A ring laser gyroscope comprises a laser block that defines an optical closed loop pathway configured to contain a lasing gas. A plurality of mirror structures are respectively mounted on the laser block, with each of the mirror structures having a respective reflective surface that is in optical communication with the optical closed loop pathway. A plurality of electrodes are coupled to the laser block, with the electrodes configured to generate a pair of counter-propagating laser beams from the lasing gas in the optical closed loop pathway. At least one optical sensor is coupled to one of the mirror structures, with the optical sensor in optical communication with the closed loop pathway. A polarizer is in optical communication with the optical sensor. The polarizer is configured to pass laser light having substantially one polarization mode to the optical sensor.