Mark Clemente-Arenas
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Mark Clemente-Arenas has a total of 43 co-authors. Here are the top co-authors by number of shared publications:
- Ruth Esther Rubio-Noriega
Pontificia Universidad Católica del Perú
5 shared publications - Julio Urbina
The Pennsylvania State University
4 shared publications - Akhlesh Lakhtakia
The Pennsylvania State University
3 shared publications Diego Penaloza-Aponte
Grupo Radio Frecuencia y Microondas G-RFM, DIDT, Universidad Nacional de Ingeniería INICTEL-UNI, San Borja, Lima 41
3 shared publications- Jorge Luis Arizaca-Cusicuna
Universidad Nacional de San Antonio Abad del Cusco
3 shared publications Juan Alvarez-Montoya
Grupo Radio Frecuencia y Microondas G-RFM, DIDT, Universidad Nacional de Ingeniería INICTEL-UNI, San Borja, Lima 41
3 shared publications
Latest Publications
- 1 April 2026
- Published by Agence Bibliographique de l'Enseignement Supérieur
Transformation electromagnetics : applications on beam controlled antenna design
Application de la transformation d'espace à la conception d'antennes à diagramme de rayonnement contrôlé: La transformation d'espace (TE) a été développée par J. B. Pendry et U. Leonhardt en 2006 et suscite un énorme intérêt depuis la démonstration expérimentale de la première cape d'invisibilité en micro-ondes. Cette technique permet de contrôler la propagation des ondes en modifiant les propriétés électromagnétiques de l'espace. Malgré quelques limitations liées à la bande passante ou aux pertes consécutives à l'utilisation de métamatériaux pour les dispositifs TE, cette technique a attiré l'attention de nombreux domaines (optique, microondes, acoustique, etc). L'objectif de cette thèse est de développer des applications de la TE dans le domaine antennaire à l'aide de matériaux conventionnels lorsque cela est possible et aussi d'ouvrir de nouvelles voies dans le contrôle du rayonnement des antennes. Trois applications ont été étudiées: le réflecteur « parabolique plat »; un superstrat tout diélectrique pour contrôler l'ouverture angulaire d'une antenne patch; et finalement un superstrat permettant de modifier drastiquement le rayonnement d'une antenne. Ce travail a été financé par les agences de défense du Royaume Uni et de la France (DSTL et DGA respectivement), dans le cadre du projet MIMiCRA (Metamaterial Inspired Microwave Conformai Radar Antennas).
- 1 April 2026
- Published by Agence Bibliographique de l'Enseignement Supérieur
Transformation electromagnetics : applications on beam controlled antenna design
Application de la transformation d'espace à la conception d'antennes à diagramme de rayonnement contrôlé: La transformation d'espace (TE) a été développée par J. B. Pendry et U. Leonhardt en 2006 et suscite un énorme intérêt depuis la démonstration expérimentale de la première cape d'invisibilité en micro-ondes. Cette technique permet de contrôler la propagation des ondes en modifiant les propriétés électromagnétiques de l'espace. Malgré quelques limitations liées à la bande passante ou aux pertes consécutives à l'utilisation de métamatériaux pour les dispositifs TE, cette technique a attiré l'attention de nombreux domaines (optique, microondes, acoustique, etc). L'objectif de cette thèse est de développer des applications de la TE dans le domaine antennaire à l'aide de matériaux conventionnels lorsque cela est possible et aussi d'ouvrir de nouvelles voies dans le contrôle du rayonnement des antennes. Trois applications ont été étudiées: le réflecteur « parabolique plat »; un superstrat tout diélectrique pour contrôler l'ouverture angulaire d'une antenne patch; et finalement un superstrat permettant de modifier drastiquement le rayonnement d'une antenne. Ce travail a été financé par les agences de défense du Royaume Uni et de la France (DSTL et DGA respectivement), dans le cadre du projet MIMiCRA (Metamaterial Inspired Microwave Conformai Radar Antennas).
