Modeling the Radiative Properties of Microscale Random Roughness Surfaces

Fu, Kang; Hsu, Pei‐feng

doi:10.1115/1.2401200

Cited by 26 publications

(11 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sufficient time steps would also be required so that steady-state results are obtained. However, a long surface and a large number of time steps will significantly increase the computation time [12]. A compromise between solution accuracy and computational time is necessary.…”

Section: Resultsmentioning

confidence: 99%

“…Another problem that may arise due to insufficient surface length is the near-to-far-field (NTFF) transformation to obtain the reflectivity property [12]. To demonstrate this problem, the reflection of incident light at θ i = 70 • from surface C was calculated with the NTFF transformation to obtain the bi-directional reflectivity.…”

Section: Resultsmentioning

confidence: 99%

“…Geometric ray tracing is limited to roughness being larger than the incident wavelength, so the wave interference effect can be neglected [9]. The finite-difference time-domain (FDTD) method produced highly accurate solutions to understand the light scattering process of microscale random roughness in perfect electric conductors (PEC) and dielectric surfaces [12]. For metallic surfaces, the original FDTD equations have to be modified to ensure solution convergence.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Radiative Properties of Gold Surfaces with One-Dimensional Microscale Gaussian Random Roughness

Hsu

2007

Int J Thermophys

Self Cite

View full text Add to dashboard Cite

The radiative properties of engineering surfaces with microscale surface textures depend on the incident wavelength, optical properties, and temperature as well as the topography of the reflective surface. In the case of slightly rough surfaces, the traditional Kirchhoff theory on rough surface scattering may be applicable. In this study, a direct numerical solution of Maxwell's equations was developed to understand scattering from weakly to very rough surfaces. The method is the finite-difference time-domain method. The problem of interest is a set of gold surfaces with Gaussian random roughness distributions. Highly accurate experimental data are available from the earlier work of Knotts and O'Donnell in 1994. Due to the negative real component of the complex dielectric constant at the infrared light source wavelengths of 1.152 and 3.392 µm, the convoluted integral was used to convert the frequency domain electrical properties to time-domain properties in order to obtain convergent solutions. The bi-directional reflectances for both normal and parallel polarizations were obtained and compared with experimental data. The predicted values and experimental results are in good agreement. The highly specular peak in the reflectivity was reproduced in the numerical simulations, and the increase of the parallel polarization bi-directional reflectance was found to be due to the effect of a variation in the optical constant from 1.152 to 3.392 µm.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Radiative Properties of Gold Surfaces with One-Dimensional Microscale Gaussian Random Roughness

Hsu

2007

Int J Thermophys

Self Cite

View full text Add to dashboard Cite

show abstract

“…The detailed numerical scheme, periodic boundary treatment, and perfectly matched layer absorbing boundary condition can be found in many references [13,14], so they are not repeated here. Only the essential difference equations are presented below.…”

Section: Numerical Algorithmmentioning

confidence: 99%

Effects of nanoscale features on infrared radiative properties of heavily doped silicon complex gratings

Wang

Hsu

Chen³

et al. 2010

Sci. China Technol. Sci.

View full text Add to dashboard Cite

The infrared radiative properties of one heavily doped silicon complex grating and its corresponding four modified complex gratings with attached features at transverse magnetic wave incidence were numerically investigated by employing the finite-difference time-domain method. For the complex grating, by properly choosing the carrier concentration and geometry, it exhibited a broadband absorptance peak at wavelengths between 7 and 12 μm resulting from the excitation of surface plasmon polaritons. As for the four modified complex gratings, though absorptance spectra of the gratings almost remained unchanged, their locations shifted towards longer wavelengths. Meanwhile, the spectral absorptance peaks of two modified complex gratings were wider than that of the grating without attached features. Such broadened peaks could be partly attributed to the cavity resonance within the grating structures demonstrated by the electromagnetic fields and Poynting vectors plots. Finally, through comparing the spectral absorptances of complex gratings with two symmetrical square features in three sizes, it was shown that the peak wavelength shifted toward longer wavelengths with enlarged feature size. This work theoretically laid a foundation for the optimized design and application of the infrared detector with high performance. cavity resonance effect, finite-difference time-domain, modified complex gratings, radiative property, surface plasmon polaritons Citation:Wang A H, Hsu P F, Chen Y B, et al. Effects of nanoscale features on infrared radiative properties of heavily doped silicon complex gratings. Sci

show abstract

“…The interests in random roughness surfaces are quite diverse. For example, we have conducted extensive work on ramifications of microscale roughness surfaces in thermal radiative environment [26][27][28]. The present study is devoted to investigating the mechanism of formation of a road surface mirage with directly measured evidence.…”

mentioning

confidence: 99%

Road surface mirage: A bunch of hot air?

et al. 2011

Self Cite

View full text Add to dashboard Cite

The inferior mirage from road surfaces is a common phenomenon, which can be easily seen in everyday life. It has been recognized in the literature as a light refraction phenomenon due to the refractive index gradient caused by the temperature gradient in the air strata above the road surfaces. However, it was also suggested that the mirage is just a phenomenon of specular reflection at grazing incidence. Because of the lack of reasonable and quantitative evidence, the generally accepted light refraction theory has not yet been refuted. Here we show some mirror-like reflection images captured from a road surface stretch in Yujiashan North Road, Wuhan, China, when there was no obvious temperature gradient on or above the road, measured on a winter day in December 2009. This provided direct evidence to doubt the temperature induced light refraction mechanism of the inferior mirage. Furthermore, the critical grazing angle of about 0.2° to the road plane where the mirror-like reflection appears could not make the rough surface scatter incident light as a smooth surface according to the Rayleigh criterion. Therefore the phenomenon is a mirrorlike observation effect of scattering from the surface, which cannot be entirely explained by light refraction via air strata. The results demonstrate that the image-formation mechanism and the observer-based-analysis method shown here potentially offer a means of understanding a wide range of scattering phenomena from rough surfaces at grazing angle; for example, the superior mirages of unusual brightness occasionally observed over frozen lakes and the off-specular reflection phenomenon.

show abstract

Modeling the Radiative Properties of Microscale Random Roughness Surfaces

Cited by 26 publications

References 20 publications

Radiative Properties of Gold Surfaces with One-Dimensional Microscale Gaussian Random Roughness

Radiative Properties of Gold Surfaces with One-Dimensional Microscale Gaussian Random Roughness

Effects of nanoscale features on infrared radiative properties of heavily doped silicon complex gratings

Road surface mirage: A bunch of hot air?

Contact Info

Product

Resources

About