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(define-param r 1.0) ;; radius of sphere
(define-param frq-cen 1.0)
(set-param! resolution 20) ;; pixels/um
(define dpml 0.5)
(define dair 1.5) ;; at least 0.5/frq_cen padding between source and near-field monitor
(define boundary-layers (list (make pml (thickness dpml))))
(set! pml-layers boundary-layers)
(define s (* 2 (+ dpml dair r)))
(define cell (make lattice (size s s s)))
(set! geometry-lattice cell)
;; circularly-polarized source with propagation axis along x
;; (is-integrated? true) necessary for any planewave source extending into PML
(define circ-pol-src (list
(make source
(src (make gaussian-src (frequency frq-cen) (fwidth (* 0.2 frq-cen)) (is-integrated? true)))
(center (+ (* -0.5 s) dpml) 0 0)
(size 0 s s)
(component Ez))
(make source
(src (make gaussian-src (frequency frq-cen) (fwidth (* 0.2 frq-cen)) (is-integrated? true)))
(center (+ (* -0.5 s) dpml) 0 0)
(size 0 s s)
(component Ey)
(amplitude 0+1i))))
(set! sources circ-pol-src)
(set! k-point (vector3 0))
(define box-flux (add-flux frq-cen 0 1
(make flux-region (center (- (* 2 r)) 0 0) (size 0 (* 4 r) (* 4 r)))))
(define nearfield-box (add-near2far frq-cen 0 1
(make near2far-region (center (- (* 2 r)) 0 0) (size 0 (* 4 r) (* 4 r)) (weight +1))
(make near2far-region (center (+ (* 2 r)) 0 0) (size 0 (* 4 r) (* 4 r)) (weight -1))
(make near2far-region (center 0 (- (* 2 r)) 0) (size (* 4 r) 0 (* 4 r)) (weight +1))
(make near2far-region (center 0 (+ (* 2 r)) 0) (size (* 4 r) 0 (* 4 r)) (weight -1))
(make near2far-region (center 0 0 (- (* 2 r))) (size (* 4 r) (* 4 r) 0) (weight +1))
(make near2far-region (center 0 0 (+ (* 2 r))) (size (* 4 r) (* 4 r) 0) (weight -1))))
(run-sources+ 10)
(display-fluxes box-flux)
(save-near2far "nearfield-box-n2f" nearfield-box)
(reset-meep)
(define nsphere 2.0)
(set! geometry (list
(make sphere
(material (make medium (index nsphere)))
(radius r)
(center 0))))
(set! geometry-lattice cell)
(set! pml-layers boundary-layers)
(set! sources circ-pol-src)
(set! k-point (vector3 0))
(define nearfield-box (add-near2far frq-cen 0 1
(make near2far-region (center (- (* 2 r)) 0 0) (size 0 (* 4 r) (* 4 r)) (weight +1))
(make near2far-region (center (+ (* 2 r)) 0 0) (size 0 (* 4 r) (* 4 r)) (weight -1))
(make near2far-region (center 0 (- (* 2 r)) 0) (size (* 4 r) 0 (* 4 r)) (weight +1))
(make near2far-region (center 0 (+ (* 2 r)) 0) (size (* 4 r) 0 (* 4 r)) (weight -1))
(make near2far-region (center 0 0 (- (* 2 r))) (size (* 4 r) (* 4 r) 0) (weight +1))
(make near2far-region (center 0 0 (+ (* 2 r))) (size (* 4 r) (* 4 r) 0) (weight -1))))
(load-minus-near2far "nearfield-box-n2f" nearfield-box)
(run-sources+ 100)
(define-param npts 100) ;; number of points in [0,pi) range of polar angles to sample far fields along semi-circle
(define-param ff-r (* 10000 r))
(map (lambda (n)
(let ((ff (get-farfield nearfield-box (vector3* ff-r (vector3 (cos (* pi (/ n npts))) 0 (sin (* pi (/ n npts))))))))
(print "farfield:, " n ", " (* pi (/ n npts)))
(map (lambda (m)
(print ", " (list-ref ff m)))
(arith-sequence 0 1 6))
(print "\n")))
(arith-sequence 0 1 npts))
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