Carrier Envelope Phase (CEP) Stabilization

Solutions for applications in high-electric field and attosecond physics

About Carrier Envelope Phase (CEP) Stabilization

For applications in high-electric field and attosecond physics, the Carrier Envelope Phase (CEP) is vitally important as the peak electric field will vary along with the CEP. As mode-locked systems produce shorter pulse durations, the relative importance of the phase becomes higher as there are fewer oscillations under each envelope.


For precision metrology and spectroscopy applications employing the frequency comb nature of mode-locked lasers, precise control of the Carrier Envelope Offset (CEO) frequency is key as it determines the experimental accuracy. The CEO frequency and the CEP can be controlled to produce an astonishingly well-defined light source tailored to the research needs. One way to achieve this is using an f-to-2f interferometer and a feedback loop that controls the CEO frequency via the pump power supplied to the ultrafast oscillator. Conventionally, the loop controls an acousto optic modulator (AOM) to vary the output from a constant power pump beam before it enters the oscillator. Provided the speed of phase offset variation is slower than the speed at which the AOM can respond, the phase offset can be held constant. A more sophisticated approach uses the signal from the interferometer to directly control the pump laser output, circumventing the AOM, enabling a higher speed and depth of the control than with an AOM.


Novanta employs its expertise enabling CEP/CEO related products:


  • Few-cycle Ti:Sapphire oscillators with an octave-spanning spectrum sufficiently broad for direct CEP stabilization
  • GHz Ti:Sapphire oscillators enabling CEO frequencies of several 100 MHz up to a few GHz
  • Ultralow noise pump lasers with direct pump modulation capability. The lower the better is a simple rule
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