Subject(s)
Chemistry Techniques, Analytical/instrumentation , Exobiology/instrumentation , Fiber Optic Technology/instrumentation , Mars , Oxygen/chemistry , Soil/analysis , Spacecraft/instrumentation , Equipment Design , Evolution, Chemical , Evolution, Planetary , Extraterrestrial Environment , Oxidation-Reduction , Research Design , Space FlightABSTRACT
Results are given for a Stark-tuned double-resonance experiment, using a CO-laser pump and a diode-laser probe. The CO laser, operating on the 13-12 P(15) line at 1775.2588 cm(-1), is locked by Lamb-dip stabilization to one of the Stark components of the a(R)R(9, 9) nu(4) line of NH(3). The diode laser probes the aQ(9, 9) nu(2) line at 921.255 cm(-1), revealing a complex spectrum of sub-Doppler features, the narrowest of which are 5.3 +/- 0.3 MHz wide. As well as the resonances associated with population depletion of the common lower levels, we see line-narrowing effects that are due to two-quantum Raman-type processes and collision-induced resonances arising from state-changing collisions that preserve the molecular velocities. The zero-field a(R)R(9, 9) nu(4) line is established to be 264.1 +/- 5.0 MHz above the CO-laser line.
ABSTRACT
Simultaneous in situ measurements of the absorption and scattering by aerosols were made in ambient room air and in air with large amounts of added aerosols, such as cigarette smoke. For room aerosols, the extinction contribution due to absorption was typically one half that from scattering. The absorption measurements were made with an acoustically resonant spectrophone powered with a 0.5-W argon laser.
ABSTRACT
Recent advances in the field of nonlinear optical phenomena are reviewed with particular emphasis placed on such topics as parametric oscillation, self-focusing and trapping of laser beams, and stimulated Raman, Rayleigh, and Brillouin scattering. The optical frequency radiation is treated classically in terms of the amplitudes and phases of the electromagnetic fields. The interactions of light waves in a material are then formulated in terms of Maxwell's equations and the electric dipole approximation. In this method, non-linear susceptibility tensors are introduced which relate the induced dipole moment to a power series expansion in field strengths. The tensor nature and the frequency dependence of the nonlinearity coefficients are considered. The various experimental observations are described and interpreted in terms of this formalism.
