Introduction to Natural Hyperbolic Materials
Researchers have discovered a natural hyperbolic material with extreme optical properties called in-plane hyperbolic. This discovery is likely to make it possible for infrared optical components to be replaced.
Hyperbolic materials have high reflection of light along a certain axis and reflect light along a vertical axis, usually with one axis within the material plane and the other axis outside of that plane. Dual axis materials on the same plane can be used to make optical components, such as ultra-thin waveplates, which can change the polarization of incident light. In addition, the reflective properties of this material allow for manipulation and limitation of light within a very small size range (less than 1% of the wavelength of the light wave).
Many crystals exhibit birefringence, where the refractive index (a measure of the speed of light in a material) varies along different axes. This characteristic can be used to control the polarization of incident light. Therefore, in the mid to far infrared band of the electromagnetic spectrum (wavelength range 3μ m-300μ); m) The crystal thickness is usually required to be a few millimeters.
Initially, it was believed that hyperbolic properties only existed in artificial materials containing reflective and transparent regions. But in 2014, researchers observed this characteristic in the natural material hexagonal boron nitride. The reflection behavior of the material and Mo3O3 is caused by lattice vibrations, where optical phonons oscillate in a highly anisotropic manner (depending on direction).
Earlier this year, preliminary research on molybdenum trioxide was reported, revealing the hyperbolic properties of long wavelength infrared light (8μ m-14μ m). Ma and his colleagues have demonstrated and described hyperbolic linearity within the same spectral range. They utilize this property to confine light to a size much smaller than its wavelength by exciting it with a material called a hyperbolic phonon polarizer (exaggerated phonon polaron) to form mixed light. The results indicate that the lifetime of the prepared polaron can reach 20 picoseconds, which is 10 times that of hexagonal boron nitride.
Due to the highly anisotropic crystal structure of molybdenum trioxide, the lengths of the three crystal axes defining the edge of the unit are different, resulting in significantly different phonon energies and refractive indices associated with these axes, leading to a birefringence of approximately 0.31. It is worth noting that research earlier this year showed that the natural substance barium titanium peptide has the same in-plane birefringence of 0.76, which is used for mid to long wave infrared. However, the exaggeration of this material was not observed.
Control infrared polarization. This material can be replaced with molybdenum trioxide sheets with a thickness of only a few tens of micrometers. The elements in a polarizer are called polarizers, which convert non polarized light (polarization points in all directions) into linearly polarized light. In the infrared band, polarizers made of traditional materials typically require thick metal grids. This structure can be replaced by a molybdenum trioxide film, which is not necessary for manufacturing. It is a nanophotonic structure made of traditional materials that can emit non polarized infrared light, but if molybdenum trioxide is used, linear polarized emission can be achieved.
The in-plane hyperbolic characteristics of molybdenum trioxide make it possible for small-sized optical components to replace traditional optical components, especially by utilizing the large plane birefringence of the material (or barium titanium sulfide). Infrared waveplates can be composed of thin sheets with a thickness of several tens of micrometers, which can operate in the long wavelength infrared band. For this band, commercially available waveplates are not common, with a thickness exceeding 1 millimeter.
In addition, by utilizing the planar hyperbolic property of the material, the polarizing element can be made of a simple 1&m thick film, and the polarizer can selectively allow incident light to vibrate in a certain direction.
Finally, hyperbolic materials such as molybdenum trioxide can also be used as basic materials for superlenses, which can generate magnified images of objects with smaller imaging wavelengths. This material can also be used in heterostructures to manufacture nanophotonic devices with controllable performance.
What nature has given us far exceeds our imagination. The future of nanophotonics was once thought to be achieved through artificial materials, but this study and other research in the past few years have shown that in many cases, the best way to find advanced materials is to search for a large amount of natural materials. The results of these studies greatly promote the development of infrared optics and nanophotonics, or make infrared imaging and detection as common as visible light imaging, enabling on-site emergency workers to; See through '; Smoke, instant medical diagnosis, and enhanced chemical spectroscopy.
