Mid-IR to near-IR image conversion by thermally induced optical switching in vanadium dioxide

Abstract

We demonstrate the image conversion from mid-IR to near-IR (NIR) exploiting high-contrast optical switching in vanadium oxide thin-film layers. The intensity distribution of a mid-IR beam is converted to NIR wavelengths exploiting the strong reflectivity changes induced by optical pumping in the mid-IR. We show an experimental setup in which the radiation of a Tm-doped fiber laser at 1940 microm and a carbon dioxide at 10.6 microm has been converted to both 850 nm and 1064 nm. The resolution was 35 microm and was reached by using an inexpensive CCD camera. The sensitivity of the device increases linearly with sample temperature. We measured a threshold of 144 mW/cm(2), with a sample temperature of 62 degrees C.

Nanothermochromics: Calculations for VO2 nanoparticles in dielectric hosts show much improved luminous transmittance and solar energy transmittance modulation

“…120 From a practical point of view, VO 2 may be awkward to prepare since the vanadium ions are in states with intermediate oxidation and it may be more facile to fabricate materials under nonoxidizing ͑metallic V͒ or fully oxidizing ͑in-sulating V 2 O 5 ͒ conditions. The limitations are not as stringent as they may seem, though, and it should be observed that metallic vanadium can be transformed to VO 2 by controlled oxidation [121][122][123][124] and that insulating V 2 O 5 van be transformed to VO 2 by controlled reduction in films. [125][126][127] There is a tendency that limited dimensions decreases c and widens the hysteresis in nanocrystalline films 46,48,[128][129][130][131][132][133][134][135] and nanorods.…”

Optimization of conditions for growth of vanadium dioxide thin films on silicon by pulsed-laser deposition

“…The marked changes in electronic and optical properties at temperatures above and below the metal-insulator transition (MIT) in rutile-type VO 2 have attracted much interest, not only in relation to fundamental science, but also for the potential device applications such as transistors, optical switches, smart windows, uncooled bolometers, thermal transistors, or thermal memories. [1][2][3][4][5][6] For VO 2 , the MIT from a high-temperature metallic phase to a low-temperature insulating phase occurs at around 68…”

“…[1][2][3][4][5][6] For VO 2 , the MIT from a high-temperature metallic phase to a low-temperature insulating phase occurs at around 68…”

“…Based on the results, we derived the P O2 versus 1/T S phase diagram for the films of vanadium oxides, which will provide a guide to optimizing the conditions for growth of VO 2 …”

Chromium–niobium co-doped vanadium dioxide films: Large temperature coefficient of resistance and practically no thermal hysteresis of the metal–insulator transition

“…3 Among these devices, VO 2 -based uncooled bolometers that detect far-IR radiation have been actively studied and developed for several decades. [4][5][6][7][8] One measure of the suitability of a material for use in a bolometer is its temperature coefficient of resistance (TCR), which is defined as |(1/ρ)(dρ/dT)|, where ρ is the resistivity or resistance and T is the temperature of the material. The TCR value of VO 2 reaches more than 70%/K near the MIT temperature (T MI ), 9 which is more than ten times that of conventional uncooled bolometer materials such as Si or Ge.…”