The conference on Advances in Optoelectronics and Micro/nano-optics (AOM) is an OSA topical meeting focusing on micro/nano scale based optoelectronics and optics. The 1st AOM was held in 2009 in Tianjin, organized by Nankai University, with Professor Guoguang Mu as the honorary conference chair, and Professors Xiaocong Yuan and Michael Fiddy as co-chairs. The 2nd AOM was held in 2010 in Guangzhou, organized by South China Normal University, with Professor Songhao Liu as the honorary conference chair, and Professors Ting Mei, Xiaocong Yuan and Michael Fiddy as co-chairs. The 3rd AOM was held in 2013 in Hongkong, organized by Hong Kong Polytechnic University, with Professors Wallace Choy and Michael Fiddy as the conference co-chairs. This 4th AOM will be held in 2014 in Xi'an, organized by Xi'an Institute of Optics and Precision Mechanics, CAS and Northwestern Polytechnical University, with Professor Wei Zhao as the conference general chair, and Professors Michael Fiddy, Ting Mei, Xiaocong Yuan and Baoli Yao as co-chairs. On behalf of the Conference Committee, we cordially invite and welcome all of you in the community to attend this conference. Xi'an is the capital city of Shaanxi province. It is famous for its centuries-old history of over 3,000 years. It had been the capital city of 13 dynasties in the history of China. There are many attractive sites around Xi'an such as the famous "Terra Cotta Warriors and Horses", which has been called "the eighth wonder of the world". Today, the old city is becoming a modern metropolis and opening its arms to welcome all friends from all over the world. During the conference, the organizers will arrange some sightseeing tour for the attendees. We hope and believe that you will have an enjoyable and memorable time in Xi'an.