Impacts of Nanoscale Features on Infrared Radiative Properties of Metallic Slit Arrays

2009 ◽  
Author(s):  
Y.-B. Chen ◽  
J.-S. Chen ◽  
P.-F. Hsu
Keyword(s):  
Transverse Magnetic ◽  
Radiative Properties ◽  
Cavity Resonance ◽  
Resonance Excitation ◽  
Angle Of Incidence ◽  
Resonance Modes ◽  
Rigorous Coupled Wave Analysis ◽  
Rigorous Coupled Wave ◽  
Nanoscale Features ◽  
Poynting Vectors

Radiative properties (absorptance, reflectance, and transmittance) of deep slits with five nanoscale slit profile variations at the transverse magnetic wave incidence are numerically investigated in this work by employing the rigorous coupled-wave analysis. For slits with attached features, their radiative properties can be much different due to the modified cavity geometry and dangled structures, even at wavelengths between 3 and 15 μm. The shifts of cavity resonance excitation result in higher transmittance through narrower slits at specific wavelengths and resonance modes are confirmed with the electromagnetic fields. Opposite roles possibly played by features in increasing or decreasing absorptance are determined by the feature position and demonstrated by Poynting vectors. Correlations among all properties of a representative slit array, the angle of incidence, and the slit density are also comprehensively studied.

Impact of Nanoscale Features of Metallic Slits on Mid-Infrared Radiative Properties

2008 ◽  
Author(s):  
Y.-B. Chen ◽  
J.-S. Chen ◽  
K. Fu ◽  
P.-F. Hsu
Keyword(s):  
Physical Mechanism ◽  
Radiative Properties ◽  
Cavity Resonance ◽  
Mid Infrared ◽  
Rigorous Coupled Wave Analysis ◽  
Slit Geometry ◽  
Rigorous Coupled Wave ◽  
Nanoscale Features ◽  
Poynting Vectors ◽  
Difference Time

Mid-Infrared radiative properties (absorptance, reflectance, and transmittance) of submicron gold slit arrays have been numerically studied with rigorous coupled-wave analysis and the finite difference time domain method. The slit width varies from 50 nm to 300 nm and a square feature may attach at either or both slit sides. Although the wavelength is one or two orders of magnitude longer than the side length of features, the attached nanoscale features can modify radiative properties significantly. Directional dependence on radiative properties has also been detail investigated by looking into electromagnetic fields and Poynting vectors of selected slit geometry. One possible physical mechanism, cavity resonance, account for unique radiative properties have been suggested and verified in the study as well.

Modeling Infrared Radiative Properties of Heavily Doped Silicon Complex Gratings With Geometric Modifications

2009 ◽  
Author(s):  
Ai-Hua Wang ◽  
Pei-feng Hsu ◽  
Yu-Bin Chen ◽  
Lin-Hua Liu
Keyword(s):  
Radiative Properties ◽  
Cavity Resonance ◽  
Resonance Excitation ◽  
Rigorous Coupled Wave Analysis ◽  
Doped Silicon ◽  
Heavily Doped ◽  
Rigorous Coupled Wave ◽  
Nanoscale Features ◽  
Difference Time ◽  
Plasmon Polaritons

Based on the prior work by authors, radiative properties of modified complex gratings with nanoscale features are studied. The purpose of this work is to demonstrate, even preliminary, the possibility of using complex gratings and nanoscale surface features to modify far field radiative properties. A finite-difference time-domain numerical scheme was used to model the infrared radiative properties of heavily doped silicon simple and complex gratings. The solutions were validated with those of rigorous coupled-wave analysis method. By properly choosing the carrier concentration and geometry, silicon complex gratings exhibit a broadband absorptance peak resulting from the excitation of surface plasmon polaritons. Meanwhile, the absorptance of four modified complex gratings with attached features has been numerically investigated for the impacts of the attached structures. Firstly, though absorptance spectra of gratings almost remain unchanged, their locations shift towards longer wavelengths. Secondly, the spectral absorptance peak of two modified complex gratings is wider than that of gratings without attached features due to the cavity resonance excitation. Thirdly, the spectral absorptance of complex gratings with square features in three sizes was compared and shows that the peak wavelength shifts toward longer wavelengths with enlarged feature size.

