BLAZED DIFFRACTIVE OPTICS

Diffractive optical elements with blazed profiles can, in theory, have 100% relative efficiency. We review several methods for making such e lements and compare their advantages and Limitations. Our emphasis is on processes to produce elements other than those with approximate, st epped surfaces, such as binary optical elements. For optical methods, we offer an expression relating the maximum numerical aperture of a di ffractive lens with a given maximum efficiency to the numerical apertu re of the recording system. (C) 1997 Optical Society of America.