High-Sensitivity Spectroscopy with Diode Lasers

Linewidth reduction of an extended cavity diode laser at 657 nm was accomplished by negative feedback to an intra-cavity ADP crystal. High resolution (170 kHz wide) saturated absorption signals were recorded of the calcium intercombination line which is of interest for a frequency standard. The spectrum of the red 6kn-92s1n cesium line in a magnetooptical cell trap was also investigated.