Study of the Absorptance of Si-gratings and of arrays of SiO2-filled trenches on Si-grating substrate

2016 ◽  
Vol 12 (2) ◽  
pp. 4278-4290
Author(s):  
Faouzi Ghmari ◽  
Ilhem Mezni
Keyword(s):  
Transverse Electric ◽  
Transverse Magnetic ◽  
Radiative Properties ◽  
Geometrical Parameters ◽  
Perfect Absorber ◽  
Angle Of Incidence ◽  
Patterned Wafers ◽  
Rigorous Coupled Wave Analysis ◽  
Rigorous Coupled Wave ◽  
Model Structures

The purpose of this paper is to study the radiative properties of two model structures. The first model (A-1) is a rectangular grating of silicon (Si). The second one (A-2) is obtained from A-1 by filling their trenches by SiO2. These patterned wafers are characterized by three geometrical parameters, the period d, the filling factorand the thickness h. To derive and compute the radiative properties we use a rigorous coupled wave analysis (RCWA) method. Our attention is focused on the absorptance of these structures when they are illuminated by a monochromatic plane wave. We investigate the effect of the filling factor on the absorptance versus the direction of the incident wave. At specific angles of incidence the effect of the period is also studied. Besides, the influence of the thickness h on the absorptance is included throughout this work. At the wavelength = 632,8nm, we especially show that we can identify several perfect absorber model structures characterized by specific parameters and by accurate angle of incidence. We show that this will be done in both transverse electric (TE) and transverse magnetic (TM) polarization cases.

Radiative Properties of Pattered Wafers With Linewidth Below 100 nm

2005 ◽  
Author(s):  
Y.-B. Chen ◽  
Z. M. Zhang ◽  
P. J. Timans
Keyword(s):  
Periodic Structures ◽  
Numerical Study ◽  
Radiative Properties ◽  
Angle Of Incidence ◽  
Patterned Wafers ◽  
Rigorous Coupled Wave Analysis ◽  
Recent Developments ◽  
Effective Medium Approach ◽  
Rigorous Coupled Wave ◽  
Very High

Temperature nonuniformity is a critical problem in rapid thermal processing (RTP) of wafers because it leads to uneven diffusion of implanted dopants and introduces thermal stress that can produce defects. One cause of the problem is nonuniform absorption of thermal radiation, especially in patterned wafers, where the optical properties vary across the surface of the wafer. Recent developments in RTP have lead to the use of millisecond-duration heating cycles, where light with very high power density is used to heat the surface of the wafer. Pattern effects are especially important here, because there is very little time for thermal diffusion to even out temperature distributions during the heating cycle. There have been very few studies on the radiative properties of patterned wafers, especially for the structures expected to be used on advanced semiconductor devices. The feature size is already below 100 nm and is comparable or smaller than the wavelengths of radiation (200–1000 nm) emitted by the flash-lamps typically used for millisecond processing. Hence, this work is devoted to a parametric numerical study of the radiative properties of patterned wafers with the smallest dimension down to 30 nm. The effects of wavelength, wave polarization, and angle of incidence on selected periodically patterned wafers are presented. The methods include the rigorous coupled wave analysis (RCWA) and the effective medium approach (EMA). RCWA is used to obtain exact solutions of Maxwell’s equations, and EMA is used to approximate the periodic structures as a planar multilayer structure with an effective dielectric function. This study provides an assessment of the applicability of EMA for simulations of radiative properties of patterned wafers.

