Wonjong Ryu, Muyoung Lee, Yong Hyub Won,
https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10531/105310T/Towards-industrial-applications-of-terahertz-real-time-imaging/10.1117/12.2287709.short?SSO=1
In order for Terahertz (THz) technology to enter
the forefront of the industry, technology to generate THz wave with simple
structure and low cost is required. This paper suggests compact and portable
THz imaging system by the use of Single Mode Fabry-Perot Laser Diodes (SMFPLD).
The existing THz system has a disadvantage that it is bulky, complicated,
expensive, and difficult to use. To compensate for this, we use an inexpensive
and simple FPLD combined with an external cavity to construct a THz imaging system.
SMFPLD shows a steady longitudinal mode state through self-injection locking by
means of a built-in aspherical lens. The position of the dominant mode changes
as the current and temperature are controlled, and the dual mode is also
generated under certain conditions. This characteristic is a great advantage in
the photomixing method that requires two lasers. Because a laser alone can
create a THz wave, and it creates two frequencies in a single family, it is not
necessary to consider polarization or phase differences. Based on these
advantages, we have constructed a laser module and combined with PCA to create
a THz imaging system. A THz imaging systems demonstrated in this paper are
superior to ordinary systems due to their inexpensive and compact structure.
