Simple scheme for temperature insensitive laser frequency stabilization*

We demonstrate two methods to combat differential intensity drifts in modulation-free laser frequency stabilization.~ The locking signal is derived from~the difference between~two frequency shifted Doppler-broadened absorption signals from a vapor cell.~ In one method, a single AOM is used in conjunction with analog divider IC's to normalize the absorption signal amplitudes before generating the dispersion-like signal.~ The other method uses two AOMs for active intensity correction.~ A sample of each beam is taken before the vapor cell and a feedback loop stabilizes the intensity by~actively attenuating~the RF sent to the AOM.~ We report on frequency stability of both setups.