- Open Access
Electronic and Optical Properties of Transition-Metal-Modified BiFeO3: A First Principles Study
The structural, electronic, magnetic, and optical properties are explored in the G-type antiferromagnetic BiFeO3 system by replacing the Fe cation with transition metals to form the BiFe0.834X0.166O3 compound (where X = Mn, Co, or Ni) by using first-principles DFT+U and TDDFT calculations. All the optimized structures preserve the rhombohedral (R3c) space group, showing moderate changes in the FeO6 octahedral distortions, lattice parameters, and Fe–O–Fe bond angles. Pristine G-type antiferromagnetic (AFM-G) BiFeO3 is a typical semiconductor material with a calculated bandgap energy eV. However, the inclusion of Ni, Co, and Mn at the Fe site introduces additional 3d states near the Fermi level, causing metallic behavior in every case. The local density of states (LDOS), density of states (DOS), and total magnetization results show that the inclusion of Ni, Co, and Mn promotes a transition from antiferromagnetic (AFM) to ferrimagnetic behavior in the modified BiFe0.834X0.166O3 compositions. On the other hand, in the visible spectral region, the time-dependent density functional theory (TDDFT) revealed that the pristine material has refractive index values between 2.8 and 3.6, showing that the presence of Co and Ni enhances the extinction and absorption coefficients in both visible and ultraviolet regions, whereas the inclusion of Mn produces less significant effects. These results demonstrate that controlled substitution at the Fe site with transition metals simultaneously modifies the structural, electronic, magnetic, and optical properties of the BiFeO3 system, offering promising potential for applications in electronic devices with multifunctional properties.Open AccessElectronic and Optical Properties of Transition-Metal-Modified BiFeO3: A First Principles Study
The structural, electronic, magnetic, and optical properties are explored in the G-type antiferromagnetic BiFeO3 system by replacing the Fe cation with transition metals to form the BiFe0.834X0.166O3 compound (where X = Mn, Co, or Ni) by using first-principles DFT+U and TDDFT calculations. All the optimized structures preserve the rhombohedral (R3c) space group, showing moderate changes in the FeO6 octahedral distortions, lattice parameters, and Fe–O–Fe bond angles. Pristine G-type antiferromagnetic (AFM-G) BiFeO3 is a typical semiconductor material with a calculated bandgap energy eV. However, the inclusion of Ni, Co, and Mn at the Fe site introduces additional 3d states near the Fermi level, causing metallic behavior in every case. The local density of states (LDOS), density of states (DOS), and total magnetization results show that the inclusion of Ni, Co, and Mn promotes a transition from antiferromagnetic (AFM) to ferrimagnetic behavior in the modified BiFe0.834X0.166O3 compositions. On the other hand, in the visible spectral region, the time-dependent density functional theory (TDDFT) revealed that the pristine material has refractive index values between 2.8 and 3.6, showing that the presence of Co and Ni enhances the extinction and absorption coefficients in both visible and ultraviolet regions, whereas the inclusion of Mn produces less significant effects. These results demonstrate that controlled substitution at the Fe site with transition metals simultaneously modifies the structural, electronic, magnetic, and optical properties of the BiFeO3 system, offering promising potential for applications in electronic devices with multifunctional properties. - 17 November 2025
- Published by Optica Publishing Group in Applied Optics
- Vol. 64 (33) , 10150-10156
Periodic pixelated structure for electro-optically and orientationally programmable asymmetric electromagnetic transmission
A pixelation approach was adopted to design an all-dielectric periodic structure without bidirectional symmetry in the thickness direction to exhibit asymmetric electromagnetic transmission (AET) at near-infrared wavelengths ranging from 1.2 to 1.8 µm. Whereas some pixels represent a dielectric solid, others represent a transparent electro-optic polymer with a high electro-optic coefficient. This structure can demonstrate AET as high as 0.90. A specific combination of an applied voltage and the angle of incidence will lead to an acceptable AET magnitude for a particular wavelength, which is promising for electro-optically and orientationally programmable optical diodes in in-line optical systems. The use of a transparent electro-optic polymer with a high electro-optic coefficient enables sub-nanosecond switching speeds desirable for optical communications.
- 17 November 2025
- Published by Optica Publishing Group in Applied Optics
- Vol. 64 (33) , 10150-10156
Periodic pixelated structure for electro-optically and orientationally programmable asymmetric electromagnetic transmission
A pixelation approach was adopted to design an all-dielectric periodic structure without bidirectional symmetry in the thickness direction to exhibit asymmetric electromagnetic transmission (AET) at near-infrared wavelengths ranging from 1.2 to 1.8 µm. Whereas some pixels represent a dielectric solid, others represent a transparent electro-optic polymer with a high electro-optic coefficient. This structure can demonstrate AET as high as 0.90. A specific combination of an applied voltage and the angle of incidence will lead to an acceptable AET magnitude for a particular wavelength, which is promising for electro-optically and orientationally programmable optical diodes in in-line optical systems. The use of a transparent electro-optic polymer with a high electro-optic coefficient enables sub-nanosecond switching speeds desirable for optical communications.
