Xiaoyue Wang, Zixu Sa, Zhenkai Yang, Zhenkai Yang, Kaixing Zhu, Yanxue Yin, Sukjoon Hong, Feng Chen, Zai-xing Yang, Zai-xing Yang
The optical encryption technique is promising for the security of an encryption system by modulating the wavelength, amplitude, polarization, or orbital angular momentum of light. In this work, the typical narrow bandgap semiconductor of GaSb nanowire (NW) is demonstrated as a competitive candidate for infrared spectral encryption by modulating the photodetection wavelength. The bandgap of GaSb NW is controlled from 0.72 to 1.28 eV, benefiting the tunable photodetection wavelength range of 1550-785 nm. As a result, an infrared spectral encryption is realized by a GaSb NW with four different bandgaps. The controlled bandgap results from the successful growth of the GaNSb ternary alloy during the easily handled and low-cost chemical vapor deposition process. In the end, infrared spectral encryption is demonstrated as a code lock of a door, covering advanced cryptographic needs. The as-studied GaSb NW infrared spectral encryption promises next-generation military or high-security encryption.