Surface roughness addresses the topography of a surface and quantifies the variations in its height on a micro-scale.
How is roughness defined? Roughness is defined by ISO standards. Depending on the type of roughness being studied, different ISO standards apply. Profile, or 2D, roughness is defined by ISO 21920. Ra and Rq are the profile values and are the arithmetic mean height and RMS surface height, respectively. For areal roughness, or 3D roughness, ISO 25178 is the standard. Sa is the arithmetic mean height over an area and Sq is the RMS surface height over an area.
Aspheric optics differ from conventional flat mirrors and lenses in ways that can have a profound impact on imaging quality. For this reason, we’ve created a grading system that packages useful and compatible tolerances in three different levels of quality and allows our customers to understand the impact on cost vs.performance. AOS quality grade options are explained here.
The growing need for advanced reflective optics operating over a broad bandwidth has motivated the development of off-axis parabolas with higher imaging performance then ever before. Specifying imaging and wavefront performance over a broad range of spatial frequencies is essential for enabling the highest levels of performance. As system level requirements have advanced, the way we specify OAPs must also change. Within recent years everything about OAP’s has evolved including tolerances for quality and performance, manufacturing methods, testing methods, thin film coatings and alignment technologies. AOS continues to re-engineer the Off-Axis Parabola to meet the needs of tomorrow’s applications. These topics are explored in a series of new application notes from Aperture Optical Sciences Inc. This paper provides instruction on how to define the key geometric features of Off-Axis Parabolic Mirrors (OAPs) and describes the concept of axial offsets as a function of off-axis angle.
Controlling quality of off-axis parabolic mirrors requires tolerances that are both traceable to performance and verifiable by measurement. Primary aspheric parameters for off-axis parabolic (OAP) mirrors, include the conic constant (k), focal length (f), off-axis angle (OAA or “θ”) and off-axis distance (OAD). However, because the primary design parameters in an asphere are interdependent, it is not always practical or even possible to verify these quantities by independent measurement as you may for a sphere or flat optic. Therefore, if something so fundamental as focal length or off-axis angle cannot easily be verified, how can the quality be guaranteed? This application note explains how AOS addresses this fundamental question. Our answer may surprise you.
Ceramic Materials enable mirrors with greater durability and resistance to mechanical and thermal loading than glass. This application notes provides you with all you need to know about Cordierite materials for optics.
The typical image that comes to mind when thinking about off-axis parabolas is the wedged-configuration mirror section cut out of a larger parent parabola. However, independently fabricated parallel configurations provide advantages in both cost and performance. This article explores why you should consider the parallel configuration first.
This publication summarizes the coatings AOS offers for its off-axis parabola products.
Learn why its important to specify optical quality by the reflected wavefront error instead of surface error in this AOS optics training Applications Note.
Presented at SPIE Optics and Photonics, San Diego CA, June 2013
Presented at OSA Optical Fabrication and Test, Monterey CA, June 2012
Presented at SPIE Optics and Photonics, San Diego CA, June 2012
30 Inch Mirror Delivered to United States Air Force, October 2010
SPIE Conference on Optical Manufacturing and Testing III, Denver CO, July 1999
SPIE Defense and Security Symposium, Orlando, April 2009
SPIE Defense and Security Symposium, Orlando, February 2008