Introduction

MadPLL^® is a powerful instrument package that allows the user to create an inexpensive, high resolution resonant scanning probe microscope using Mad City Labs nanopositioning systems. In short, MadPLL^® can be used to create an “instant” closed loop AFM or NSOM at a fraction of the cost of commercial systems.

MadPLL^® has been specifically designed for resonant probes such as tuning forks and Akiyama probes. In addition MadPLL^® is fully compatible with Mad City Labs’ high resolution nanopositioning systems which makes it easy for users to build a scanning probe microscope with a flexibility that cannot be achieved with other commercial systems. The seamless integration of hardware combined with the built-in automated control of MadPLL^® means that you can concentrate on getting results.

MadPLL^® is ideal for research and teaching laboratories offering high performance, versatility, simplicity and excellent value.

Features Low costSoftware, PLL controller, sensor amplifier, and probe boards includedEasy and flexible configurationFully self contained - no external signals requiredAutomated software controlAuto PCC controlAuto Q Calculation, auto resonant frequency detectionIntegrated Z axis PI control loopFully compatible with Mad City Labs positioning products

  What is MadPLL^®?

MadPLL^® is an integrated solution that includes the digital phase lock loop (PLL) controller, software, sensor amplifier, probe board mount, and resonant probe mounting board. Simply add your Akiyama probe or tuning fork to the probe board to create a powerful force sensor for scanning probe measurements.

The MadPLL® package includes the MadPLL® digital PLL controller, sensor board,  probe board, and MadPLL® software.  Ease of integration with resonant probes and Mad City Labs' low noise nanopositioning systems give users the ability to create high performance, low cost NSOM and AFM instruments.

The PLL controller contains a digitally controlled proportional integral (PI) loop designed to work seamlessly with Mad City Labs’ nanopositioning systems. The addition of closed loop nanopositioners adds to the high performance of MadPLL^®. Additional options are available for multi-axis closed loop nanopositioning control.

The PLL controller has three operational modes: self oscillation, PLL driven, and (lock-in) DDS driven. The probe can be controlled in constant excitation or constant signal mode. Measured outputs from the controller include changes in frequency, amplitude or phase shift.

The digital MadPLL® controller has three operational modes: self oscillation, PLL driven, and DDS driven. The probe can be controlled in constant excitation amplitude or constant signal amplitude. Changes in frequency, amplitude, or phase are measured for Z control.

The sensor amplifier is the interface between the MadPLL^® controller and the probe. The sensor amplifier contains a preamplifier, an excitation signal attenuator, and a parasistic capacitance compensation (PCC) circuit.  The probe board mount and probe board assemblies  are compact and can be fitted to existing instrumentation. The probe board  simply plugs into the probe board mount. The mount can be fixed to a precision  positioner such as a closed loop nanopositioning system. The probe board has  been designed for use with tuning forks and Akiyama probes. These probes are easy to mount and alignment free.

MadPLL® includes a sensor amplifier, probe boards, and intermediate probe mount.  The probe boards are designed for use with tuning forks, Akiyama probes and Accutune probes.

  MadPLL^® Software

MadPLL^® software simplifies the control of your scanning probe microscope.  All of the functions of MadPLL^® are fully automated but accessible via individual software control.  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.  MadPLL^® software integrates seamlessly with Mad City Labs' AFMView™ software.  AFMView™ software is part of our complete SPM development system.

  Application - AFM Video Tutorial

Instant AFM - just add science!

MadPLL^® can be used to create a customized, high resolution Akiyama probe or tuning fork atomic force microscope (AFM) at a fraction of the cost of commercial systems. MadPLL^® has been designed to directly interface with Mad City Labs’ low noise single and multi-axis nanopositioning systems, making it possible to create a fully closed loop AFM. The AFM described is suitable for both research and teaching environments and can be further customized for vacuum operation. MadPLL^® is suitable for nanoscale characterization and nanoscale fabrication applications such as optical antennas, nano-optics, semiconductors, data storage, and more.

Video Bill of Materials SPM-M KitMadPLL® Instrument Packagedigital phase lock loop (PLL) controllerAkiyama probe mounting boardsensor amplifier boardNano-SPM200 nanopositioning stage (XY)Nano-OP30 nanopositioning stage (Z)3 axis closed loop Nano-Drive® controllerZ axis open loop/close loop switch (OCL option)Adapter plate between preamplifier and Nano-OP30Adapter plate to Thorlabs MT1 micropositionerXY and Z coarse motion: standard stages available from optical component suppliersProbe: Akiyama probeHardware: standard optical mounting fixturesPC: Windows XP/Vista/7 (32 bit or 64 bit compatible)  This configuration is a highly flexible, low cost, multi-axis, closed loop Akiyama or tuning fork AFM called the SPM-M Kit. All Mad City Labs nanopositioning systems have low noise PicoQ® sensor technology and closed loop feedback control. Using MadPLL® the user can create a high performance scanning probe instrument at low cost.Additional options available from Mad City Labs   Quartz Crystal Tuning ForksAFMView software (included with SPM-M Kit)Other configurations of 3 axis closed loop nanopositioners*   (e.g. Nano-HS3 Series, Nano-OP30 (Z), Nano-H Series (XY))Vacuum compatible nanopositioners Isolation enclosureCoaxial illuminatorTungsten tip etching kit * All Mad City Labs nanopositioning systems include the Nano-Drive® controller which is fully LabVIEW/C++/MATLAB compatible.AFM configurations typically achieve Z resolutions of 0.5nm (rms) and a scanning frequency of 1Hz. Higher resolutions and scan speeds can be achieved using different nanopositioner combinations. All Mad City Labs nanopositioning systems have low noise PicoQ® sensor technology and closed loop feedback control.Recommended additional items  Vibration isolation tableCoarse Z-axis approach (manual or automated)

  Image Gallery

Seeing is Believing!

