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Explore second-order fluctuations and non-linearity in optical resonance. Learn solutions for unexpected problems like dynamic instability and spectral cleanliness. Improve output field intensity and PDH signal processing. Discover advancements in QPO and WHEEL oscillators for enhanced performance.
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‘unexpected’ problems 1) Second-orderfluctuations
Non-linearity If is small the linearization works Otherwise the second order expansion has to be used
Non-linearity • Simultaneous acquisition of time series of • Output field intensity • PDH signal Non linearized with optical resonance’s transfer function Intensity PSD (W2/Hz) Direct Derived from PDH signal Frequency (Hz)
‘unexpected’ problems 1) Second-orderfluctuations Solution: - higher input couplertransmission (lower Finesse) - cleanerspectrum (low frequencymechanicalmodes are important) 2) Dynamicinstabilityof ‘light’ modes at low frequency (within or closeto the lockingbandwidth)
The problemconcerns QPO oscillators, but WHEEL oscillatorshavelower Q
‘unexpected’ problems 1) Second-orderfluctuations Solution: - higher input couplertransmission (lower Finesse) - cleanerspectrum (low frequencymechanicalmodes are important) 2) Dynamicinstabilityof ‘light’ modes at low frequency (within or closeto the lockingbandwidth) Solution: - new QPO withlow-frequencymodesup-shifted - new WHEEL oscillatorswithbalancednodalsuspension (enhancedde-couplingfrom the background and increased Q