After reviewing the nature of off-shell field and creation/measurement processes of DP, nanometer-sized optical logic gate devices are demonstrated that triggered rapid development of off-shell science. Next, two technologies are reviewed that exhibit novel phenomena of Table 1.1 . One is the nanofabrication technology. Its essential by-product is the successful estimation of the maximum size of the DP. The other is silicon light-emitting devices. It is pointed out that a cluster of photons emitted from these devices behaves as if it is a single photon. Portions of Chap. 2 have been reproduced from Ref. [15] (an open access article published under a CC BY license (Creative Commons Attribution 4.0 International License)), from Ref. [47] with permission from Elsevier, and from Sakuma, H., Ojima, I. and Ohtsu, M., Perspective on an Emerging Frontier of Nanoscience Opened up by Dressed Photon Studies. Nanoarchitectonics, 1, 1–23 (2024) (an open access article distributed under a CC BY license (Creative Commons Attribution 4.0 International License)).