National Repository of Grey Literature 91 records found  beginprevious44 - 53nextend  jump to record: Search took 0.01 seconds. 
Stabilized laser for spectroscopy on trapped calcium ions
Čížek, Martin ; Pham, Minh Tuan ; Lešundák, Adam ; Hucl, Václav ; Řeřucha, Šimon ; Hrabina, Jan ; Lazar, Josef ; Číp, Ondřej
The paper focuses on the ongoing development of clock laser assembly operating at a wavelength of 729 nm, which will be used for 40Ca+ calcium spectroscopy. As a primary source of coherent radiation, a diode laser with an external resonator operating at a wavelength of 729 nm is used. The width of the spectral line of the free-running laser is approx. 300 kHz. The laser is tunable by a piezoelectric actuator in the range of 10 GHz with a maximum bandwidth of 2 kHz. Fast fine-tuning in hundreds of MHz is possible by modulating the pump current of the laser diode with 50MHz bandwidth. The optical frequency of the laser is locked by means of electronic control loops on a resonator with a finesse better than 300 000 with a mode spectral width of approx. 8 kHz. The cavity of the resonator is made of ULE material and placed in a thermally stabilized vacuum chamber. The entire optical assembly is mounted on an active anti-vibration pad in a wooden box plated with acoustic and thermal isolation. The tuning of the primary laser to the resonator mode is detected by the Pound-Drever-Hall technique.
Trapping and cooling of single ions for frequency metrology and quantum optics experiments
Slodička, L. ; Pham, Minh Tuan ; Lešundák, Adam ; Hucl, Václav ; Čížek, Martin ; Hrabina, Jan ; Řeřucha, Šimon ; Lazar, Josef ; Obšil, P. ; Filip, R. ; Číp, Ondřej
Single trapped ions trapped in Paul traps correspond to ideal candidates for realization of extremely accurate optical atomic clocks and practical studies of the light–atom interactions and nonlinear mechanical dynamics. These systems benefit from both, the superb isolation of the ion from surrounding environment and excellent control of its external and internal\ndegrees of freedom, at the same time, which makes them exquisite platforms for experimental studies and applications of light matter interaction at its most fundamental level. The exceptional degree of control of single or few ion's state enabled in past decade number of major advancements in the applications from the fields of experimental quantum information\nprocessing and frequency metrology, including recent realization of scalable Shor's\nalgorithm, fractional uncertainties of the frequency measurements close to 10-18 level, or simulations of complex quantum many-body effects. These results, together with the rapid advancements in the production of low-noise segmented micro-traps, promise prompt access to long-desired regimes of quantum optomechanics and further development and applications\nof optical atomic clocks.
Digital audio wireless transmission
Juráň, Jeroným ; Hrabina, Jan (referee) ; Szabó, Zoltán (advisor)
This document describes the design of evaluation boards for wireless transmission of audio signal. The boards use WiSA compliant modules. It describes schematics of transmitter board, receiver board and boards of both AD and DA converter. Secondly the document describes the designed PCBs and demonstrates the results by photodocumentation. It also includes description of C library for using FLASH memory to store data and the C driver for FT800 chip and the typical application using this chip including touch
SMV-2016-23: Molecular references for ultra-compact laser standards
Hrabina, Jan ; Holá, Miroslava ; Oulehla, Jindřich ; Pokorný, Pavel ; Lazar, Josef
The contractual research was oriented towards development of a set of optical frequency references intended for frequency stabilization of ultra-compact laser sources. These optical references were based on absorption cells filled with ultra-pure absorption gases and they allow precise locking of the lasers with the methods of laser spectroscopy.
