Numerical Simulation of a Hollow-Core Woodpile-Based Mode Launcher for Dielectric Laser Accelerators

Abstract

Hollow core microstructures powered by infrared lasers represent a new and promising area of accelerator research, where advanced concepts of electromagnetism must be used to satisfy multiple requirements. Here, we present the design of a dielectric electromagnetic band gap (EBG) mode launcher–converter for high-power coupling in dielectric laser accelerators (DLAs). The device is based on a silicon woodpile structure, and it is composed of two perpendicularly coupled hollow-core waveguides—a transverse electric (TE)-like mode waveguide (excited from laser power) and a transverse magnetic (TM)-like mode (accelerating) waveguide—in analogy with the TE10-to-TM01 waveguide mode converters of radio frequency (RF) linear accelerators (LINACs). The structure is numerically designed and optimized, showing insertion losses (IL) 0.5 dB and efficient mode conversion in the operating bandwidth. The operating wavelength is 5 μm, corresponding to a frequency of ≈60 THz, in a spectral region where solid-state continuous-wave (CW) lasers exist and are actively developed. The presented woodpile coupler shows an interaction impedance in the order of 10 kΩ, high power handling and efficiency.

Keywords

• dielectric laser accelerators
• photonic crystals
• woodpile
• LINAC
• numerical simulation