Tunable radiation generation

Pumping is with a flashlamp, as in the case of the ruby laser, and a pulse energy of the order 1 J may be achieved. Frequency doubling (second harmonic generation) can provide tunable radiation in the 360-400 nm region. 

Spectra with higher resolution are now available. The development of new experimental techniques such as tunable, vacuum ultraviolet radiation, generated by gas-phase four-wave-mixing processes, permits the resolution of rotational structure. 

TUNABLE VUV AND XUV RADIATION GENERATED BY FREQUENCY MIXING IN GASES... 

Tunable radiation is generated by a)xuv=4o)uY+(jOY. With the radiation of a second dye laser (Ay=216-800 nm) the six-wave mixing should cover the whole range of 58 to 72 nm. 

An efficient way to generate coherent, tunable radiation in the far infrared is the difference frequency generation by mixing the output of an CO2 laser kept on a selected line with the output of a tunable CO2 waveguide laser in a MIM diode (Vol. 1, Sect. 5.8). With this technique Stark spectra of CHsOH were measured over a broad spectral range [149]. 

FIGURE 16 Level diagram for producing tunable radiation with two-photon resonantly enhanced four-wave sum-frequency mixing. Pump radiation at >i is tuned to the two-photon resonance, pump radiation at 0)2 is tuned over the range >2,min to ft>2,max, and the frequency of the generated radiation tunes over the range... 

TABLE XII Wavelength Range (nm) of Tunable UV and VUV Radiation Generated by Stimulated Raman Scattering in H2 (Au= 4155 cm ) with Dye Lasers ... 

Similar to the induced Raman effect, the hyper-Raman effect can also be used to generate coherent radiation in spectral ranges where no intense lasers exist. One example is the generation of tunable radiation around 16 xm by the stimulated hyper-Raman effect in strontium vapor [8.69]. 

R. Hilbig, R. Wallenstein Narrow band tunable VUV-radiation generated by nonresonant sum- and difference-frequency mixing in xenon and krypton. Appl. Opt. 21, 913 (1982)... 

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