Abstract: A method of detection of electromagnetic fields is provided. The method includes the steps of: providing a first beam in a first direction through a vapor cell, the first beam having a frequency ?p; providing a second beam in a second direction through the vapor cell, the second beam having a frequency ?d; providing a third beam in the second direction through the vapor cell, the third beam having a frequency ?c; frequency stabilizing the first beam, the second beam, and the third beam to successive stepwise resonant transitions resulting in the excitation of a Rydberg state; applying symmetrical radio frequency sidebands to the third beam, the symmetrical RF sidebands with frequency spacing ?RF from ?c;coherently transferring the symmetrical RF sidebands to the first beam via a nonlinear wave mixing in the vapor cell; and determining an electromagnetic field inside the vapor cell.

Abstract: A seal assembly for use between a pair of abutting planar surfaces with opposed grooves which combine to form a seal groove to receive the seal assembly. The seal assembly includes a stiffly flexible body element having portions which surround, protect and compress a pair of more resilient members. The compressed resilient members hold portions of the body element in sealing engagement with faces of the seal groove formed between the abutting planar surfaces.