diff --git a/src/new/finesse/prepare_files/FT_read_mirror_parameters_from_blocks.m b/src/new/finesse/prepare_files/FT_read_mirror_parameters_from_blocks.m
index fcfb37786c325c5166a932c0b63428e3fb23ae16..f62311a19249a22768185b4603e76c2aedcd5a4c 100644
--- a/src/new/finesse/prepare_files/FT_read_mirror_parameters_from_blocks.m
+++ b/src/new/finesse/prepare_files/FT_read_mirror_parameters_from_blocks.m
@@ -35,31 +35,31 @@ function [R,T,L,phi] = FT_read_mirror_parameters_from_blocks(blocks,mirror)
         if length(k)>0
             % Read constant value
             tmp_param = FT_remove_phrase_from_string(tmp_param,'$');
-            params{i-2} = num2str(FT_read_const_from_blocks(blocks,tmp_param));
+            params(i-2) = FT_read_const_from_blocks(blocks,tmp_param);
         else
             % Store parameter value
-            params{i-2} = tmp_param;
+            params(i-2) = FT_kat_str2num(tmp_param);
         end
     end
-        
+    
     % Convert from string to number, including checking for FINESSE units,
     % i.e. u for micro etc.
-    phi = FT_kat_str2num(params{3});
+    phi = params(3);
     
     % Convert reflection, transmission and loss coefficients to numbers and
     % calculating the final parameter (depending on which mirror type, 0,
     % 1 or 2 is used
     if mtype==0
-        R = FT_kat_str2num(params{1});
-        T = FT_kat_str2num(params{2});
+        R = params(1);
+        T = params(2);
         L = 1-T-R;
     elseif mtype==1
-        T = FT_kat_str2num(params{1});
-        L = FT_kat_str2num(params{2});
+        T = params(1);
+        L = params(2);
         R = 1-T-L;
     elseif mtype==2
-        R = FT_kat_str2num(params{1});
-        L = FT_kat_str2num(params{2});
+        R = params(1);
+        L = params(2);
         T = 1-R-L;
     end