diff options
Diffstat (limited to 'gbeam_propagation_froward_only.m')
| -rw-r--r-- | gbeam_propagation_froward_only.m | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/gbeam_propagation_froward_only.m b/gbeam_propagation_froward_only.m new file mode 100644 index 0000000..ba8c1cf --- /dev/null +++ b/gbeam_propagation_froward_only.m @@ -0,0 +1,40 @@ +function q = gbeam_propagation_froward_only(x_pos, q_in, x_in, optics_elements) +% calculate the 'q' parameter of the Gaussian beam propagating through optical +% 'optics_elements' only in the positive direction along 'x' axis at points 'x_pos' +% takes the gaussian beam with initial q_in parameter at x_in +% +% all x_pos must be to the right of x_in +% x_pos must be monotonic! + if (any(x_pos < x_in)) + error('all beam positions must be to the right of the x_in'); + end + + optics_elements=arrange_optics_along_x(optics_elements); + + % Forward propagation to the right of x_in + Np=length(x_pos); % number of 'x' points + Nel=length(optics_elements) ; + q=0*x_pos; % q vector initialization + q_last_calc=q_in; + x_last_calc=x_in; % the furthest calculated point + for i=1:Np + x_pos_i=x_pos(i); + for k=1:length(optics_elements) + % iterates through optics_elements to make sure + % we take them in account for the beam propagation + el=optics_elements{k}; + if ( (x_last_calc < el.x) && (el.x <= x_pos_i) ) + abcd=abcd_free_space(el.x-x_last_calc); + q_last_calc=q_afteer_element(q_last_calc,abcd); + q_last_calc=q_afteer_element(q_last_calc,el.abcd); + x_last_calc=el.x; + endif + endfor + if (x_pos_i > x_last_calc); + abcd=abcd_free_space(x_pos_i-x_last_calc); + q_last_calc=q_afteer_element(q_last_calc,abcd); + x_last_calc=x_pos_i; + endif + q(i)=q_last_calc; + endfor +end |