Optical systems based on Bound States in the Continuum (BIC) generally possess higher Quality Factors (Q) and narrower operational linewidths compared with traditional photonic crystals or metasurfaces. The higher Q values offer extensive possibilities for high-performance optoelectronic devices. However, the narrower linewidths often pose challenges in practical applications, as fabrication errors during production inevitably lead to discrepancies between real optical devices and their ideal designs, which resulting in mismatches between actual and ideal operating wavelengths. To address this issue, we explore the dynamic tuning effect of liquid crystal (LC) on quasi-Bound States in the Continuum (q-BIC), aiming to compensate for wavelength shifts caused by fabrication errors. A photonic crystal slab with cross-shaped holes serves as the platform for generating q-BIC. Compared to the modulation induced by the tilt angles of incident light on q-BIC, LC has a lesser impact on the system's Q factor when shifting the same operational wavelength. For instance, shift the central wavelength λ0 of q-BIC by 5.32 nm using a tilted incident angle results in a reduction of the Q factor by up to 75.84% (from 3809.05 to 920.28). Whereas shifting the central wavelength λ0by 5.63 nm through the tilt angle θ of LC leads to an increase of Q factor of 14.27% (from 3809.05 to 4352.65). This demonstrates the significant potential of LC dynamic tuning in high-Q and ultra-narrowband q-BIC devices. Finally, the mechanism of LC within the q-BIC system is discussed. The smaller impact of LC on the Q factor is attributed to its minimal disruption of the q-BIC system's symmetry. Although LC also affects system symmetry within the cross-shaped holes, after adjusting the asymmetry parameters of the system, the Q factor and the LC tuning process can be well matched. The results of our research provides valuable references for extensive research related to q-BIC.
下载: