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Carrier-envelope phase (CEP) stabilized Titanium: Sapphire ultrafast laser amplifier
Carrier-envelope phase (CEP) stabilized Titanium: Sapphire ultrafast laser amplifier
Customized FEMTOPOWER compact PRO amplifier from Femtolasers GmbH. This system has dual CEP stabilized outputs, delivering: i) 2.5 nJ pulses with sub-7 fs duration at a repetition rate of 80 MHz (from the included Femtolasers Rainbow CEP laser oscillator); ii) up to 1 mJ pulses with sub-30 fs duration at a repetition rate of 1 kHz. This system is a key tool for advanced (high-resolution and CEP-dependent) ultrafast science, including ultrafast nonlinear optics, ultrafast laser-matter interaction and ultrafast pump-probe spectroscopy experiments.
Contact: Dr. Helder Crespo (hcrespo@fc.up.pt)
Home-built Titanium:Sapphire ultrafast laser oscillator
Home-built Titanium:Sapphire ultrafast laser oscillator
This was the first few-cycle femtosecond laser in Portugal (built in 2000). It delivers 10 fs pulses at a repetition rate of 80 MHz and a central wavelength of 800 nm, with an average power of up to 600 mW. These pulses can be used in a variety of experiments, from nonlinear excitation and propagation to pump-probe studies. The emitted laser pulses can also be tuned over a broad spectral range (700 – 900 nm). By propagating the pulses in a short piece of photonics crystal fiber this system enables the generation of ultra-broadband coherent spectra (also known as super continua) spanning over the ultraviolet, visible and near-infrared regions, which has also enabled producing the shortest soliton-compressed pulses in the world (sub-5 fs).
Contact: Dr. Helder Crespo (hcrespo@fc.up.pt)
Home-built hollow-fiber compressor for few-cycle pulse generation
Home-built hollow-fiber compressor for few-cycle pulse generation
This system takes advantage of the nonlinear propagation of amplified laser pulses in noble gas-filled hollow capillaries to produce unprecedentedly short laser pulses. Using a proprietary measurement and compression scheme (dispersion-scan) based on a set of ultra-broadband dispersion compensation mirrors, we have achieved the shortest pulses ever obtained from a single-channel pulse compressor: 3.0 fs. These pulses are already in the single-cycle regime and enable the direct observation of field-dependent phenomena in many materials.
Contact: Dr. Helder Crespo (hcrespo@fc.up.pt)
Dispersion-scan system (d-scan)
Dispersion-scan system (d-scan)
Dispersion-scan (d-scan) is an innovative technique (patent pending) for the simultaneous measurement and compression of ultrashort laser pulses. D-scan (invented in our group, in collaboration with Lund University in Sweden) is more robust, much easier to implement and more performing than other conventional pulse measurement techniques. Our in-house design includes automated measurement/acquisition and pulse retrieval.
Contact: Dr. Helder Crespo (hcrespo@fc.up.pt)
Sub-30 fs deep-ultraviolet pulse source at 266 nm
Sub-30 fs deep-ultraviolet pulse source at 266 nm
Ultrashort UV light is generated by non degenerate four-wave mixing of femtosecond pulses at 800 nm and their second-harmonic at 400 nm. These pulses can be used to directly excite and probe energetic levels in atoms and molecules at femtosecond time scales.
Contact: hcrespo@fc.up.pt
Complex dielectric permittivity and dielectric relaxation
Complex dielectric permittivity and dielectric relaxation
This technique measures both the real and imaginary parts of the dielectric permittivity ranging the tempereature from 10 to 350 K, and the frequency from 2 Hz to 2 MHz. Measurements can be made as a function of the ac measuring voltage (50 mV to 5 V) as well as the external applied voltage (up to 40 V). Moreover, dielectric relaxation can be carried out at fixed temperature by sweeping frequency (2 Hz to 2 MHz).
