Broadened spectrum of LARS. For illustration, the light leaving the optical fiber was dispersed with a small diffraction grating and projected onto a nearby wall. Toward the red, the wavelength range is limited by the transmission range of the single-mode fiber (and by the sensitivity of the camera used for the photograph). The blue end depends on the optical power used for spectral broadening of the frequency comb. In this example we reach a wavelength coverage of about 480 nm to 700 nm.