Laboratory of OptoSpintronics

 

Laboratory of Optospintronics (LOS) is a joint laboratory of Faculty of Mathematics and Physics, Charles University in Prague and Institute of Physics, Academy of Sciences CR. The Laboratory was established in 2011 as an output of an extensive collaboration between Division of Quantum Optics and Optoelectronics Faculty of Mathematics and Physics and Department of Spintronics and Nanoelectronics of the Institute of Physics. The Head of LOS is P. Němec (e-mail: nemec@karlov.mff.cuni.cz).

Starting from 2017, the research performed in LOS is partially supported by European research grant ASPIN awarded within the Future and Emerging Technologies program that is part of the Excellence pillar of the Framework Programme Horizon 2020.

 

From left to right: Tomáš Jungwirth, Petr Němec, and Vít Novák. Photo by Renata Louvarová.

 

Major scientific equipment

a) femtosecond Ti:sapphire laser (Mai Tai HP, Spectra Physics), which generates laser pulses at 690 – 1040 nm (1.8– 1.2 eV) with a duration of 200 fs  and an energy up to  30nJ at a repetition rate of 82MHz; the repetition rate can be reduced down to single pulse using a pulse picker.

b) optical parametric oscillator (Inspire HF, Spectra Physics) pumped by Mai Tai HP described above - the system provides gap-free tuneability from 350 nm (3.5 eV) to 2.2 µm (0.56 eV).

c) continuous Ti:sapphire laser (model 3900S pumped by Millenia Prime 6, Spectra Physics), which is tunable from 700 to 1000 nm (1.8– 1.2 eV).

d) closed-cycle helium cryostat (Advanced Research Systems) with a temperature range 10   800 K that has an extremely low level of sample vibrations (~ tens of nm) and that is equipped with 18 wires for standard transport/electrical experiments, and 1 microwave cable for electrical experiments with frequencies up to 50 GHz.

e) electromagnet (Walker Scientific, model HV-4H) generating magnetic field up to 1.5 T.

 

Experimental techniques

a) basic optical characterization – absorption, reflection and photoluminescence spectra

b) magneto-optical characterization – spectra of magnetic circular dichroism (MCD) and birefringence (MCB), magnetic linear dichroism (MLD) and birefringence (MLB)

c) time-resolved ultrafast laser spectroscopy – pump-and-probe (measurement of transient absorption and reflection), time-resolved magneto-optical Kerr effect (TR MOKE), and laser-induced dynamic grating experiment (four-wave-mixing)

 

 

The research performed in LOS is described here.

 

Awards

2017  Czech Head, category Doctorandus in technical sciences: Vít Saidl.

2017  Jana Marka Marci prize of Czech Spectroscopic Society, Contest of the best work of young authors, category B – published papers: Lukáš Nádvorník, Long-range and high-speed electronic spin-transport at a GaAs/AlGaAs semiconductor.

2017  Jana Marka Marci prize of Czech Spectroscopic Society, Contest of the best work of young authors, , category A – diploma thesis: Miloslav Surýnek, Optická spektroskopie magneticky uspořádaných materiálů.

2016  Czech Physical Society, Prize of Milan Odehnal: Lukáš Nádvorník.

2015  Grant L'Oreal For Women in Science awarded to Eva Schmoranzerová, nee Rozkotová.

2014  Bedřich Hrozný Prize awarded by the president of the Charles university to the group of scientists from Faculty of Mathematics and Physics and Institute of Physics, Academy of Sciences of the Czech Republic.

2012  Josef Hlávka Award: Eva Schmoranzerová, nee Rozkotová.

2012   Jana Marka Marci prize of Czech Spectroscopic Society, Contest of the best work of young authors, , category A – diploma thesis: Tomáš Janda, Dynamics of spin polarization in semiconductors.

2012  Schollarship of Fulbright commission: Helena Reichlová.

2010  Jana Marka Marci prize of Czech Spectroscopic Society, Contest of the best work of young authors, , category A – diploma thesis: Helena Reichlová, Ultrafast laser spectroscopy of ferromagnetic semiconductor GaMnAs.

2009  Jana Marka Marci prize of Czech Spectroscopic Society, Contest of the best work of young authors, category B – published papers: Eva Rozkotová, Investigation of ferromagnetic semiconductor (Ga,Mn)As by ultrafast laser spectroscopy.