Ultra‐High Transmission Broadband Tunable VO₂ Optical Limiter

Abstract

An optical limiter (OL) is a nonlinear device that protects sensitive photodetectors or human eyes from high‐intensity illumination. However, current OLs have low open‐state transmittance and a limited turndown ratio in some cases. In this study, first it is demonstrated that combining the insulator‐to‐metal transition (IMT) of vanadium dioxide (VO2) with anti‐reflection layers can enable both high and broadband open‐state transmittance (>−0.9 dB at the peak wavelength) while preserving a large turndown ratio (>21.8 dB). Furthermore, optothermal simulation is conducted to analyze the performance of the VO2 OL under ultrafast laser irradiation. The result reveals that IMT of the VO2 OL occurs at 0.23 µs when the incident laser intensity is 90 kW cm−2. These benefits offer a promising alternative to OLs in technologies ranging from sensor protection to human eye defense.

Effects of oxygen vacancies and interfacial strain on the metal–insulator transition of VO2 nanobeams

“…Vanadium dioxide (VO 2 ) has attracted considerable amounts of attention recently as a strong electron-correlated material since it exhibits a reversible metal-insulator transition (MIT) at a crucial temperature (T MIT ) of about 340 K. 1 This transition of VO 2 , which transforms it from its low-temperature insulating monoclinic phase to the high-temperature metallic rutile phase, correlates with a significant jump in resistance of 3-5 orders of magnitude and a significant variation in optical transmittance, particularly at near-infrared wavelengths. 2,3 VO 2 materials and devices have intriguing applications in smart windows, 4 optical and electrical switches, 5,6 photodetectors, 7,8 and chemical sensors 9,10 attributed to the extraordinary electrical and optical switching features established at the MIT. The Mott transition, which is driven by electron-electron interactions, and the Peierls transition, corresponding to the transformation of the lattice (electron-lattice coupling), 11 have been the two primary mechanisms employed to explain the microscopic origin of MIT in VO 2 .…”

Laser protection by using vortex wavefront coding imaging system

“…There are two feasible technical ways to prevent laser blindness in the photoelectric imaging system: one is to use laser protective materials and the other is to develop new photoelectric imaging systems. Laser protective material technology utilizes linear materials, 5,6 nonlinear materials, [7][8][9][10] and phase change materials [11][12][13][14] to make light filters for the protection of photoelectric imaging devices, which is a relatively common laser protection method; however, so far, there are still disadvantages, such as narrow protective bandwidth, slow reaction speed, and low protective strength. 15 At the same time, the increasing power and wavelength broadening of lasers [16][17][18] make laser protection of photoelectric imaging systems more difficult.…”