Diffraction theory, developed in vectorial form and coded into ray tracing routines, permits tracing rays of any wavelength through surfaces that are plane, spherical, conical, or aspheric polynomial. Ruled diffraction gratings may run in either X-direction or Y-direction, where Z is optical axis

Howell, B. J.

English

NASA Technical Reports Server

August 1971	 Brief 71-10294 
NASA TECH BRIEF 
Goddard Space Flight Center	 - A 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the. Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Ray Tracing Program with Options for Diffraction Gratings 
.
The problem: 
To devise a ray tracing program capable of trac-
ing rays of any wavelength through surfaces with 
ruled diffraction gratings. The surfaces may be plane, 
spherical, conical, or general aspheric polynomial, 
and the rulings may run in either the X-direction or 
the Y-direction, where Z is the optical axis. The 
diffraction may be of any order, positive or negative. 
The solution: 
Diffraction theory, developed in a vectorial 
form and coded into ray tracing routines, with 
options indicating the direction of the grating 
rulings. The coding is added to SPADE, a Sperry 
Automatic Design program written in FAP for the 
IBM-7094 computer, and the coding is written in 
FORTRAN for a ray tracing program for the 
CDC-3 100 computer. 
How it's done: 
The convention employed uses a right-hand system 
of coordinates, and reflection is accomplished by 
changing the sign of the refraction index of the space 
following the surface. Rays are treated as unit vectors 
at refraction. Equations compatible with the sign 
conventions add the diffraction vector to the re-
fraction (or reflection) vector. 
The grating is mathematically generated on the 
surface by the intersection of a set of parallel
planes with the optical surface. The generating 
planes are in either the X-Z direction or the 
Y-Z direction, depending on a code introduced 
with the surface data. 
Reference: 
Howell, B. J.; A Ray Tracing Program for Crossed 
Dispersion Systems. Paper presented to Opt. Soc. 
Amer. (Hollywood, Florida), September 30, 1970. 
Notes: 
1. This program is written in FORTRAN IV for use 
on the CDC-3 100 computer. 
2. Requests for further information may be directed 
to:
COSMIC 
Barrow Hall 
University of Georgia 
Athens, Georgia 30601 
Reference: B71-10294 
Patent status: 
No patent action is contemplated by NASA. 
Source: B. J. Howell 
Sperry Rand Corporation

under contract to

Goddard Space Flight Center

(G SC- 1 1305) 
Category 09 
This documefct was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately ownedrights.
https://ntrs.nasa.gov/search.jsp?R=19710000293 2020-03-17T02:22:00+00:00Z


Ray tracing program with options for diffraction gratings

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server