Infrared imaging based on quantum dot optical phase modulation

In the past two decades, there is an increasing interest in developing new infrared photodetectors based on novel nanostructures, such as quantum well infrared photodetector (QWIP) and quantum dot infrared photodetector (QDIP). However, the commonly used electrical read-out approach limits the resolution of QWIP/QDIP infrared imaging to around 1 mega pixel. In this paper, we reported our theoretical study on an all-optical readout based on quantum dot phase modulation, which provides a new way for the intersubband infrared detection by measuring the phase change in the transmitted interband near infrared (NIR) and allows a high-resolution middle infrared (MIR) or far infrared (FIR) imaging. Utilizing the long life time in the quantum dots, the intersubband infrared resonant light is used to control the interband NIR resonant light phase. An infrared image can be converted into a visible or near infrared image, which can be easily captured with a high resolution CCD camera. It provides a new way to obtain a high resolution infrared image.