National Repository of Grey Literature 23 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Stable optical frequency transfer between ISI and CESNET workplaces
Čížek, Martin ; Pravdová, Lenka ; Hucl, Václav ; Jelínek, Michal ; Hrabina, Jan ; Řeřucha, Šimon ; Mikel, Břetislav ; Lazar, Josef ; Číp, Ondřej ; Smotlacha, V. ; Havliš, O. ; Vojtěch, J.
The contribution reports on the current state of a 306km long experimental line for transfering stable optical frequency from a telecommunication band laser standard between ISI CAS (Brno) and CESNET (Prague). The bidirectional link uses a telecommunication fiber with a dedicated DWDM window of 1540-1546 nm.1540-1546 nm. In the Czech rep. this technology can be utilized currently in two fields: remote comparisons of optical frequency standards and remote callibration of instruments (optical spectral analyzers) in industrial applications that do not allow transporting the device to a specialized laboratory. The stability of the optical frequency transfer was evaluated. A long-term measurement of transport delay was conducted. \n
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.
SMV-2017-22: Development of a multiaxis interferometric system of coordinate measurement
Holá, Miroslava ; Lazar, Josef ; Hucl, Václav ; Čížek, Martin
The aim of the project of the contractual research was development of a multiaxis interferometric system for coordinate measurement. This system make possible to contactless measurement of displacement in axis x, y with compensation refractive index of air. The emphasis was placed on with high accuracy and repeatability measurement on nanometre level for wavelength 633 nm. Part of the contractual research was development and realization driving system for detection of signals. We used homodyne detection system. The measurement system was tested in laboratory and then was installed in the aim system.
Frequency stabilized semiconductor laser source for high-resolution interferometry
Řeřucha, Šimon ; Hucl, Václav ; Holá, Miroslava ; Čížek, Martin ; Pham, Minh Tuan ; Pravdová, Lenka ; Lazar, Josef ; Číp, Ondřej
We have assembled an experimental iodine stabilized Distributed Bragg Reflector (DBR) diode based laser system lasing at a wavelength that is in a close proximity to the wavelength of a stabilized He-Ne lasers traditionally used for metrological applications (λ=632.9 nm in vacuum). The aim was to verify whether such a system could be used as an alternative to the He-Ne laser while yielding wider optical frequency tuning range, higher output power and high frequency modulation capability. We have measured the basic characteristics of the laser source and then we have compared the performance of the laser system with that of a traditional frequency stabilized He-Ne laser with a series of experimental arrangements similar to those usually found in laser interferometry and displacement metrology applications. The results indicate that DBR diode laser system provides a good laser source for applications in dimensional (nano)metrology since it provides more output power and advanced tunability options than stabilized He-Ne lasers while maintaining fundamental requirements such as the frequency stability, coherence length and also a defined traceability.\n\n
Optical low dispersion rezonator as length sensor using optical frequency comb
Pravdová, Lenka ; Hucl, Václav ; Lešundák, Adam ; Lazar, Josef ; Číp, Ondřej
Ultra-high precis measurements are domain of lasers interferometers. An optical resonator measuring method using broad spectrum of radiation of an optical frequency comb was designed and experimentally verified at our workplace. The measuring of a quantity – a distance of resonator mirrors – is provided by its conversion to the value of repetition frequency of the pulse laser with mode-locked optical frequency comb. In this paper the comparison of the absolute scale of the optical resonator with an incremental interferometer scale is introduced. The incremental interferometer is implemented for verification of the optical resonator scale. The double beam incremental interferometer is operating at the wavelength of 633 nm and the measuring mirror with piezo actuator is used as one of its reflectors. It turns out that the major error signal is the reflection of the periodic nonlinearity of the incremental resonator scale. The relative resolution of our method reaches values up to 10-9 while maintaining measuring scale.
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
A pair of phase-synchronized semiconductor lasers for length metrology
Hucl, Václav ; Holá, Miroslava ; Čížek, Martin ; Řeřucha, Šimon ; Pham, Minh Tuan ; Pravdová, Lenka ; Lazar, Josef ; Číp, Ondřej
Semiconductor lasers are increasingly widespread in areas that have been so far dominated by He-Ne lasers. One of such areas is the length metrology, where He-Ne laser operating at 633nm wavelength is still a traditional source of coherent light for laser interferometers distance measuring. The advantages of semiconductor lasers compared with He-Ne laser are greater optical power and a significantly wider range of wavelength tuning without mode jumps. Another advantage is the possibility of frequency modulation of wavelength of the laser diode by directly changing the injection current. The benefits predetermine these laser diodes for the realization of dual-frequency laser sources for heterodyne interferometry. In this case, using a phase-locked loop technique the optical frequency of a laser diode is locked to the optical frequency of another laser diode with a certain frequency offset in the MHz order. In our contribution we present utilization of DBR laser diodes in implementing a dual-frequency laser source for laser interferometry with heterodyne detection.\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.

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