Improved collection efficiency for spectrally encoded imaging using 4f configuration

Spectrally encoded imaging (SEI), providing valuable structural information of the specimen, is an indispensable tool to study on diverse phenomenon in scientific and technological applications. In this method, a broadband light beam was incident on a diffraction grating, and then focused on an illuminating sample to collect multiple spatial point data. A major challenge in SEI is implementation of dispersing the incident light to multiple wavelengths and efficiently converging them into a small-diameter receiver, also referred as wavelength-to-space mapping. Here, we propose and demonstrate a compact and high-performance SEI system combining with 4f configuration in 1.5 μm band, which immensely improves the collection efficiency of wavelength-to-space mapping procedure. Proof-of-concept experiment with a high spatial resolution SEI scheme is successfully performed, and the overall collection efficiency of wavelength-to-space mapping increases to 70% through 4f system.