Open AccessUltrathin broadband nearly perfect absorber with symmetrical coherent illumination
Author(s) -
Mingbo Pu,
Feng Qin,
Min Wang,
Chenggang Hu,
Cheng Huang,
Xiaoliang Ma,
Zeyu Zhao,
Changtao Wang,
Xiangang Luo
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.002246
Subject(s) - broadband , optics , bandwidth (computing) , narrowband , absorptance , interferometry , silicon , coherent control , physics , materials science , absorption (acoustics) , optoelectronics , telecommunications , reflectivity , computer science , laser
As highlighted by recent articles [Phys. Rev. Lett. 105, 053901 (2010) and Science 331, 889-892 (2011)], the coherent control of narrowband perfect absorption in intrinsic silicon slab has attracted much attention. In this paper, we demonstrate that broadband coherent perfect absorber (CPA) can be achieved by heavily doping an ultrathin silicon film. Two distinct perfect absorption regimes are derived with extremely broad and moderately narrow bandwidth under symmetrical coherent illumination. The large enhancement of bandwidth may open up new avenues for broadband applications. Subsequently, interferometric method is used to control the absorption coherently with extremely large contrast between the maximum and minimum absorptance. Compared with the results in literatures, the thin film CPAs proposed here show much more flexibility in both operation frequency and bandwidth.