Sensitivity of the dual-carrier scheme for the contact-free detection of current noise

A configuration for the detection of current noise is proposed. in which no electrical contacts to the sample under measurement are necessary. The threshold sensitivity of the detection of the current fluctuation can be considerably improved by applying the correlation technique to obtain the spectrum of the fluctuations to be measured. It was demonstrated that a relative conductance fluctuation as low as 10 ^-6 is detectable with the proposed configuration. The most significant limiting factor to the sensitivity is the fluctuation of the ambient temperature, which must be suppressed to a level less than 0.1 K-rms/1 Hz at 1 Hz