RESUMO
Amplification of continuous laser radiation propagating in a monomode optical fiber was obtained by evanescent field coupling within a pumped dye solution deposited in the neighborhood of the fiber core. A factor-of-25 signal gain was recorded for 632.8-nm He-Ne radiation and DCM dye solution.
RESUMO
Using the photoelastic effect in transparent solids to detect stresses induced by a gravitational wave is proposed. The induced birefringence is measured by a polarimeter. The phase difference is amplified by a Fabry-Perot cavity containing the medium. The sensitivity of this optical strain sensor is discussed, and that of the antenna is estimated.
RESUMO
A system which measures the Stokes parameters of light automatically over a wide range of wavelengths is described. The method requires two piezooptic modulators, three lock-in amplifiers, and an on-line minicomputer for data processing. The absence of a static retardation plate provides an unprecedented insensitivity to beam wandering. Typical performance parameters such as response time, accuracy, and detectivity as a function of the incident polarization are given.
RESUMO
A transmission channel may be characterized by its capacity, i.e., the largest quantity of mean mutual information transmitted between the emitter and the receiver. The channel we have studied is a light beam traveling in the low atmosphere, and the capacity has been calculated for polarization (PCM/PL) and intensity (IM) modulation, assuming a Poisson detection process and log-normal fluctuations for scintillation. The depolarization of light has been neglected, and the polarizers have been considered perfect. The appended graphs show that PCM/PL modulation has a greater capacity in all investigated cases.