Available equipment: Impedance meters and multimeters.
Contact: Dr. Joaquim Agostinho Moreira (jamoreir@fc.up.pt)
Thermal stimulated currents and polar relaxation
Thermal stimulated currents and polar relaxation
This technique is addressed to carry out measurements of currents that are originated by temperature changes. This is most attractive in those materials exhibiting electric polarization that changes with temperature. Some examples for this type of materials are: Multiferroics, magnetoelectrics, ferroelectrics, relaxors, electrets and micro- and nano-scale heterostructures of these materials. In this technique a constant temperature rate is fixed and the current measured using a short-circuit method.
Available equipment: Electrometers and multimeters.
Contact: Dr. Joaquim Agostinho Moreira (jamoreir@fc.up.pt)
Polarization inversion, and hysteresis cycles
Polarization inversion, and hysteresis cycles
The electric polarization/electric field curves can be obtained at fixed temperature using a modified Sawyer-Tower circuit. Materials showing non-linear behaviour are adequately studied with this technique, in particular those exhibiting ferroelectric ground states.
Contact: Dr. Joaquim Agostinho Moreira (jamoreir@fc.up.pt)
Specific heat
Specific heat
The heat capacity is measured in an ARS Cryocooler, between 8 and 300 K, in a quasi-adiabatic fashion by means of an impulse heating technique.
Contact: Dr. Joaquim Agostinho Moreira (jamoreir@fc.up.pt)
Temperature control and measurement
Temperature control and measurement
The temperature is changed and controlled using close-cycle cryostats (8 K – 350 K) and Linkam furnaces (80 K – 900 K). The temperature precision is ~0.1 K.
Measurements procedures and acquisition of data are computer-controlled.
Contact: Dr. Joaquim Agostinho Moreira (jamoreir@fc.up.pt)
High-Pressure System
High-Pressure System
The applied hydrostatic pressure up to 100 GPa is obtained by a Membrane Diamond Anvil Cell (MDAC) with Neon as pressure transfer medium. A ring-heater can simultaneously control temperature up to 1000 K.
Contact: Dr. Joaquim Agostinho Moreira (jamoreir@fc.up.pt)
Dielectric Spectrometer
Dielectric Spectrometer
The dielectric spectrometer system enables access to the real and imaginary parts of the dielectric permittivity and consists of a high resolution dielectric analyzer ALPHA. This equipment possesses a broadband dielectric converter with high input impedance on the entry and displays a resolution of ~10-5. Temperature can be ranged from 110 to 675 K and frequency from 0.3 μHz to 1 MHz.
Contact: Dr. Joaquim Agostinho Moreira (jamoreir@fc.up.pt)
MOKE
MOKE
Magneto-optical Kerr effect (MOKE) magnetometry allows for the characterization of nano-structured magnetic materials. Information, such as the magnitude of coercive fields or anisotropy strengths, can be readily obtained from MOKE measurements. This state-of-the-art vectorial MOKE magnetometer is an extremely versatile, accurate, and sensitivity unit.
Contact: Dr. João Pedro Araújo (jearaujo@fc.up.pt)
Bottom-up Nanofabrication Laboratory
Bottom-up Nanofabrication Laboratory
Self-organized nano structuring using template synthesis is a very promising and rapidly expanding field for the preparation of different nano structures and templates ranging from the micrometer to the 6 nm range. One appealing branch of self-organization is based on anodization methods, deeply interfacing with physical/chemistry. This technique is very versatile since the pore size, pore density and height can be readily controlled by the electrolyte species, anodizing temperature, voltage and time. The templates are well suited for the subsequent preparation of many ordered nano structures using different deposition methods.
