2 research outputs found
Deep-subwavelength Phase Retarders at Mid-Infrared Frequencies with van der Waals Flakes
Phase retardation is a cornerstone of modern optics, yet, at mid-infrared
(mid-IR) frequencies, it remains a major challenge due to the scarcity of
simultaneously transparent and birefringent crystals. Most materials resonantly
absorb due to lattice vibrations occurring at mid-IR frequencies, and natural
birefringence is weak, calling for hundreds of microns to millimeters-thick
phase retarders for sufficient polarization rotation. We demonstrate mid-IR
phase retardation with flakes of -molybdenum trioxide
(-MoO) that are more than ten times thinner than the operational
wavelength, achieving 90 degrees polarization rotation within one micrometer of
material. We report conversion ratios above 50% in reflection and transmission
mode, and wavelength tunability by several micrometers. Our results showcase
that exfoliated flakes of low-dimensional crystals can serve as a platform for
mid-IR miniaturized integrated polarization control.Comment: 8 pages, 5 figure
Deeply subwavelength mid-infrared phase retardation with α-MoO3 flakes
Abstract Phase retardation is a cornerstone of modern optics, yet, at mid-infrared (mid-IR) frequencies, it remains a major challenge due to the scarcity of simultaneously transparent and birefringent crystals. Most materials resonantly absorb due to lattice vibrations occurring at mid-IR frequencies, and natural birefringence is weak, calling for hundreds of microns to millimeters-thick phase retarders for sufficient polarization rotation. Here, we demonstrate mid-IR phase retardation with flakes of α-MoO3 that are more than ten times thinner than the operational wavelength, achieving 90 degrees polarization rotation within one micrometer of material. We report conversion ratios above 50% in reflection or transmission mode, and wavelength tunability by several micrometers. Our results showcase that exfoliated flakes of low-dimensional crystals can serve as a platform for mid-IR miniaturized integrated low-loss polarization control