{"id":17626,"date":"2021-04-13T23:33:38","date_gmt":"2021-04-14T03:33:38","guid":{"rendered":"https:\/\/iridian.com.cn\/?page_id=17626"},"modified":"2021-09-27T14:57:42","modified_gmt":"2021-09-27T18:57:42","slug":"effect-of-an-optical-coating-on-in-band-and-out-of-band-transmitted-and-reflected-wavefront-error-measurements-dup","status":"publish","type":"post","link":"https:\/\/iridian.com.cn\/en\/learning_center\/effect-of-an-optical-coating-on-in-band-and-out-of-band-transmitted-and-reflected-wavefront-error-measurements-dup\/","title":{"rendered":"Effect of an optical coating on in-band and out-of-band transmitted and reflected wavefront error measurements"},"content":{"rendered":"

[et_pb_section fb_built=”1″ _builder_version=”4.9.4″ hover_enabled=”0″ custom_margin=”0px|0px||0px|false|true” custom_padding=”0px|0px||0px|false|true” sticky_enabled=”0″][et_pb_row _builder_version=”4.9.4″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” hover_enabled=”0″ width=”100%” custom_margin=”0px|0px||0px|false|true” custom_padding=”0px|0px||0px|false|true” sticky_enabled=”0″][et_pb_column type=”4_4″ _builder_version=”3.25″ custom_padding=”|||” custom_padding__hover=”|||”][et_pb_text _builder_version=”4.9.4″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” custom_padding=”||10px||false|false” hover_enabled=”0″ sticky_enabled=”0″]<\/p>\n

Graham Carlow,* Brian T. Sullivan, Claude Montcalm, AND Alexander Miles
Iridian Spectral Technologies Ltd., 2700 Swansea Crescent, Ottawa, Ontario K1G 6R8, Canada<\/em>
*Corresponding author: graham.carlow@iridian.ca<\/em><\/p>\n

 <\/p>\n

Abstract<\/strong><\/h4>\n

The wavefront error (WE) of a surface with an optical coating (\u201cfilter\u201d) is ideally measured at the in-band wavelength of the filter. However, quite often this is not possible, requiring that the filter be measured at an out-of-band wavelength (typically 633 nm), assuming that the filter transmits (for transmitted WE, or TWE) or reflects (for reflected WE, or RWE) at this wavelength. This out-of-band TWE\/RWE is generally assumed to provide a good estimation of the desired in-band TWE\/RWE. It will be shown in this paper that this is not the case for a large class of filters (i.e., bandpass) where the group delay is significantly different at the in-band and out-of-band wavelengths and where the optical filter exhibits a thickness non-uniformity across the surface. A theoretical explanation will be given along with an approach to predict the in-band TWE\/RWE based on the coating non-uniformity, the measured out-of-band TWE\/RWE, and the theoretical properties of the optical filter at the in-band and out-of-band wavelengths. A reasonable agreement between theory and measurement was demonstrated by measuring the TWE of an 11 nm wide bandpass filter (centered at 1048 nm) at both in-band (lambda <\/span>= <\/span>1048<\/span><\/span><\/span><\/span>n<\/span>m<\/span><\/span><\/span><\/span><\/span><\/span><\/span>) and out-of-band (lambda <\/span>= <\/span>625<\/span><\/span><\/span><\/span>n<\/span>m<\/span><\/span><\/span><\/span><\/span><\/span><\/span>) wavelengths. A similar treatment is provided for RWE.<\/p>\n

\u00a9 2020 Optical Society of America<\/p>\n

 <\/p>\n

[\/et_pb_text][et_pb_button button_url=”https:\/\/www.osapublishing.org\/ao\/abstract.cfm?uri=ao-59-5-A135″ url_new_window=”on” button_text=”Full Article” _builder_version=”4.2.2″ custom_margin=”||50px||false|false”][\/et_pb_button][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":"

The wavefront error (WE) of a surface with an optical coating (\u201cfilter\u201d) is ideally measured at the in-band wavelength of the filter. However, quite often this is not possible, requiring that the filter be measured at an out-of-band wavelength (typically 633\u00a0nm), assuming that the filter transmits (for transmitted WE, or TWE) or reflects (for reflected WE, or RWE) at this wavelength. This out-of-band TWE\/RWE is generally assumed to provide a good estimation of the desired in-band TWE\/RWE. It will be shown in this paper that this is not the case for a large class of filters (i.e., bandpass) where the group delay is significantly different at the in-band and out-of-band wavelengths and where the optical filter exhibits a thickness non-uniformity across the surface. <\/p>\n","protected":false},"author":159,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_et_pb_use_builder":"on","_et_pb_old_content":"

Abstract<\/h2>

The wavefront error (WE) of a surface with an optical coating (\u201cfilter\u201d) is ideally measured at the in-band wavelength of the filter. However, quite often this is not possible, requiring that the filter be measured at an out-of-band wavelength (typically 633\u00a0nm), assuming that the filter transmits (for transmitted WE, or TWE) or reflects (for reflected WE, or RWE) at this wavelength. This out-of-band TWE\/RWE is generally assumed to provide a good estimation of the desired in-band TWE\/RWE. It will be shown in this paper that this is not the case for a large class of filters (i.e., bandpass) where the group delay is significantly different at the in-band and out-of-band wavelengths and where the optical filter exhibits a thickness non-uniformity across the surface. A theoretical explanation will be given along with an approach to predict the in-band TWE\/RWE based on the coating non-uniformity, the measured out-of-band TWE\/RWE, and the theoretical properties of the optical filter at the in-band and out-of-band wavelengths. A reasonable agreement between theory and measurement was demonstrated by measuring the TWE of an 11\u00a0nm wide bandpass filter (centered at 1048\u00a0nm) at both in-band (\u03bb<\/mi>=<\/mo>1048<\/mn><\/mrow>n<\/mi>m<\/mi><\/mrow><\/math>\"><\/span>=<\/span>1048<\/span><\/span><\/span><\/span>n<\/span>m<\/span><\/span><\/span><\/span><\/span><\/span><\/span>) and out-of-band (\u03bb<\/mi>=<\/mo>625<\/mn><\/mrow>n<\/mi>m<\/mi><\/mrow><\/math>\"><\/span>=<\/span>625<\/span><\/span><\/span><\/span>n<\/span>m<\/span><\/span><\/span><\/span><\/span><\/span><\/span>) wavelengths. A similar treatment is provided for RWE.<\/p>

\u00a9 2020 Optical Society of America<\/p>

\u00a0<\/p>","_et_gb_content_width":"","footnotes":""},"categories":[2205,2211],"tags":[],"class_list":["post-17626","post","type-post","status-publish","format-standard","hentry","category-learning_center","category-tech_notes"],"acf":[],"_links":{"self":[{"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/posts\/17626","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/users\/159"}],"replies":[{"embeddable":true,"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/comments?post=17626"}],"version-history":[{"count":5,"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/posts\/17626\/revisions"}],"predecessor-version":[{"id":18143,"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/posts\/17626\/revisions\/18143"}],"wp:attachment":[{"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/media?parent=17626"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/categories?post=17626"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/iridian.com.cn\/en\/wp-json\/wp\/v2\/tags?post=17626"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}