Observation of multiple bulk bound states in the continuum modes in a photonic crystal cavity

• Rui Chen,
• Yi Zheng,
• Xingyu Huang,
• Qiaoling Lin,
• Chaochao Ye,
• Meng Xiong,
• Martijn Wubs,
• Yungui Ma,
• Minhao Pu and
• Sanshui Xiao

Beilstein J. Nanotechnol. 2023, 14, 544–551, doi:10.3762/bjnano.14.45

• of the incident field away from the Г point, a small extent of symmetry breaking occurs and the Q factor decreases, as shown in Figure 1c. The Q factor discussed above is the radiative Q factor (Qr), which only depends on the ideal mode radiation loss. The Q factor of any realistic device is

Quasi-guided modes resulting from the band folding effect in a photonic crystal slab for enhanced interactions of matters with free-space radiations

• Kaili Sun,
• Yangjian Cai,
• Uriel Levy and
• Zhanghua Han

Beilstein J. Nanotechnol. 2023, 14, 322–328, doi:10.3762/bjnano.14.27

• , Qtotal is determined solely by Qrad of the structure. Its value or the radiation loss can be obtained from the real and imaginary parts of its complex eigenfrequency from the numerical calculations. The calculated Q-factors of these QGMs are presented in Figure 3a. The value is infinite at the Γ point

Double-layer symmetric gratings with bound states in the continuum for dual-band high-Q optical sensing

• Chaoying Shi,
• Jinhua Hu,
• Xiuhong Liu,
• Junfang Liang,
• Jijun Zhao,
• Haiyan Han and
• Qiaofen Zhu

Beilstein J. Nanotechnol. 2022, 13, 1408–1417, doi:10.3762/bjnano.13.116

• complex eigenfrequencies of mode 1 and mode 2 are 248.08 and 238.35 THz, respectively. In addition, it is apparent that the γ value of both modes are close to zero, which means that there is almost no radiation loss resulting in an infinite value for the Q-factor (the ideal BIC). Here, the spacing between

• each RDG is completely equal and exactly the same as the side length of the RDG (d = l = w = 200 nm), at which time the device is a periodic structure with a double-layer single grating. Moreover, the γ value of both modes increases with α, which leads to an increase in the radiation loss of the device

• Equation 3: Tuning the cavity length h, when the round-trip phase shift is 2mπ (m = 0, 1, 2, …), the complex eigenfrequency of one mode in Equation 4 is ω0 ± κ – 2iγ with twice as much radiation loss as before. And the complex eigenfrequency of the other mode is ω0 ± κ with a pure real number, which

Design of photonic microcavities in hexagonal boron nitride

• Sejeong Kim,
• Milos Toth and
• Igor Aharonovich

Beilstein J. Nanotechnol. 2018, 9, 102–108, doi:10.3762/bjnano.9.12

• shown in Figure 1d, the Q-factor of the mode starts to saturate at H ≈ 12 because the Q-factor is limited not only by the in-plane component, but also by radiation loss. Considering both the Q-factor and scaling of the simulation time with domain size, we fixed H at 12 for subsequent modelling

Radiation losses in the microwave K_u band in magneto-electric nanocomposites

• Talwinder Kaur,
• Sachin Kumar,
• Jyoti Sharma and
• A. K. Srivastava

Beilstein J. Nanotechnol. 2015, 6, 1700–1707, doi:10.3762/bjnano.6.173

• explained. Further studies revealed that the prepared material is a nanocomposite. FTIR spectra show the presence of expected chemical structures such as C–H bonds in a ring system at 1512 cm−1. Keywords: emulsion polymerization; magneto-electric composite; radiation loss; vector network analyser

• -particle interaction [5]. Radiation loss study The dependence of the calculated reflection loss for composite samples on the frequency in the range of 12.4–18.0 GHz (Ku band) is shown in Figure 6. A distinct pattern reveals that the reflection loss depends on the presence of polyaniline and the magnetic

• hexaferrite alone. This may be due to the electrical properties of polyaniline. Multiple reflections, due to the embedding of ferrite in polyaniline and polarization, because of electron hopping between ferric ions and magnetic losses collectively, increase the reflection loss. For radiation loss measurements