Smith-Purcell radiation from ultraviolet to infrared using a Si-field emitter

Smith-Purcell radiation using a Si-field emitter has been generated and detected in both ultraviolet and infrared regions. We passed a 200 nA beam current accelerated in 25-30 kV over a 550 nm pitch grating and detected the 1st harmonic waves of SPR in the infrared region from 1300 to 1400 nm by using an InGaAs detector. In addition to them, the 4th harmonic waves of SPR in the ultraviolet region from 320 to 360 nm were clearly observed by using a CCD detector. These spectra also coincided with those of the calculation using the SPR theory and blue-shifted with increasing the acceleration voltage. As results, we have successfully observed SPR from ultraviolet to infrared using a Si field emitter for the first time.