Honggang Gu

Honggang Gu
Huazhong University of Science and Technology | hust · State Key Laboratory of Digital Manufacturing Equipment and Technology

32.42
 · 
Doctor of Philosophy

About

68
Publications
6,197
Reads
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268
Citations

Publications

Publications (68)
Article
Full-text available
The attitude metrology of moving objects has always been a hot topic in engineering applications. In this article, a novel optical method based on the high-speed Mueller matrix ellipsometry (MME) is proposed for real-time remote attitude sensing. With the help of an electric level, all the attitude angles of a free-moving object with a birefringent...
Article
Remote measurement of object orientation is often required in many applications. Out of the six degrees of freedom (DoF) that determine object orientation in space, the roll angle is the most difficult to measure using optical methods. In this letter, we propose a remote Stokes roll-angle sensor that measures roll angles from the detected Stokes ve...
Article
A high-speed Mueller matrix ellipsometer (MME) based on photoelastic modulator (PEM) polarization modulation and division-of-amplitude polarization demodulation has been developed, with which a temporal resolution of 11 µs has been achieved for a Mueller matrix measurement. To ensure the accuracy and stability, a novel approach combining a fast Fou...
Article
A ferroelectric liquid crystal polarization rotator (FLCPR) has been widely used in polarization measurement due to its fast and stable modulation characteristics. The accurate characterization of the modulation performance of FLCPR directly affects the measurement accuracy of the instrument based on liquid crystal modulation. In this study, FLCPR...
Article
A novel, to the best of our knowledge, optical method using a high-speed polarimetry is proposed for real-time attitude tracking in an ultra-large measurement range. The attitude metrology utilizes the field-of-view effect in birefringent crystals, which is known as the birefringence deviates with the field-of-view angle of polarized light. The bas...
Article
Nonuniform depolarization properties of ${\text{SiO}_2}$SiO2 thin film, two-dimensional (2D) Si grating, and three-dimensional Si cylinder grating, were systematically investigated by Lu-Chipman decomposition. We find that introducing surface profiles with dimensions comparable to the detecting wavelengths can lead to obvious nonuniform depolarizat...
Article
A novel Mg0.55Al2.36O3.81N0.19 transparent ceramic with an infrared transmission range comparable to c-plane sapphire was prepared based on the intentional design of the composition. This material possesses outstanding optical properties, such as a high in-line transmittance up to 86.5% at 3.7 µm, a refractive index of 1.7240 at 589.3 nm and an abs...
Article
Full-text available
Although imaging scatterometry has been demonstrated to be a powerful technique for characterization of nano-gratings when high lateral resolution is required, some limits of this novel technique are still undisclosed yet, such as the constraint for the imaging numerical aperture (NA), the number of unit cells for accurate grating reconstruction, a...
Article
Long-term native oxidation of polycrystalline Cu films with different thicknesses is investigated using spectroscopic ellipsometry. In order to more accurately determine the thickness of the oxide layer, a three-phase Maxwell-Garnett effective medium approximation model has been proposed to fit both the ellipsometric parameters and reflectance. X-r...
Article
Full-text available
Spatial chirp induced by the misaligned gratings and mirrors in a parallel grating pair pulse stretcher can significantly affect the performance of the output pulses. Firstly, a detailed analysis about the spatial chirp of the stretched pulses caused by the misalignments has been carried out using the ray tracing simulation method. According to the...
Article
Overlay target design is an important issue in overlay metrology, whose aim is to probe the optimal overlay target to achieve good performance on measurement precision and accuracy even in the presence of process variation. In this paper, the target design problem is first formulated as a multiobjective optimization problem and then solved by the m...
Article
Annealing temperature dependency of the optical and structural properties of Cu films is carefully studied using multiple means such as spectroscopic ellipsometry, x-ray diffraction, white-light interferometry, atomic force microscopy, scanning electron microscope (SEM), and the four-probe method. A wide annealing temperature range from 300 to 1200...
Article
Tandem organic solar cells show great potential due to advantages such as the utilization of wide-spectrum light and low thermalization loss. The current mismatch between sub-cells is one of the major issues reducing the final output efficiency of a tandem device. In this paper, we propose an optical analysis method based on the 4×4 matrix formalis...
Article
