A tuneable resonant scanning mirror

Scanning mirrors are widely used in optical systems to direct reflected light. Hittech Group, a first-tier system supplier in mechatronics and optomechatronics, carries out research on laser scanning. Existing products such as galvanometers and resonant scanners are intended for accurate positioning at a low-frequency range and for fast scanning at a specified high frequency, respectively. However, when a wide frequency range is involved, these devices may not be able to fulfil the requirements. In the project described in this Mikroniek article, a novel solution was proposed, by tuning the resonant frequency of a scanning mirror and exciting higher-order modes to cover a wide frequency range of 500 Hz to 5 kHz. A test set-up has been developed, of which the results demonstrate that this frequency range can be covered, with a scanning angle range of 1 mrad for the reflected beam.