{"id":300,"date":"2025-08-27T20:10:40","date_gmt":"2025-08-27T11:10:40","guid":{"rendered":"https:\/\/www.hulinks.co.jp\/en\/?page_id=300"},"modified":"2025-10-07T17:23:45","modified_gmt":"2025-10-07T08:23:45","slug":"new-thin-film","status":"publish","type":"page","link":"https:\/\/www.hulinks.co.jp\/en\/tfcalc\/examples\/list-of-coating-design\/new-thin-film\/","title":{"rendered":"New Thin Film Polarizing Beamsplitter"},"content":{"rendered":"\n

List of coating design exapmles<\/h1>\n\n\n\n

New Thin Film Polarizing Beamsplitter<\/h2>\n\n\n\n

In the paper*,
Li Li and J.A. Dobrowolski, \u201cNew developments in thin film polarizing beamsplitters\u201d, in Optical Interference Coatings, Vol. 9, OSA Technical Digest Series, (Optical Society of America, Washington DC, 1998), pp. 158-160.<\/p>\n\n\n\n

given at the Optical Interference Coatings conference in June 1998, the authors discuss a new design for a high-performance polarizing beamsplitter based on frustrated total internal reflection. This polarizer has the following advantages: non-absorbing, broad band, wide-angle, and high extinction ratios (Ts\/Tp and Rp\/Rs). The diagram below illustrates the operation of this polarizer.<\/p>\n\n\n

\n
\"\"<\/figure><\/div>\n\n\n

The coating is sandwiched between two prisms. Note that S polarized light is transmitted, which is the opposite of other designs. Also, note that light strikes the coating at a very high angle.<\/p>\n\n\n\n

Although the authors do not give the exact details of the coating design, it is possible to use TFCalc to create such a polarizer. Here we design a polarizer for 400-700 nm to operate for the angles 65-75 degrees in the prism. This design requires a high-index glass prism. An index of 1.85 is used in this design. This means that the range of angles in air is \uff719.28, which is considered wide-angle. We use the following 22 continuous optimization targets:<\/p>\n\n\n\n

    \n
  • S Transmittance > 99.9% for wavelengths 400-700 nm at angles 65,66,\u2026,75<\/li>\n\n\n\n
  • P Optical Density > 3.0 for wavelengths 400-700 nm at angles 65,66,\u2026,75<\/li>\n<\/ul>\n\n\n\n

    There are many ways to design this coating. One simple method is to start with a stack such as (0.5H L 0.5H)^n that reflects the P polarization for the wavelengths and angles given above, and then use optimization to force the coating to transmit S polarization. Here H and L represent quarter-wave layers of index 2.35 and 1.45, respectively. Some tests show that if we start with the 21-layer design created by setting n=10, then the optimization targets given above will be met. The performance is shown below, with the left scale for the optical density of P reflectance and the right scale for S transmittance. The extinction ratio is greater than 1000 for all design angles and wavelengths.<\/p>\n\n\n

    \n
    \"\"<\/figure><\/div>\n\n\n

    Here is the design, with the first layer closest to the substrate and thickness given in nm:<\/p>\n\n\n\n

        H     11.16\n    L     48.87\n    H     35.94\n    L     68.58\n    H     39.50\n    L     79.77\n    H     46.20\n    L     96.61\n    H     49.71\n    L    102.74\n    H     50.49\n    L    102.74\n    H     49.71\n    L     96.61\n    H     46.20\n    L     79.77\n    H     39.50\n    L     68.58\n    H     35.94\n    L     48.87\n    H     11.16<\/code><\/pre>\n\n\n\n
    Note, curiously, that optimization preserved the symmetry of the original design (i.e., layers 1 and 21, 2 and 20, 3 and 19, etc., have the same thickness).<\/p>\n\n\n\n
    The authors are commended for this ingenious polarizer, which is the subject of a patent application. However, it seems that this polarizer has two drawbacks: (1) the dimensions of the prisms may prevent its use in some applications and (2) the prisms seem to require a high-index glass, which presents other problems.<\/p>\n\n\n\n
    *Recently, a paper was published that gives much more detail about this polarizer. See<\/p>\n\n\n\n
      \n
    • Li Li and J.A. Dobrowolski, \u201cHigh-performance thin-film polarizing beam splitter operating at angles greater than the critical angle\u201d, Applied Optics, Vol. 39, No. 16, pp. 2754-71.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
      List of coating design exapmles New Thin Film Polarizing Beamsplitter In the paper*,Li Li and J.A. Dobrowolski, \u201cNew developments in thin film polarizing beamsplitters\u201d, in Optical Interference Coatings, Vol. 9, OSA Technical Digest Series, (Optical Society of America, Washington DC, 1998), pp. 158-160. given at the Optical Interference Coatings conference in June 1998, the authors…<\/p>\n","protected":false},"author":15,"featured_media":0,"parent":258,"menu_order":17,"comment_status":"closed","ping_status":"closed","template":"liquid.php","meta":{"footnotes":""},"tags":[],"class_list":["post-300","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/300","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/comments?post=300"}],"version-history":[{"count":4,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/300\/revisions"}],"predecessor-version":[{"id":681,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/300\/revisions\/681"}],"up":[{"embeddable":true,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/258"}],"wp:attachment":[{"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/media?parent=300"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/tags?post=300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}