Newsletter: UP Researchers Record First Measurement of Elusive Light Shift in Low-Loss Dielectric Materials

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By: Eunice Jean C. Patron

A laser reflecting off glass looks like it follows the mirror rule—angle in equals angle out. But with sensitive tools, the spot shifts slightly, no bigger than a strand of hair. This elusive effect, called the Goos–Hänchen (GH) shift, was recently explored by scientists from the UP Diliman College of Science (UPD-CS) in materials that barely absorb light—such as those used in semiconductors and photonics.

Newsletter: UP Scientists Uncover Influence of Reflected Shock Waves on Plasma Behavior

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By: Eunice Jean Patron

Scientists around the world have extensively studied the expansion of laser-produced plasma (LPP) and the shock waves it generates in a background gas. However, little attention has been given to how the reflected shock wave—one that bounces back from a surface—affects the expanding plasma, despite its potential impact on LPP behavior.

Number density maps of copper and background gas species (helium and argon) at maximum plume compression under different background gas pressures. The times at which maximum plume compression occurs are indicated in the maps. (Photo credit: Emperado et al., 2025).

Dr. Rommil Emperado, Dr. Myles Allen Zosa, and Dr. Wilson Garcia of the University of the Philippines – Diliman College of Science’s National Institute of Physics (UPD-CS NIP), together with Dr. Lean Dasallas of the UPD-CS Materials Science and Engineering Program (MSEP), analyzed the interaction of copper LPP with surrounding gas through the direct simulation Monte Carlo (DSMC) method, which simulates particle behavior using random numbers.