Optimization of polarization spectroscopy for rubidium D lines

Polarization spectroscopy of the D lines of rubidium atoms is investigated experimentally, especially with different pump powers and cell temperatures. We found that there are four candidate transitions suitable for frequency stabilization, and optimal pump powers and cell temperatures are also presented to obtain a perfect signal with maximal amplitude and slope. The optimal signal is insensitive to the fluctuations of laser power and the temperature, which can enhance the performance of frequency locking.