Mid-infrared integrated optics: versatile hot embossing of mid-infrared glasses for on-chip planar waveguides for molecular sensing

Abstract

Abstract. The versatility of hot embossing for shaping photonic components on-chip for mid-infrared (IR) integrated optics, using a hard mold, is demonstrated. Hot embossing via fiber-on-glass (FOG), thermally evaporated films, and radio frequency (RF)-sputtered films on glass are described. Mixed approaches of combined plasma etching and hot embossing increase the versatility still further for engineering optical circuits on a single platform. Application of these methodologies for fabricating molecular-sensing devices on-chip is discussed with a view to biomedical sensing. Future prospects for using photonic integration for the new field of mid-IR molecular sensing are appraised. Also, common methods of measuring waveguide optical loss are critically compared, regarding their susceptibility to artifacts which tend artificially to depress, or enhance, the waveguide optical loss.

Chalcogenide Glasses for Infrared Photonics

“…An interesting point lies in the choice of materials with high refractive index contrast for controlling light at very small scales, opening new prospects. Among them, chalcogenide glass films suitable for chemical and biological sensing have been developed lately . They allow extension of the operating wavelength range from the visible to far infrared .…”

Direct nanoimprinting of moth-eye structures in chalcogenide glass for broadband antireflection in the mid-infrared

“…Moreover, the relatively low glass transition temperature allows for precision glass molding of IR optical elements based on chalcogenide glasses [4][5][6]. This has enabled numerous chalcogenide glass-based applications, such as chemical sensing [7,8], nonlinear optical devices [9,10], supercontinuum generation [11][12][13][14][15], and thermal imaging [4,6].…”

Advances in Mid-Infrared Spectroscopy for Chemical Analysis

“…Hence, recently emerging waveguide technologies focus on alternative MIR materials to facilitate the development and fabrication of planar single-mode MIR waveguide structures, enabling on-chip MIR photonics for label-free chem/bio and assay applications. Consequently, approaches using plasmonic structures (81,82), MCT (35), GaAs/AlGaAs, ZnSe, Ge (83,84), and diverse chalcogenide glasses (85) On-chip integration of waveguides offers the opportunity to use the same optical architecture for the waveguide and the active transducer element. As useful semiconductor materials usually have high refractive indices relative to the surrounding liquid or gas phase sample, sensing via the evanescent field is enabled.…”