Effect of the spatial coherence length on the self-reconfiguration of a speckle field

Exploring Disordered Light Transport in Scattering Media to Optimize Random Lasers

“…The impact of disordered light patterns on optimizing RL efficiency can also be assessed by measuring the total distance traveled by coherently backscattered photons within a scattering medium. However, since the measurements were conducted with disordered light patterns, it was necessary to control their spatial coherence by managing the illumination area of the light diffusers. , This was achieved by placing the diffusers inside a telescope, as depicted in Figure a, in such a way that the smaller the diffuser’s illuminated area, the lower the spatial coherence loss of the incident beam, and the larger the spatial coherence length of the hot spots. , Figure a shows the transverse intensity profile collected by the camera that was generated to illuminate the scattering samples (with and without Rh6G). In contrast to the disordered light patterns used in refs , for RL excitation, a smaller number of larger-sized hot spots were observed by illuminating the diffuser with an area of hundreds of μm 2 .…”

“…However, since the measurements were conducted with disordered light patterns, it was necessary to control their spatial coherence by managing the illumination area of the light diffusers. 34,35 This was achieved by placing the diffusers inside a telescope, as depicted in Figure 1a, in such a way that the smaller the diffuser's illuminated area, the lower the spatial coherence loss of the incident beam, and the larger the spatial coherence length of the hot spots. 34,35 Figure 3a shows the transverse intensity profile collected by the camera that was generated to illuminate the scattering samples (with and without Rh6G).…”

Three-Dimensional Speckle Light Self-Healing-Based Imaging System

“…This is the so-called self-reconfiguration effect 21 . Additionally, a theoretical model was presented with an explicit equation to the reconfiguration length τ 22 , where δ is the transverse coherence length, λ is the wavelength of the light source and D is the disc diameter. One can explain the self-reconfiguration effect through the Huygens’ Principle.…”

“…Assuming small divergence, the portion of the spots that is not blocked by the obstruction reconstructs the speckle pattern beyond the shadow of the disk at a distance , where D is the disc diameter, resembling Eq. 1 22 . An interesting point though is that, we can align as many different opaque objects as we want along the beam axis and separated by a distance , and after τ from the last object, a homogeneous speckle pattern will be observed.…”

“…Here we present a 3D microscopy system where it is possible to obtain independent images of superimposed planes in a direct way, without the necessity of complex computational algorithms to descramble the images and stringent system calibrations. The idea is based on the self-reconfiguration effect 21 , where the speckles after being partially blocked can be reconfigured after the reconfiguration length 21 , 22 . Using this principle, it is possible to explore most of the applications that has been done with Bessel beams but with speckles features.…”