Dye laser Hansch-type

The experimental apparatus is discussed elsewhere. Briefly, a lOkW peak power Hansch-type dye laser with a 0.5 cm" bandwidth is focused into a sodium heat-pipe cell. The laser intensity at the focus is 10 Mw/cm. The sodium cell is 20 cm in length. Argon at a few torrs pressure is used as a buffer gas. 

Fig. 5.43. Short Hansch-type dye laser cavity with Lillrow grating and mode selection either with an internal etalon or an external FPI as mode filter [5.58]...

Fig.5.83, Hansch-type dye laser with transverse pumping and beam expander [5.171]. The wavelength is tuned by turning the Littrow grating. Light with a different wavelength Xd + AX is diffracted out of the resonator...

Measurement of ratios. An example of this type of measurement was given by WIEMAN and HANSCH, [6] who successfully measured the ground state Lamb shift of H and D by comparing a laser at Balmer 8 at 4860 A with another dye laser which was doubled to look at the two-photon transition 1S-2S, Lyman a. The measured... 

Our experimental apparatus consists of a sodium containing heat-pipe cell with an active length of 20 cm the buffer gas is argon at a few torr pressure. The sodium density is in the range of 10 -10 cm". The dye laser is Hansch type and is pumped by a 30 kW peak power copper-halide laser with a 25 nsec duration pulse. The dye laser bandwidth is 0.5 cm . The laser beam is spatially filtered and focused into the sodium cell. The laser intensity at the focus is about 10 Mw/cm and is sufficient to form self-trapped filaments. The spectrum of the emission is monitored by 1.2 cm resolution McPearson 0.3m monochromator. The forward emission is photographed by an Alphax B216 camera placed after the sodium cell without any imaging optics. The laser beam is blocked with an on-axis disk. 

For high-resolution spectroscopy the bandwidth of the dye laser should be as small as possible. With two etalons having different free spectral ranges, single-mode operation of the Hansch-type laser (Fig. 5.83) can be achieved. For continuous tuning both etalons and the optical length of the laser resonator must be tuned synchronously. This can be realized with computer control (Sect. 5.4.5)... 

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