Near-infrared light emitting device, spectroscopic apparatus, and spectroscopy

A near-infrared light emitting device comprising:

• a solid-state light emitting element;
• and
• a wavelength converter that includes a visible phosphor which emits visible fluorescent light having a maximum fluorescence intensity in a wavelength range of visible light, and a near-infrared phosphor which emits near-infrared fluorescent light having a maximum fluorescence intensity in a wavelength range of near-infrared light, wherein
• the near-infrared light emitting device emits output light including the visible fluorescent light and the near-infrared fluorescent light,
• the output light includes a visible fluorescence component having a spectral intensity in a wavelength range of visible light, and a near-infrared fluorescence component having a spectral intensity in a wavelength range of near-infrared light, the near-infrared light emitting device is configured to satisfy a relationship of 0.853MVIS≤MNIR<1.147MVIS,
• the MVIS is a ratio of Imax-VIS-150 to Imax-VIS-30,
• the Imax-VIS-30 is a maximum fluorescence intensity of the visible fluorescence component when a temperature of the wavelength converter is 30° C.,
• the Imax-VIS-150 is a maximum fluorescence intensity of the visible fluorescence component when a temperature of the wavelength converter is 150° C., the MNIR is a ratio of Imax-NIR-150 to Imax-NIR-30,
• the Imax-NIR-30 is a maximum fluorescence intensity of the near-infrared fluorescence component when a temperature of the wavelength converter is 30° C., and
• the Imax-NIR-150 is a maximum fluorescence intensity of the near-infrared fluorescence component when a temperature of the wavelength converter is 150° C.