Reliability of 3D Imaging by Digital Holography at Long IR Wavelength

We present test results of DH in the IR range, in several configurations, in transmission and reflection mode and their performance when used on several different materials. Moreover, we show the feasibility of large object holography using a CO2 laser and a digital thermal camera.

Digital Holography (DH) in the infrared (IR) range presents some peculiar aspects compared with the more common DH in the visible range. The current major drawback is due to the size of the pixel pitch of presently available thermal cameras, which is rather large compared to what would be optimal, and what is possible with analog films. However, since the CO2 laser wavelength is 15 times longer than average visible wavelength, a much higher stability, a wider view angle, and shorter acquisition distances are achievable, allowing easier acquisition of large object holograms.