We present a new type of sub-wavelength blazed grating characterized by structures having a "pie-slice" form with sub-wavelength feature sizes in the direction lateral to the dispersion direction. We rigorously compute efficiency curves and compare them to binary blazed and conventional échelette gratings. We find that in the resonance domain the performance of laterally blazed structures is superior to conventional blaze gratings. For very small periods binary blazed gratings show the best performance, which is a consequence of a wave guiding phenomenon occurring in the sub-wavelength ridges. Outside this region, however, the laterally blazed gratings have comparable blaze efficiencies.
© 2004 Optical Society of AmericaPDF Article