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  • Lift mode scan for Nano-Magnetometry
  • Integrated PLL and motion control
  • Amplitude oscillation controllable to 1 nm
  • Low noise atomic step performance
  • Software switch between force feedback and positiion feedback
  • Automated software and hardware setup
  • Compatible with Mad City Labs nanopositioners
  • Compatible with Akyama type and QZabre probes
  • Includes AFMView™2 software

Typical Applications
  • Scanning NV center Magnetometry
  • Magnetic Force Microscopy
  • Electric Force Microscopy
  • Atomic Force Microscopy

Product Description

QS-PLL™ is an atomic force microscope (AFM) controller designed for use with resonant probes, such as tuning forks, and Mad City Labs nanopositioners and micropositioners.  The controller integrates motion control and phase lock loop (PLL) control thus streamlining the hardware interface.   Hardware and the digital PLL are controlled via the AFMView™2 software supplied with the QS-PLL™ controller.   The QS-PLL™ controller allows users to customize a resonant probe AFM instrument with the unique feature of “Lift Mode” scans in addition to the usual scanning modes.  This instrument is ideal for scanning probe microscopy where tip-surface interactions are modulated by a field, such as scanning NV magnetometry.

The QS-PLL™ is compatible with all Mad City Labs closed loop nanopositioners and stepper motor driven micropositioners.   Up to 3 axes of piezo nanopositioning is supported and up to 4 axes of micropositioning, giving an unparalled ability to configure an instrument for your application.   In addition, there is an option to add encoders to 3 axes of the micropositioning.  A breakout box is supplied to facilitate cable management between the motion control devices and QS-PLL™.   Mad City Labs closed loop nanopositioners offer superb stability and precision via our proprietary PicoQ® sensors.   Our nanopositioners have been deployed previously in resonant probe AFM instruments with atomic step resolution.   As a result, many different instrument configurations can be formed to enable optical and sample access.

The phase lock loop (PLL) contains a digitally controlled proportional integral (PI) loop designed to work seamlessly with Mad City Labs’ nanopositioning systems and provide amplitude oscillations down to 1nm.   This high degree of control with resonant probes offers significant advantages for applications that require high sensitivity and low optical noise. 

The QS-PLL™ controller is compatible with tuning forks, Akiyama probes, and QZabre probes.   There is also capability to bias the probe via the DAC output which is controllable within the AFMView™2 software.

AFMView™2 software, which is supplied with the controller, simplifies the control of your atomic force microscope.  Among the software features are automated setup, configuration control, auto-Q calculation and automatic parasitic capacitance compensation (PCC) control. These included features are designed to simplify setup and accelerate the data acquisition process.

Technical Specifications


Motion Control

Closed Loop Nanopositioners 1-3 axis
Position DAC Control
20 Bit
Position ADC's
24 Bit
Number of Micropositioners 1-4 axis
Microposition minimum step size 95 nm
Encoders 1-3 axis
Encoder Resolution 50 nm
Phase Locked Loop Control Digital

I/O Connectors

Nanopositioners DB-37
Micropositioners DB-50
Feedback Monitor 1 x BNC
16 bit DAC output -10V to +10V
16 bit ADC input 0-10V (2 x BNC)
Sensor Amplifier DB-9
Pixel Clock TTL)
Line Clock TTL)
Frame Clock TTL)
AUX Clock TTL)

PLL Features

Feedback Modes Amplitude/Frequency/Phase Shift
Automatic Range Selection YES
Parasitic Capacitance Compensation (PCC) YES
Automatic PCC YES
Adjustable PI loop filter YES
Digitally Set Parameters YES
Error Signal Inversion Capability YES
Automatic Loop Filter Setup YES, after initialization
Frequency Range 10 kHz - 100 kHz


AC Power 90 - 260 (50/60 Hz)
Controller Dimensions 16.75" x 14" x 3.5" (42.6 cm x 35.6 cm x 8.9 cm)
Breakout Box Dimensions 8.375" x 8" x8.9" (21.3 cm x 20.3 cm x 8.9 cm)
PC Connection USB 2.0
Operating System Windows 7/8/10/11

AFM Verification using the QS-PLL.

Image of 1.5 nm steps on SiC substrate measured by AFM.
AFM Demonstration:
Image of SiC stepped surface taken with an AFM incorporating the QS-PLL and AFMView™2 software. The measurement was made using an etched W tip attached to a tuning fork . The AFM used a custom Nano-3D200 with 200 x 200 um scan range and 20 um of Z motion. The system was set up as a sample scanner with a tuning fork sensor mounted to a three axis micropositioner. The X and Y axis of the micropositioner was manual while the Z axis was motorized.

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mclgen@madcitylabs.com       phone: 608.298.0855       fax: 608.298.9525

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