Progress in stabilization of the He-Ne/¹²⁷I₂wavelength standard at 633 nm and results of an international comparison between the PTB and the UME

Abstract

A detailed description of the He-Ne/ 127 I 2 laser wavelength standards developed at the National Metrology Institute of Turkey (UME), using high-frequency modulation and featuring a long-term relative instability of a few parts in 10 14 , is presented. The frequency dependence of the lasers on the iodine gas pressure, modulation width and saturating field intensity have been studied with a very low uncertainty level, and the common effect of these parameters on the output frequency has been demonstrated. A new method of accurately measuring modulation width has been realized, making an important contribution to the improvement of reproducibility of this type of wavelength standard. An international comparison between the laser standards of the Physikalisch-Technische Bundesanstalt (PTB) and the UME has been performed. Several iodine cells studied in a laser with an accurate servo-system, reveal a correlation between the spacing of the molecular resonances, the gas contamination in the iodine cell, and the output frequencies of the laser when locked to different iodine components.

Longitudinal correlation properties of an optical field with broad angular and frequency spectra and their manifestation in interference microscopy

“…In addition, a second comparison of the UME-L3 laser with the PTB01 laser was made at PTB in 1994 [5].…”

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.…”

Absolute Frequency Measurement and Comparison of UME and BIPM He-Ne/I2 Lasers

“…In addition, a second comparison of the UME-L3 laser with the PTBO1 laser was made at PTB in 1994 [5].…”