Astrella Ultrafast Ti : Sapphire Amplifier The Astrella laser from Coherent is an ultrafast femto-second laser system that comes with an integrated Vitara Ti:sapphire oscillator laser pulse of repetition rate 80 MHz, which is amplified using a nonlinear crystal providing the amplified output pulse energy of nearly 6 mJ and the pulse reputation rate of 1 kHz. The pulse width of the amplified laser out is nearly 35 fs that allows us to perform the ultrafast pump-probe laser spectroscopy of the exciting materials and superconductors. Reference
Photoconductive Antenna based THz-TDS system GaAs based Photoconductive antenna switches are one of the most used Terahertz generation sources. It is driven by a low power femto-second pulses which generates the charge carriers within the crystal. Application of voltage bias on emitter accelerates the charge carriers to generate THz radiation and this radiation is further detected when its field is used to drive the charge carriers on the detector end.
ZnTe crystal based THz-TDS system We have ZnTe crystal-based terahertz time domain spectroscopy setup. In the setup an amplified femto-second optical pulse of wavelength 800 nm is shined on <110> cut ZnTe crystal and under the proper phase matching conditions, the THz pulse is generated through optical rectification processes. To detect the generated THz, electro-optic sampling method has been used where the low power optical pulse passing through another ZnTe detector crystal experiences the polarization rotation due to the incident THz electric field. Reference
Optical Pump-Terahertz Probe system We employ ZnTe crystal-based THz system for the time resolved optical pump and terahertz probe (OPTP) measurements. We have 400 and 800 nm optical pump beam to photoexcite the samples where we can scan the dynamics at nanoseconds time scales.
Picometrix T-Ray 5000 T-Ray 5000 Picometrix setup allows state of the art terahertz research to be performed in the real-time platform. The modular construction facilitates the laser propagation through the fibre which eliminates the optical bench significantly. This striking advantage allows an easy modulation in the system to perform characterizations in transmission as well as reflection geometry.
Advanced Research 4K Cryostat We use a closed cycle (ARS) optical cryostat to cool down the superconducting samples. In this system, low temperature is achieved by cooling the helium vapors which is in contact with sample space. In this process, the refrigerator of the cryostat is kept in a vacuum to eliminate convection heat transfer to the cold internal parts to maintain low temperatures. A radiation shield is used to minimize the radiant heat load on the cold stage and is cooled by helium exhausting from the heat exchanger. A temperature controller and thermocouple are used to control and monitor the temperature of the sample holder, respectively.
TeraScan 1550 The TeraScan 1550 combine mature DFB diode lasers with state-of-the-art GaAs or InGaAs photomixers. The system sets new benchmarks in terms of terahertz power, spectral selectivity, high resolution and dynamic range. Continuous-wave (CW) terahertz radiation is obtained by so-called optical heterodyning in high-bandwidth semiconductors: The output of two CW lasers is converted into terahertz radiation, exactly at the difference frequency of the lasers. Thermal tuning of the grating pitch yields very wide continuous frequency scans (typ. > 1000 GHz / diode).
Virginia Diodes Inc The Virginia Diodes Inc (VDI) frequency extension modules expand the operating range of microwave signals generators up into the millimetre frequency range (260GHz to 400 GHz). They combine high output power and low phase noise with broad frequency coverage over full waveguide bands. Standard features include TTL-controlled on/off modulation up to approximately 1 kHz and voltage-controlled RF attenuation (UCA). The VDI setup paired with the signal generator and analyzer enables experimental measurements of conventional and photonic topological insulators (PTI) waveguiding and also free space measurements if the horn antenna attachment is used.
NTU Centralized Facility
The establishment at Nanyang Nano Fabrication Centre (N2FC) houses state-of-the-art fabrication facilities to provide wide range of support for the various kind of on-going research activities in NTU, Singapore. The objective of in-house centralized facilities is to facilitate users with necessary equipment and infrastructure support, together with safe environment, to accomplish their research objective. The N2FC typically specializes in material growth, patterning, etching, and provide wide range of tools for thin film and device characterization.
Centre for Disruptive Photonic Technologies (CDPT), NTU
Physical Vapour Disposition (PVC) UNIVEX 250 is manually controlled and semi-automatic vacuum deposition system, which supports two different mode for coating and thin-film deposition: thermal evaporation and sputtering.
Nano Fabrication The FEI Helios NanoLabTM DualBeamTM integrates Focused Ion Beam (FIB) and Scanning Electron Microscope systems (SEMs) technology to provide dual beam platform for 3D characterization, sample preparation and nano prototyping.
Atomic Layer Deposition (ALD) Beneq TFS 200 gives flexible ALD platform in terms of versatility, modularity and ease of operation. It can coat wafers, planar objects and porous bulk materials, as well as complex 3D objects with very high aspect ratio features.
Spectrophotometry Spectrophotometer coves wide range of activity, such as collection of transmittance/reflectance spectra of a sample, measurement of the band gap and film thickness of semiconductors, which can be performed through Jasco MSV-5200 Microspectrophotometer.
Cathodoluminescence Microscope Attolight CL is cathodoluminescence microscope provides an optional time-resolved detector with 10 picoseconds time resolution. The set-up combines a proprietary scanning electron microscope (SEM) with an integrated light microscope. A 6-degrees-of-freedom displacement system ensures arbitrary positioning of sample with 1 nm increments.
Reactive-ion etching (RIE) The JLS Designs Ltd Mini-Lab Plasma-Pod System offers dry etching technology, generally used in microfabrication. The Plasma Pod is equipped with up to 3 gas lines, 300 watt RF generator, automatic matching unit, turbo molecular pump, automatic pressure control and full PLC control unit with touch screen interface.