摘要
Since the advent of lasers,high order multiphoton upconversion processes(HOMUPs)have been widely investigated throughout the scientific community owing to their great fundamental significance and numerous applications in short wavelength light generation,optical imaging,and spectroscopy.Especially,upconversion pumping by means of intrinsic energy level matching of certain rare-earth(RE)ions plays a significant role in achieving short-wavelength light,due to ample availability of high power semiconductor diode lasers in the
Since the advent of lasers, high order multiphoton upconversion processes （HOMUPs） have been widely investigated throughout the scientific communityowing to their great fundamental significance and numerous applications in short wavelength light generation, optical imaging, and spectroscopy. Especially, upconversion pumping by means of intrinsic energy level matching of certain rare-earth （RE） ions plays a significant role in achieving short-wavelength light, due to ample availability of high power semiconductor diode lasers in the near-infrared （NIR） range. In the past decades, many efforts have been devotedto getting breakthroughs in HOMUPs,
