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We report on the fabrication and practical use of high-quality optical elements based on Au mirrors coated with diamond layers with flat, nanocolumnar, and nanoporous morphologies. Diamond layers (100 nm thickness) are grown at low temperatures (about 300 °C) from a methane, carbon dioxide, and hydrogen gas mixture by a pulsed microwave plasma system with linear antennas. Using grazing angle reflectance (GAR) Fourier transform infrared spectroscopy with p-polarized light, we compare the IR spectra of fetal bovine serum proteins adsorbed on diamond layers with oxidized (hydrophilic) surfaces. We show that the nanoporous diamond layers provide IR spectra with a signal gain of about 600% and a significantly improved sensitivity limit. This is attributed to its enhanced internal surface area. The improved sensitivity enabled us to distinguish weak infrared absorption peaks of <10-nm-thick protein layers and thereby to analyze the intimate diamond-molecule interface.

Diamond thin films have remarkable properties comparable with natural diamond. Because of these properties it is a very promising material for many various applications (sensors, heat sink, optical mirrors, chemical and radiation wear, cold cathodes, tissue engineering, etc.) In this paper we report about design, deposition and measurement of properties of optical planar waveguides fabricated from nanocrystalline diamond thin films. The nanocrystalline diamond planar waveguide was deposited by microwave plasma enhanced chemical vapor deposition and the structure of the deposited film was studied by scanning electron microscopy and Raman spectroscopy. The design of the presented planar waveguides was realized on the bases of modified dispersion equation and was schemed for 632.8 nm, 964 nm, 1 310 nm and 1 550 nm wavelengths. Waveguiding properties were examined by prism coupling technique and it was found that the diamond based planar optical element guided one fundamental mode for all measured wavelengths. Values of the refractive indices of our NCD thin film measured at various wavelengths were almost the same as those of natural diamond.

Heavily boron doped nanocrystalline diamond films grown on glass substrates by the method of plasma-chemical deposition, were investigated using Raman spectroscopy. Analysis of the spectra showed both the phonon confinement effect in nanocrystalline grains and Fano interference effect due to the contribution of electron Raman scattering in heavily doped p-type diamond films. The increase of boron concentration led to decrease of the size of crystalline diamond grains. The films are semitransparent and have good conductivity, so that it can be used as transparent electrodes in giant-scale electronics and optoelectronics. [ABSTRACT FROM AUTHOR]

Monocrystalline germanium is considered a highly useful material for infrared optical applications due to its relatively low price, low toxicity and high optical transparency in the infrared spectral range (5500–870 cm −1 ). However, it is limited by its low chemical, mechanical, and thermal stability. The thin film diamond coating can provide a mechanical protection of a Ge surface against scratching, chemical protection against solutions, and make a well-defined hydrophilic/hydrophobic surface. Here, we compare low temperature (250–400 °C) diamond growth on Ge substrates and attenuated total reflection prisms, using a chemical vapor deposition in linear antenna microwave plasma and focused microwave plasma reactors. We show that by employing a thin amorphous silicon interlayer (20–30 nm), a homogeneous diamond coating with no degradation of the Ge surface is achieved. The infrared spectroscopy of proteins adsorbed on the diamond coated Ge prism demonstrates usability and advantages in comparison with bare Si or Ge prisms and even with the diamond-coated Si prism. [ABSTRACT FROM AUTHOR]