Laser-plasma interactions

Laser–plasma interactions form the foundation of modern high-field science, enabling extreme states of matter and new acceleration regimes. When an ultra-intense laser pulse propagates through plasma, it drives collective electron oscillations, excites wakefields, and triggers relativistic nonlinear processes that cannot be observed in conventional materials. These fundamental interactions govern how energy is transferred from light to charged particles and radiation, laying the groundwork for compact particle accelerators, bright radiation sources, and laboratory astrophysics. 


The development of advanced plasma sources is essential for achieving precise control in laser–plasma experiments. Various methods such as supersonic gas jets, capillary discharge plasmas, and tailored density profiles allow researchers to create plasmas with tunable lengths, densities, and gradients. Producing high-quality electron beams from plasma accelerators is central to their practical use in science and technology. While laser wakefield accelerators naturally generate relativistic electron beams, maintaining low emittance, narrow energy spread, and long-term stability requires sophisticated control. Techniques such as controlled injection schemes, plasma density tailoring, and external guiding channels have enabled remarkable improvements.  We have developed new type of a plasma target which is the segemented capillary gas-cell that produce very stable electron beam with improved qualities such as reduced energy spread, reproducibility, stable pointing and energy jitter by the simple tuning of the module structure and pressures.  Such innovations not only enhance the stability and reproducibility of wakefield acceleration but also enable novel regimes of beam and radiation generation, making them a critical component of next-generation plasma-based technology.


Betatron radiation emerges when electrons accelerated in plasma wakefields undergo transverse oscillations due to the plasma’s focusing forces. These oscillations are analogous to those in synchrotron light sources, yet they occur in centimeter-scale plasmas, yielding bright, ultrashort X-ray pulses. Compact betatron X-ray sources combine femtosecond time resolution with micron-scale spatial resolution, opening opportunities in biomedical imaging, ultrafast science, and probing matter at high energy density conditions. This compact bright X-ray sources can be located at universities, hospitals and industrial applications which enable more accessible for the user than previous few and large conventional X-ray facilities.    


A promising hybrid approach is to inject high-quality electron beams from conventional RF accelerators into plasma wakefields. External injection allows precise control of the injected beam’s phase space, enabling synchronization with plasma waves for efficient acceleration. By combining the stability and maturity of RF linacs with the ultra-high gradients of plasma accelerators, this method provides a path toward scalable, high-brightness sources for advanced applications such as free-electron lasers and high-energy colliders. 


Plasma lenses exploit the collective electromagnetic fields of plasma to focus relativistic electron beams with strengths far exceeding those of conventional quadrupole magnets. Their compact size and ultra-strong focusing gradients make them attractive for beam transport, staging of plasma accelerators, and preserving beam quality in compact facilities. Plasma lenses are thus a crucial enabling technology for the integration of plasma-based accelerators into real-world applications. 


Terahertz (THz) generation from laser–plasma interactions leverages mechanisms such as ponderomotive-driven currents, transition radiation, and plasma wave excitation. Unlike solid-state sources, plasma-based THz emitters can sustain extremely high laser intensities, producing THz pulses with strong fields and broadband spectra. These sources are attractive for applications in ultrafast spectroscopy, non-invasive imaging, and even controlling material properties at the quantum level. 

  

Plasma acts as a unique optical medium capable of manipulating the most intense laser pulses. Applications include plasma mirrors for enhancing laser contrast, plasma gratings for compressing pulses, and nonlinear effects such as self-focusing. Because plasma does not suffer damage at extreme intensities, unlike solid optics, it offers an indispensable platform for the next generation of ultra-intense laser experiments, paving the way for discoveries in strong-field physics and high-energy-density science.