Detection of frequency noise properties of diode laser working on 729 nm
Pham, Minh Tuan ; Čížek, Martin ; Hucl, Václav ; Lazar, Josef ; Hrabina, Jan ; Řeřucha, Šimon ; Lešundák, Adam ; Číp, Ondřej
Paper report on the frequency noise investigation of the Extended Cavity Diode Laser (ECDL), working at 729 nm. The ECDL will be used as an excitation laser for the forbidden transition in a trapped and laser cooled 40Ca+ ion. For that an Hz of sub-Hz level linewidth is required. We present the experimental design for linewidth narrowing and frequency noise analysis. The linewidth is first narrowed with a phase lock loop of the ECDL onto a selected component of an optical frequency comb where the frequency noise was suppressed with a fast electronic servo-loop controller that drives the laser injection current with a high bandwidth.\n
Radio frequency resonator for feeding ion trap
Jedlička, Petr ; Pham, Minh Tuan ; Čížek, Martin ; Pavelka, Jan ; Lešundák, Adam ; Hucl, Václav ; Hrabina, Jan ; Řeřucha, Šimon ; Lazar, Josef ; Číp, Ondřej
Two versions of resonators were designed and manufactured - asymmetric and symmetric.\nThe resonator consists of a coil and capacity of ion trap which makes parallel resonant circuit.\nEnergy is supplied to the resonator through the coupling inductance. Resonator assembly was equipped with outputs for monitoring high-frequency voltage. Both versions have been tuned and tested.\n\n
Optical frequency references
Hrabina, Jan
Optical frequency references based on absorption cells represent a traditional and essential tool for frequency locking of precise laser standards. One of the most often used absorption media is a molecular iodine 127I2, which offers a rich atlas of strong and narrow absorption lines across mostly whole visible part of optical spectrum. The main disadvatage of this media can be seen in its high corrosivity and sensitivity to presence of foreign substances. This contribution is oriented to comparison of possible measurement methods for bulk- and also optical fiber- based iodine absorption cells quality and chemical purity testing.\n\n
Phase coherent transfer of stable optical frequency for sensory networks
Čížek, Martin ; Pravdová, Lenka ; Hucl, Václav ; Řeřucha, Šimon ; Hrabina, Jan ; Mikel, Břetislav ; Lazar, Josef ; Číp, Ondřej
Using long-haul optical fiber links for phase coherent transfers of stable optical frequencies has been developed by metrological laboratories for at least a decade. Present boom of optical fiber sensors puts a demand on transferring this technology from laboratories to industrial practice. A remote calibration of fiber Bragg grating tensometers can be an example. In our contribution we present a 306 km long fiber link between laboratories of ISI in Brno and CESNET in Prague. The line uses a telecom fiber with a dedicated DWDM window at 1540-1546 nm. The setup implements a phase coherent transfer of a laser standard working with 1540.5nm wavelength and a bi-directional transfer of 1PPS timestamps from radiofrequency standards at the both ends of the line. A long-term measurement of transport delay fluctuations and relative stability of the line are discussed.
Laser cooling of the trapped ions for frequency and time metrology
Číp, Ondřej ; Pham, Minh Tuan ; Čížek, Martin ; Lešundák, Adam ; Hucl, Václav ; Hrabina, Jan ; Řeřucha, Šimon ; Jedlička, Petr ; Lazar, Josef
In the laser cooled trapped ions field current research is oriented to yield isolated ions in their basic state of the motion. The detection of the Doppler cooled iont excitation to its quadrupole transition of the electronic structure gives the opportuniny to stabilize highly coherent lasers of the optical frequency of the hundreds of THz. This way a new standart of the time or optical frequencies called „Optical atomic clock“ can be defined. Institute of the Scientific Instruments in Brno in the cooperation with the Department of the Optics of the Palacky University in Olomouc implemented a unique research infrastructure for laser cooling of 40Ca+ ions and subsequent experiments of the quantum mechanics and spectroscopy in a joint laboratory in Brno. Currently 40Ca+ ions are routinely generated and captured. The Doppler cooling of those ions is performed using dipole transition at a wavelength of the 397 nm. Also detection and spectroscopy of the electronic structure of the ion and the presence of his dark resonances is implemented.\n
Metal detector for industrial use
Stehno, Rostislav ; Hrabina, Jan (referee) ; Szabó, Zoltán (advisor)
The goal of this project is explore and study the ways of metal detecting and create a metal detector for industrial use. When the device were inventing, a lot of methods were studied and the impulse detect method were chosen as the most perspective way of metal detecting, thanks to a huge electronics parts possibilities. After experiences with preceding device was necessary to redesign it. Main target of this thesis is to increase the computing power of detector. For this purpose will device need a new microcontroller. Device will communicate with PC trough a USB port. The device will have a battery which allows device to run for a few hours. Processing of measured data will be make even with DFT which will lead to better analyze of mass and type of conductor under device.

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1 Hrabina, Jakub
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