High steady-state column density of I((2)P3/2) atoms from I2 photodissociation at 532 nm: Towards parity non-conservation measurements.

G E Katsoprinakis,E Stratakis,J A Kypriotakis,T P Rakitzis,G Chatzidrosos

doi:10.1038/srep33261

Abstract

Steady-state column densities of 1017 cm−2 of I(2P3/2) atoms are produced from photodissociation of I2 vapour at 290.5 K using 5 W of 532 nm laser light. Recombination of the I(2P3/2) atoms at the cell walls is minimized by coating the cell surface with a hydrophobic silane (dimethyldichlorosilane/DMDCS). Operation at room temperature, and at an I2 vapour pressure of ~0.2 mbar, without using a buffer gas, allows relatively low Lorentz and Doppler widths of ~2π × 1.5 (FWHM) and ~2π × 150 (HW at 1/e2) Mrad/s, respectively, at the M1 transition of atomic iodine at 1315 nm. These high column densities and low linewidths are favorable for parity nonconservation optical rotation measurements near this M1 transition. Furthermore, as the cell is completely sealed, this method of production of high-density 127I(2P3/2) atoms is also compatible with using iodine radioisotopes, such as for the production of high-density 129I(2P3/2).

Highlights

Steady-state column densities of 1017 cm−2 of I(2P3/2) atoms are produced from photodissociation of I2 vapour at 290.5 K using 5 W of 532 nm laser light
The aim of this paper is to demonstrate the feasibility of producing I(2P3/2) atoms from I2 photodissociation, at high single-pass column densities of at least 1017 cm−2, while achieving low Lorentz and Doppler widths
We study the dependence of the produced atomic I(2P3/2) density on the photodissociating laser power, and investigate the effects of varying molecular iodine density and of various coatings of the iodine cell walls

Summary

Introduction

Steady-state column densities of 1017 cm−2 of I(2P3/2) atoms are produced from photodissociation of I2 vapour at 290.5 K using 5 W of 532 nm laser light. At an I2 vapour pressure of ~0.2 mbar, without using a buffer gas, allows relatively low Lorentz and Doppler widths of ~2π × 1.5 (FWHM) and ~2π × 150 (HW at 1/e2) Mrad/s, respectively, at the 52P3°/2 → 52P1°/2 M1 transition of atomic iodine at 1315 nm These high column densities and low linewidths are favorable for parity nonconservation optical rotation measurements near this M1 transition. Katsoprinakis et al.[10] proposed to compensate for this smaller value of R by using large cavity-enhanced pathlengths (~1000 m) to achieve column densities of about 1020 cm−2 and higher, and by generating the I(2P3/2) atoms from the photodissociation of I2 molecules using 532 nm laser light, at low pressure and near room temperature, so that the Lorentz and Doppler widths can be significantly reduced, to ~2π × 1 Mrad/s and ~2π × 150 Mrad/s, respectively. We study the dependence of the produced atomic I(2P3/2) density on the photodissociating laser power, and investigate the effects of varying molecular iodine density and of various coatings of the iodine cell walls

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Conclusion