We demonstrated an efficient sequential two-step near-infrared (NIR) quantum splitting (QS) in a Ho3+ singly doped β-NaYF4. An incident high-energy ultraviolet (UV)-to-visible photon in the wavelength range of 300−560 nm, which enables the Ho3+:5F4,5S2 states excited, could be efficiently split into two NIR photons at 1015 and 1180 nm. Underlying mechanisms for the sequential two-step NIR-QS process are analyzed in terms of the diffuse reflection spectrum, static and dynamic photoemission spectra and monitored excitation spectra. Internal quantum yield is obtained up to 110% on the basis of experimental and theoretical calculation results

The freshness of beef was analyzed and identified via its volatiles using long optical-path infrared spectroscopy. The spectral characteristics of some compounds, especially ammonia, were observed and demonstrated to have obvious differences between fresh and decayed beef.