Reactive ion beam etching of highly dispersive, high-efficiency transmission gratings for the VIS range

Annemarie Finzel,Felix Koch,Frank Frost,Dennis Lehr,Gregor Dornberg,Tilman Glaser

doi:10.1117/1.oe.58.9.092614

Abstract

Reflection losses due to refractive index mismatch limit the obtainable diffraction efficiencies for transmission gratings in the highly dispersive regime, i.e., with period to wavelength ratios smaller than 0.7. The design and fabrication of such gratings with high-diffraction efficiencies (≥94 % , Littrow configuration) will be discussed with an emphasis on process strategies to control the profiles in the reactive ion beam etching step. Experimental results from the manufacturing of monolithic fused silica pulse compression gratings with 3000 L / mm optimized for a center wavelength of 519 nm will be presented. The influence of different etching parameters such as etch gas mixture, ion incidence angle, and acceleration voltage of the ion source on profile depth, side-wall angle, duty cycle, and ultimately diffraction efficiencies will be discussed.

Highlights

With the growing importance of ultrashort pulse lasers, in fundamental research and for industrial applications, e.g., material processing[1,2] and biomedical technology,[3] the demand for tailored optical components arises
A major step toward the successful establishment of ultrafast laser technology was the technique of chirped pulse amplification (CPA), which enabled the generation of highenergy pulses, overcoming the severe limitations imposed by nonlinear self-focusing effects in conjunction with the damage threshold properties of optical materials, the gain medium.[4]
An advantage of reactive ion beam etching (RIBE) is the large range of selectivities that can be realized by varying the mixture of the reactive gases

Summary

Introduction

With the growing importance of ultrashort pulse lasers, in fundamental research and for industrial applications, e.g., material processing[1,2] and biomedical technology,[3] the demand for tailored optical components arises. Dispersive surface transmission gratings are attractive for further applications, e.g., spectral beam combining[15] for laser diode

Methods

Results

Conclusion