Terahertz quantum cascade lasers have very broad wavelength gain and can provide output at multiple wavelengths. However they suffer from poor output beam quality because of their long wavelength and inability to be collimated with traditional methods.
In "Plasmonics for Beam Shaping and Wavefront Engineering," Federico Capasso covers the emerging and growing area of plasmonic and metamaterial applications to this problem.
Federico Capasso is the Robert Wallace Professor of Applied Physics at Harvard University. His research has spanned a broad range of areas including electronics, photonics, material science, nanotechnology and quantum electrodynamics. He pioneered the approach widely known as band-structure engineering in the design of heterostructure materials and devices, and is a co-inventor of the quantum cascade laser.
Cappasso is a member of the National Academy of Sciences, the National Academy of Engineering, a fellow of the American Academy of Arts and Sciences and an Honorary Member of the Franklin Institute. He is a SPIE Fellow and has authored over 80 presentations and publications for the Society.