Semiconductor laser excitation of Ramsey fringes by using a Raman transition in a cesium atomic beam

An amplitude-modulated semiconductor laser is used to excite a 9.2-GHz Raman transition in a cesium atomic beam. Separated-field Ramsey fringes as narrow as 1 kHz wide are observed with a high signal-to-noise ratio, even for semiconductor laser linewidths as wide as 20 MHz. These narrow resonances have potential application in the development of high-accuracy, optically excited atomic clocks.