Observation of Lamb-Dip and Transient Nutation at Microwave Frequency
Several nonlinear effects at microwave frequency have been observed in interaction of molecules with a coherent radiation field. From the klystron, a microwave oscillator, a coherent radiation is available, which is as good as the laser radiation in spectral purity, photon flux density, directivity and so on. In the microwave frequency region may be found the counterparts of the various nonlinear phenomena which have been observed in the infrared and visible wavelength regions by laser spectroscopic methods. Those effects might be very usefully employed for an investigation of the fast process of rotational relaxation in molecules. In the first part of the present article an observation of saturation dip in the microwave absorption line is described. In the second part a transient change in the intensity of molecular absorption line caused by a fast switching of microwave field, will be discussed.
KeywordsMicrowave Frequency Decay Time Constant Rotational Quantum Number Inversion Transition Microwave Transition
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- 1).T. Shimizu and C. C. Costain, “Observation of Saturation Dip in the Microwave Spectral Line”, to be submitted.Google Scholar
- 3).T. Amano and T. Shimizu, “Observation of Transient Nutation Effect in Microwave Transitions of Ammonia Molecules”, to be published in J. Phys. Soc. Japan.Google Scholar