Black gold deposits as absorbers for far infrared radiation

Abstract

Dedicated to Professor Dr. K. W. BOER on the occasion of his 70th birthday Thermal infrared sensors with maximal sensitivity and minimal response time require radiation absorbing layers with small heat capacity and high absorbance. In the near infrared these conditions are well met by black gold layers. In order to examine the question whether black gold layers are suitable absorbers as well in the far infrared, their reflectance is measured in a wave number range from k = 14 to 650 cm-', corresponding to a range in wavelength 1 = l / k between 15 and 710 pm.The samples are prepared at various residual gas pressures. The influence of tempering o m the absorbance and the spectral absorption behavior at low temperatures is discussed. The experimental results may be accounted for by a dielectric function according to the Bergman formalism. The spectral dependence of the absorption coefficient and the real and imaginary parts of the refractive index following from it are presented.

Thermal effects in femtosecond laser ablation of metals

“…9 and 10 demonstrate that the black halo has a structure of spherical nanoparticle aggregates that is typically seen in gold-black films. 27,28 The gold-black films have been known for their high absorptance in the infrared. 29,30 Therefore, the gold-black halo can enhance the absorption of low-intensity wings of the incident Gaussian beam and contribute to residual heating of the sample.…”

Enhanced performance of VOx-based bolometer using patterned gold black absorber

“…Devices are typically optimized for mid-wave IR (MWIR, 3-5 µm wavelength) or long-wave IR (LWIR, [8][9][10][11][12] µm wavelength) by Fabry-Perot 1,2 and other resonant structures, [3][4][5] whose peak absorbance and bandwidth depend on resonator Q and hence on fabrication tolerances. In contrast, gold black is a well-known absorber with very high absorption over a broad spectral range, 6 and which is easily deposited using an ordinary thermal evaporator. Thus, a multiband sensor can be fabricated using a single material with minimal fabrication tolerances.…”

IR characterization of graphite black-coating for cryogenic detectors

“…Other paints and oxide coatings have been developed for damage-resistant coatings for UV measurement applications. Other metal blacks such as silver-black, platinum-black or gold-black [7,8] have been used to enhance the IR sensitivity of thermal detectors. The process by which these metal-blacks is deposited on thermal detectors, remains difficult somewhat black-paints deposition [8,9].…”