CaLa2S4 transparent ceramics for Infrared Applications – CALASIR

The aim of the CALASIR project is to develop transparent CaLa2S4 ceramics from visible/near IR to far IR. CaLa2S4 has many advantages over existing commercial products. Compared to ZnS, the broadband IR reference material, it offers a better transparency in LWIR band, up to 14µm (12µm for ZnS) and a higher hardness (twice that of ZnS).
This material meets the growing demands for more efficient and cost-effective optical systems in the military (missile domes, improved erosion resistance, multispectral transmission) and civil industries where the arrival of affordable uncooled IR sensors (IRNR) will boost applications and markets.
A better hardness is particularly indicated to withstand harsh environments (severe abrasion, sand wind, salt mist….) to which, for example, protective windows of multispectral optronic equipment for the Army or the Navy are subjected. A higher transparency in the infrared significantly improves the performance of the infrared optical system and/or allow the use of IRNR detectors (operate beyond 12µm), resulting in a significant reduction in system cost.
This type of material is very interesting for thermal imaging. Civil applications mainly concern surveillance and security with very strong growth for assisted driving cars, autonomous vehicles and smartphones. These civil applications are, however, hampered by the cost of the optics that are still manufactured mainly using monocrystalline germanium, a rare and expensive element.
Thus, the development of new optical materials is a scientific, technical and economical challenge for the optronic industry and presents an opportunity to create new activities with high added value on our territory. The production, in the long term, of this strategic material in France also makes it possible to overcome the restrictions of use, supply or export (ITAR regulation).
In this project, we intend to:
- develop, on a larger scale, the finalized process of the initial project (DGA co-financed Solcera PhD) of preparation of pure nanometric CaLa2S4 powders
- develop an industrializable process of shaping and sintering to obtain multispectral CaLa2S4 ceramics.
- demonstrate the optical and thermomechanical qualities of the ceramics for use as optical windows on a 70mm diameter demonstrator.
This project proposes a powder metallurgy process compatible with mass production for large diffusion applications. This method offers many advantages over chemical vapor deposition (CVD) techniques, in particular shaping ("Near net shape" parts), manufacturing time and large-scale production and thus cost.
The consortium consists of an academic laboratory and an industrial partner recognized in their fields of expertise