Speckle-free imaging is attractive in laser-illuminated imaging systems. The evolutionary process of supercontinuum decoherence in extra-large mode area step-index multimode fiber is analyzed to provide high-quality broadband light source for speckle-free imaging. It is found that spectral bandwidth, number of spatial transverse modes, and decoherence among different modes all greatly contribute to speckle reduction. The combination of supercontinuum and extra-large mode area step-index multimode fiber can considerably increase the efficiency of decoherence process for speckle-free imaging. This work may enrich the research of speckle-free imaging and also provide guidance on speckle-free imaging using fiber-optics based light source.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1364/OE.26.026758 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
Laser Laboratory, Dept. of Physics, The University of Burdwan, Burdwan 713104, India.
The angular dependence of random laser (RL) generation in a commercially available rhodamine 6G (Rh6G) dye has been demonstrated using ZnO-CuO heterostructure as passive scatterers. The grass-like superstructure formed at a 1M:1M molar ratio of ZnO-CuO significantly enhances scattering, resulting in RL spikes with a full width at half maximum (FWHM) of just a few nanometer and a noticeable reduction in the RL threshold. RL emission spectra were collected over an angular spread of 0-180 degrees, revealing a remarkable shift in RL emission from 566 nm to 580 nm.
View Article and Find Full Text PDFNanoscale
September 2024
Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, P. R. China.
Controlling the random lasing action from disordered media is important to obtain customizable lasers with unprecedented properties. In this paper, systematic investigations of random scattering based on GaAs/AlGaAs axial heterostructure nanowire (NW) arrays are presented. By manipulating the diameter and density of GaAs/AlGaAs axial heterostructure NWs during growth, different types of random lasers (Anderson localized and delocalized random lasers) have been successfully realized.
View Article and Find Full Text PDFUltrasonography
September 2024
Department of Robotics and Mechatronics Engineering, Daegu Gyeongbuk Institute of Science and Techology, Daegu, Korea.
Purpose: Deep learning-based image enhancement has significant potential in the field of ultrasound image processing, as it can accurately model complicated nonlinear artifacts and noise, such as ultrasonic speckle patterns. However, training deep learning networks to acquire reference images that are clean and free of noise presents significant challenges. This study introduces an unsupervised deep learning framework, termed speckle-to-speckle (S2S), designed for speckle and noise suppression.
View Article and Find Full Text PDFRandom lasers (RLs), with their low spatial coherence, are ideal illumination sources for speckle-free imaging. However, it is still challenging for RLs to maintain low spatial coherence with the need for integration and directionality. Here, a disordered multimode random polymer fiber laser (RPFL) is proposed and implemented as a low-spatial-coherence light source.
View Article and Find Full Text PDFWe develop and validate a model-based iterative reconstruction framework for digitally correcting coherent images corrupted by deep turbulence. In general, this framework is applicable to coherent-imaging approaches that gain access to the complex-optical field; however, we demonstrate our approach with multi-shot digital holography data. To test our image correction framework, we generate calibrated deep-turbulence conditions from our laboratory testbed.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!