Spinning disk as a spatial light modulator for rapid infrared imaging

A novel spinning disk approach is reported, to achieve video-rate compressive imaging at infrared (IR) and terahertz (THz) frequencies. It uses a 200-mm-diameter circular stainless steel disk with a number of chemically etched 2-mm-diameter holes as a spatial light modulator (SLM). The authors demonstrate that this mechanical SLM is well suited for imaging at both optical and THz frequencies since the stainless steel is opaque to all optical and electromagnetic radiations while the holes are totally transparent. Using a single pair of IR emitter and receiver, the authors demonstrate that the system is capable of capturing a 96 × 96 video sequence at 10 frames/s. The achieved spatial resolution is better than 2 mm using the spinning disk where the diameter of the holes is 2 mm. The authors also present a key-frame extraction method based on this SLM disk, which allows us to capture the shape of a sample even when its size is larger than the effective imaging area of the system.