Experimental realization of Helicon Maser in magnetized solid-state plasma

Radio frequency (RF) magnetoplasmic waves known as helicons will propagate in solid-state plasmas when a strong magnetic field is applied. In our device for the first time the helicons were excited by RFs (the range 100-2000 MHz) much higher than the helicon generation frequency (the main peak at 20 MHz). It is expedient to call this experimental device a Helicon Maser (HM) and the higher frequency field--a pumping field. In full analogy with the usual maser (or laser) the semiconductor sample plays the role of active material and the connecting cable--the role of high-quality external resonator. The bandwidth of HM is much narrower than the bandwidth of isolated sample (exactly the same situation as in case of laser). In the experimental device the n-InSb was used for the active material. The constant magnetic field varied within the interval 0-23 T