Contact: Dr. Célia Sousa (celiasousa@fc.up.pt) / Dr. João Pedro Araújo (jearaujo@fc.up.pt)
Flexible Electronics Laboratory (LEF)
Flexible Electronics Laboratory (LEF)
LEF focus on the fabrication of electronic components on flexible materials, such as PET, Kapton, and textiles, using a variety of advanced techniques. Key processes include screen printing, spin coating, spray coating, as well as custom coating methods, alongside sputtering for thin-film deposition. These techniques provide precise control over film thickness, material uniformity, and surface properties.
In addition, LEF explores the optimization of conditions for polymer and nanomaterial synthesis, specifically tailoring them for the production of inks designed for flexible applications. Controlled oven treatments are employed to ensure material stability and performance. This comprehensive approach enables the creation of durable, high-performance flexible electronics for a broad range of applications, including energy storage, energy generation, electromagnetic shielding, and the integration of quantum materials, such as topological materials and magnetic materials.
These quantum materials, along with spin-orbitronics devices, hold immense potential for new magnetic sensors, logic memories, and optoplasmonic systems. Together, these cutting-edge innovations are pushing the boundaries of next-generation technologies, revolutionizing the fields of flexible electronics and quantum-enabled devices.
Contact: Dr. André Pereira (ampereira@fc.up.pt) / Dr. Ana Pires (ana.pires@fc.up.pt) /Mariana Rocha (mariana.rocha@fc.up.pt)
Screen-printing
Screen-printing
Screen printing is a key technique for fabricating electronic devices on flexible substrates. The process involves transferring inks, such as conductive or dielectric materials, onto a substrate through a mesh screen that is selectively blocked to create specific patterns or designs. In this screen-printing setup, a rubber squeegee serves as the blade, manually guided across the screen to deposit the ink. This method offers flexibility and control for small-scale or customized designs, making it ideal for prototyping and low-volume production. Additionally, the facility allows for screen customization with any desired design using UV-activated polymers and shadow masks. Three types of screens are available, ranging from wide to tight meshes, providing flexibility in pattern resolution and ink deposition.
Contact: Dr. Ana Sousa (anarita.sousa@fc.up.pt)
Magneto-Sputtering Deposition
Magneto-Sputtering Deposition
Metallic, semiconductor, and oxide thin films with sub-nm thicknesses of various materials can be fabricated in the Multifunctional Magnetic Materials and Nanostructures group using a Magneto-Sputtering Deposition system from XCY Scientific Instruments in either DC or RF current mode. This machine is also equipped with a heating system which allows for in-situ thermal treatment. The unit's primary application is the production of metalli0, thermoelectric and magnetic thin films and multi-layered structures.
Contact: Dr. Ana Pires (ana.pires@fc.up.pt)
3D Printing
3D Printing
In addition to being a versatile technique for fabricating electronic components by depositing materials layer by layer, 3D printing is also utilized to assist in the construction of custom setups and devices for experimental systems. It supports the design and production of specialized components that aid in the assembly of intricate measurement setups or the creation of housings and fixtures for electronic devices. The capability to work with conductive, dielectric, and insulating materials enables the development of both functional components and structural elements. With precise control over geometry, 3D printing allows for the rapid prototyping and fabrication of multi-layer devices or bespoke parts necessary for specific experimental needs. The enclosed print area and aluminium print bed ensure consistent print quality, reducing issues like warping. Furthermore, its compatibility with a wide range of third-party filaments provides flexibility in material selection, making it ideal for diverse research and development applications.
Contact: Dr. Mariana Rocha (mariana.rocha@fc.up.pt)
Ion Beam Deposition
Ion Beam Deposition
Ion Beam Deposition of thin films. Both metallic and oxide films with sub-nm thicknesses can be fabricated in the Multifunctional Magnetic Materials and Nanostructures group using an Ion Beam Deposition system from Commonwealth Scientific. This unit is also equipped with a manual load-lock/oxidation chamber and allows for in-situ measurements to be performed. The main use of the unit is the fabrication of magnetic thin films and nano structures.
Contact: Dr. João Ventura (joventur@fc.up.pt)
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