Multifunctional probe system
At the disposal of the laboratory "Metamaterials" there is a multifunctional probe system (MPS) designed for complex nanoscale investigations of optical metamaterials, plasmonic nanostructures, etc. Along with a variety of methods aimed on the investigations of the surface properties by means of atomic force microscopy (AFM), MPS provides a wide range of tools for the investigation of the optical properties of samples, including Scanning Near-Field Optical Microscopy (SNOM) method in various configurations and confocal Raman spectroscopy.
The system comprises two probe microscopy modules and an optical microscopy and spectroscopy module.
Probe microscopy modules
Both probe microscopy modules are a fully-automated scanning probe microscope with fast 100 ?m scanner. Together with the optical microscopy and spectroscopy module these systems allow one to perform fluorescence or Raman scattering measurements simultaneously with AFM scanning without any cross-interference.
The set includes Mitutoyo M Plan Apo 10x/0.28, M Plan Apo 50x/0.55, M Plan Apo 100x/0.7, M Plan Apo 100x/0.9 objectives.
The set includes Olympus UPlanFL N 20x/0.5, UPlanFL N 40x/0.75, UPlanSApo 60x/1.2, PlanFL 100x/0.95.
- Full-contact, semicontact and non-contact Atomic Force Microscopy (AFM);
- Lateral force microscopy;
- Phase-contrast measurements;
- Force modulation method;
- Force spectroscopy;
- Kelvin probe microscopy;
- Magnetic force microscopy;
- Electric force microscopy;
- Piezoresponse force microscopy;
- Scanning capacitance microscopy;
- Contact and semicontact AFM in liquid;
- Ground current AFM;
- Volt-ampere characteristics measurements;
- Scanning Tunnel Microscopy (STM);
- Photocurrent mapping;
- Current nanolithography;
- Measurements in surface shear forces regime;
- Shear-Force microscopy.
Scanning Near-Field Optical Microscopy
AIST SmartSPM™ system allows to perform SNOM measurements with a fiber or a cantilever in contact mode or plane scan mode (with a surface liftoff) in reflection geometry.
AIST CombiScope system allows to perform SNOM measurements with a fiber or a cantilever in contact mode or plane scan mode (with a surface liftoff) in transmission geometry.
In both cases collection and excitation modes can be implemented. The consequent lasers are used for excitation:
- 30 mW HeNe laser (? = 633 nm).
- 80 mW solid-state laser with diode pumping (? = 532 nm).
- 75 mW solid-state laser with diode pumping (? = 405 nm).
Photomultiplier Hamamatsu H10722 is used as a highly sensitive detector.
Optical microscopy and spectroscopy module
Both scanning probe modules are combined with confocal Raman spectrometer Horiba LabRAM™ HR UV-VIS-NIR. This allows one to perform fluorescence or Raman scattering measurements simultaneously with AFM scanning without any cross-interference. With top as well as side access to the sample available, one can probe the sample with laser radiation with fixed polarization and collect the light scattered from the sample surface, which is extremely important for SERS/TERS experiments.
Two photodetectors are used in the setup:
- CCD camera for visible spectral range with water cooling Andor iDus DU420A-OE, spectral range 200-1000 nm
- InGaAs camera for IR spectral range with water cooling Andor iDus DU492A-1.7, spectral range 800-1700 nm
The setup includes three diffraction gratings (600 g/mm and 1800 g/mm gratings for visible spectral range, and one 600 g/mm grating for IR spectral range). The consequent lasers are used for Raman spectroscopy:
- HeNe laser, 633 nm, 30 mW.
- Solid state laser with diode pumping, 532 nm, 80 mW.
Figure: Image of the sample surface with golden nanoantennas as high as 25 nm obtained on AIST SmartSPM™ module using cantilever AFM method.
Figure: AFM image of a 200 nm hole etched in a thin golden layer (left panel) and optical signal collected using fiber SNOM method in transmission geometry on AIST CombiScope™ module (right panel).
Figure: AFM image of the surface of a glass-metal nanocomposite grating with line width 50, 100 and 150 nm (left panel) and corresponding optical signal collected using fiber SNOM method in reflection geometry on AIST SmartSPM™ module (right panel).
Figure: AFM image of the surface (left panel) and Raman mapping (right panel) of a Si test sample, pitch depth 1 ?m.
Direct laser writing setup
Metamaterials laboratory possesses a DLW setup designed for 3D microfabrication based on two-photon polymerization.
The method is based on nonlinear process of two-photon absorption. A tightly focused beam of femtosecond pulse laser is scanned within the volume of the photopolymerizable material in all three dimensions. The scanning process is controlled by a computer, which allows one to fabricate micro- and nanostructures of a predefined design. The high resolution of the method (down to 100 nm in lateral plane) is achieved due to threshold-like behavior of two-photon polymerization. The polymerization itself occurs in the highly-localized volume with the dimensions smaller than the beam waist size.
Figure: The general view of DLW setup.
Figure: Principal difference between single-photon polymerization and two-photon polymerization.
