Fabry-Perot domain

An alternative approach to obtaining microwave spectroscopy is Fourier transfonn microwave (FTMW) spectroscopy in a molecular beam [10], This may be considered as the microwave analogue of Fourier transfonn NMR spectroscopy. The molecular beam passes into a Fabry-Perot cavity, where it is subjected to a short microwave pulse (of a few milliseconds duration). This creates a macroscopic polarization of the molecules. After the microwave pulse, the time-domain signal due to coherent emission by the polarized molecules is detected and Fourier transfonned to obtain the microwave spectmm. 

Frequency-domain BSS. In this mode, the spectrum of the diffracted probe light is obtained by using a Fabry-Perot interferometer. Light is diffracted by incoherent thermal phonons and the scattering wavevector is determined by the detection angle, which can be accurately fixed by limiting the collection aperture. 

We have performed optically heterodyne-detected optical Kerr effect measurement for transparent liquids with ultrashort light pulses. In addition, the depolarized low-frequency light scattering measurement has been performed by means of a double monochromator and a high-resolution Sandercock-type tandem Fabry-Perot interferometer. The frequency response functions obtained from the both data have been directly compared. They agree perfectly for a wide frequency range. This result is the first experimental evidence for the equivalence between the time- and frequency-domain measurements. 

The quantum fluctuations of the radiation phase manifest qualitative difference from those calculated within the Pegg-Barnett approach. In particular, the phase bunching effect can be observed for a multipole radiation in a spherical cavity in the quantum domain of low intensity. This effect does not occur in a linear cavity (Fabry-Perot resonator). 

We are now ready to discuss pulsed time-domain spectroscopy carried out in a Fabry-Perot cavity. We will start with the static gas problem. This will allow us to draw out some features of the high-Q, standing wave phenomena common to both the static-gas and pulsed nozzle experiments, while still treating a familiar problem. 

The CW microwave spectrometer just described is a typical frequency-domdim instrument. In the late 1970s it was demonstrated that pulsed /m -domain microwave spectroscopy could be practically performed in analogy to the techniques already well known in other fields such as NMR spectroscopy. Figure 2 depicts a block diagram of a modern version of a pulsed Fourier-transform microwave spectrometer. The particular instrument shown utilizes a Fabry-Perot cavity and a pulsed-gas nozzle, and is especially useful for detecting microwave... 

In addition to the substantial literature on solvent and small-molecule translational diffusion, there is also a significant literature on small-molecule rotational diffusion. Experimental methods that report rotational diffusion behavior include VH tight scattering, as examined in different time domains with Fabry-Perot interferometry and photon correlation methods, nuclear magnetic resonance, oscillatory electrical birefringence, and time-resolved optical spectroscopy. 

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