We explore and demonstrate the feasibility of an optical-frequency-to-radio-frequency division method that is based on visible or near-infrared laser oscillators only. Comparing harmonic and sum frequencies, we generate the arithmetic average of two visible frequencies. Cascading n stages provides difference-frequency division by 2n. For a demonstration we have phase locked the second harmonic and the sum frequency of two independent diode lasers.
© 1990 Optical Society of America
H. R. Telle, D. Meschede, and T. W. Hänsch, "Realization of a new concept for visible frequency division: phase locking of harmonic and sum frequencies," Opt. Lett. 15, 532-534 (1990)