A bandwidth independent linear method for detection of carrier envelope phase drift

Measurement and control of the carrier-envelope phase (CEP) has opened the route to attoscience and to applications of femtosecond pulses in metrology. It is common belief that CEP measurement schemes have to involve a nonlinear optical conversion step and that they require octave coverage of the input spectrum, as is the case for the widespread f to-2f interferometers. Here we will show that neither is required and discuss a linear optical interferometric method that allows for direct measurements of the CEP slippage rate of pulses with arbitrarily narrow spectrum and low power level.