Figure 8
From: In vivo terahertz sensing of psoriasis and eczema patients
(a) shows a diagram of a typical THz TDS reflection system: a femtosecond laser is split by a beamsplitter. One part of the beam is sent to an photoconductive antenna serving as an emitter and the other to a photoconductive antenna serving as a detector. The path length to the detector is altered by changing the length inside the optical delay unit (ODU). The THz light from the emitter is focused by a pair of TPX lenses onto to outer face of a quartz sampling window. The resulting reflection is focused by a second pair of lenses into the detector. The generated electric signal is processed by a lock-in amplifier and a computer system inside the Menlo Terasmart. This mechanism has been compacted into the handheld Skinometer device shown in (b). The diagram in Fig. 8 was produced in AutoDesk Fusion 2024 (https://www.autodesk.co.uk/products/fusion-360).
