Double-Track Waveguides inside Calcium Fluoride Crystals

Abstract

Calcium Fluoride (CaF2) was selected owing to its cubic symmetry and excellent luminescence properties as a crystal of interest, and ultrafast laser inscription of in-bulk double-track waveguides was realized. The guiding properties of these waveguides in relation to the writing energy of the femtosecond pulse are presented. The modified double-track waveguides have been studied by systematic developments of beam propagation experiments and numerical simulations. Furthermore, an adapted model and concepts were engaged for the quantitative and qualitative characterization of the waveguides, particularly for the transmission loss measurements and the three-dimensional refractive index mappings of the modified zones. Additionally, polarization-dependent guiding was investigated.

Ferroelectric Nanodomain Engineering in Bulk Lithium Niobate Crystals in Ultrashort-Pulse Laser Nanopatterning Regime

“…During the last two decades, direct laser writing emerged as versatile tool in nano- and micro-fabrication of integrated photonic circuits, Bragg gratings, optical memory bits, microfluidic and optofluidic channels, phase and polarizing elements and devices in bulk dielectrics [ 1 , 2 , 3 , 4 , 5 ]. Inscription in a homogeneous dielectric medium requires a formation of a new high-contrast refractive-index interface, possible via densification in silica materials [ 6 , 7 ] and rarefaction in other dielectrics [ 8 ], boosting empty nanovoids [ 9 ] or drilling of hollow microchannels [ 10 ]. Meanwhile, rather recently—about one decade ago—a new fundamental high-NA (numerical aperture) laser inscription process (“bulk nanopatterning”, BN), relying on nanoplasmonic self-organization of birefringent grating arrays in bulk dielectrics as functional microbits, was matured for design and fabrication of innovative optical elements and devices.…”

A flexible, fast and benchmarked vectorial model for focused laser beams

“…In the last two decades, laser processing in the bulk of optical materials has attracted intensive attention in a wide range of academic researches and industrial engineering. In-volume laser direct writing enables precise three-dimensional structuring and has allowed many innovative applications that include the fabrication of channels [2][3][4][5], waveguides [6][7][8][9][10], gratings [11], data storage [12], and photonics quantum gates [13,14]. The nature of the in-bulk processing also innovates new manufacturing procedures such as bonding [15][16][17][18][19] and dicing [20] of brittle materials.…”