Calendar
SPIE Photonics West 2010
Jan. 23-28, 2010
Booth 500
San Jose, California
Visit SPIE Web site
Introduction to CODE V
March 15-19, 2010
Pasadena, California
See details or enroll
Advanced Topics in CODE V
March 22-26, 2010
Pasadena, California
See details or enroll
For a complete list of CODE V events worldwide, visit our Web site:
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Quick Tips – Using Finite Difference Derivative Increments During Optimization
CODE V 10.1 includes an enhancement for determining initial derivative increments used during optimization. Derivative increments determine the size of the change made to each variable during optimization. Ideally, the derivative increments should be just large enough so that the change in the variable causes a small but measureable change in the error function. The default values for the starting derivative increments are based on achieving approximately one wave of OPD change at the edge of the pupil, and the values are updated after each cycle of optimization. The default derivative increments work well for most systems, especially for optical error functions such as blur spot size or RMS wavefront error. However, there are some cases when you may wish to override the default for better convergence during optimization. Specific examples include optimization based on a user-defined error function or for systems where higher order aspheric terms or user-defined feature parameters are variables.
CODE V 10.1 includes several commands that allow the user more control over the derivative increments. Among these is the DER FDF command which tells CODE V to determine initial derivative increments based on a finite difference computation related to the effect that each variable has on the error function. While using this finite difference method can lead to improved convergence, it also adds some overhead to the optimization process.
A 9-minute video overview of the derivative increment enhancements, including a specific example, is available for viewing here.
“Idle Diffractions” is ORA’s New Blog
ORA’s new blog, Idle Diffractions: Musings on the Past, Present, and Future of Optics, features topics by Dr. Kevin Thompson, VP of Optical Engineering, who has more than three decades of experience designing advanced optical systems. Those particularly interested in optical design, and more specifically, the history of optics and optical design, will find this blog useful and informative.
Past entries have covered:
- Early American astronomical observatories
- Virtual reality
- The oldest telescopes, Large Binocular Telescope, and the Hubble Telescope
- Collecting rare books on optics
- The Lick Observatory and first glimpses of galaxies
- Solar energy technology
In an entry called, “The Speed of Light: An Evolving History of Computers and Optical Design,” Dr. Thompson wrote about the first computers used in optical design and the ray trace equations that were adopted for use on these machines. In another blog entry, he briefly discusses nodal aberration theory. The figure here is one such example and is the first known physical evidence of binodal astigmatism.
In future posts, Dr. Thompson will be spotlighting emerging optical technologies, exploring industry hot topics and events, and continuing to share his knowledge of optics history. Visit our blog today!
Updates to the Customer Support Web Site
The following updates have been made to ORA's Customer Support Web Site, www.oraservice.com, under CODE V Support:
- The November issue of CODE V Enews, which features a tip on using the Beam Synthesis Propagation™ (BSP) feature to interferometers in CODE V has been added under CODE V Enews & Tips.
- A copy of the paper Using Nodal Aberration Theory to Understand the Aberrations of Multiple Unobscured Three Mirror Anastigmatic Telescopes, Thompson, et al, SPIE 2009, has been added under Technical Papers. Lens models featured in this paper are also available for download.
- Two new macros from ORA Tech Support are available under Macros and User-defined Feature Downloads > CODE V Macros from ORA Tech Support. mtf_v_fre_all_fields.seq plots MTF vs Frequency for all fields on a single graph. Similarly, mtf_flds_through_focus.seq plots through focus MTF at a specific frequency for all fields on a single graph.
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