The thermal (emitted) infrared frequency bands (typically 20-40 THz and 60-100 THz)
are best known for remote sensing applications that include temperature measurement (e.g., noncontacting
thermometers and thermography), night vision and surveillance (e.g., ubiquitous motion
sensing and target acquisition). This unregulated part of the electromagnetic spectrum also offers
commercial opportunities for the development of short-range secure communications. The ‘THz
Torch’ concept, which fundamentally exploits engineered blackbody radiation by partitioning
thermally-generated spectral radiance into pre-defined frequency channels, was recently
demonstrated by the authors. The thermal radiation within each channel can be independently pulsemodulated,
transmitted and detected, to create a robust form of short-range secure communications
within the thermal infrared. In this paper, recent progress in the front-end enabling technologies
associated with the ‘THz Torch’ concept is reported. Fundamental limitations of this technology are
discussed; possible engineering solutions for further improving the performance of such thermalbased
wireless links are proposed and verified either experimentally or through numerical
simulations. By exploring a raft of enabling technologies, significant enhancements to both data rate
and transmission range can be expected. With good engineering solutions, the ‘THz Torch’ concept
can exploit 19th century physics with 20th century multiplexing schemes for low-cost 21st century
ubiquitous applications in security and defence.