wedge PSLC cell.

Methods and Devices of Speckle-Noise Suppression (Review)

“…Experimental setup for studying light modulation using a PSLC cell at different values of the control voltage (Ref. [39], Figure 3).…”

Laser speckle reduction using polymer-stabilized liquid crystals doped with Ag nanowires

“…Liquid crystals (LCs) have been widely used in the display field because of their excellent electro-optical properties and have become ideal fillers for static diffusers. Some research groups have reported studies on speckle reduction by LCs [ [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] ] because LC molecules have unique birefringence properties and can be modulated by an electric field. LCs are typically used for speckle reduction in the form of polymer LC composites, in which dynamic transition between the scattering and transparent states can be achieved by voltage control.…”

3D Remote Healthcare for Noisy CT Images in the Internet of Things Using Edge Computing

“…However, speckle noise in CT images causes severe visual interference and obscures the image's features [5]. Speckle noise is caused by the interference of ultrasound on human tissues, and its component information is complex.…”