During the past few years, the terahertz （THz） frequency regime has had renewed scientific and technological interest because of recent breakthroughs in the areas of high power sources, sensitive detectors, novel ma...During the past few years, the terahertz （THz） frequency regime has had renewed scientific and technological interest because of recent breakthroughs in the areas of high power sources, sensitive detectors, novel materials, and high resolution video imaging. Because it lies between the radio frequencies and infrared wavelengths, the terahertz electromagnetic region was thought to be promising for practical applications （300 micrometers wavelength corresponds to 1 THz frequency）, but it suffered from very high attenuation through the atmosphere （above 1 dB/meter）, and was found to be difficult to generate, modulate, and detect. On the other hand, many non-polar dielectric materials are transparent to THz waves,展开更多
Electrically pumped high power terahertz （THz） emitters that operated above room temperature in a pulse mode were fabricated from nitrogen-doped n-type 6H-SiC. The emission spectra had peaks centered on 5 THz and 12...Electrically pumped high power terahertz （THz） emitters that operated above room temperature in a pulse mode were fabricated from nitrogen-doped n-type 6H-SiC. The emission spectra had peaks centered on 5 THz and 12 THz （20 meV and 50 meV） that were attributed to radiative transitions of excitons bound to nitrogen donor impurities. Due to the relatively deep binding energies of the nitrogen donors, above 100 meV, and the high thermal conductivity of the SiC substrates, the THz output power and operating temperature were significantly higher than previous dopant based emitters. With peak applied currents of a few amperes, and a top surface area of 1 mm2, the device emitted up to 0.5 mW at liquid nitrogen temperature （77 K）, and tens of microwatts up to 333 K. This result is the highest temperature of THz emission reported from impurity-based emitters.展开更多
文摘During the past few years, the terahertz （THz） frequency regime has had renewed scientific and technological interest because of recent breakthroughs in the areas of high power sources, sensitive detectors, novel materials, and high resolution video imaging. Because it lies between the radio frequencies and infrared wavelengths, the terahertz electromagnetic region was thought to be promising for practical applications （300 micrometers wavelength corresponds to 1 THz frequency）, but it suffered from very high attenuation through the atmosphere （above 1 dB/meter）, and was found to be difficult to generate, modulate, and detect. On the other hand, many non-polar dielectric materials are transparent to THz waves,
基金supported by the NSF Award No.DMR-0601920ONR Contract No.N0001-4-00-1-0834
文摘Electrically pumped high power terahertz （THz） emitters that operated above room temperature in a pulse mode were fabricated from nitrogen-doped n-type 6H-SiC. The emission spectra had peaks centered on 5 THz and 12 THz （20 meV and 50 meV） that were attributed to radiative transitions of excitons bound to nitrogen donor impurities. Due to the relatively deep binding energies of the nitrogen donors, above 100 meV, and the high thermal conductivity of the SiC substrates, the THz output power and operating temperature were significantly higher than previous dopant based emitters. With peak applied currents of a few amperes, and a top surface area of 1 mm2, the device emitted up to 0.5 mW at liquid nitrogen temperature （77 K）, and tens of microwatts up to 333 K. This result is the highest temperature of THz emission reported from impurity-based emitters.
