太赫兹波在生物学和危爆物检测等领域有广泛的应用前景，但其在成像上会受到探测器灵敏度的限制。搭建一套基于太赫兹量子级联激光器的自混合相干成像系统，将全息成像技术与自混合干涉测量相结合，实现太赫兹波段的大景深成像。利用自混合收发一体的特性，在不同偏焦程度下，对分辨率板上每毫米2个线对的区域进行二维成像，在偏焦56倍波长条件下得到与焦平面处相同的图像对比度。

Terahertz waves have a wide range of applications in biology and hazardous explosive detection, but they suffer limitations in imaging owing to the sensitivity of the corresponding detectors. Herein, we demonstrate a self-mixing coherent imaging system with a terahertz quantum cascade laser. We achieve imaging with a large depth of field in the terahertz band by combining the holographic imaging technology and self-mixing interferometric measurement. We imaged an area of 2 pair line per millimeter on a resolution board in the off-focus plane in two dimensions using a feature like self-mixing of a transceiver. We obtain the same image contrast as that on the focal plane when the imaging plane is 56 times the wavelength offset.