Monday, December 14, 2015

USDOE-Patent "Absorber for terahertz radiation management"

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.

Inventors:Biallas, George HermanApeldoorn, CornelisWilliams, Gwyn P.Benson, Stephen V.Shinn, Michelle D.
Issue Date:2015-12-08
OSTI Identifier:OSTI ID: 1227938
Patent Number(s):9,209,587
Application Number:14/662,322
DOE Contract Number:ACO5-060R23177
Research Org:Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:USDOE
Country of Publication:United States

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