Sub-Doppler Spectroscopy With a CMOS Transmitter

A compact and low-power complementary metal oxide semiconductor (CMOS)-based transmitter with an operational bandwidth of 90-105 GHz has been deployed as the radiation source in a high-resolution sub-Doppler (Lamb-dip) absorption spectrometer. The source output can be both frequency and amplitude modulated allowing for the application of highly sensitive detection schemes commonly used in molecular spectroscopy. The CMOS transmitter has been shown to have sufficient output power to perform spectral hole burning saturation experiments and a phase-noise floor low enough to determine spectral line positions with a precision of 1 part in 10⁹ to accuracy within the error of measurements made with traditional millimeter-wave sources.