Feasibility study of a new heterodyne technique based on HgCdTe varactor photodetectors for space‐borne wind lidars

Abstract

Doppler Lidar is a good candidate for wind velocity measurement. But the total Doppler shift experienced by the backscattered laser pulses with a conical scanning instrument varies in a wide frequency range. Narrowing intermediate frequency bandwidth could provide better performances for both detection and low noise amplification. Therefore, optical mixing and parametric amplification in the same device have been investigated with HgCdTe photodetectors cooled at liquid nitrogen temperature. The optical and microwave setup needed for simulating Doppler and testing these detectors is described. Some experimental results, which demonstrate the feasibility of this new heterodyning process, are given. © 1995 John Wiley & Sons. Inc.

Two‐dimensional heterostructure promoted infrared photodetection devices

“…Utilizing a reverse flow from the substrate to the source, the excessive thermal degradation and uncontrolled nucleation when the temperature swings between two growth stages was avoided, and thus the block-byblock epitaxial growth was realized. Through this step-by-step growth method, many complex structures, such as WS 2 Figure 2C. The fabricated heterostructures were applied as tunneling diodes with room temperature negative differential resistance.…”

“…Infrared (IR) photodetection has drawn great interest in recent years due to its potential for optical communication, imaging, photomemory, etc . Conventional high‐performance IR photodetectors, including HgCdTe, GaSb/InAs, and InSb photodetectors with a specific detectivity ranging from 10 10 to 10 11 Jones, have been widely applied in mid‐ and long‐wave IR photodetection from 1 to 30 μm. However, the practical application of these IR photodetectors has been impeded by three factors: the ultralow operating temperature, the difficult molecular beam epitaxy process, and the immutable bandgaps .…”