UCLA researchers in the Department of Electrical Engineering have invented a swept source laser that operates in the visible light range with a broad sweeping bandwidth.
Existing swept source lasers on the market typically operate at wavelengths that fall within the invisible/near-infrared range of electromagnetic spectrum. This is due to dispersion of light, poor gain media bandwidth and accessibility, as well as optical loss. These obstacles hinder applications of swept source lasers in the visible range frequencies, which could provide huge benefits in many fields of imaging, including ophthalmic imaging, fluorescent imaging and fluorescent lifetime imaging (FLIM). Although the frequencies of near-infrared range light sources can be doubled using BBO crystals to produce visible range light sources, this solution limits the operating frequency range for swept source lasers.
A novel broadband swept source laser that operates in visible range frequencies have been developed to address the aforementioned issues. This innovative approach doubles the frequencies of near-infrared light sources via second-harmonic generation in a BBO crystal. It also solves the issue of narrow bandwidth by modulating the frequency sweep of the laser into short bursts of pulses, which are then consecutively amplified to high instantaneous powers. This solution enables doubling of laser source frequencies while achieving wide frequency modulation range and great resulting light intensities at the same time. Applications of this innovation can greatly improve fields of fluorescence imaging and many more. For example, when coupled with fined tuned diffraction and a fast photodetector, this swept source laser can perform extremely fast scanning of samples to produce fluorescence lifetime images (FLIM).
Swept Source Laser, Second-Harmonic Generation, BBO Crystal, Pulse Modulation, fluorescent lifetime imaging (FLIM), Fluorescence Imaging