- Open Access
High-Q Terahertz Perfect Absorber Based on a Dual-Tunable InSb Cylindrical Pillar Metasurface
Perfect absorbers operating in the terahertz (THz) band are key enablers for next-generation wireless systems. However, conventional metal–dielectric designs suffer from Ohmic losses and limited reconfigurability. Here, we propose an all-dielectric indium antimonide (InSb) cylindrical pillar metasurface that achieves near-unity absorption at THz with a high quality factor of . Critical coupling between coexisting electric and magnetic dipoles enables perfect impedance matching, while InSb’s low damping minimizes energy loss. The resonance is tunable via temperature and magnetic bias at sensitivities of , , and , respectively, without compromising absorption strength. At zero magnetic bias (), the metasurface is polarization-independent under normal incidence; under magnetic bias (), it maintains near-unity absorbance for both TE and TM, while the resonance frequency becomes polarization-dependent. Additionally, the 90% absorptance bandwidth () can be modulated from 8.3 GHz to 3.3 GHz with temperature, or broadened from 8.5 GHz to 14.8 GHz under magnetic bias. This allows gapless suppression of up to 14 consecutive 1 GHz-spaced channels. This standards-agnostic bandwidth metric illustrates dynamic spectral filtering for future THz links and beyond-5G/6G research. Owing to its sharp selectivity, dual-mode tunability, and metal-free construction, the proposed absorber offers a compact and reconfigurable platform for advanced THz filtering applications.Open AccessHigh-Q Terahertz Perfect Absorber Based on a Dual-Tunable InSb Cylindrical Pillar Metasurface
Perfect absorbers operating in the terahertz (THz) band are key enablers for next-generation wireless systems. However, conventional metal–dielectric designs suffer from Ohmic losses and limited reconfigurability. Here, we propose an all-dielectric indium antimonide (InSb) cylindrical pillar metasurface that achieves near-unity absorption at THz with a high quality factor of . Critical coupling between coexisting electric and magnetic dipoles enables perfect impedance matching, while InSb’s low damping minimizes energy loss. The resonance is tunable via temperature and magnetic bias at sensitivities of , , and , respectively, without compromising absorption strength. At zero magnetic bias (), the metasurface is polarization-independent under normal incidence; under magnetic bias (), it maintains near-unity absorbance for both TE and TM, while the resonance frequency becomes polarization-dependent. Additionally, the 90% absorptance bandwidth () can be modulated from 8.3 GHz to 3.3 GHz with temperature, or broadened from 8.5 GHz to 14.8 GHz under magnetic bias. This allows gapless suppression of up to 14 consecutive 1 GHz-spaced channels. This standards-agnostic bandwidth metric illustrates dynamic spectral filtering for future THz links and beyond-5G/6G research. Owing to its sharp selectivity, dual-mode tunability, and metal-free construction, the proposed absorber offers a compact and reconfigurable platform for advanced THz filtering applications. - Open Access
Thermally Tunable Bi-Functional Metasurface Based on InSb for Terahertz Applications
In this work, we propose and analyze a thermally tunable metasurface based on indium antimonide (InSb), designed to operate in the terahertz (THz) frequency range. The metasurface exhibits dual functionalities: single-band perfect absorption and efficient polarization conversion, enabled by the temperature-dependent permittivity of InSb. At approximately 280 K, InSb transitions into a metallic state, enabling the metasurface to achieve near-unity absorptance (100%) at 0.408 THz under normal incidence, independent of polarization. Conversely, when InSb behaves as a dielectric at 200 K, the metasurface operates as an efficient polarization converter. By exploiting structural anisotropy, it achieves a polarization conversion ratio exceeding 85% over the frequency range from 0.56 to 0.93 THz, while maintaining stable performance for incident angles up to 45°. Parametric analyses show that the resonance frequency and absorption intensity can be effectively tuned by varying the InSb square size and the silica (SiO2) layer thickness, achieving maximum absorptance at a SiO2 thickness of 16 μm. The proposed tunable metasurface offers significant potential for applications in THz sensing, imaging, filtering, and wavefront engineering.
