International comparisons of He-Ne lasers stabilized with¹²⁷I₂at   = 633 nm (July 1993 to September 1995). Part I: General

Abstract

After the adoption of the new mise en pratique of the de® nition of the metre in 1992, a wide-ranging program me of laser comparisons at l 633 nm, the most used of the recommended wavelengths, was carried out involving national laboratories and the Bureau International des Poids et Mesures (BIPM ). During the period July 1993 to Septem ber 1995, six grouped and ® ve bilatera l comparisons were made involving thirty-® ve national laboratories. This report will comprise six different parts. The ® rst part, this paper, describes the general conditions for such comparisons and the results of the unpublished bilateral comparisons, and in the ® ve following parts, the detailed results of the grouped comparisons will be presented and discussed. Except for a few lasers which exhibited some malfunction, the frequency differenc es between the lasers being compared lay inside the standard uncertainty (2,5 parts in 10 11 ) given in the mise en pratique, once the lasers had been adjusted to have the recom mended parameter values.

International comparisons of He-Ne lasers stabilized with127I2at 633 nm (July 2000). Part X: Comparison of INMETRO (Brazil), INTI (Argentina), NRC-INMS (Canada), CENAM (Mexico), and BIPM lasers at 633 nm

“…Table 2, column 2, lists the frequency differences, , for the first matrix measurements between the other lasers and the BIPMP3 laser, all working in their usual fashion with operational parameters normally close to the values recommended by the CIPM. Considering the five lasers belonging to the national laboratories, for two lasers the results are in the region of the 12 kHz standard uncertainty (1 ) given by the CIPM. Regarding the other lasers, two lie inside the 2 range, and the other lies inside the 3 range.…”

“…This is the tenth in a series of reports describing the results obtained during an extensive programme of laser comparisons carried out over the period July 1993 to March 2001 [1][2][3][4][5][6][7][8][9][10].…”

Optimization of Calibrating HeNe Laser Interferometers by Sample-Period Simulation

“…In 1993, the key comparison of International Bureau of Weights and Measures (BIPM.L-K10) between national metrology institutes was initiated to provide a basis for demonstrating equivalence of national realizations having taken into consideration only the 633 nm HeNe standards: the measurand of the comparison was the difference of the average frequency of the hyperfine components d, e, f, and g in the 127 I 2 , 11-5 transition, obtained by matrix measurements [1]. During the period 1993 to 1997, the comparisons were performed all over the world.…”

Portable 543 nm length standard and magnetic-induced zero-crossing shift on length standard transition

“…Nowadays, 633 nm iodine-stabilized He-Ne laser systems and 532 nm iodine-stabilized Nd:YAG laser systems are the most popular length-standard lasers in the visible region. However, the performance of the former laser system is limited by the configuration of the intracavity iodine cell [3][4][5][6] and the aggregate cost of the latter laser system is much higher than that of He-Ne lasers. A compromise must be reached that leads to the ideas of establishing other visible, extra-cavity, and low-cost length-standard lasers, such as iodine-stabilized 543 nm He-Ne lasers.…”