Lock-in modules

The lock-in modules let you modulate and demodulate any of the input and output signals available in the Nanonis SPM controller with frequencies up to 40 kHz. Up to 8 lock-in modules can be used independently from each other or synchronized in a phase coherent manner when the generation of multiple frequencies is required. With the multi-frequency option a single module can demodulate up to 8 harmonics of the same signal or independent input signals. The advantage of an internal lock-in detector over an external device is 

• Higher resolution and dynamic range
• Multifrequency and multi-input operation
• Over 120 dB linearity
• Over 100 dB dynamic reserve
• No need for gain and attenuation switching
• Steeper filters (up to 8. order) 
• Up to 8 lock-ins, which can also be synchronized for phase-coherent operation
• Lock-in can be synchronized with OC4. Measure STM current at the exact oscillation frequency of the probe
• Synchronization with data acquisition when using Sync filtering
• Integration avoids errors due to insufficient settling time with slow filter responses 
• no additional noise source through external cabling
• no potential grounding problems
• Tandem-demodulation is straightforward to configure
• flexible and simple setup
• Guided filter set-up utility
• Ability to turn on and off the excitation through software during the experiment
• Ability to turn on and off the excitation for different bias ranges through software during the experiment

Applications range from regular dI/dV, CITS, inelastic electron tunneling spectroscopy (IETS), transport experiments, Hall measurements, multi-frequency and multi-demodulator measurements of open and closed loop transfer functions and every type of phase sensitive measurements.

The lock-in filter array is also available for signals unrelated to lock-in measurements. The filters in the array are freely assignable, meaning that it is possible to use a subset of the filters for lock-in measurements and the remaining filters for generic purposes.

All lock-in modules also feature a sync output option. In addition to the main signal output, the lock-in module can generate a synchronization signal with the same frequency as the main signal. The amplitude can be configured independently from that of the main signal, and it is also possible to use harmonics of the main signal frequency as a sync signal. The sync signal is used to synchronize external instruments (for example other lock-ins, optical choppers,…) with the frequency of the internal lock-in. The output connector for the sync signal is user-selectable.