Ali in Tibet,5100 m above sea level,is one of the most suitable locations in the world for infrared spectral observations.The atmospheric transmittances at Ali Observatory and Mauna Kea Observatory were calculated by ...Ali in Tibet,5100 m above sea level,is one of the most suitable locations in the world for infrared spectral observations.The atmospheric transmittances at Ali Observatory and Mauna Kea Observatory were calculated by MODTRAN using radiosonde data.The results were 0.848 and 0.789 respectively which indicated better conditions at Ali Observatory.A self-made instrument with a 320×256-pixel HgCdTe infrared focal plane array and a 7.5-cm diameter telescope was utilized for the actual measurements.Without the help of standard stars,the on-site and real-time atmospheric transmittance can be obtained as 0.831 by fitting the relation between the measured atmospheric radiation intensity and the zenith angle based on radiation transfer equations.This paper firstly reports the atmospheric transmittance in the M'band(4.605–4.755μm)at the 5100 m-altitude Ali observatory by actual measurement.It shows that the high-altitude Ali observatory with sufficiently low water vapor content is suitable for observation in the mid-infrared bands.展开更多
A gradient-index Reuleaux-triangle-shaped hole array was fabricated on germanium(Ge)by nanoimprint lithography and inductively coupled plasma processing as a broadband mid-infrared(IR)antireflective surface.The intera...A gradient-index Reuleaux-triangle-shaped hole array was fabricated on germanium(Ge)by nanoimprint lithography and inductively coupled plasma processing as a broadband mid-infrared(IR)antireflective surface.The interaction between the{111}planes of cubic crystalline Ge and a circular mold successfully produced an orderly and periodically distributed Reuleaux-triangle-shaped hole array.As a result,the average transmittance increased 15.67% over the waveband at 3–12μm and remained stable at the incidence angle of up to 60°.The vertices of the Reuleaux triangle showed local enhancement of the electric field intensities due to interference of the incident and reflected radiation fields.It was also found that nonuniform hole depths acted to modulate the transmittance over the 3–12μm waveband.展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.11673064,11803089,U1931124)。
文摘Ali in Tibet,5100 m above sea level,is one of the most suitable locations in the world for infrared spectral observations.The atmospheric transmittances at Ali Observatory and Mauna Kea Observatory were calculated by MODTRAN using radiosonde data.The results were 0.848 and 0.789 respectively which indicated better conditions at Ali Observatory.A self-made instrument with a 320×256-pixel HgCdTe infrared focal plane array and a 7.5-cm diameter telescope was utilized for the actual measurements.Without the help of standard stars,the on-site and real-time atmospheric transmittance can be obtained as 0.831 by fitting the relation between the measured atmospheric radiation intensity and the zenith angle based on radiation transfer equations.This paper firstly reports the atmospheric transmittance in the M'band(4.605–4.755μm)at the 5100 m-altitude Ali observatory by actual measurement.It shows that the high-altitude Ali observatory with sufficiently low water vapor content is suitable for observation in the mid-infrared bands.
基金supported by the National Natural Science Foundation of China(No.61722502)
文摘A gradient-index Reuleaux-triangle-shaped hole array was fabricated on germanium(Ge)by nanoimprint lithography and inductively coupled plasma processing as a broadband mid-infrared(IR)antireflective surface.The interaction between the{111}planes of cubic crystalline Ge and a circular mold successfully produced an orderly and periodically distributed Reuleaux-triangle-shaped hole array.As a result,the average transmittance increased 15.67% over the waveband at 3–12μm and remained stable at the incidence angle of up to 60°.The vertices of the Reuleaux triangle showed local enhancement of the electric field intensities due to interference of the incident and reflected radiation fields.It was also found that nonuniform hole depths acted to modulate the transmittance over the 3–12μm waveband.