Open AccessThermally Tunable Bi-Functional Metasurface Based on InSb for Terahertz Applications
In this work, we propose and analyze a thermally tunable metasurface based on indium antimonide (InSb), designed to operate in the terahertz (THz) frequency range. The metasurface exhibits dual functionalities: single-band perfect absorption and efficient polarization conversion, enabled by the temperature-dependent permittivity of InSb. At approximately 280 K, InSb transitions into a metallic state, enabling the metasurface to achieve near-unity absorptance (100%) at 0.408 THz under normal incidence, independent of polarization. Conversely, when InSb behaves as a dielectric at 200 K, the metasurface operates as an efficient polarization converter. By exploiting structural anisotropy, it achieves a polarization conversion ratio exceeding 85% over the frequency range from 0.56 to 0.93 THz, while maintaining stable performance for incident angles up to 45°. Parametric analyses show that the resonance frequency and absorption intensity can be effectively tuned by varying the InSb square size and the silica (SiO2) layer thickness, achieving maximum absorptance at a SiO2 thickness of 16 μm. The proposed tunable metasurface offers significant potential for applications in THz sensing, imaging, filtering, and wavefront engineering.
- Open Access
- 29 January 2025
- Published by Universite Clermont Auvergne in Journal International de Technologie, de l'Innovation, de la Physique, de l'Energie et de l'Environnement
- Vol. 9 (1)
Détection des défauts d'arc par radiation électromagnétique utilisant la technologie des antennes
Les défauts d’arc dans les systèmes électriques représentent un risque majeur pour la sécurité et nécessitent des méthodes de détection fiables. Alors que les techniques traditionnelles reposent sur l’analyse du courant, cette étude explore l’utilisation de la radiation électromagnétique émise lors des défauts d’arc pour leur détection. Une antenne fractale de Hilbert de quatrième ordre (HCFA) a été conçue, fabriquée et testée afin de capter les émissions électromagnétiques à large bande générées par les décharges d’arc. Les résultats expérimentaux révèlent une forte corrélation entre les variations brusques de tension et la radiation électromagnétique émise. L’analyse fréquentielle montre que le spectre de radiation est principalement concentré dans les bandes 22–44 MHz et 50–68 MHz. De plus, l’analyse par transformation de Fourier à court terme (STFT) met en évidence les caractéristiques temps-fréquence du rayonnement d’arc, permettant d’identifier précisément son initiation, sa durée et son extinction. Ces résultats confirment la faisabilité de la détection des arcs par radiation électromagnétique et ouvrent la voie au développement de systèmes de surveillance en temps réel basés sur des antennes pour les environnements électriques complexes.
- 29 January 2025
- Published by Universite Clermont Auvergne in Journal International de Technologie, de l'Innovation, de la Physique, de l'Energie et de l'Environnement
- Vol. 9 (1)
Open AccessDétection des défauts d'arc par radiation électromagnétique utilisant la technologie des antennes
Les défauts d’arc dans les systèmes électriques représentent un risque majeur pour la sécurité et nécessitent des méthodes de détection fiables. Alors que les techniques traditionnelles reposent sur l’analyse du courant, cette étude explore l’utilisation de la radiation électromagnétique émise lors des défauts d’arc pour leur détection. Une antenne fractale de Hilbert de quatrième ordre (HCFA) a été conçue, fabriquée et testée afin de capter les émissions électromagnétiques à large bande générées par les décharges d’arc. Les résultats expérimentaux révèlent une forte corrélation entre les variations brusques de tension et la radiation électromagnétique émise. L’analyse fréquentielle montre que le spectre de radiation est principalement concentré dans les bandes 22–44 MHz et 50–68 MHz. De plus, l’analyse par transformation de Fourier à court terme (STFT) met en évidence les caractéristiques temps-fréquence du rayonnement d’arc, permettant d’identifier précisément son initiation, sa durée et son extinction. Ces résultats confirment la faisabilité de la détection des arcs par radiation électromagnétique et ouvrent la voie au développement de systèmes de surveillance en temps réel basés sur des antennes pour les environnements électriques complexes.
