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High-redshift gamma-ray bursts (GRBs) provide a powerful tool to probe theearly universe, but still for relatively few do we have good observations ofthe afterglow. We here report the optical and near-infrared observations of theafterglow of a relatively high-redshift event, GRB\,220101A, triggered on NewYear's Day of 2022. With the optical spectra obtained at XL2.16/BFOSC andNOT/ALFOSC, we determine the redshift of the burst at $z= 4.615$. Based on ouroptical and near-infrared data, combined with the X-ray data, we performmultiband fit with the python package \emph{afterglowpy}. A jet-break at $\sim$0.7 day post-burst is found to constrain the opening angle of the jet as $\sim$3.4 degree. We also determine circumburst density of $n_0 = 0.15\ {\rmcm}^{-3}$ as well as kinetic energy $E_{\rm K, iso} = 3.52\times 10^{54}$ erg.The optical afterglow is among the most luminous ever detected. We also find a``mirror'' feature in the lightcurve during the prompt phase of the burst from80 s to 120 s. The physical origin of such mirror feature is unclear.

Optical and Near-infrared Observations of the Distant but Bright 'New Year's Burst' GRB 220101A