  Allowing a high quality factor (Q-factor) to a sub-wavelength dielectric
resonator, quasi-bound states in the continuum (Q-BIC) has gained much
interest. However, the Q-BIC resonance condition is too sensitive to the
geometry of the resonator and its practical broadband generation on a
single-wafer platform has been limited. Here, we present that employing the
base angle as a structural degree of freedom, the truncated nano-cone resonator
supports the Q-BIC resonance with a high Q-factor of >150 over a wide
wavelength range of >100 nm. We expect our approach will boost the utilization
of the Q-BIC resonance for various applications requiring broadband spectral
tuning.
