The potential for improving the penetration depth of optical coherence tomography systems by using light sources with longer wavelengths has been known since the inception of the technique in the early 1990s.Neverthel...The potential for improving the penetration depth of optical coherence tomography systems by using light sources with longer wavelengths has been known since the inception of the technique in the early 1990s.Nevertheless,the development of mid-infrared optical coherence tomography has long been challenged by the maturity and fidelity of optical components in this spectral region,resulting in slow acquisition,low sensitivity,and poor axial resolution.In this work,a mid-infrared spectral-domain optical coherence tomography system operating at a central wavelength of 4μm and an axial resolution of 8.6μm is demonstrated.The system produces two-dimensional cross-sectional images in real time enabled by a high-brightness 0.9-to 4.7-μm mid-infrared supercontinuum source with a pulse repetition rate of 1 MHz for illumination and broadband upconversion of more than 1-μm bandwidth from 3.58–4.63μm to 820–865 nm,where a standard 800-nm spectrometer can be used for fast detection.The images produced by the mid-infrared system are compared with those delivered by a state-of-the-art ultra-high-resolution near-infrared optical coherence tomography system operating at 1.3μm,and the potential applications and samples suited for this technology are discussed.In doing so,the first practical mid-infrared optical coherence tomography system is demonstrated,with immediate applications in real-time non-destructive testing for the inspection of defects and thickness measurements in samples that exhibit strong scattering at shorter wavelengths.展开更多
Thermal nanoimprinting is a fast and versatile method for transferring the anti-reflective properties of subwavelength nanostructures onto the surface of highly reflective substrates, such as chalcogenide glass optica...Thermal nanoimprinting is a fast and versatile method for transferring the anti-reflective properties of subwavelength nanostructures onto the surface of highly reflective substrates, such as chalcogenide glass optical fiber end faces. In this paper, the technique is explored experimentally on a range of different types of commercial and custom-drawn optical fibers to evaluate the influence of geometric design, core/cladding material, and thermo-mechanical properties. Up to32.4% increased transmission and 88.3% total transmission are demonstrated in the 2–4.3 μm band using a mid-infrared(IR) supercontinuum laser.展开更多
基金the financial support from Innovation Fund Denmark through ShapeOCT Grant No.4107-00011Athe NIHR Biomedical Research Center at Moorfields Eye Hospital NHS Foundation Trust+3 种基金the UCL Institute of Ophthalmologythe Royal Society Wolfson Research Merit Award.the support from H.C.Orsted COFUNDED Marie-Curie action fellowshipfinancial support from H.C.Orsted for the running cost.
文摘The potential for improving the penetration depth of optical coherence tomography systems by using light sources with longer wavelengths has been known since the inception of the technique in the early 1990s.Nevertheless,the development of mid-infrared optical coherence tomography has long been challenged by the maturity and fidelity of optical components in this spectral region,resulting in slow acquisition,low sensitivity,and poor axial resolution.In this work,a mid-infrared spectral-domain optical coherence tomography system operating at a central wavelength of 4μm and an axial resolution of 8.6μm is demonstrated.The system produces two-dimensional cross-sectional images in real time enabled by a high-brightness 0.9-to 4.7-μm mid-infrared supercontinuum source with a pulse repetition rate of 1 MHz for illumination and broadband upconversion of more than 1-μm bandwidth from 3.58–4.63μm to 820–865 nm,where a standard 800-nm spectrometer can be used for fast detection.The images produced by the mid-infrared system are compared with those delivered by a state-of-the-art ultra-high-resolution near-infrared optical coherence tomography system operating at 1.3μm,and the potential applications and samples suited for this technology are discussed.In doing so,the first practical mid-infrared optical coherence tomography system is demonstrated,with immediate applications in real-time non-destructive testing for the inspection of defects and thickness measurements in samples that exhibit strong scattering at shorter wavelengths.
基金supported by the European Commission (Nos. 317803, 722380, and 732968)the Innovation Fund Denmark (No. 4107-00011A)+2 种基金the Danish Maritime Fund (No. 2019-137)the Lundbeck Foundation (No. R276-2018869)the Independent Research Fund Denmark (No. 8022-00091B)。
文摘Thermal nanoimprinting is a fast and versatile method for transferring the anti-reflective properties of subwavelength nanostructures onto the surface of highly reflective substrates, such as chalcogenide glass optical fiber end faces. In this paper, the technique is explored experimentally on a range of different types of commercial and custom-drawn optical fibers to evaluate the influence of geometric design, core/cladding material, and thermo-mechanical properties. Up to32.4% increased transmission and 88.3% total transmission are demonstrated in the 2–4.3 μm band using a mid-infrared(IR) supercontinuum laser.
