Petr Balling

Absolute frequency measurement of wavelength standard at 1542nm: acetylene stabilized DFB laser

The frequency of a wavelength standard at 1542 nm (194 THz) developed in CMI for the telecommunication band C was measured with a fiber femtosecond frequency comb. The measurement was done for three transitions of acety(13)C(2)H(2): P(14), P(15) and P(16). The results agree well with values in the recommendation for Practical realization of the definition of the metre [1] and even better with recent measurements made in NMIJ/AIST [2,3] - the differences are lower than 2 kHz (or 1x10-(-11) rel.) for all three transitions. This agreement is significant considering the fact that the CMI laser uses an extremely simple spectroscopic arrangement and substantially lower saturation power.

Length and refractive index measurement by Fourier transform interferometry and frequency comb spectroscopy

In this paper we describe the progress we have made in our simultaneous length measurement and the femtosecond comb interferometric spectroscopy in a conventional arrangement with a moving mirror. Scanning and detection over an interval longer than the distance between two consecutive pulses of the frequency comb allow for a spectral resolution of the individual frequency modes of the comb. Precise knowledge of comb mode frequency leads to a precise estimation of the spectral characteristics of inspected phenomena. Using the pulse train of the frequency comb allows for measurement with highly unbalanced lengths of interferometer arms, i.e. an absolute long distance measurement. Further, we present a non-contact (double sided) method of measurement of the length/thickness of plane-parallel objects (gauge blocks, glass samples) by combining the fs comb (white light) with single frequency laser interferometry. The position of a fringe packet is evaluated by estimating the stationary phase position for any wavelength in the spectral band used. The repeatability of this position estimation is a few nanometres regardless of whether dispersion of the arms is compensated (transform limited fringe packet ?10 fringes FWHM) or highly different (fringe packet stretched to >200 fringes FWHM). The measurement of steel gauge block by this method was compared with the standard method, and deviation (+13 ? 12) nm for gauge blocks (2 to 100) mm was found. The measurement of low reflecting ceramic gauges or clear glass samples was also tested. In the case of glass, it becomes possible to measure simultaneously both the thickness and the refractive index (and dispersion) of flat samples.

Comparison of 127I2-stabilized frequency-doubled Nd:YAG lasers at the Bureau International des Poids et Mesures.

A frequency comparison was carried out between iodine-stabilized Nd:YAG lasers at 532 nm from the Bureau International des Poids et Mesures, the Centre for Metrology and Accreditation, the Czech Metrology Institute, and the Bureau National de Métrologie-Institut National de Métrologie. The frequency differences between lasers, as well as the frequency reproducibility of each system,were investigated. Pressure-, modulation-, and power-induced shifts were studied. A frequency dispersion (1 sigma) of 3.5 kHz (6.2 x 10(-12) in relative terms) with an average reproducibility for each laser of the order of 0.4 kHz (7.1 x 10(-13) in relative terms) was observed over the duration of the comparison. Relative stabilities better than 1 x 10(13) at 1 s were demonstrated for the third-harmonic systems.

A Single-Ion Trap with Minimized Ion-Environment Interactions

AbstractWe present a new single-ion endcap trap for high-precision spectroscopy that has been designed to minimize ion–environment interactions. We describe the design in detail and then characterize the working trap using a single trapped

Analysis of thermal radiation in ion traps for optical frequency standards

^{171}{\rm Yb}^{+}

Absolute Distance Measurement Using Frequency Comb and a Single-Frequency Laser

171Yb+ ion. Excess micromotion has been eliminated to the resolution of the detection method, and the trap exhibits an anomalous phonon heating rate of

Absolute distance measurement by multi-heterodyne interferometry using a frequency comb and a cavity-stabilized tunable laser

d\langle n\rangle /{\mathrm{d}}t = 24 ^{+30}_{-24}\,{\rm s}^{-1}