Showing papers on "Extinction ratio published in 1969"

An ultrafast light gate

Abstract: A device has been built which is capable of gating light on and off on the picosecond time scale. The gate is built in much the same fashion as traditional Kerr cells, the difference lying in the use of powerful optical pulses rather than electrical pulses to induce a birefringence in various liquids. In the experiment, powerful light pulses from a mode-locked Nd:glass laser, ∼5 psec in duration (wavelength 1.06µ), are used to induce a birefringence in a number of liquids including CSµ, nitrobenzene, chlorobenzene, dichloroethane and others. The transmission of the gate as a function of time is probed by means of 0.53µ green light pulses derived from the 1.06µ pulses by second harmonic generation. With CS 2 the transmission curve has a width of 8 psec; the peak transmission is 10% and the extinction ratio is 200. With nitrobenzene the curve has an exponentially falling tail on one side. The associated decay time is 32± 6 psec. Since 32 psec is a time characteristic of molecular reorientation times, this observation provides direct support for the long held belief that orientational effects dominate light induced refractive index changes in nitrobenzene.

Attenuation of the Rayleigh Component in Brillouin Spectroscopy Using Interferometric Filtering

Abstract: A filter based on an unequal-arm Michelson interferometer is described that will attenuate a strong spectral line by a factor of 100 or more but transmit without reduction a weaker but more interesting line separated by a few hundred MHz from the strong line. The factors limiting the extinction ratio of the filter are considered and a practical instrument that gives results in good agreement with the theory is described.