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He defended his thesis "Development and application of beam shaping elements fabricated by laser micromachining in the NIR and THz wavelength ranges for material processing and imaging". Academic supervisor: Dr Vytautas Jukna.

Congratulations to our colleague on his excellent work, and best wishes for continued success!

 

The thesis focuses on laser beam shaping in the near-infrared and terahertz wavelengths. These beams are extremely narrow and concentrated emissions of light produced by lasers. Such beams are used in applications ranging from medicine to industry, and communications.

 

"Near-infrared radiation is controlled using geometric phase elements [special optical components that allow ultra-precise control of the properties of light waves], also known as Pancharatnam-Berry phase elements.

 

They are based on nanolattices of ultrashort pulses inscribed in the glass volume - periodic densifications and thinning of the material. By producing the lattices, we can control their rotation angle and other properties and use this to control the phase, polarisation or amplitude of the waves that pass through them," says the physicist.

 

The technology was developed exclusively by Lithuanian and UK researchers.

 

In the thesis, other materials, such as silicon and steel foils, were used to control terahertz waves, producing light-guiding elements with so-called diffractive or metasurface structures. According to Ernestas, these two wavebands are very different, the first is close to the visible light spectrum, while the second is closer to the radio spectrum. However, similar wave-forming principles can be applied to them - just with different materials.

 

How can all this benefit us all?

 

"This work explores new, unique beam distributions that have potential practical applications.

 

Two methods for high quality laser glass cutting have been demonstrated with geometric phase elements. We have also demonstrated a way to create high-power flat-top beams with complex polarisation distributions - such beams have been used in practice in the selective laser ablation of thin coatings [a process in which a material is removed from a surface using intense laser light]," explains E. Nacius.

 

 

 

In addition, his "light-breaking" diffractive elements for terahertz waves have been used in practical imaging experiments. For example, a special lens has been developed to form a so-called Airy beam, which enables the registration of an image behind an opaque obstacle. In other words, it allows you to see what is "around the corner".

 

This work by Ernestas and his fellow physicists at FTMC has been highly acclaimed internationally and even made the cover of the prestigious journal Laser & Photonics Reviews! We have already written in May 2024 about it.