We have previously shown our и . Today you can look at the optical laboratory of the Faculty of Physics and Technology at ITMO University.
Pictured: XNUMXD nanolithograph
The Laboratory of Low-Dimensional Quantum Materials belongs to the Research Center for Nanophotonics and Metamaterials () on the base .
Its employees are engaged properties : plasmons, excitons and polaritons. These studies will make it possible to create full-fledged optical and quantum computers. The laboratory is divided into several working areas covering all stages of work with low-dimensional quantum materials: sample preparation, fabrication, characterization, and optical studies.
The first zone is equipped with everything necessary for sample preparation .
To clean them, an ultrasonic washer is installed, and in order to ensure safe work with alcohols, a powerful hood is equipped here. Some materials for research are supplied to us by partner laboratories in Finland, Singapore and Denmark.
A BINDER FD Classic.Line oven is available for sterilizing samples indoors. The heating elements inside it maintain the temperature from 10 to 300°C. It has a USB interface for continuous temperature monitoring during the experiment.
This chamber is also used by laboratory staff for stress and aging tests. Such experiments are necessary to understand how materials and devices behave under certain conditions: standard and extreme.
A three-dimensional nanolithograph is installed in the next room. It allows fabrication of three-dimensional structures with a size of several hundred nanometers.
The principle of its operation is based on the phenomenon of two-photon polymerization. It is essentially a 3D printer that uses lasers to form an object from a liquid polymer. The polymer solidifies only at the point where the laser beam is focused.
Pictured: XNUMXD nanolithograph
Unlike standard lithography techniques, which are used to create processors and work with thin layers of materials, the two-photon polymerization method allows you to create complex three-dimensional structures. For example, these are:
The next laboratory room is used for optical experiments.
There is a large optical table almost ten meters long, filled with numerous installations. The main elements of each installation are radiation sources (lasers and lamps), spectrometers and microscopes. One of the microscopes has three optical channels at once - top, side and bottom.
It can measure not only transmission and reflection spectra, but also scattering. The latter provide very rich information about nanoobjects, such as the spectral characteristics and radiation patterns of nanoantennas.
In the photo: the effect of light scattering on silicon particles
All equipment is located on a table with a single vibration suppression system. The radiation of any laser can be sent to any of the optical systems and microscopes with just a few mirrors and continue research.
A CW gas laser with a very narrow spectrum makes it possible to carry out experiments on . The laser beam is focused on the surface of the sample, and the scattered light spectrum is recorded by a spectrometer.
Narrow lines are observed in the spectra, which correspond to inelastic light scattering (with a change in wavelength). These peaks provide information about the crystal structure of the sample, and sometimes even about the configuration of individual molecules.
A femtosecond laser is also installed in the room. It is capable of generating very short (100 femtoseconds - one ten trillionth of a second) pulses of laser radiation with enormous power. As a result, we get the opportunity to study nonlinear optical effects: generation of doubled frequencies and other fundamental phenomena that are unattainable in natural conditions.
The laboratory also has our cryostat. It allows optical measurements with the same set of sources, but at low temperatures - up to seven Kelvin, which is approximately equal to -266°C.
Under such conditions, a number of unique phenomena can be observed, in particular, the regime of strong binding of light with matter, when a photon and an exciton (electron-hole pair) form a single particle - an exciton-polariton. Polaritons hold great promise in the fields of quantum computing and devices with strong non-linear effects.
In the photo: INTEGRA probe microscope
In the last room of the laboratory, we placed our diagnostic devices - и . The first one makes it possible to obtain an image of the surface of an object with a high spatial resolution and to study the composition, structure, and other properties of the near-surface layers of each material. To do this, he scans them with a focused beam of electrons accelerated by high voltage.
A scanning probe microscope does the same with a probe that scans the surface of the sample. In this case, it is possible to simultaneously obtain information about the "landscape" of the sample surface, and about its local properties, such as electric potential and magnetization.
In the photo: scanning electron microscope S50 EDAX
These instruments help us to characterize samples for further optical studies.
Projects and plans
One of the main projects of the laboratory is related to hybrid states of light and matter in quantum materials—exciton-polaritons already mentioned above. A mega-grant from the Ministry of Education and Science of the Russian Federation is devoted to this topic. The project is led by the lead scientist from the University of Sheffield, Maurice Shkolnik. Experimental work on the project is carried out by Anton Samusev, and the theoretical part is led by Professor of the Faculty of Physics and Technology Ivan Shelykh.
The laboratory staff is also studying ways to transmit information using solitons. Solitons are waves that are not affected by dispersion. Due to this, the signals transmitted using solitons do not “blur” as they propagate, which makes it possible to increase both the speed and the transmission range.
At the beginning of 2018, scientists from our University and colleagues from the university in Vladimir model of a solid-state terahertz laser. The peculiarity of the development is that terahertz radiation is not "delayed" by objects made of wood, plastic and ceramics. Thanks to this property, the laser will find application in passenger and baggage screening areas for a quick search for metal objects. Another area of applicability is the restoration of ancient art objects. The optical system will help to obtain images hidden under layers of paint or ceramics.
Our plans are to equip the laboratory with new equipment in order to conduct even more complex research. For example, to purchase a tunable femtosecond laser, which will significantly expand the range of materials under study. This will help with tasks related to quantum chips for next generation computing systems.
How ITMO University works and lives:
Source: habr.com