Single-comb Vernier method for precise optical-frequency measurement

We propose a method for measuring laser frequency using only one optical frequency comb (OFC), eliminating the need for high-precision wavelength meters. By leveraging a Vernier effect within the OFC, we geometrically increase the comb-mode-number difference and sequentially stabilize the OFC. This method enables an accurate and reliable determination of the comb-mode number. Because the method is robust against relative fluctuations in mode spacing up to 3.6 × 10^-10, it significantly relaxes fluctuation requirements compared with traditional methods, thus broadening practical applications in metrology standards and precision spectroscopy.