Thin Film Optical Coatings

Ristau, Detlev; Ehlers, Henrik

doi:10.1007/978-0-387-30420-5_6

Cited by 2 publications

(1 citation statement)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, there are several key properties that are generally sought after in the materials for optical coatings, which include optical transparency, refractive index, bandgap, stability (mechanical, thermal, and optical), and adhesion. In addition, the coatings should be environmentally friendly [4]. Materials for optical coatings usually have wide bandgaps, with that of magnesium fluoride (MgF 2 ) being 13.0 eV [5].…”

Section: Introductionmentioning

confidence: 99%

A Comparative Thermodynamic Study of AlF3, ScF3, Al0.5Sc0.5F3, and In0.5Sc0.5F3 for Optical Coatings: A Computational Study

Alruqi,

Ongwen

2023

Coatings

View full text Add to dashboard Cite

Optical coatings are thin layers of materials applied to optical components in order to modify the transmission, reflection, or polarization properties of light. The common materials used for optical coatings include magnesium fluoride (MgF2), scandium trifluoride (ScF3), and aluminum trifluoride (AlF3), owing to their desirable optical properties, spectral range, and compatibility with substrates. However, each of these materials has its own drawbacks. For instance, AlF3 has been found to exhibit limited resistance to attack by chemicals, as well as poor thermal stability, while MgF2 has low durability, as well as being hygroscopic. In this study, we undertook ab initio calculations in order to compare the thermal properties of AlF3, ScF3, Al0.5Sc0.5F3, and In0.5Sc0.5F3 in order to obtain the best material for optical coatings. MgF2 was also included in the study as a reference. The calculations used PBE pseudopotentials and the extended generalized gradient approximation within the quantum espresso algorithm. The study demonstrated that the computed results agree with the information found in the literature. ScF3 exhibited a negative coefficient of thermal expansion, unlike the other four. Moreover, AlF3 was found to be the best candidate for optical coatings that are used in high-power laser systems with high thermal dissipation, due to its superior thermal expansion coefficient as well as its better response to thermal stress. The large variation between the cp and cv of ScF3 is not desirable. Moreover, due to its negative thermal expansion coefficient, ScF3 is not thermally stable. The highest thermal stability was exhibited by In0.5Sc0.5F3. Since Al0.5Sc0.5F3 and In0.5Sc0.5F3 have been modeled in this study for the first time, experimental determination of their crystal structures needs to be investigated.

show abstract

Section: Introductionmentioning

confidence: 99%

A Comparative Thermodynamic Study of AlF3, ScF3, Al0.5Sc0.5F3, and In0.5Sc0.5F3 for Optical Coatings: A Computational Study

Alruqi,

Ongwen

2023

Coatings

View full text Add to dashboard Cite

show abstract

Analysis of Thin-Film Polymers Using Attenuated Total Internal Reflection–Raman Microspectroscopy

et al. 2015

View full text Add to dashboard Cite

Two methods commonly employed for molecular surface analysis and thin-film analysis of microscopic areas are attenuated total reflection infrared (ATR-IR) microspectroscopy and confocal Raman microspectroscopy. In the former method, the depth of the evanescent probe beam can be controlled by the wavelength of light, the angle of incidence, or the refractive index of the internal reflection element. Because the penetration depth is proportional to the wavelength of light, one could interrogate a smaller film thickness by moving from the mid-infrared region to the visible region employing Raman spectroscopy. The investigation of ATR Raman microspectroscopy, a largely unexplored technique available to Raman microspectroscopy, was carried out. A Renishaw inVia Raman microscope was externally modified and used in conjunction with a solid immersion lens (SIL) to perform ATR Raman experiments. Thin-film polymer samples were analyzed to explore the theoretical sampling depth for experiments conducted without the SIL, with the SIL, and with the SIL using evanescent excitation. The feasibility of micro-ATR Raman was examined by collecting ATR spectra from films whose thickness measured from 200 to 60 nm. Films of these thicknesses were present on a much thicker substrate, and features from the underlying substrate did not become visible until the thin film reached a thickness of 68 nm.

show abstract

Thin Film Optical Coatings

Cited by 2 publications

References 52 publications

A Comparative Thermodynamic Study of AlF3, ScF3, Al0.5Sc0.5F3, and In0.5Sc0.5F3 for Optical Coatings: A Computational Study

A Comparative Thermodynamic Study of AlF3, ScF3, Al0.5Sc0.5F3, and In0.5Sc0.5F3 for Optical Coatings: A Computational Study

Analysis of Thin-Film Polymers Using Attenuated Total Internal Reflection–Raman Microspectroscopy

Contact Info

Product

Resources

About