N2laser

N2Laser, commonly called a nitrogen laser, is a type of gaslaser that uses nitrogen as the active gain medium and emits ultraviolet light at 337.1 nm from the B3Πg → X1Σg+ electronic transition. Lasing is produced when nitrogen molecules are excited by a high-voltage discharge, typically in a sealed tube containing pure nitrogen or a nitrogen-based gas mixture.

A simple nitrogen laser consists of a short discharge tube with electrodes, a UV-transparent window, and two mirrors forming a basic laser cavity. The discharge is driven by a pulsed power supply, delivering fast, high-voltage pulses. The pulses are nanoseconds in duration, and output energies are usually in the microjoule to tens of microjoules range.

Because the upper laser level is short lived, the emission is short, high-contrast UV pulses with relatively low efficiency. The devices are valued for their simplicity and compactness, requiring only modest infrastructure compared with other UV lasers, but they produce modest average power and require careful high-voltage safety.

Developed in the 1960s as one of the first practical UV gas lasers, nitrogen lasers were widely used as compact ultraviolet pulse sources and as pump sources for dye lasers and other UV systems. They have found applications in holography, time-resolved spectroscopy, photomultiplier calibration, and educational demonstrations.

Common variants include pure N2 and nitrogen-helium or nitrogen-neon mixtures to improve discharge stability. Safety concerns include ultraviolet radiation, high-voltage operation, and ozone generation in air; appropriate shielding and ventilation are essential.