We proposed a completely analytical method to determine the complex refractive index of an ultra-thin film on an arbitrary substrate by ellipsometry. The method is based on directly solving the polynomial equation derived from the 2nd-order Taylor expansion of ellipsometric functions without any prior knowledge about electronic transitions of the m...
Article
Dielectric properties and their evolutions are fundamental to reveal the optical responses of topological insulators and to guide the design of related devices. Here, we systematically investigate the layer-dependent dielectric permittivity of Bi2Se3 over an ultra-broad spectral range (0.73–6.43 eV) by combining the spectroscopic ellipsometry, ener...
Article
The complex optical conductivities of 2D materials are fundamental for extended applications of related optoelectronic devices. Here, we systematically investigate the layer-dependent evolutions in the complex optical conductivities of 1–6 layer 2D MoS2 over an ultra-wide spectral range (0.73–6.42 eV) by spectroscopic ellipsometry. We identify five...
Poster
Full-text available
A birefringent medium exhibits different refractive indices for two orthogonal components of the polarized light, and therefore a retardance is introduced. Birefringent media are widely used in devices that manipulate the polarized light, such as polarized elements, optical fiber, laser systems. In practical applications, accurate determination of...
Article
Full-text available
Two-dimensional (2D) materials usually exhibit interesting layer-dependent dielectric and optical properties, which play important roles in structure optimization and performance improvement of related devices. Recently, 2D WSe2 has attracted considerable attention in the atomically thin electronics and optoelectronics, due to its exotic photoelect...
Article
Full-text available
Artificial ammonia synthesis (Haber-Bosch process) is a prototypical exothermic reaction of maximum catalytic yield restricted by the unbreakable equilibrium law. This is because bottlenecked N 2 dissociation necessitates high temperature, but high temperature reversely shifts the thermal equilibrium toward NH 3 decomposition. To surmount this equi...
Article
Full-text available
We derive explicit power dissipation functions for stratified anisotropic OLEDs based on a radiation model of dipole antennas inside anisotropic microcavity. The dipole field expressed by vector potential is expanded into plane waves whose coefficients are determined by scattering matrix method, and then an explicit expression is derived to calcula...
Article
Full-text available
We propose a universal method for optimal design of a wide field-of-view (FOV) angle linear retarder with an ultra-flat retardance response based on paired positive/negative birefringent plates. The mechanism and rules for the FOV effect compensation are revealed to determine the structure of the proposed retarder by introducing the partial derivat...
Article
Magnesium aluminum oxynitride (Mg0.27Al2.58O3.73N0.27, termed as MgAlON) ceramics with high transparency and complicated shape were prepared by aqueous gelcasting, pressureless sintering and followed by hot isostatic pressing. No obvious hydration was found by the characterizations of X‐ray diffraction, pH value, Fourier transform infrared and ther...
Article
Full-text available
We present a novel optical roll-angle sensor called Stokes roll-angle sensor. The measurement principle relies on modulating the roll angular displacement into the change of state of polarization (SoP) of polarized probe light by a quarter-wave plate (QWP). The SoP of the emerging elliptically polarized light from QWP is then detected by a Stokes p...
Article
Full-text available
We report about a flexible substrate incorporating surface-confined silver nanoparticles on transparent polyimide (PI). The incorporated silver nanoparticles (Ag NPs), which possessed excellent adhesive strength with the PI substrate, induced localized surface plasmon resonance and light scattering effects by changing the particle size and interpar...
Article
Full-text available
Volume grating is a key optical component due to its comprehensive applications. Other than the common grating structures, volume grating is essentially a predesigned refractive index distribution recorded in materials, which raises the challenges of metrology. Although we have demonstrated the potential application of ellipsometry for volume grati...
Conference Paper
The dielectric functions of 2–10 QL Bi2Se3 are investigated by spectroscopic ellipsometry. We find that the hybridization influences surface plasmons and the joint density of states dominates the evolution in imaginary dielectric function.
Conference Paper
Tandem organic solar cells are optimized based on an optical analysis method considering current mismatch under oblique incidence between two sub-cells to optimized the device structure and obtained higher efficiency.
Conference Paper
Based on the dipole radiation method in anisotropic layer systems, optical formulations are derived to inversely fit the emitter features (including emitter orientation and distribution) of anisotropic OLED from the radiation patterns.
