Multilayer terahertz thickness imaging at 1.6-kHz pixel rate

Terahertz layer thickness measurements is one of the most promising fields of applications for terahertz technology. Measuring subwavelength layers in multilayer systems is most commonly achieved by applying retrieval algorithms. These algorithms are computational demanding, which makes it hard for the evaluation to keep up with the increasing speed of modern terahertz systems. ECOPS-based systems now achieve measurement rates above 1 kHz. By applying a highly efficient algorithm based on desktop-grade CPU, we achieve multilayer imaging at 1.6 kHz measurement rate. A three-layer system on a metal disk of 300 mm diameter is measured in 2.5 minutes with 240000 pixels.