Hyperbolic materials have high reflection of light along a certain axis and reflect light along a vertical axis, usually with one axis within the material plane and the other axis outside of that plane. Dual axis materials on the same plane can be used to make optical components, such as ultra-thin waveplates, which can change the polarization of incident light. In addition, the reflective properties of this material allow for manipulation and limitation of light within a very small size range (less than 1% of the wavelength of the light wave).
Many crystals exhibit birefringence, where the refractive index (a measure of the speed of light in a material) varies along different axes. This characteristic can be used to control the polarization of incident light. Therefore, in the mid to far infrared band of the electromagnetic spectrum (wavelength range 3μ m-300μ); m) The crystal thickness is usually required to be a few millimeters.
Initially, it was believed that hyperbolic properties only existed in artificial materials containing reflective and transparent regions. But in 2014, researchers observed this characteristic in the natural material hexagonal boron nitride. The reflection behavior of the material and Mo3O3 is caused by lattice vibrations, where optical phonons oscillate in a highly anisotropic manner (depending on direction).
Earlier this year, preliminary research on molybdenum trioxide was reported, revealing the hyperbolic properties of long wavelength infrared light (8μ m-14μ m). Ma and his colleagues have demonstrated and described hyperbolic linearity within the same spectral range. They utilize this property to confine light to a size much smaller than its wavelength by exciting it with a material called a hyperbolic phonon polarizer (exaggerated phonon polaron) to form mixed light. The results indicate that the lifetime of the prepared polaron can reach 20 picoseconds, which is 10 times that of hexagonal boron nitride.
Due to the highly anisotropic crystal structure of molybdenum trioxide, the lengths of the three crystal axes defining the edge of the unit are different, resulting in significantly different phonon energies and refractive indices associated with these axes, leading to a birefringence of approximately 0.31. It is worth noting that research earlier this year showed that the natural substance barium titanium peptide has the same in-plane birefringence of 0.76, which is used for mid to long wave infrared. However, the exaggeration of this material was not observed.
Control infrared polarization. This material can be replaced with molybdenum trioxide sheets with a thickness of only a few tens of micrometers. The elements in a polarizer are called polarizers, which convert non polarized light (polarization points in all directions) into linearly polarized light. In the infrared band, polarizers made of traditional materials typically require thick metal grids. This structure can be replaced by a molybdenum trioxide film, which is not necessary for manufacturing. It is a nanophotonic structure made of traditional materials that can emit non polarized infrared light, but if molybdenum trioxide is used, linear polarized emission can be achieved.
The in-plane hyperbolic characteristics of molybdenum trioxide make it possible for small-sized optical components to replace traditional optical components, especially by utilizing the large plane birefringence of the material (or barium titanium sulfide). Infrared waveplates can be composed of thin sheets with a thickness of several tens of micrometers, which can operate in the long wavelength infrared band. For this band, commercially available waveplates are not common, with a thickness exceeding 1 millimeter.
In addition, by utilizing the planar hyperbolic property of the material, the polarizing element can be made of a simple 1&m thick film, and the polarizer can selectively allow incident light to vibrate in a certain direction.
Finally, hyperbolic materials such as molybdenum trioxide can also be used as basic materials for superlenses, which can generate magnified images of objects with smaller imaging wavelengths. This material can also be used in heterostructures to manufacture nanophotonic devices with controllable performance.
What nature has given us far exceeds our imagination. The future of nanophotonics was once thought to be achieved through artificial materials, but this study and other research in the past few years have shown that in many cases, the best way to find advanced materials is to search for a large amount of natural materials. The results of these studies greatly promote the development of infrared optics and nanophotonics, or make infrared imaging and detection as common as visible light imaging, enabling on-site emergency workers to; See through '; Smoke, instant medical diagnosis, and enhanced chemical spectroscopy.