{"id":364,"date":"2025-08-27T20:12:11","date_gmt":"2025-08-27T11:12:11","guid":{"rendered":"https:\/\/www.hulinks.co.jp\/en\/?page_id=364"},"modified":"2025-10-07T17:37:48","modified_gmt":"2025-10-07T08:37:48","slug":"four-wavelength","status":"publish","type":"page","link":"https:\/\/www.hulinks.co.jp\/en\/tfcalc\/examples\/list-of-coating-design\/four-wavelength\/","title":{"rendered":"Four-Wavelength Bandpass Filter"},"content":{"rendered":"\n

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

Four-Wavelength Bandpass Filter<\/h2>\n\n\n\n

This idea came from a graduate student who needed a bandpass filter for detecting light at four wavelengths: 630, 690, 760, and 885 nm. Between these wavelengths the filter is allowed to transmit 10%. The filter is to be coated on glass having index 1.52. The filter operates at normal incidence. So that the demo version of TFCalc can be used to design this filter, we use SIO2 and TIO2 as the two coating materials.<\/p>\n\n\n\n

We use a total of nine optimization targets: eight discrete targets of 100% transmission at each of the four desired wavelengths \uff711 nm and one continuous target asking for less than 10% transmission from 600 to 950 nm. Although it may seem contradictory to have a continuous target that includes the eight discrete targets, it works in TFCalc because each discrete target has the same weight as the entire continuous target.<\/p>\n\n\n\n

There is no theory for a bandpass filter of this type. Hence we use TFCalc\u2019s needle\/tunneling optimization<\/a> to design the filter from \u201cscratch\u201d. That is, we start with one thin layer of TIO2 and have TFCalc grow that layer into a filter meeting the requirements. After a few minutes, TFCalc finds a 21-layer design having the transmission curve shown below.<\/p>\n\n\n

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

Here is the design with thicknesses given in nm:<\/p>\n\n\n\n

TIO2      75.13\nSIO2     126.59\nTIO2      78.97\nSIO2     128.10\nTIO2      79.51\nSIO2     200.03\nTIO2     113.53\nSIO2     153.01\nTIO2      43.45\nSIO2      20.85\nTIO2      84.08\nSIO2     140.53\nTIO2      19.37\nSIO2      59.24\nTIO2      84.74\nSIO2     194.55\nTIO2     122.32\nSIO2     128.32\nTIO2      79.15\nSIO2     127.49\nTIO2      77.77<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
List of coating design exapmles Four-Wavelength Bandpass Filter This idea came from a graduate student who needed a bandpass filter for detecting light at four wavelengths: 630, 690, 760, and 885 nm. Between these wavelengths the filter is allowed to transmit 10%. The filter is to be coated on glass having index 1.52. The filter…<\/p>\n","protected":false},"author":15,"featured_media":0,"parent":258,"menu_order":33,"comment_status":"closed","ping_status":"closed","template":"liquid.php","meta":{"footnotes":""},"tags":[],"class_list":["post-364","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/364","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=364"}],"version-history":[{"count":4,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/364\/revisions"}],"predecessor-version":[{"id":695,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/364\/revisions\/695"}],"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=364"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/tags?post=364"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}