A confocal feedback system (CFS) has been modified in three ways to include space variance, time sampling, and a second feedback loop. The space-variant system performs analog solution of partial differential equations (PDE’s) with variable coefficients. The time-sampling system solves PDE’s in three dimensions. The CFS with a second feedback loop has a more flexible feedback transfer function and can solve an extended range of PDE’s. Finally, a combination of time sampling and a second feedback loop can solve four-dimensional problems. Experimental results verifying the abilities of each of these new confocal feedback systems have been obtained.
© 1981 Optical Society of America
Jack Cederquist and Sing H. Lee, "Confocal feedback systems with space variance, time sampling, and secondary feedback loops," J. Opt. Soc. Am. 71, 643-650 (1981)