Mid-infrared optics

High volume precision optical manufacturer Reo has introduced a new range of mid-infrared optics that provide a higher laser damage threshold, a better spectral performance, improved environmental stability and greater mechanical durability.

These zinc sulphide (ZnS or Cleatran) components are intended for use with Ho:YAG pumped optical parametric oscillators (OPO’s) and other laser systems operating in the 2µm to 5µm spectral range. The ZnS substrates are precision ground and polished and then coated using ion beam sputtering (IBS) technology.  

The IBS process yields fully densified thin films that are virtually impervious to water absorption and extremely stable. These characteristics make them particularly well suited to demanding applications such as IR countermeasures, laser designating/rangefinding, atmospheric sensing, and small molecule spectroscopy.

This series of ZnS optics includes both flat and radiused components with substrates ranging from 5mm to 150mm in diameter. They all feature high surface accuracy (λ/10 at 632.8nm) and excellent surface quality (20-10), and are offered with a wide range of antireflection, high reflection and multi-spectral coating options. The laser damage threshold of the antireflection bands of these coatings has been measured to be >8J/cm² (at 2.05µm in a 75nsec pulse), while high reflection bands have demonstrated a damage resistance of >50J/cm² for the same pulse specifications.