- Practical aplanatic optics crafted from transpar- ent dielectrics can approach the thermodynamic limit for ra- diative transfer in near-field systems. Designs are presented for the particularly challenging realm of high numerical aper- ture NA at the source and/or target. These light couplers can alleviate difficulties in aligning system components and can achieve the fundamental compactness limit for optical devices that satisfy Fermat's principle. Examples and perfor- mance estimates based on ray-trace simulations are presented. © 2006 Society of Photo-Optical Instrumentation Engineers.