! 	filename: depth.zpl	date: 2/27/96	rev: 2
!  Calculates depth of focus for the system based on
!  several sources for the equation.
!  Author:  Bob Householder

!-----User Input
  INPUT "Enter beam trucation: ", T
  INPUT "Enter k-factor: ", G
  INPUT "Enter 1/e^2 spot size at the image plane (microns): ",S
  INPUT "Enter allowable spot growth (i.e. 10% is 0.1): ", growth
  INPUT "Enter residual defocus from field curvature (mm): ", field_curv

!! DOF from Raliegh range.

  pie=3.14159264
  wave=WAVL(PWAV())
  GETSYSTEMDATA 1
  dof_ray=(4*wave*.001*POWR(vec1(10),2))/pie
  dof_ray=dof_ray-field_curv

  PRINT "Here are the 5 different equations for DOF."
  PRINT "1.  The DOF using Raliegh range criteria (1/4 wave)= ",dof_ray, " mm"

!! DOF from Gaussian propagation

  ! 10% spot size growth
  p=1.1		
  dof_gaus=(2*(4*wave*.001)/pie)*(SQRT(ABSO(p*p-1))*POWR(vec1(10),2))
  dof_gaus=dof_gaus-field_curv

  PRINT "2.  The DOF using Gaussian propagation= ",dof_gaus, " mm"


!! DOF from Smith 2nd Edition p.329

  ! Refractive index of last surface (default is air N=1)
  
  dof_smith=wave*.001*POWR(vec1(10),2)
  dof_smith=dof_smith-field_curv

  PRINT "3.  The DOF using eq'n from Smith 2nd ed. p.329= ",dof_smith, " mm"


!! DOF from Optical Scanning p.226

  S=S*.001

  dof_optscan=(1.8*T*G*POWR(S,2)*SQRT(growth))/(wave*.001)
  dof_optscan=dof_optscan-field_curv

  PRINT "4.  The DOF using eq'n from Optical Scanning p.226= ",dof_optscan, " mm"


!!  DOF from Melles Optics Guide 95/96 p. 2-7

  w0=S/2
  delta_z=(2*.32*pie*POWR(w0,2))/(wave*.001)
  delta_z=delta_z-field_curv

  PRINT "5.  The DOF using eq'n from MG p.2-7= ", delta_z, " mm"

PRINT " "
PRINT "Beam trucation: ", T
PRINT "k-factor: ", G
PRINT "1/e^2 spot size at the image plane (microns): ",S
PRINT "Allowable spot growth (i.e. 10% is 0.1): ", growth
PRINT "Residual defocus from field curvature (mm): ", field_curv