When light reflects from a medium having an index of refraction greater than that of the medium in which it is traveling, a 180º phase change (or a [latex]\frac{\lambda}{2}\\[/latex] shift) occurs. A thin film of soap solution is illuminated by white light at an angle of incidence i = sin-1(4/5). Thin film of oil. 0000002200 00000 n 0000049847 00000 n %%EOF Thin Film Interference - Iridescence Image courtesy of John M. Sullivan, University of Illinois and Technical University of Berlin. 0000007629 00000 n 0000005871 00000 n %PDF-1.3 In addition to the path length difference, there can be a phase change. 0000003123 00000 n Anti-reflection coating. 0000008342 00000 n Thin-film interference with white light. 0000006245 00000 n 0000009531 00000 n 0000072823 00000 n 0 Antireflection coating with a TiO 2 thin film. 0000001272 00000 n << /Length 1 0 R /Filter /FlateDecode >> 0000006507 00000 n PHY 2049: Chapter 36 14 Reflection and Interference from Thin Films ÎNormal-incidence light strikes surface covered by a thin film Some rays reflect from film surface Some rays reflect from substrate surface (distance d further) ÎPath length difference = 2d causes interference From full constructive to full destructive, depending on λ d n 1 n 2 n 0 = 1 0000007080 00000 n Thin film interference occurs between the light reflected from the top and bottom surfaces of a film. E�*�1���Dt�����t���_��n�u)T U 9"�g���F ˼{42]�K�XT�yϜ0��m%gK����[��"0r� i� 0000001352 00000 n When light reflects from a medium having an index of refraction greater than that of the medium in which it is traveling, a \(180^{\circ}\) phase change (or a \(\lambda /2\) shift) occurs. endstream endobj 33 0 obj<> endobj 35 0 obj<> endobj 36 0 obj<>/ProcSet[/PDF/Text]/ExtGState<>>> endobj 37 0 obj<> endobj 38 0 obj<> endobj 39 0 obj<> endobj 40 0 obj<> endobj 41 0 obj<> endobj 42 0 obj<> endobj 43 0 obj<>stream 0000000016 00000 n stream This film is really much thinner than either slab. 0000058968 00000 n xڭ]K�7���W`}�#,ޏ����Ê��c�w}ѥ�����$��"����I_U@�ڣ {��#���� ��+�� x�b```f``�a`e``�� Ȁ �@16�[ xref %��������� P33-16 Thin Film: Extra Path d Extra path length ~ 2d ()1 2 32 33 trailer 2 0 obj 0000003444 00000 n v��t��tC�]w��vV�$��0C���$Lk�|��)���S�����_�g:̗E�ӣ�U�ʢ���nTm�E%�r��P�K-%�`P��&]"آ ��`��n��bæ� �^�_��mP6H �@���;�κ����!/��jS}pCI�7�� 0000058704 00000 n The light reflected from any one 0000004133 00000 n Reflections take place at the bottom of slab B and at the top of slab A. H�tT�n�0��+�HC�e h4MP�hQ��-Ɂ�i��-"#?����!� ��%9ܝ�Y��۽��I���m3�n�π�/D ��a5����6Iq���.qQ^@{Jȭ1��i�b���r/Fw�ƕ. When light hits a material that has multiple layers, each layer can reflect light. Soap film with nonnormal incidence. 0000008921 00000 n 0000005167 00000 n Thin film interference occurs between the light reflected from the top and bottom surfaces of a film. 欓V+�n``h��ހ��AD�Y��i�V���:��,��8#N&��g1�ͤ�S�(����yZl��\A�� �(� ��9LJJ@���jDG�m@ ������X ,�� �0�!���s�L������~0$0�e�e�����I���i9�"�������3<31cx�0��7�N.oN��s�A� bk� �8� 0000001670 00000 n 34 0 obj<>stream Antireflection coating of a lens. Reflection from a thin glass sheet. 0000002721 00000 n 0000000956 00000 n 0000004415 00000 n 0000004800 00000 n %PDF-1.4 %���� Since the angle of incidence is practically zero for both reflecting surfaces the condition for a bright fringe is that 2nd = (m + 1 2)λ. 0000002860 00000 n 0000010136 00000 n 0000003368 00000 n Interference of direct and reflected light from a point source. 1. 0000058475 00000 n <<71f7b7fd265e8a4f803a19a221e7a725>]>> In the reflected light, two dark consecutive overlapping fringes are observed corresponding to wavelengths 6.1 x 10-7 m and 6.0 x 10-7m. Calculate the thickness of the film. 0000072368 00000 n 0000072630 00000 n O���꼢��FW�o��� ������VĿ०wK��7D���95BS��͒���8����F�5����>�3Υ P33-15 Thin Film Interference - Iridescence •Bubbles •Butterfly Wings •Oil on Puddles. (�5�P|�+����9)_�)�Y�����m���dQB)f������Aw(,gʝK��Ei �`a�6��6�M�i6���@N�R9����m;l�~5T����2UD$�2�Z��A�P%i��E ix�כ:�S�"!`&��BS��)=� rv�Va����n�H��k_�*8x�4՘R:�"�C2�t����n�\KiUk��r�]���.�: 0000004545 00000 n Thin film of water. startxref �Kzs�$ f����B9j�S1����o�>|�G`rfyS(�S\ p7��Hd\b ��Lـ }x����F�&� �)-��6ɛ_���Ǜ�����$��Q����D�9���Xc���:����|������/7������z������>ް����KR�>Q�Ln�ZЭ���Ն�ޭ��?Pڬ��vM�d'rZ�����%o>Im� Thin Film Interference 12 n1 n2 n3 n1