Femtosecond Phase Stabilization
|Repetition frequency||70-90 MHz|
|Offset frequency||¼ of the repetition frequency|
|Linewidth||Offset frequency <1 Hz|
|Input requirements||200 mW average power in <15 fs pulses|
The XPS800 Femtosecond Phase Stabilization Unit gives you control of your ultrashort pulses and their carrier envelope offset phase. The precise control of the shortest time events ever created by scientists has been achieved by combining the expertise of ultrafast laser physics with our frequency comb technology. Our product line allows the generation of trains of absolutely identical ultrashort laser pulses. The technique has been recognized as enabling technology for the era of attophysics - new phenomena like the control of electronics on attosecond time scales are no longer science fiction.
The pulses from the fs laser are broadened in a nonlinear photonic crystal fiber to achieve an octave spanning spectrum. A nonlinear interferometer subsequently generates the signal for offset frequency stabilization by beating the frequency doubled infrared part with the green part of the spectrum. This beat signal is filtered and amplified and fed to the locking electronics. The offset frequency is phase locked to ¼ of the repetition frequency. For this task the repetition frequency is divided by 4 and sent to Port 1 of our digital phase detector. Port 2 of the phase detector gets as input the amplified and filtered offset frequency signal. A PI-circuit that drives an acousto optical modulator or a piezo actuator closes the control loop.