- Open Access
Integrated Modeling and Target Classification Based on mmWave SAR and CNN Approach
This study presents a numerical modeling approach that utilizes millimeter-wave (mm-Wave) Frequency-Modulated Continuous-Wave (FMCW) radar to reconstruct and classify five weapon types: grenades, knives, guns, iron rods, and wrenches. A dataset of 1000 images of these weapons was collected from various online sources and subsequently used to generate 3605 samples in the MATLAB (R2022b) environment for creating reflectivity-added images. Background reflectivity was considered to range from 0 to 0.3 (with 0 being a perfect absorber), while object reflectivity was set between 0.8 and 1 (with 1 representing a perfect electric conductor). These images were employed to reconstruct high-resolution weapon profiles using a monostatic two-dimensional (2D) Synthetic Aperture Radar (SAR) imaging technique. Subsequently, the reconstructed images were classified using a Convolutional Neural Network (CNN) algorithm in a Python (3.10.14) environment. The CNN architecture consists of 10 layers, including multiple convolutional, pooling, and fully connected layers, designed to effectively extract features and perform classification. The CNN model achieved high accuracy, with precision and recall values exceeding 98% across most categories, demonstrating the robustness and reliability of the model. This approach shows considerable promise for enhancing security screening technologies across a range of applications.
Open AccessIntegrated Modeling and Target Classification Based on mmWave SAR and CNN Approach
This study presents a numerical modeling approach that utilizes millimeter-wave (mm-Wave) Frequency-Modulated Continuous-Wave (FMCW) radar to reconstruct and classify five weapon types: grenades, knives, guns, iron rods, and wrenches. A dataset of 1000 images of these weapons was collected from various online sources and subsequently used to generate 3605 samples in the MATLAB (R2022b) environment for creating reflectivity-added images. Background reflectivity was considered to range from 0 to 0.3 (with 0 being a perfect absorber), while object reflectivity was set between 0.8 and 1 (with 1 representing a perfect electric conductor). These images were employed to reconstruct high-resolution weapon profiles using a monostatic two-dimensional (2D) Synthetic Aperture Radar (SAR) imaging technique. Subsequently, the reconstructed images were classified using a Convolutional Neural Network (CNN) algorithm in a Python (3.10.14) environment. The CNN architecture consists of 10 layers, including multiple convolutional, pooling, and fully connected layers, designed to effectively extract features and perform classification. The CNN model achieved high accuracy, with precision and recall values exceeding 98% across most categories, demonstrating the robustness and reliability of the model. This approach shows considerable promise for enhancing security screening technologies across a range of applications.
- 23 February 2024
- Published by Optica Publishing Group in Journal of the Optical Society of America B
- Vol. 41 (3) , 691-697
Non-metallic magnetostatically tunable metasurface absorber for terahertz waves
- 23 February 2024
- Published by Optica Publishing Group in Journal of the Optical Society of America B
- Vol. 41 (3) , 691-697
Non-metallic magnetostatically tunable metasurface absorber for terahertz waves
- Open Access
- 1 February 2024
- Published by Institute of Advanced Engineering and Science in Indonesian Journal of Electrical Engineering and Computer Science
- Vol. 33 (2) , 812-823
Mutual coupling effects in 2×2 antenna array for ground penetrating radar on multilayered soil
Caral stands as the Americas’ oldest city, boasting a heritage spanning 5,000 years. Over time, various natural forces have woven a complex geological stratum. To gain a deeper understanding of the Caral civilization, non-intrusive exploration methodologies like ground penetrating radar (GPR) are beginning to be used. This method safeguards the integrity of ancient subterranean remains. A GPR system is in development, tailored to the [200-500] MHz range, employing a 2×2 antenna array with dual polarization. These features enhance resolution without compromising penetration depth. However, using multiple antennas within complex, multi-layered environments introduce impedance band constraints and exacerbates antenna coupling issues. This study assesses the coupling of two antenna candidates: the Vivaldi with defected ground structures (DGS) and the log periodic dipole array (LPDA). The scattering parameters show that the LPDA antenna performed better considering measured and simulated data. Cross-polarization exhibited a broader bandwidth in the LPDA antenna, evident in both simulated and measured data. Additionally, a comprehensive comparison of GPR simulations for each antenna type within an 11-level multilayer medium, with different electromagnetic properties, further highlights LPDA. This antenna boasts a 209 MHz bandwidth and a coupling better than -23 dB for the cross-polarization configuration, firmly showing its best performance.
