The Nanosurf LensAFM from Nanosurf AG is an atomic force microscope that goes beyond the resolution limits of optical microscopes and profilometers. It is installed in the same manner as a standard objective lens, thereby increasing the resolution and measuring skills of these instruments.
The LensAFM can be used to analyze different physical properties of a measurement sample in addition to providing 3D surface topography data.
- Can increase user’s resolution capabilities by a factor of up to 100
- Can be installed on virtually any optical microscope or 3D optical profilometer
- A combination of optical and AFM techniques
The unique combination of compact design, optical access, and intuitive operation of the LensAFM made it the perfect platform for our instrument development. We believe that much of the success of our project has been achieved through the excellent communication that we have enjoyed between ourselves, Nanosurf, their UK distributor Windsor Scientific, and AFM probe manufacturer Nanosensors. We now look forward to future developments with the LensAFM to optically probe magnetic materials deep into the nanoscale.
Dr. Paul S. Keatley, Senior Experimental Officer (SEO), Exeter Time Resolved Magnetism Facility, University of Exeter
Perform AFM Measurements with the Instruments of Choice
In a typical laboratory setting, two dedicated instruments would be required, and the sample would need to be transferred from one device to another. This is not the case with the LensAFM. With its tiny size and smart mounting process, all users have to do is rotate the turret on the optical microscope or profilometer and run the scan.
The LensAFM seamlessly incorporates into the user’s workflow. After attaching it to the optical microscope’s turret — similar to a regular objective lens — users can screen the sample with standard targets to find points of interest.
Following that, the topic of interest is easily located using the incorporated 8x optical lens, and users can then conduct the AFM assessment to obtain higher resolution 3D data. It works in the same manner as before, but with a significant increase in resolution and capabilities.
The LensAFM has a rapid release pattern that allows users to easily install and detach the LensAFM from the turret. The kinematic mounting ensures that users can replace it with greater precision than 10 µm.
Alignment grooves on the chip mount also make sure that the tip of the next cantilever is within 4 m of the same position, enabling the same feature to be found again even after a cantilever exchange. With these alignment grooves, users do not even have to execute a laser alignment on the cantilever, which also saves time.
The LensAFM adds all of these measurement skills to the optical microscope without reconsidering the user’s entire workflow. Look at the video to see how simple it is to improve such skills.
Nanosurf LensAFM -- Adding AFM to your Optical Microscope
Video Credit: Nanosurf AG
Boost the Capabilities of the Optical Microscope
As the wavelength of light limits the resolution of optical microscopy, there is indeed a restriction to the resolution users can achieve with the optical system. This necessitates the use of optical and atomic force microscopy in an exponential rise. Furthermore, AFM overcomes difficulties in characterizing transparent samples or samples that are otherwise hard to assess optically.
Not only is the topography of a sample of interest, but AFM also enables the acquisition of knowledge of other mechanical properties, such as hardness variability, surface quality, magnetism or electrical conductance/resistance.
LensAFM Imaging modes
The following are the modes suitable for the instrument. Certain modes may require added components or software options.
Standard Imaging Modes
- Static Force Mode
- Dynamic Force Mode (Tapping Mode)
- Phase Imaging Mode
- Conductive AFM (C-AFM)
- Electrostatic Force Microscopy (EFM)
- Scanning Spreading Resistance Microscopy (SSRM)
- Force Modulation
- Force Spectroscopy
- Force Mapping
- Magnetic Force Microscopy
Other Measurement Modes
- Lithography and Nanomanipulation
Table 1. LensAFM scan head specifications. Source: Nanosurf AG
|Maximum scan range (XY)(1,2)
|XY-linearity mean error
|Z-measurement noise level (RMS, static mode)(3)
||typ. 350 pm (max. 500 pm)
|Z-measurement noise level (RMS, dynamic mode)(3)
||typ. 90 pm (max. 150 pm)
|Automatic sample approach
||Built-in motorized parallel approach with 4.5 mm travel
||Automatic self-adjustment through alignment chip technology
||Built-in 8× objective lens with 45 or 60 mm parfocal distance(5)
|AFM measurement repositioning precision
||±10 µm (including cantilever exchange, scan head remounting and approach)
(1) Manufacturing tolerance: ±15%
(2) Maximum scan range at 45° rotation of the AFM scan direction
(3) Measured using the C3000i controller, with active vibration isolation on a stable desk, and in a low-noise laboratory environment (no air conditioning)
(4) Adapters with a correct parfocal distance are available for the different optical microscope types
Table 2. C3000i controller—Core hardware specifications. Source: Nanosurf AG
|X/Y/Z-axis scan and position controller
||3× 24-bit DAC (200 kHz)
|X/Y/Z-axis position measurement
||1× 24-bit ADC (200 kHz)
|Excitation & modulation outputs
||2× 16-bit DAC (20 MHz)
|Analog signal input bandwidth
|Main input signal capturing
||2× 16-bit ADC (20 MHz)
2× 24-bit ADC (200 kHz)
|Additional user signal outputs
||1× 24-bit DAC (200 kHz)
||Sync Out 1/2: digital outputs, signal range 0/5V TTL pulses
|FPGA module and embedded processor
80 MHz, 256 MB RAM,
||USB 2.0 Hi-Speed to PC and scan head interface
||Internal quarts (10 MHz) or external clock
||90–240 V AC, 70 W, 50/60 Hz
Table 3. Cantilever. Source: Nanosurf AG
||min. 28 μm
||min. 225 μm or XY corrected
||Required on complete cantilever
|Resonance frequency dynamic mode
||15 kHz to 350 kHz
||Single rectangular cantilevers only
Scan Head Dimensions
Image Credit: Nanosurf AG