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Absorber for terahertz radiation management

United States Patent

December 8, 2015
View the Complete Patent at the US Patent & Trademark Office
Thomas Jefferson National Accelerator Facility - Visit the Technology Review Committee Website
A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.
Biallas; George Herman (Yorktown, VA), Apeldoorn; Cornelis (Gloucester, VA), Williams; Gwyn P. (Yorktown, VA), Benson; Stephen V. (Yorktown, VA), Shinn; Michelle D. (Newport News, VA), Heckman; John D. (Lanexa, VA)
14/ 662,322
March 19, 2015
The United States Government may have certain rights to this invention under Management and Operating Contract No. DE-ACO5-060R23177 from the Department of Energy.