THz metrology with monolithic tunable two-color diode lasers

We use a slotted Y-branch Laser for Terahertz thickness measurements of high resistive float zone silicon wafers of different thicknesses. The laser provides two-color emission in the 1550 nm region with an optical beat frequency of 1 THz. It is used as a photonic source for thickness measurements of high resistive silicon wafers with continuous wave Terahertz radiation. Frequency tuning is obtained through segment current tuning of the individual branches. We determine the sample's refractive index and thickness by MSE fitting of the theoretical etalon transmission to the experimental results without additional knowledge.