Conference Paper
The in-plane optical constant (the extinction coefficient k and the refractive index n) of ZrTe5 single crystal was measured by spectroscopic Mueller ellipsometer, which show great in-plane optical anisotropy.
Article
Full-text available
The development of necessary instrumentation and metrology at the nanoscale, especially fast, low-cost, and nondestructive metrology techniques, is of great significance for the realization of reliable and repeatable nanomanufacturing. In this work, we present the application of a homemade novel optical scatterometer called the tomographic Mueller-...
Article
The calibration of the polarization effect of a high-numerical-aperture (high-NA) objective lens (OL) is of great significance for high-precision polarized light micro-imaging. In this work, we propose a method to calibrate the polarization effect of a high-NA OL with Mueller matrix polarimetry in a retro-reflection configuration by using a spheric...
Article
Full-text available
Light-driven heterogeneous catalysis provides a promising way to accomplish chemical reactions by the use of light energy, which reduces the consumption of chemical energy sources. Here, we show that Ru/CeO2 catalysts exhibit high activity for the hydrogenation of CO2 to methane under illumination only, reaching CO2 conversion over 99.9% at low tem...
Article
Polarization distortion in a beam splitter is a phenomenon where the polarization state of output light deviates from the theoretical expectation, which is inevitable and will result in significant errors in the optical systems. A theoretical analysis method based on Mueller matrix ellipsometry is proposed for characterizing the beam splitters and...
Article
Full-text available
Composite waveplates (CWs) consisting of multiple single waveplates are basic polarization elements and widely used to manipulate the polarized light in optical systems, and their performances affect the final accuracy and precision significantly. This research proposes a method for the comprehensive characterization of an arbitrary CW based on spe...
Article
Full-text available
In this paper, we describe the development of a novel instrument, tentatively called tomographic Mueller-matrix scatterometer (TMS), which enables illuminating sequentially a sample by a plane wave with varying illumination directions and recording, for each illumination, the polarized scattered field along various directions of observation in the...
Article
The molecular structures play a critical role in forming horizontal orientation of the emission transition dipole of light-emitting TADF materials which can improve light outcoupling efficiency of OLEDs. Here, two TADF emitters of IndCzpTr-1 and IndCzpTr-2 based indolocarbazole derivatives with the stereoscopic and linear structures were designed a...
Article
Non-stoichiometric MgO·1.8Al2O3 spinel transparent ceramic was prepared from synthesized single phase powder through an aqueous gel-casting forming technique. In order to prevent hydrolysis, the powder was specially treated in toluene with stearic acid and then dispersed in an aqueous solution with the help of amphoteric compound Tween 80 and dispe...
Article
Full-text available
Ferroelectric thin films have been utilized in a wide range of electronic and optical applications, in which their morphologies and properties can be inherently tuned by a qualitative control during growth. In this work, we demonstrate the evolution of the Pb0.865La0.09(Zr0.65Ti0.35)O3 (PLZT) thin films on MgO (200) with high uniformity and optimiz...
Article
As dynamic loading experiments such as a shock compression test are usually characterized by short duration, unrepeatability and high costs, high temporal resolution and precise accuracy of the measurements is required. Due to high temporal resolution up to a ten-nanosecond-scale, a Stokes polarimeter with six parallel channels has been developed t...
Article
In the field of organic solar cells (OSCs), tandem structure devices exhibit very attractive advantages for improving power conversion efficiency (PCE). In addition to the well researched novel pair of active layers in different subcells, the construction of interconnecting layer (ICL) also plays a critical role in achieving high performance tandem...
Article
Measurement configuration optimization (MCO) is a ubiquitous and important issue in optical scatterometry, whose aim is to probe the optimal combination of measurement conditions, such as wavelength, incidence angle, azimuthal angle, and/or polarization directions, to achieve a higher measurement precision for a given measuring instrument. In this...
Article
Full-text available
Optical properties of mono-graphene fabricated by chemical vapor deposition (CVD) and highly oriented pyrolytic graphite (HOPG) are comparatively studied by Mueller matrix ellipsometry (MME) over an ultra-wide energy range of 0.73∼6.42 eV. A multilayer stacking model is constructed to describe the CVD mono-graphene, in which the roughness of the gl...
Article