The images below were acquired using MadPLL^® with Mad City Labs closed loop nanopositioning systems.  

Si (111) Atomic Steps    (312pm monatomic layer thickness)    2µm x 2µm    Data taken using MadPLL® with Nano-HS3 3-axis nanopositioning system and etched tungsten tip on a quartz tuning fork.   Si (111) Atomic Steps    (312pm monatomic layer thickness)    1.76µm x 2.02µm    Data taken using MadPLL® with Nano-HS3 3-axis nanopositioning system and Akiyama probe.   Calibration grid    (100nm tall lines, 2µm apart)    10µm x 10µm    Unidirectional scan    Self oscillation mode, constant probe signal    Z force feedback: frequency    Data taken using MadPLL® with Nano-HS3 3-axis nanopositioning system and Akiyama probe.   Calibration grid    (100nm tall pegs, spaced 2µm apart)        10µm x 10µm        Unidirectional scan        Self oscillation mode, constant probe signal        Z force feedback: frequency        Data taken using MadPLL® with Nano-HS3 3-axis nanopositioning system and Akiyama probe.Fly eye    100µm x 100µm    Bidirectional scan    PLL mode, constant probe signal    Z force feedback: frequency    Data taken using MadPLL® with Nano-OP30 nanopositioning system (Z-axis), Nano-OP100 nanopositioning system (XY axes) and Akiyama probe.Human hair    100µm x 100µm    Bidirectional scan    Self oscillation mode, constant probe signal    Z force feedback: frequency    Data taken using MadPLL® with Nano-OP30 nanopositioning system (Z-axis), Nano-OP100 nanopositioning system (XY axes)   and Akiyama probe.PMMA pattern, uncured        10 µm x 10 µm        Bidirectional scan        Self oscillation mode, constant probe signal        Z force feedback: frequency        Data taken using MadPLL® with Nano-OP30 nanopositioning system (Z-axis), Nano-OP100 nanopositioning system (XY axes) and Akiyama probe.Integrated circuit    100 µm x 100 µm    Bidirectional scan     Self oscillation mode, constant probe signal      Z force feedback: frequency      Data taken using MadPLL® with Nano-OP30 nanopositioning system (Z-axis), Nano-OP100 nanopositioning system (XY axes)     and Akiyama probe.Calibration grid    40 µm x 40 µm    Unidirectional scan     Self oscillation mode, constant probe signal      Z force feedback: frequency      Data taken using MadPLL® with Nano-OP30 nanopositioning system (Z-axis), Nano-OP100 nanopositioning system (XY axes)     and Akiyama probe.Calibration grid      (100nm tall, 10µm pitch)      70 µm x 70 µm        Unidirectional scan        PLL mode, constant probe signal        Z force feedback: frequency        Data taken using MadPLL® with Nano-OP30 nanopositioning system (Z-axis), Nano-OP100 nanopositioning system (XY axes)      and Akiyama probe.Etched structures      80 µm x 80 µm    Bidirectional scan     Self oscillation mode, constant probe signal      Z force feedback: frequency      Data taken using MadPLL® with Nano-OP30 nanopositioning system (Z-axis), Nano-OP100 nanopositioning system (XY axes)     and Akiyama probe.

  Technical Specifications

Lock-In AmplifierPhase Shifter0° to 360°Demodulation Bandwidth3 kHz
Phase Lock LoopAuto Range SelectionYESMeasurement Range± 500 HzMeasurement Resolution50 mHz
PreamplifierInput Gain (Attenuator)0x to 1x (16 bit internal DAC)Parasitic Capacitance Compensation (PCC)YES (16 bit internal DAC)Automatic PCCYES
Probe Oscillation LoopOperating Modesself oscillationPLL driven  lock-in/DDS drivenAmplitude Control Modesconstant excitationconstant signalAmplitude Setpoint16 bit internal DACAmplitude ControlYES, adjustable PI loop filterInput Voltage Range±10 V(peak)Input Voltage Gain2x to 40xFrequency Range10 kHz to 100 kHzOutput Voltage Range±10 V(peak)
PI Loop Filter (Z-Axis)Integration Time Constantdigitally controlledDigitally Set ParametersYESError Signal Inversion CapabilityYESSensor Signalsfrequencyphaseexcitation amplitudesignal amplitudeCommand Signal16 bit internal DACAutomatic Loop Filter SetupYes, after initializationLoop Output0 to 14V
GeneralSpectrum Analysisamplitude, phaseFeedback Monitor BNCfrequencyphaseexcitation amplitudesignal amplitudeProbe Signal Monitor (BNC)sinewave amplitude probe (diagnostic)Power Supply90 to 260 VAC (50/60 Hz)Controller Dimensions16.75“ x 14“ x 1.75“ (1U)    (42.55cm x 35.56cm x 4.45cm)PC ConnectionUSBOperating System32 bit: Windows 2000/XP Pro/Vista/7  64 bit: Windows XP Pro/Vista/7LabVIEW Software OS32 bit: Windows 2000/XP Pro/Vista/764bit: Windows XP Pro/Vista/7

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