A physics module of a chip-scale atomic clock, comprising: a housing ; a laser source disposed in the housing and generating a laser beam; a vapor cell disposed above the laser source to generate a transmitted beam from the laser beam; and a detector disposed above the vapor cell to detect the transmitted beam, wherein the vapor cell comprises a plurality of optical patterns configured to polarize the incident and transmitted laser beam, wherein the vapor cell comprises: a transparent box ; and an alkali gas filled in the transparent box , and wherein the optical patterns are arranged on an outer wall of the transparent box , and wherein the transparent box comprises: a lower substrate ; an upper substrate on the lower substrate ; and a side wall part configured to seal the alkali gas between the upper substrate and the lower substrate , and wherein the optical patterns are made of a material different from that of each of the lower substrate and the upper substrate , characterized in that the optical patterns comprise: lower patterns disposed below the lower substrate ; and upper patterns disposed on the upper substrate . a housing ; a laser source disposed in the housing and generating a laser beam; a vapor cell disposed above the laser source to generate a transmitted beam from the laser beam; and a detector disposed above the vapor cell to detect the transmitted beam, wherein the vapor cell comprises a plurality of optical patterns configured to polarize the incident and transmitted laser beam, wherein the vapor cell comprises: a transparent box ; and an alkali gas filled in the transparent box , and wherein the optical patterns are arranged on an outer wall of the transparent box , and wherein the transparent box comprises: a lower substrate ; an upper substrate on the lower substrate ; and a side wall part configured to seal the alkali gas between the upper substrate and the lower substrate , and wherein the optical patterns are made of a material different from that of each of the lower substrate and the upper substrate , characterized in that the optical patterns comprise: lower patterns disposed below the lower substrate ; and upper patterns disposed on the upper substrate . a transparent box ; and an alkali gas filled in the transparent box , and wherein the optical patterns are arranged on an outer wall of the transparent box , and wherein the transparent box comprises: a lower substrate ; an upper substrate on the lower substrate ; and a side wall part configured to seal the alkali gas between the upper substrate and the lower substrate , and wherein the optical patterns are made of a material different from that of each of the lower substrate and the upper substrate , characterized in that the optical patterns comprise: lower patterns disposed below the lower substrate ; and upper patterns disposed on the upper substrate . a lower substrate ; an upper substrate on the lower substrate ; and a side wall part configured to seal the alkali gas between the upper substrate and the lower substrate , and wherein the optical patterns are made of a material different from that of each of the lower substrate and the upper substrate , characterized in that the optical patterns comprise: lower patterns disposed below the lower substrate ; and upper patterns disposed on the upper substrate . lower patterns disposed below the lower substrate ; and upper patterns disposed on the upper substrate . <EOS>