"What is the data type this array?"   Answer: struct array
" How to achieve this?"   something like this
info_temp = struct('f1',num2cell(1:50), 'dicom','');
whos info_temp
info_temp(23).dicom = 'd23';
info_temp(23).dicom
info_temp(48).dicom
which outputs
Name Size Bytes Class Attributes
info_temp 1x50 11728 struct
ans =
d23
ans =
''