Radiative Properties of Patterned Wafers With Nanoscale Linewidth

2006 ◽  
Vol 129 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Y.-B. Chen ◽  
Z. M. Zhang ◽  
P. J. Timans
Keyword(s):  
Numerical Solutions ◽  
Radiative Properties ◽  
Wafer Surface ◽  
Angle Of Incidence ◽  
Patterned Wafers ◽  
Rigorous Coupled Wave Analysis ◽  
Recent Developments ◽  
Effects Of Temperature ◽  
Rigorous Coupled Wave ◽  
Feature Dimension

Abstract Temperature nonuniformity is a critical problem in rapid thermal processing (RTP) of wafers because it leads to uneven diffusion of implanted dopants and introduces thermal stress. One cause of the problem is nonuniform absorption of thermal radiation, especially in patterned wafers, where the optical properties vary across the wafer surface. Recent developments in RTP have led to the use of millisecond-duration heating cycle, which is too short for thermal diffusion to even out the temperature distribution. The feature size is already below 100nm and is smaller than the wavelength (200-1000nm) of the flash-lamp radiation. Little is known to the spectral distribution of the absorbed energy for different patterning structures. This paper presents a parametric study of the radiative properties of patterned wafers with the smallest feature dimension down to 30nm, considering the effects of temperature, wavelength, polarization, and angle of incidence. The rigorous coupled wave analysis is employed to obtain numerical solutions of the Maxwell equations and to assess the applicability of the method of homogenization based on effective medium formulations.

SURFACE-COVERED 1×3 GRATING WITH DIELECTRIC-METAL SLABS UNDER SECOND BRAGG INCIDENCE

2020 ◽  
Vol 27 (09) ◽  
pp. 1950201
Author(s):  
CHEN FU ◽  
BO WANG ◽  
WENHUA ZHU ◽  
KUNHUA WEN ◽  
ZIMING MENG ◽  
...  
Keyword(s):  
Incident Light ◽  
Polarized Light ◽  
Transverse Magnetic ◽  
Second Order ◽  
Bragg Angle ◽  
Efficiency Ratio ◽  
First Order ◽  
Rigorous Coupled Wave Analysis ◽  
Rigorous Coupled Wave ◽  
The Given

This paper designed a novel three-port reflective surface-covered grating with a connecting layer. The grating can be used as a splitter, and the polarized light can be divided into zero order, first order and second order. Through rigorous coupled-wave analysis, the efficiency of the three orders of diffraction light is close to 33% under the condition that the incident light at 1550 nm is incident at the second Bragg angle and the given duty cycle is 0.5. The efficiency and bandwidth of the surface-covered grating are improved compared with that of the surface-relief grating reported in the past. Especially for transverse magnetic polarized light, the beam splitting effect is more uniform, the efficiency ratio of the zeroth order to first order can reach 1.01, and the efficiency ratio of the first order to second order can reach 1.

Reflective three-port high-efficiency grating with two dielectric layers based on a sandwiched configuration

2016 ◽  
Vol 30 (12) ◽  
pp. 1650072 ◽  
Author(s):  
Hongtao Li ◽  
Bo Wang ◽  
Hao Pei ◽  
Wenhao Shu ◽  
Li Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Transverse Electric ◽  
Transverse Magnetic ◽  
Wave Analysis ◽  
Beam Splitting ◽  
Practical Applications ◽  
Rigorous Coupled Wave Analysis ◽  
Dielectric Layers ◽  
Rigorous Coupled Wave ◽  
Sandwiched Structure

In this paper, we describe a novel reflective sandwiched three-port grating with two dielectric layers. The two-layer sandwiched grating can separate incident wave into the [Formula: see text] and the 0th-order with high-efficiency beam splitting and good splitting ratios for both transverse electric (TE) and transverse magnetic (TM) polarizations. The grating parameters can be optimized by using rigorous coupled-wave analysis (RCWA) with a special duty cycle of 0.6. With the optimized results, efficiencies more than 32% in the [Formula: see text]st-orders and the 0th-order can be obtained. Furthermore, performance of the incident bandwidth and aspect ratio can be improved. Compared with conventional surface-relief grating, the grating with sandwiched structure is aimed at cleaning and protecting grating surface. The presented reflective two-layer sandwiched three-port grating would be put into practical applications for its beneficial performances.

