div class=ts-pagebuttonPage 1button div class=ts-image amp-img class=ts-thumb alt=Page 1: 3560 After a laser beam passes through two thin parallel · 3560 After a laser beam passes through two thin parallel s ts the first completely dark fringes occur at ± 1900 src=https:reader034vdocumentsusreader034viewer20220430005f74a8ff34702f3fea1224b0html5thumbnails1jpg width=142 height=106 layout=responsive amp-img divdiv