Hembach Photonik GmbH’s Post

Optical Particle Sizing Optical particle sizing is an important application of volumetric light scattering, needed across numerous industries.  Figure (a) shows a typical measurement setup simulated in RayJack ONE®: a sample cell, which is filled with an aqueous suspension of particles, is illuminated by a convergent laser beam; concentric ring-shaped photodiodes measure the scattered light flux and are numbered with increasing diameter. The latter ranges from fractions of a mm for the inner to centimeters for the outer photodiodes. The suspension is assumed to have a bimodal particle size distribution (b). Mie theory is used for evaluation, taking into account side effects such as multiple scattering.  The resulting sensor signal is shown in (c), with the larger particles producing more signal on the inner photodiodes. Although it might look straightforward, reconstructing the particle size distribution from the sensor signals is a really difficult task, requiring advanced mathematical algorithms such as regularization.   Follow us on LinkedIn for the latest news, learn more about RayJack ONE® on our website, https://lnkd.in/d_bzNUA and our YouTube channel: https://lnkd.in/eKQHaUFg #RayJackONE #OpticalParticleSizing #illumination #scattering #MieTheory 

Happy Friday! Enjoy this micrograph of a used spark plug anode, showing corrosion, wear, and cracking on the surface. This photo was taken using a scanning electron microscope in backscatter mode, at 450x magnification. #MASTest #MaterialsScience #MaterialsTesting #Micrograph Image description: Grayscale image taken with a scanning electron microscope in backscatter mode, showing corrosion, wear, and cracking on the surface of a used spark plug anode. This image was taken at 450x magnification.

Diamond powder Grade D40 image under microscope

Material parameters for volume scattering – part two In the previous post, we discussed the retrieval of material parameters for volume scattering. The theoretical framework for simulations is the radiative transfer equation (RTE – see more details on Wikipedia), which is a quite complicated integro-differential equation. The most commonly used approximate solution is achieved through Monte-Carlo integration, which directly leads to stochastic ray-tracing: a ray undergoes a sequence of straight propagation, deflection through scattering, or absorption (shown in the left picture). While this method is highly versatile, it tends to be slow and susceptible to statistical noise More efficient methods for solving the Radiative Transfer Equation (RTE) exist, particularly when symmetries are present. One such method is the Adding-Doubling method, which is applicable to slabs of infinite lateral extent and rotationally symmetric illumination. In this approach, the reflection and transmission matrices of thin slabs are iteratively "added" to form thicker slabs until the desired slab thickness is achieved, as illustrated in the right picture. Both Monte-Carlo method and Adding Doubling are implemented in RayJack ONE® and – except for statistical noise - yield the same results (right lower picture). Adding doubling is often orders of magnitude faster than Monte-Carlo (since it involves no ray tracing), depending on system parameters which makes it the method of choice for retrieving scattering parameters, if the symmetry conditions are met. Learn more about RayJack ONE® on our website: https://lnkd.in/dJfMUa3 and our YouTube channel: https://lnkd.in/e6U_cKFu #RayJackONE #illumination #scattering  

Diamond powder Grade D90 image under microscope

Material parameters for volume scattering – part two In the previous post, we discussed the retrieval of material parameters for volume scattering. The theoretical framework for simulations is the radiative transfer equation (RTE – see more details on Wikipedia), which is a quite complicated integro-differential equation. The most commonly used approximate solution is achieved through Monte-Carlo integration, which directly leads to stochastic ray-tracing: a ray undergoes a sequence of straight propagation, deflection through scattering, or absorption (shown in the left picture). While this method is highly versatile, it tends to be slow and susceptible to statistical noise More efficient methods for solving the Radiative Transfer Equation (RTE) exist, particularly when symmetries are present. One such method is the Adding-Doubling method, which is applicable to slabs of infinite lateral extent and rotationally symmetric illumination. In this approach, the reflection and transmission matrices of thin slabs are iteratively "added" to form thicker slabs until the desired slab thickness is achieved, as illustrated in the right picture. Both Monte-Carlo method and Adding Doubling are implemented in RayJack ONE® and – except for statistical noise - yield the same results (right lower picture). Adding doubling is often orders of magnitude faster than Monte-Carlo (since it involves no ray tracing), depending on system parameters which makes it the method of choice for retrieving scattering parameters, if the symmetry conditions are met. Learn more about RayJack ONE® on our website: https://lnkd.in/d_bzNUA and our YouTube channel: https://lnkd.in/eKQHaUFg #RayJackONE #illumination #scattering  

Nonlinear Thomson scattering: velocity asymmetry inherent in electron figure-8 motion https://lnkd.in/exqBsNvG

HoSb offers a unique platform for exploring the interplay between extremely large magnetoresistance, magnetism and topology in an AFM matrix.

Diamond powder Grade D30 image under microscope

Here is another one from the series of posts that nobody asked for. Related to the previous post about the slit nozzle, here is an interesting application. Place 100 microns wire (or whatever diameter you want) longitudinally in the middle of the slit nozzle. As shown in the figure, the wire modulates the density profile transversely and generates a profile that looks like a waveguide in one plane. The applications are various: for instance, you can use it to guide the laser and the electron beam in one plane and reduce the electron beam pointing in the direction of the polarization of the laser. Another possible application is the enhancement of the betatron emission when the laser beam is injected at a small angle relative to this waveguide. If you have more ideas for the experiment, please leave comments. Be nice and share.