摘要
In this paper,we propose a dual-wavelength digital holographic interferometry method based on a compact dual vertical-cavity surface-emitting laser(VCSEL)source.The source simultaneously emits light from two highly stabilized coherent light sources with slightly different wavelengths.A highly stabilized and adjustable current source enables the application of digital holographic dual-wavelength techniques to measure the shape of an object with height steps of a few millimeters.The wavelength drift over 12 h over the entire measurement range,which was evaluated using a wavemeter,was smaller than 1 pm.In addition to the low measurement uncertainty at large height jumps,the dual-wavelength digital holographic system distinguishes itself by its robustness to environmental disturbances such as air turbulence,heat load,and/or mechanical vibrations.This is enabled via a fiber-based almost common-path single-shot digital holographic acquisition of the information of the two different wavelengths using angular multiplexing.The experimental setup and data evaluation are discussed,and we present measurements of non-cooperative objects with specular reflective and/or diffuse reflective surfaces having different colors.