Dual-function splitting of the embedded grating with connecting layer

2019 ◽  
Vol 33 (11) ◽  
pp. 1850129
Author(s):  
Wenhua Zhu ◽  
Bo Wang ◽  
Chenhao Gao ◽  
Kunhua Wen ◽  
Ziming Meng ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Groove Depth ◽  
Transverse Magnetic ◽  
Dual Function ◽  
First Order ◽  
Rigorous Coupled Wave Analysis ◽  
Rigorous Coupled Wave ◽  
Plane Light ◽  
High Diffraction ◽  
Modal Method

We design and optimize the embedded dual-function grating with connecting layer in Littrow mounting. By using modal method and rigorous coupled-wave analysis, grating parameters are analyzed and calculated including grating groove depth, thickness of connecting layer, and so on. The grating device can diffract the transverse electric-polarized plane light mainly in the first-diffractive order with high-diffraction efficiency of 98.36%. Meanwhile, for the transverse magnetic-polarized plane light, the diffraction efficiencies in the zeroth-order and the first-order corresponding to 49.34% and 49.29% are obtained, respectively.

Widening Absorption Band of Grating Structure With Complex Dual-Groove Grating

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Y. Jiao ◽  
L. H. Liu ◽  
P.-F. Hsu
Keyword(s):  
Far Infrared ◽  
Radiative Properties ◽  
Effective Bandwidth ◽  
Grating Structure ◽  
Rigorous Coupled Wave Analysis ◽  
Periodic Grating ◽  
Rigorous Coupled Wave ◽  
Rectangular Groove ◽  
Far Infrared Spectra ◽  
High Absorption

The wavelength-selective radiative property is becoming a noticeable requirement in various technological fields. There are many researches that have been focused on the radiative properties of metal periodic microstructure surface. However, the spectral bandwidth of high absorptance is often too narrow if excited by the conventional grating structures. In order to solve this problem, two novel periodic grating structures are proposed in this paper, which can increase the effective bandwidth of high absorption peaks. One of the new periodic grating structures, called dual-groove grating, is constructed by adding a rectangular groove at the bottom of the simple grating's groove through a secondary microscale processing. The other grating structure, which is called complex dual-groove grating, is constructed by superposing a dual-groove grating with a simple grating within one period. Aluminum grating structure is taken as an example to show the advantage of proposed structures on increasing effective bandwidth of high absorption peaks within mid-infrared and far-infrared spectra. The rigorous coupled-wave analysis (RCWA) is used to calculate the absorptance of periodic grating structures. The results shows that, two close absorption peaks and three connecting absorption peaks are obtained respectively for the two periodic grating structures. The effective bandwidth of high absorption peaks within interested wavelength band is improved obviously by these two microscale grating structures.

Measurement of Coherent Thermal Emission From Subwavelength Grating Structures by the Excitation of Magnetic Polaritons

2012 ◽  
Author(s):  
L. P. Wang ◽  
Z. M. Zhang
Keyword(s):  
Elevated Temperatures ◽  
Thermal Emission ◽  
Infrared Region ◽  
Radiative Properties ◽  
Scattering Rate ◽  
Rigorous Coupled Wave Analysis ◽  
Space Cooling ◽  
Dielectric Spacer ◽  
Magnetic Polaritons ◽  
Rigorous Coupled Wave

Tailoring radiative properties such as spectral control of thermal emission is beneficial in many applications such as space cooling and energy harvesting. The effect of magnetic polaritons (MPs) on spectral modulation has been analyzed previously and shown to exhibit omnidirectional behaviors when magnetic polaritons are excited in metallic grating structures with a dielectric spacer on a metallic film. The present work provides an experimental demonstration of coherent thermal emission from such a microstructure in the infrared region at both room and elevated temperatures. Samples with different patterns are fabricated to study the geometric effect on the MPs. The emittance at elevated temperatures is directly measured using a home-built emissometer, while the room-temperature emittance is indirectly obtained from the reflectance measurements. The rigorous coupled-wave analysis and the LC model are employed to elucidate the mechanisms, by incorporating the Drude model with a temperature-dependent scattering rate.

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