Studies on diamondlike carbon films for antireflection coatings of infrared optical materials

Zhang, G. F.; Guo, Liping; Xiu, Xianming; Zheng, Xiaolong

doi:10.1063/1.357813

Cited by 32 publications

(4 citation statements)

References 9 publications

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“…(1) well with Ge substrate (n = 4.0) [5]. The results of the Ge window with single layer of DLC coatings were reported [6,7] but the multi-layer of DLC coatings were generally adopted to more increase the transmittance or to enlarge the transmission bands [8,9]. By using multi-layer DLC coating, the transmittance of the Ge window can be increased to a value near 1 in the long-wavelength infrared (LWIR) region [9].…”

Section: Introductionmentioning

confidence: 94%

Controlling the infrared optical properties of rf-sputtered NiO films for applications of infrared window

Shim

Kang

Jeon

et al. 2015

Infrared Physics & Technology

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Section: Introductionmentioning

confidence: 94%

Controlling the infrared optical properties of rf-sputtered NiO films for applications of infrared window

Shim

Kang

Jeon

et al. 2015

Infrared Physics & Technology

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“…The past few decades, this coating is typically a diamond like carbon (DLC) coating due to its intermediate refractive index and good physical properties. [13][14][15] The exact properties of the anti-reflective coating of the lens used during the measurement campaign are unknown. The incident laser radiation however has a wavelength of 1.07µm which is about an order of magnitude smaller than the wavelengths for which the coating is designed.…”

Section: The Anti-reflection Coatingmentioning

confidence: 99%

Numerical investigation of thermal effects of high-energy laser irradiation on a germanium lens

Desnijder

Vandewal²

2022

High-Power Lasers and Technologies for Optical Countermeasures

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High energy lasers (HEL) are increasingly seen as a versatile tool to counter observation systems by directly damaging or dazzling the electro-optical (EO) or infrared (IR) sensors used for detection, recognition, tracking, and targeting. The main mechanism through which high energy lasers affect their target is by heat. In the case of thermal sensors which use germanium optics, this heat is applied on the outer optical component as germanium isn’t transmissive at the typical wavelengths at which current HEL lasers operate. Germanium is a brittle material and therefore is prone to shattering due to mechanical stresses caused by local thermal expansion of the hotspot. Furthermore, germanium becomes opaque to thermal IR radiation at elevated temperatures and starts emitting radiation itself. This mechanism allows an out-of-band high-energy laser to indirectly dazzle thermal infrared sensors which is referred to as pseudo-in-band dazzling. Because this effect depends on the temperature of the germanium, the sensor can remain dazzled some time after the laser irradiation has stopped while the germanium lens is cooling down. To be able to assess the effectiveness of a laser beam to dazzle or destroy a germanium lens, one must know the evolution of the heat distribution throughout the lens. In this work a thermal simulation model is presented that takes in account several aspects that influence the propagation of heat in a realistic lens. The simulation results are compared to experimentally obtained results from an earlier measurement campaign. The potential impact of the incident radiation distribution on the heating and cooling times are discussed.

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“…[1][2][3][4][5][6][7] The IR imaging systems operate in either the long-wave infrared (LWIR, 8-12.5 µm/800-1250 cm −1 ) or mid-wave infrared (MWIR, 3-5 µm/2000-3300 cm −1 ) thermal IR spectral windows. [8] While diamond-like carbon has widely been exploited as a protective coating for LWIR Ge optical elements, [16] the use of 2D carbon materials and nanocarbon allotropes has hardly been explored for application to LWIR optics. π-conjugated carbon-based materials such as graphite, graphene, and carbon nanotubes (CNTs) have remarkable chemical, electrical, optical, and mechanical properties that make them very attractive in fields such as environmental remediation, [17,18] biomedicine, [19] energy generation/storage, [20] and photocatalysis, [21] to cite but a few.…”

Section: Introductionmentioning

confidence: 99%

π‐Conjugated Carbon‐Based Materials for Infrared Thermal Imaging

Cho

Pratik

Pyun

et al. 2023

Advanced Optical Materials

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Infrared (IR) thermal imaging is receiving a great deal of attention due to its wide range of applications. Given multiple issues (like cost and availability) with the inorganic materials currently exploited for IR imaging, there is nowadays a great push of developing organic imaging materials. Carbon‐based materials are known to have significant transparency in the visible and IR regions and some are used as transparent conductors. Here, whether π‐conjugated carbon‐based materials are suitable for long‐wave (LW) and mid‐wave (MW) IR imaging applications is computationally assessed. Using density functional theory calculations, the IR‐vibrational properties of molecules from acenes to coronenes and fullerenes, and of periodic systems like graphene and carbon nanotubes are characterized. Fullerenes, graphenes, and double‐walled carbon nanotubes are found to be very attractive as they are transparent in both the LWIR and MWIR regions, a feature resulting from the absence of hydrogen atoms. Also, it is found that replacing hydrogen atoms in a molecule with deuterium or sulfur atoms can be an efficient way to improve their LWIR or MWIR transparency, respectively. For fused‐ring systems having hydrogen atoms on the periphery, designing molecules with trio CH‐units is another way to enhance the transparency in the LWIR region.

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Studies on diamondlike carbon films for antireflection coatings of infrared optical materials

Cited by 32 publications

References 9 publications

Controlling the infrared optical properties of rf-sputtered NiO films for applications of infrared window

Controlling the infrared optical properties of rf-sputtered NiO films for applications of infrared window

Numerical investigation of thermal effects of high-energy laser irradiation on a germanium lens

π‐Conjugated Carbon‐Based Materials for Infrared Thermal Imaging

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