Ensuring reliable single-frequency laser performance for holography and other interferometric techniques in production environments

摘要

Several holographic and other interferometry-based techniques have recently grown in commercial interest and feasibility, in part thanks to advancements in new laser technology that is capable of meeting the demanding optical performance requirements in these techniques. White-light analog holography is now capable of generating ultra-realistic true-color replicas of 3D objects that can be used to record and display museum artefacts. Laser-based holographic techniques have recently also drawn a lot of attention for its use in the production of holographic optical elements (HOEs) used for image projection in virtual reality (VR) and augmented reality (AR) devices. Other interferometry-based techniques, such as laser doppler velocimetry (LDV) and laser ultrasonics (LUS) are also increasingly being introduced as on-line process control tools in production environments, for example for OLED display manufacturing.All of these holographic and interferometric techniques require single-frequency or single-longitudinal-mode (SLM) lasers in the visible spectrum with long coherence length, excellent wavelength stability and precision, as well as high, stable output powers.As the applications of these techniques are transitioning from laboratory settings to production-scale environments the demands on performance reliability and stability over long time periods and variable environmental conditions are increasing.Here we present how combining a robust optical assembly technology with advanced procedures for laser optimization and performance verification enables manufacturing of high power SLM lasers that deliver robust spectral performance over long time periods and in varying environmental conditions. We will demonstrate a novel automated SLM test procedure that ensures stable single-frequency performance and show wavelength stability over large temperature cycles.