Abstract: Two-photon absorption measurements are made at various points remote from monitoring apparatus by apparatus which includes two lasers that produce counter-propagating beams through the earth's atmosphere. The lasers are tuned such that the sum of the energies of the photons in each of the laser beams equals that associated with a predetermined transition of a gas in the earth's atmosphere. In one embodiment, a pulsed laser and a CW laser are used. The pulse from the pulsed laser propagates along the CW beam produced by the CW laser and overlaps the CW beam at positions determined by a range gating technique, which makes possible the measurement of the two photon absorption at the various positions of overlap or coincidence. In one embodiment, the subject apparatus is utilized for pollution monitoring, in which the frequencies of the lasers are tuned such that the energies of the photons from these lasers add up to a transition of a predetermined pollutant.

Abstract: Improvements to dispersive delay lines are provided which involve bifurcation to provide for low insertion loss and a non-dispersive/dispersive delay line which allows for non-simultaneous input/output operation, and removes input/output leakage as a limitation to dynamic range.

Abstract: An angular accelerometer comprising a pair of misaligned, spaced apart, cantilevered optical fibers whereby angular accelerations occasion modulation of an optical signal coupled between the two spaced apart, cantilevered-beam optical fibers.

Abstract: A magnetometer which includes a pair of spaced apart optical fibers at least one of which comprises a cantilevered beam having a dipolar magnet thereon such that fluctuations of the magnetic H field will cause fluctuating mechanical torque on the magnet which will be applied to the cantilevered optical fiber to deflect same and occasion modulation of an optical signal transmitted between the two fibers.

Abstract: Improvements to dispersive delay lines are provided which involve bifurcation to provide for low insertion loss and a non-dispersive/dispersive delay line which allows for non-simultaneous input/output operation, and removes input/output leakage as a limitation to dynamic range.

Abstract: A dispersive delay line and method for fabricating the delay line is described in which coaxial cable is utilized and in which the dispersive or bandpass characteristic is established by the crimping of the coaxial cable in such a manner that the axial crimp length is small compared to the wavelength, thereby providing a discontinuity which behaves like a simple shunt capacity. A simple fabrication technique is utilized in which the crimps are applied to the line at selected points by use of a four-tooth crimping tool.