1. Formation of coupled-cavities in quantum cascade lasers using focused ion beam milling
- Author
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Piotr Karbownik, Maciej Bugajski, Jacek Ratajczak, Andrzej Czerwiński, Piotr Gutowski, Adam Łaszcz, Kamil Pierściński, Mariusz Płuska, and Dorota Pierścińska
- Subjects
Materials science ,business.industry ,Single-mode optical fiber ,Nanotechnology ,Condensed Matter Physics ,Laser ,Focused ion beam ,Atomic and Molecular Physics, and Optics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Reliability (semiconductor) ,law ,Cascade ,Optoelectronics ,Electrical measurements ,Electrical and Electronic Engineering ,Safety, Risk, Reliability and Quality ,Quantum cascade laser ,business ,Quantum - Abstract
Focused ion beam (FIB) systems have become very useful tools used in the nanotechnology because they provide easy prototyping or post-processing customization of individual devices. A practical application of such post-processing is modification of monolithic quantum cascade laser (QCL) to obtain the structure with coupled cavities (CC-QCL), enabling its single mode performance, critical in many QCL applications. In-situ electrical measurements of the test structures showed that the main problem is avoiding a secondary deposition of the milled material. The redeposition can significantly reduce the performance and reliability of lasers. An avoidance of FIB imaging after final FIB cleaning of walls was revealed as an important factor leading to high quality of structures. The paper describes the solution by developing appropriate patterning procedure. This enabled the formation of exemplary single mode CC-QCLs with excellent performance at 9.45 μm wavelength with 30 dB side-mode suppression ratio, operating at room temperature. Performance of obtained single-mode coupled cavity quantum cascade lasers was stable, repeatable and no reliability problems were observed.
- Published
- 2015