Scanning digital holography at 10.6 mu m for large scene reconstruction

We demonstrate amplitude reconstruction of a very large scene hologram recorded by means of digital holography at 10.6 microns. Infrared digital holography is characterized by a low vibration sensitivity and a large field of view with respect to the analog technique in the visible range and it is, therefore, particularly suited for outdoor remote monitoring of large scenes. However, given the typical infrared sensor sensitivities, the power density scattered back by a large irradiated scene is usually not sufficient to produce a high signal to noise ratio hologram unless very high power lasers are used. Here we show that Mid Infrared Scanning Digital Holography can solve this problem. In particular, we report on the hologram amplitude reconstruction of a 6 m x 6 m scene from a distance of 30 min outdoor condition using a compact 60 W CO2 laser and a microbolometric camera.