Diamond Turning and Replication of High-Efficiency Diffractive Optical Elements

Abstract

Diffractive optical elements can provide a significant advantage in the design of many optical systems that require aspheric or chromatic correction. For high-numerical aperture systems that have tight size and weight constraints, a diffractive element can often provide the necessary leverage to obtain a suitable optical design. For extremely narrow wavelength applications, a diffractive singlet can be used to produce the desired aspheric wavefront; however, for large wavelength range applications the diffractive asphericity must be tempered to reduce spherochromatism. The unique dispersion characteristics of diffractive surfaces provide the ability to correct primary or secondary chromatic aberrations.[1,2] Recent literature has shown that there are numerous potential optical designs that could benefit from the application of diffractive optical elements.[3] The main impediments that inhibit system engineers from manufacturing more optical designs containing diffractive elements is uncertainty about predicted performance and cost. We have developed manufacturing techniques that utilize the accurate machining potential of single-point diamond turning (SPDT) to generate robust metal master surfaces suitable for replication. By utilizing several replication techniques, a variety of different optical component configurations can be efficiently manufactured to provide exceptional wavefront performance and high diffraction efficiency.