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   _____     ___     _    _     ______    _  __  
  / ___//   / _ \\  | |  | ||  /_   _//  | |/ // 
  \___ \\  / //\ \\ | |/\| ||   -| ||-   | ' //  
  /    // |  ___  |||  /\  ||   _| ||_   | . \\  
 /____//  |_||  |_|||_// \_||  /_____//  |_|\_\\ 
`-----`   `-`   `-` `-`   `-`  `-----`   `-` --`

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Text this: Angular-adjustable single-channel narrow-band filter based on one-dimensional photonic crystal heterostructure