Perturbation analysis of Terahertz confocal microscopy

We propose a terahertz (THz) confocal microscope. The THz field is modulated by dithering an objective lens, and the signal is detected through a pinhole. The modulated signal is converted to an image using an analytic model based on perturbation analysis. The analytic model can successfully predict the surface profile of a test sample. This confirms that the proposed confocal microscope has a great potential for sample profiling in a THz imaging system.