跳转到主要内容
Search

Optical Chopper Measurement

Related Products: MFLIMF-MD

未发布
MFLI Double chopper experiment

The use of lock-in amplifiers in combination with optical choppers is one of the most common low frequency lock-in amplifier applications. In order to make this a bit more interesting, James shows in the following video how to easily set up an experiment that makes use of 2 different choppers simultaneously. This helps to save valuable real estate in the lab and reduce the complexity of the setup.

Requirements

Dual chopper measurement Setup using the Zurich Instruments MFLI Lock-in Amplifier

Tips and Tricks

  • Adjust the input ranges
  • Sometimes it's handy to use the Auxiliary Inputs on the front panel as external reference input
  • Auto-zero the phase
  • Use the Plotter tool to display the chopper frequency, as tracked by the internal PLL, over time - the Math sub-tab offer plenty of statistical function for further signal analysis
  • By adjusting the Harmonic field you can adjust the demodulation frequency to higher harmonics but also sub-multiples of the chopper reference frequency; this can be useful when using the same blade at multiple slot pitches
  • Use the Sinc filter to increase temporal resolution while keeping SNR high, when demodulation bandwidth gets into the same range as demodulation frequency
  • Use the FFT Spectrum Analyzer to determine SNR and see other components in the spectrum
  • For analog outputs to the Auxiliary Output adjust the Offsets, the scaling factor and limits as needed

MFLI Key Features for Optical Chopper applications

  • Works with any chopper model
  • Best noise performance 2.5 nV/√Hz at 1 kHz and above; 7 nV/√Hz at 10 Hz; 40 nV/√Hz at 1 Hz
  • Easy lock to the chopper reference (TTL or analog signals)
  • Demodulate at higher harmonics and sub-multiple frequencies
  • 4 easy to configure analog outputs (pre-offset, scaling, offset, limits)
  • LabOne toolset: Scope, FFT Spectrum Analyzer, Parametric Sweeper, Plotter, etc.

 

联系我们