A SIMPLE REAL-TIME WAVEMETER FOR PULSED LASERS

A simple and easy-to-operate real-time wavemeter that can discern the 10 Hz wavelength jitter of a pulsed laser is constructed. Only a single set of solid fused silica etalon and a 1024-channel diode array is needed to detect the wavelength jitters for various lasers. An optical fibre is used for easy alignment and operation without uncovering the wavemeter for various light sources. A method of determining the centre of an asymmetric etalon fringe, which sometimes has an ambiguous peak and is likely to change in intensity, is discussed in detail. The wavemeter is used to detect the relative wavelength change of a scanning dye laser, an injection-seeded Nd-YAG laser and a commercial He-Ne laser, and is tested by an iodine-stabilized He-Ne laser. The results are analysed and discussed in relation to the characteristics of the lasers and the capabilities of the wavemeter.