- 1 February 2024
- Published by Institute of Advanced Engineering and Science in Indonesian Journal of Electrical Engineering and Computer Science
- Vol. 33 (2) , 812-823
Open AccessMutual coupling effects in 2×2 antenna array for ground penetrating radar on multilayered soil
Caral stands as the Americas’ oldest city, boasting a heritage spanning 5,000 years. Over time, various natural forces have woven a complex geological stratum. To gain a deeper understanding of the Caral civilization, non-intrusive exploration methodologies like ground penetrating radar (GPR) are beginning to be used. This method safeguards the integrity of ancient subterranean remains. A GPR system is in development, tailored to the [200-500] MHz range, employing a 2×2 antenna array with dual polarization. These features enhance resolution without compromising penetration depth. However, using multiple antennas within complex, multi-layered environments introduce impedance band constraints and exacerbates antenna coupling issues. This study assesses the coupling of two antenna candidates: the Vivaldi with defected ground structures (DGS) and the log periodic dipole array (LPDA). The scattering parameters show that the LPDA antenna performed better considering measured and simulated data. Cross-polarization exhibited a broader bandwidth in the LPDA antenna, evident in both simulated and measured data. Additionally, a comprehensive comparison of GPR simulations for each antenna type within an 11-level multilayer medium, with different electromagnetic properties, further highlights LPDA. This antenna boasts a 209 MHz bandwidth and a coupling better than -23 dB for the cross-polarization configuration, firmly showing its best performance.
- 5 September 2022
- Published by Institute of Electrical and Electronics Engineers (IEEE)
- Vol. 11, 255-257
Toward non-metallic infrared metasurface filters with electrical and thermal controllability
A bicontrollable metasurface containing VO 2 , a non-linear optical polymer, and teflon was simulated to function as a bandpass filter in the infrared spectral regime. The metasurface is a singly periodic array of identical unit cells composed of parallel rectangular VO 2 rods mounted on a silicon-dioxide substrate and covered with BAYI electro-optical polymer. The unit-cell dimensions are chosen such that the transmittance has a maximum in the 1418-to-l635-nm wavelength range, when the polymer face is normally illuminated by a plane wave with electric field parallel to the axis of the VO 2 rods. When the crystallographic phase of VO 2 is switched from monoclinc to tetragonal, the maximum transmittance redshifts from 1513 nm to 1656 nm, provided that no electrostatic field is present. However, when a dc potential of 50 V is applied across the polymer in the thickness direction, the minimum blueshifts from 1513 nm to 1418 nm at temperature $T\lt 58^{\circ}\mathrm{C}$ temperature (VO 2 is monoclinic), and from 1656 nm to 1513 nm at $T\gt 72^{\circ}\mathrm{C}$ temperature (VO 2 is tetragonal).- 5 September 2022
- Published by Institute of Electrical and Electronics Engineers (IEEE)
- Vol. 11, 255-257
Toward non-metallic infrared metasurface filters with electrical and thermal controllability
A bicontrollable metasurface containing VO 2 , a non-linear optical polymer, and teflon was simulated to function as a bandpass filter in the infrared spectral regime. The metasurface is a singly periodic array of identical unit cells composed of parallel rectangular VO 2 rods mounted on a silicon-dioxide substrate and covered with BAYI electro-optical polymer. The unit-cell dimensions are chosen such that the transmittance has a maximum in the 1418-to-l635-nm wavelength range, when the polymer face is normally illuminated by a plane wave with electric field parallel to the axis of the VO 2 rods. When the crystallographic phase of VO 2 is switched from monoclinc to tetragonal, the maximum transmittance redshifts from 1513 nm to 1656 nm, provided that no electrostatic field is present. However, when a dc potential of 50 V is applied across the polymer in the thickness direction, the minimum blueshifts from 1513 nm to 1418 nm at temperature $T\lt 58^{\circ}\mathrm{C}$ temperature (VO 2 is monoclinic), and from 1656 nm to 1513 nm at $T\gt 72^{\circ}\mathrm{C}$ temperature (VO 2 is tetragonal).