Frequency stabilization of a semiconductor laser using water-vapor absorption lines

Abstract

Distance measurements based on the principle of optical interferometry require stabilized laser frequencies. Recently frequency stabilization of lasers has been successfully achieved using, for example, rubidium and iodine absorption lines. These materials are used to stabilize a single frequency. For some applications, especially in the field of optical metrology, it is necessary to stabilize several wavelengths in a region of about 10 nm simultaneously. The simple molecule water vapor shows a system of many vibrational-rotational absorption lines in the near-infrared region. We show that it is possible to use water-vapor absorption lines for frequency stabilization by locking a semiconductor laser to the 791-nm (379-THz) absorption line. We discuss the stability of a synthetic wavelength that could be achieved by stabilizing two lasers independently on two different water-vapor absorption lines.