Generation of surface-wave microwave microplasmas in hollow-core photonic crystal fiber based on a split-ring resonator

The striplastron: A new circular stripline microwave launcher for plasma generation in capillary tubes

Until now, microwave plasmas could be ignited in small capillary tubes (inner diameter less than 1 mm) by generating surface waves propagating along their dielectric surfaces using mainly surfatron launchers or stripline-based launchers, such as "split-ring resonators." This work presents a novel launcher, which is called the "striplastron," because it is halfway between surfatrons and stripline launchers. It is a circular stripline directly excitated by a microcoaxial cable. Compared with the surfatron, it is smaller and the part of the plasma hidden by the launcher is limited to its thickness (∼1-2 cm). Moreover, its frequency response presents an intense and large resonance. Eventually, its geometry could allow the simultaneous ignition of several microplasmas in capillaries arranged in parallel, which could be very interesting for applications, such as the use of multi-tube microplasmas as metamaterials.

Hollow-Core Fiber Technology: The Rising of “Gas Photonics”

Since their inception, about 20 years ago, hollow-core photonic crystal fiber and its gas-filled form are now establishing themselves both as a platform in advancing our knowledge on how light is confined and guided in microstructured dielectric optical waveguides, and a remarkable enabler in a large and diverse range of fields. The latter spans from nonlinear and coherent optics, atom optics and laser metrology, quantum information to high optical field physics and plasma physics. Here, we give a historical account of the major seminal works, we review the physics principles underlying the different optical guidance mechanisms that have emerged and how they have been used as design tools to set the current state-of-the-art in the transmission performance of such fibers. In a second part of this review, we give a nonexhaustive, yet representative, list of the different applications where gas-filled hollow-core photonic crystal fiber played a transformative role, and how the achieved results are leading to the emergence of a new field, which could be coined “Gas photonics”. We particularly stress on the synergetic interplay between glass, gas, and light in founding this new fiber science and technology.