A lidar, comprising: a rotor, wherein the rotor has an emitting chamber and a receiving chamber that are separated from each other, wherein the emitting chamber and the receiving chamber are asymmetrically distributed; a laser emitting system disposed in the emitting chamber and comprising a laser emitter bracket and at least one laser emitter emitting board fixed to the laser emitter bracket; and a receiving system disposed in the receiving chamber, wherein the laser emitting system comprises a laser emitter (2015, 510, 520) disposed on the laser emitter emitting board, wherein the laser emitter (2015, 510, 520) comprises: a base (511, 521) having a positioning portion (5111, 5211) thereon; a laser emitter chip (512, 522) disposed on the base (511, 521) and having a light-emitting surface (5121, 5221); and a laser beam shaping element (513, 523) positioned opposite to the light-emitting surface (5121, 5221) of the laser emitter chip (512, 522) through the positioning portion (5111, 5211), wherein the laser emitter emitting board comprises a circuit board (531, 541) and a plurality of laser emitters (2015, 510, 520) disposed on the circuit board (531, 541), wherein light-emitting surfaces (5121, 5221) of laser emitter chips (512, 522) of the laser emitters (2015, 510, 520) are oriented in the same direction, wherein the plurality of laser emitters (2015, 510, 520) are soldered on the circuit board (531, 541), wherein a slow axis direction of the light-emitting surfaces (5121, 5221) of the plurality of laser emitters (2015, 510, 520) are perpendicular to the circuit board (531, 541). a rotor, wherein the rotor has an emitting chamber and a receiving chamber that are separated from each other, wherein the emitting chamber and the receiving chamber are asymmetrically distributed; a laser emitting system disposed in the emitting chamber and comprising a laser emitter bracket and at least one laser emitter emitting board fixed to the laser emitter bracket; and a receiving system disposed in the receiving chamber, wherein the laser emitting system comprises a laser emitter (2015, 510, 520) disposed on the laser emitter emitting board, wherein the laser emitter (2015, 510, 520) comprises: a base (511, 521) having a positioning portion (5111, 5211) thereon; a laser emitter chip (512, 522) disposed on the base (511, 521) and having a light-emitting surface (5121, 5221); and a laser beam shaping element (513, 523) positioned opposite to the light-emitting surface (5121, 5221) of the laser emitter chip (512, 522) through the positioning portion (5111, 5211), wherein the laser emitter emitting board comprises a circuit board (531, 541) and a plurality of laser emitters (2015, 510, 520) disposed on the circuit board (531, 541), wherein light-emitting surfaces (5121, 5221) of laser emitter chips (512, 522) of the laser emitters (2015, 510, 520) are oriented in the same direction, wherein the plurality of laser emitters (2015, 510, 520) are soldered on the circuit board (531, 541), wherein a slow axis direction of the light-emitting surfaces (5121, 5221) of the plurality of laser emitters (2015, 510, 520) are perpendicular to the circuit board (531, 541). a base (511, 521) having a positioning portion (5111, 5211) thereon; a laser emitter chip (512, 522) disposed on the base (511, 521) and having a light-emitting surface (5121, 5221); and a laser beam shaping element (513, 523) positioned opposite to the light-emitting surface (5121, 5221) of the laser emitter chip (512, 522) through the positioning portion (5111, 5211), wherein the laser emitter emitting board comprises a circuit board (531, 541) and a plurality of laser emitters (2015, 510, 520) disposed on the circuit board (531, 541), wherein light-emitting surfaces (5121, 5221) of laser emitter chips (512, 522) of the laser emitters (2015, 510, 520) are oriented in the same direction, wherein the plurality of laser emitters (2015, 510, 520) are soldered on the circuit board (531, 541), wherein a slow axis direction of the light-emitting surfaces (5121, 5221) of the plurality of laser emitters (2015, 510, 520) are perpendicular to the circuit board (531, 541).