Abstract

We developed a diode laser spectrometer with an intrinsic amplitude stability of a few parts in 10⁶, a tunability of more than 20 nm, an instrumental linewidth less than 1 MHz and a frequency stability better than 100 KHz. Wide tunability was achieved by combining the extended cavity diode laser configuration^[1] with low temperature tuning operation. In Fig. 1 is illustrated the diode laser source where the grating provides the optical feedback (one facet of the diode laser is a.r. coated) and selects the wavelength (±5 nm), while the vacuum box containing the laser allows temperature tuning operation (about 2 nm per K). In a different version, temperatures down to 80 K can be reached by means of a miniaturized Joule-Thomson refrigerator. The extended cavity configuration is also responsible of the linewidth narrowing and frequency stability features.^[2]

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