The main components of the system and their respective parameters
- Range: 150x100x100 mm
- Feedback resolution: 0.5 nm
- Accuracy: ±200 nm
- Repeatability: ±50 nm
- Max. speed: 30 mm/s
- Max. acceleration: 10 m/s2
- Synchronized with A3200 controller
- Scan angles: ±0.35 rad
- Max. scan speed: 1 m/s
- Supports up to 32 axes
- Real-time operating system
- Could be programmed in CNC-codes, C/C++, VB, Labview
- Wavelength: 715-980 nm
- Pulse duration: <100 fs
- Linewidth (800 nm): >8 nm
- Pulse repetition rate: 80 MHz
- Output power: <0.5W
- Beam divergence: <1 mrad
Figure: Examples of structures fabricated by DLW .
Dimensions: 9х5х4 m (length, width, height)
Very high performance broadband pyramidal ABSORBER: Eccosorb VHP-12-NRL Manufacturer: EMERSON & CUMING Microwave Products; Guaranteed maximum reflectivity of Eccosorb VHP-12-NRL:
|120 MNz||200 MNz||300 MNz||500 MNz||1 GHz|
|3 GHz||5 GHz||10 GHz||15 GHz||24 GHz|
Microwave division allows to prepare, to carry out and to analyze different experiments in the microwave frequency range. For the realization of experiments the anechoic chamber and a large number of modern high-tech equipment are used.
Printer dimensions: 450x430x420 (LxWxH, mm);
The maximum possible size of the printed model: 195x195x150 (LxWxH, mm);
The material used for printing: plastic ABC, PLA, PP, HDPE, LDPE
Working Area: 330/300/100 mm;
Max. Travel Speed: 800/320 mm/sec;
Memory Capacity: 9999 points/prog. 100 programs
Frequency range 2 GHz to 26 GHz
Gain of more than 30dB
Power output up to 27dBm
Frequency range GHz: 0,75-18
The gain of 6-24 dB.
Based on precision positioners AL-560-1
Frequency range GHz: 0,75-18
The gain of 6-24 dB.
10 MHz to 20 GHz;
123 dB dynamic range and <0.006 dB trace noise;
less 26 usec/point measurement speed;
TRL/LRM calibration, on-wafer, in-fixture, waveguide, and antenna measurements;
Mixer conversion loss, return loss, isolation, and absolute group delay;
Amplifier gain compression, harmonic, IMD, and pulsed-RF
- Licensed software for numerical simulation of electromagnetic processes and devices: CST Microwave Studio, ANSYS HFSS, SONNET, COMSOL Multiphysics, Lumerical FDTD Solutions
- More than 20 high-performance PCs including HP Z400 Workstation based on quad-core processors Intel Xeon W3550 3.06 GHz.
- Server for multiscale modeling based on 4xCPU Intel Xeon E5-4617 512Gb RAM
- Linux cluster with 168 cores for parallel calculations with performance up to 1 TFlops.
- System for supercomputing Tesla S2050 based on NVIDIA CUDA ™ GPU architecture with performance up to 2.5 TFlops.
The major task of the chemistry department is to develop optical metamaterials using various chemical and electrochemical methods. The fabrication of ordered, fine structures of metal nanorods using anodic porous alumina as a template has attracted growing interest owing to their novel optical properties. The formation of such structures is a multistage process, which can be divided into two main stages:
1) Fabrication of a matrix-template with ordered porosity
2) Deposition of metals into the pores
In the first stage porous film of aluminum oxide is grown on aluminum anode during the electrolysis in an acidic solution, for example in aqueous solution of phosphoric acid. The current density, concentration and temperature of the electrolyte, electrolysis time, quality of aluminum substrates and its purity have significant influences on the surface nanostructuring by anodizing. Subsequently, oxidic film separated from the aluminum acts as "mask" for the cathode by electrodeposition of metal from the electrolyte solution, for example, from nickel sulfate with various additives.
Special equipment to obtain the aluminum oxide films by electrochemical anodization the has been successfully implemented on the basis of the chemistry department. Basic element of the machine is an electrochemical cell presented at the photo. The electrolyte has placed in stainless steel vessel covered with chemically resistant fluoropolymer lacquer. This coating allows to work with various acids in a wide range of temperatures and concentrations. Furthermore, the surface contacting with the electrolyte, can be periodically updated by applying a new layer of lacquer.
Temperature control of the cell has carried out by a Peltier element, located at the bottom of the vessel. This design allows to reduce the temperature by 30 degrees compared with the environment. Thermocouple in a protective case has placed into vessel to create a feedback control loop. Electrodes has positioned in the volume of electrolyte vertically opposite each other, constant stirring of the solution has also performed.
Power source for the electrolysis supports current up to 1A or potential to200V. Control of all the listed parameters has carried out using a PC to support the values specified for an extended period and allows to minimize the involvement of the researcher in the ongoing process. Electrochemical polishing the aluminum surface before anodization can be successfully carried out in this unit. In this case, a individual cell, equipped with an electric heater,locating around of vessel, will be used.