Strontium vapor laser

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A strontium vapor laser is a laser that produces at its output, high-intensity pulsed light at a wavelength of 430.5 nm in the blue-violet region of the visible spectrum via vaporized strontium metal gas contained within a glass tube.

History

Laser action on two of the infra-red transitions in Sr⁺ was first discovered in the

. In 1973, Latush and Sém from Rostov-on-Don State University, Russia, observed visible laser action from the strontium vapor laser for the first time, at wavelengths of 430.5 nm and 416.2 nm.^[3] The active volume was contained in a ceramic tube 8 mm in diameter and 60 cm long. Small pieces of strontium were placed inside the tube at equally spaced intervals and the necessary vapor pressure was produced by externally heating the assembly. Helium was used as the buffer gas, at pressures ranging from 2.5–35 torr. Output power was found to increase with increasing buffer gas pressure.

Population Inversion Mechanism

The

. Average gas temperatures are in the region of 800°C.

A

occurs, permitting three-body electron-electron-Sr²⁺ collisions to occur to form the most highly excited states of Sr⁺, as shown:

Sr²⁺ + 2e⁻ → Sr^+* + e⁻ + K.E.

The excess

metastable

and ground levels also by collisions with electrons.

References