Experiments were conducted to study light propagation in a light waveguide loop consisting of linearly and circularly moving segments. We found that any segment of the loop contributes to the total phase difference between two counterpropagating light beams in the loop. The contribution is proportional to a product of the moving velocity v and the projection of the segment length l on the moving direction, 4v l=c. It is independent of the type of motion and the refractive index of waveguides. The finding includes the Sagnac effect of rotation as a special case and suggests a new fiber optic sensor for measuring linear motion with nanoscale sensitivity.

A novel squaraine-based chemosensor SQ-1 has been synthesized, and its sensing behavior toward various metal ions was investigated by UV-vis and fluorescence spectroscopies. In AcOH-H(2)O (40:60, v/v) solution, Hg(2+) ions coordinate with SQ-1 causing a deaggregation which induces a visual color and absorption spectral changes as well as strong fluorescence. In contrast, the addition of other metals (e.g., Pb(2+), Cd(2+), Cu(2+), Zn(2+), Al(3+), Ni(2+), Co(2+), Fe(3+), Ca(2+), K(+), Mg(2+), Na(+), and Ag(+)) does not induce these changes at all. Thus SQ-1 is a specific Hg(2+) sensing agent due to the inducing deaggregation of the dye molecule by Hg(2+).

A fiber optic conveyor has been developed for investigating the travel-time difference between two counter-propagating light beams in uniformly moving fiber. Our finding is that there is a travel-time difference Δt = 2vΔl/c 2 in a fiber segment of length Δl moving with the source and detector at a speed v, whether the segment is moving uniformly or circularly.

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Up to now all experiments used to verify the special theory of relativity have been done with the earth as the reference system. A suggested new Michelson-Morley experiment in Space Lab will be the first to examine the relativity principle in an inertial system other than the earth.