Fig. 1. (a) Voltaic pile with zinc, copper, and cardboard soaked in salt water. ©1996 IEEE. Reprinted with permission [
3]. (b) First electric lamp by Davy and Faraday [
6]. Reproduced with permission of IOP Publishing. (c) Swan (left) and Edison (right) filament lamps [
7]. (d) Development of the LED lamp from 1907. Photograph of a white LED lamp. Adapted with permission [
10]. ©2017, Wiley (e) Mixing of color with R, G, and B lasers to make white light. Image reproduced with permission [
36] under the terms of the Creative Commons Attribution 4.0 International license. (f) Sub-micrometer-sized metallic tips for near-field scanning optical microscope imaging; photograph of scattering of an evanescent field at a probe tip. Adapted with permission from [
16] ©1994, The Optical Society. (g) Demonstration of a nanowire light source, which can be tunable as well as coherent [
18]. ©2017, Nature Publishing Group. (h) Metal–insulator–semiconductor (MIS) structure for an incandescent light source. Adapted with permission [
20]. ©2019, Wiley. (i) Selectively generated photon emitters in 2D materials. Image reproduced with permission [
21] under the terms of the Creative Commons Attribution 4.0 International license. Other images are also reprinted by following individual copyright rules.
© Appl. Sci. Converg. Technol.