Additive manufacturing of precision optics at micro and nanoscale

Abstract
This review focuses on recent developments in additive manufacturing of precision optical devices, particularly devices consisting of components with critical features at the micro- and nanoscale. These include, but are not limited to, microlenses, diffractive optical elements, and photonic devices. However, optical devices with large-size lenses and mirrors are not specifically included as this technology has not demonstrated feasibilities in that category. The review is roughly divided into two slightly separated topics, the first on meso- and microoptics and the second on optics with nanoscale features. Although additive manufacturing of precision optics is still in its infancy with many unanswered questions, the references cited on this exciting topic demonstrate an enabling technology with almost unlimited possibilities. There are many high quality reviews of additive manufacturing processes of non-optical components, hence they are not the focus of this review. The main purpose of this review is to start a conversion on optical fabrication based on information about 3D additive manufacturing methods that are available to date, with an ultimate long-term goal of establishing new optical manufacturing methods that are low cost and highly precise with extreme flexibility.