About

This research group focuses on nuclear quantum optics, an emerging field at the intersection of quantum optics and nuclear physics, studying X-ray and γ-ray radiation, nuclear systems, and their interactions. Our research seeks to address several pivotal challenges in the field, including:

• Coherent control of γ-photons and nuclear excitations
• Quantum optics with single γ-photon quantum states
• Stimulated emission within nuclear systems and γ-ray lasing

The experimental approach to studying photon-nuclei interactions is primarily based on the nuclear resonant scattering of γ-photons by nuclear ensembles, exploiting recoilless absorption and emission of γ-photons, known as the Mössbauer effect. Mössbauer isotopes, exhibiting energy transitions between 5 and 100 keV, are embedded in solid-state materials acting as resonant environments. Our group focuses on employing radioactive γ-ray sources, with particular emphasis on the 14.41 keV resonance of the ⁵⁷Fe isotope, which offers suitable characteristics for this type of research.

Research teams

1. Fundamental research, theoretical modelling and data analysis
   contact person: Vlastimil Vrba
   The team focuses on the development and experimental testing of theoretical frameworks for quantum γ-optical phenomena. The addressed topics include coherent control of γ-ray intensity waveforms via ultrasonic vibrations, control of single γ-photon entangled states in temporal and polarization degrees of freedom, or generation and detection of correlated γ-photon pairs. Semi-classical models can be efficiently applied for data analysis, simulation and optimization of experiments. Quantum mechanical frameworks show promise in describing advanced physical phenomena including the γ-photon entanglement and stimulated emission.
   team members:
   Post-docs: Petr Obšil
   PhD students: Michal Hausner, Michal Koutný
   Master students: Dalimil Doubrava, Tomáš Jüngling

2. Methods and instrumentation development
   contact person: Vít Procházka
   The team focuses on the experimental development in nuclear quantum optics, with a primary emphasis on time-domain experiments aimed at generating γ-ray pulses of arbitrary temporal characteristics and polarization. The γ-ray intensity profiles are controlled via their propagation through environments containing resonating nuclei. This manipulation involves mainly the utilization of ultrasonic vibrational techniques. The team activities involve the ongoing development of equipment essential for our research. This includes development of electronics for data acquisition, implementation of time-coincidence experiments, and the design and construction of specialized experimental setups and γ-optics components.
   team members:
   Post-docs: Jan Kočiščák, Petr Novák, Aleš Stejskal
   PhD students: Michal Brázda, Vítězslav Heger

Our laboratory

The laboratory is equipped with a comprehensive array of resources, including:

• More than five spectrometers facilitating a diverse range of γ-optics experiments

• Fast γ-ray detectors based on scintillation materials

• 4π detectors for conducting nuclear lifetime and γ-echo experiments

• A fully equipped chemical laboratory with tools for handling ⁵⁷Fe enriched materials and ⁵⁷Co, enabling the
  creation of radioactive sources tailored to specific research objectives

• A wide assortment of electronic equipment ecompassing oscilloscopes, generators, Doppler modulation units,
  high-frequency piezoelectric actuators, time-coincidence units, detector power supplies and circuit board
  fabrication tools

• Room temperature Mössbauer spectrometers

• Mössbauer spectrometer with a resonant detector

• Two cryostats designed for low-temperature Mössbauer spectroscopy

• Cryostat designed for Mössbauer spectroscopy in magnetic fields up to 7 Tesla, allowing parallel or perpendicular alignment with respect to γ-ray beam direction

• Regulatory authorization for handling of closed and open radioisotopes, specifically ¹¹⁹Sn and ⁵⁷Co

Recent publications

2025

• Vrba, V.; Hausner, M.; Stejskal, A.; Procházka, V.: Acoustically controlled periodic gamma-optical signals described by semiclassical theory, Physical Review Reasearch 7, 023243, doi:10.1103/l33j-xstp
• Hausner, M.; Procházka, V.; Vrba, V.: Stimulated emission and coherent control of gamma photons described by quantum mechanical model, Physical Review Reasearch 7, 023229, doi:10.1103/PhysRevResearch.7.023229
• Stejskal, A.; Vrba, V.; Procházka, V.: Toward flexible intensity control of resonantly scattered γ-rays using multi-frequency vibrating resonant absorber, Applied Physics Letters 126, 084102, doi:10.1063/5.0249167

2024

• Vondrášek, R.; Pechoušek, J.; Procházka, V.: Preparation of specific‐purpose ⁵⁷Co radiation sources for specialised Mössbauer techniques, Journal of Radioanalytical and Nuclear Chemistry xx(xx)xx, doi:10.1007/s10967-024-09923-7,

2023

• Stejskal, A.; Procházka, V.; Dudka, M.; Vrba, V.; Kočiščák, J.; Šretrová, P.; Novák, P.: A dual Mössbauer spectrometer for material research, coincidence experiments and nuclear quantum optics. Measurement 215, 112850 doi:10.1016/j.measurement.2023.112850,
• Novák, P.; Schlattauerová, T.; Procházka, V.; Kopp, J.; Vrba, V.: Lamb–Mössbauer factor of powders determined by Mössbauer spectroscopy with resonant detector. Chemical Papers 77(12)7283–7288 , doi:10.1007/s11696-023-02844-x

2022

• Kočiščák, J.; Novák, P.; Stejskal, A.; Kopp, J.; Procházka, V.: High time and energy resolution semi-transparent scintillation detectors for application in γ optics and Mössbauer spectroscopy, Measurement 206, 112225, doi:10.1016/j.measurement.2022.112225
• Procházka, V.; Novák, P.; Stejskal, A.; Dudka, M.; Vrba, V.: Lamb-Mössbauer factor determination by resonant Mössbauer spectrometer, Physics Letters A 442, 128195, doi:10.1016/j.physleta.2022.128195
• Novák, P.; Procházka, V.; Stejskal, A.: Universal drive unit for detector velocity modulation in Mössbauer spectroscopy, Nuclear Instruments and Methods in Physics A1031, 166573, doi:10.1016/j.nima.2022.166573