Birefringent waveplates are indispensable optical elements for polarization state modification in various optical systems. The retardance of a birefringent waveplate will change significantly when the incident angle of the light varies. Therefore, it is of great importance to study such field-of-view errors on the polarization properties, especiall...
Article
A novel environment-friendly system is proposed to fabricate polymer brush, which has the advantages including non-toxic and inexpensive initiator (eosin Y), visible-light exposure (λ = 515 nm), water medium and ambient environment. The experimental results from UV-Vis spectroscopy, AFM-based single molecule force spectroscopy (SMFS) and other meas...
Article
Full-text available
Overlay control is of vital importance to good device performances in semiconductor manufacturing. In this work, the differential Mueller matrix calculus is introduced to investigate the Mueller matrices of double-patterned gratings with overlay displacements, which helps to reveal six elementary optical properties hidden in the Mueller matrices. W...
Article
The biplate that consists of two single wave plates made from birefringent materials with their fast axes oriented perpendicular to each other is one of the most commonly used retarders in many optical systems. The internal alignment of the optical axes of the two single wave plates is a key procedure in the fabrication and application of a biplate...
Conference Paper
The diagnosis and control of the polarization aberrations is one of the main concerns in a hyper numerical aperture (NA) lithography system. Waveplates are basic and indispensable optical components in the polarimetric diagnosis tools for the immersion lithography system. The retardance of a birefringent waveplate is highly sensitive to the inciden...
Article
The authors apply Mueller matrix ellipsometry to characterize the curved surface layers, by utilizing the noticeable anisotropy observed from the measured data. The authors demonstrate that this anisotropy is introduced by the curved surface shape as well as the misalignment between the illumination spot and the surface vertex. An optical model is...
Article
Accurate measurement of the Mueller matrix over a broad band is highly desirable for the characterization of nanostructures and nanomaterials. In this paper, we propose a general composite waveplate (GCW) that consists of multiple waveplates with flexibly oriented axes as a polarization modulating component in the Mueller matrix ellipsometer (MME)....
Article
Dual-rotating compensator Mueller matrix ellipsometer (DRC-MME) has been designed and applied as a powerful tool for the characterization of thin films and nanostructures. The compensators are indispensable optical components and their performances affect the precision and accuracy of DRC-MME significantly. Biplates made of birefringent crystals ar...
Article
Mueller matrix ellipsometry has been demonstrated as a powerful tool for nanostructure metrology in high-volume manufacturing. Many factors may induce depolarization effect in the Mueller matrix measurement, and consequently, may lead to accuracy loss in the nanostructure metrology. In this paper, we propose to apply a Mueller matrix decomposition...
Article
Full-text available
Composite waveplates consisting of two or more single waveplates are widely used in optical instruments, such as ellipsometry, polarimetry, cryptography, and photoelasticity. Accurate calibration of the misalignment errors in composite waveplates is of great importance (to minimize or correct the spurious artifacts in the final collected spectral d...
Conference Paper
We propose a method to calibrate the depolarization parameters of the imperfect compensators in dual-rotating compensator Mueller matrix polarimeters, and deduce a set of correction equations for the Mueller matrix calculation.
Article
Optical scatterometry, also referred to as optical critical dimension (OCD) metrology, has been introduced for critical dimension (CD) monitoring and overlay metrology with great success in recent years. Forward modeling to calculate the optical signature from the measured diffractive structure is one of the most important issues in OCD metrology....
Article
Misalignment errors of the composite wave-plate, a typical kind of compensator used in spectroscopic ellipsometers (SE), can lead to spurious oscillations in the SE measurement. In this paper, we construct an equivalent model of the three-inone composite wave-plate through mathematical derivation, and propose a method to analyze and extract the mis...

Projects

Projects (3)
Project
Optical modeling, analysis, and optimization of stratified optoelectronic devices, such as organic light-emitting diodes (OLEDs) and organic photovoltaic (OPV) solar cells.
Project
Characterizing and investigating the optical properties of polarized elements, such as waveplate, optical retarder, polarizer, liquid crystal, beam splitter, and hyper-NA lens. Aiming to guide the optimal design, alignment and calibration, installation and commissioning, and error analysis and compensating for polarized elements and related optical systems.