Can anyone explain the how to find the physical lattice parameter.

Hello
I am in the early stages of learning MPB. I am currently working on 2D and 3D crystal lattices trying to optimize a bandgap for a specific application.

I have recently managed to get a bandgap in those structures. But my question is about how to transfer the normalized lattice parameters to the physical parameters. Could anyone please explain the detailed conversion of the frequency (c/a) to normalized frequency (a/lambda).

Also I am facing difficulties trying to convert the normalized lattice parameters to physical parameters after overlapping the band diagrams with the light cone. Could anyone please help me with these questions.

Thanks in advance.
Attached my code and epsilon

;Triangular Lattice Photonic Crystal

(define-param zno 3.3856)
(define-param low-eps 1)
(define-param h 1)
(define-param supercell 3)
(define-param r1 0.35)
(define-param l 10);latticce lenght
(define-param w 10);lattice width
(define-param a 1) ; lattice constant
;lattice set-up
(set! geometry-lattice (make lattice (size l w supercell)
;(basis1 (/ (sqrt 3) 2) 0.5)
;(basis2 (/ (sqrt 3) 2) -0.5)
))

(set! default-material (make dielectric (epsilon low-eps)))
(set! geometry (list (make block (material (make dielectric (epsilon low-eps)))(center 0 0 0) (size infinity infinity supercell))
(make block (material (make dielectric (epsilon zno)))(center 0 0 0)(size  l  w  h))))
;triangular hole arrangement
(define-param pos-x 0)
(define-param pos-y 0)
(do ((x -4 (+ x 1))) ((> x 4))
(do ((y -8 (+ y 1))) ((> y 8))
(if (odd? (+ x y))
(and (set! pos-x (* x (/ (sqrt 3) 2))) 
(set! pos-y(* y 0.5))
(set! geometry (append geometry (list (make cylinder (material (make dielectric (epsilon low-eps)))(center (* a pos-x) (* a pos-y) 0)(radius r1)(height h)))))))))
; 1st Brillouin zone of a triangular lattice
(set! k-points (list  (vector3 0 0 0)(vector3 0 0.5 0)(vector3 (/ 1 -3) (/ 1 3) 0)(vector3 0 0 0)))
; the number of k points to interpolate
(set! k-points (interpolate 4 k-points))
(set-param! num-bands 4)
(set-param! resolution 8)
(run)


Gap information : 4.42%

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