發送短信 : The Essence of Dielectric Waveguides

 _____     _    _    _    _     _____     _____   
|  __ \\  | || | || | || | ||  |  ___||  |__  //  
| |  \ || | || | || | || | ||  | ||__      / //   
| |__/ || | \\_/ || | \\_/ ||  | ||__     / //__  
|_____//   \____//   \____//   |_____||  /_____|| 
 -----`     `---`     `---`    `-----`   `-----`