Electron-Spin Echoes at 604 GHz Using Far Infrared Lasers

Electron-electron scattering in far-infrared quantum cascade lasers.

A large depolarization shift indicates a strong nonequilibrium intersubband electron-electron scattering ~G! in tunneling structure. For a far-infrared subband separation D;10 meV, the rate G scales with the uppersubband occupation and is never significantly reduced by screening. Despite this nonradiative decay a finite population inversion can be maintained. Finally, the applied bias changes t...

Electron Spin Resonance with Far Infrared Light

Far-infrared free-electron lasers and their applications

Free electron lasers based on radio-frequency linear accelerators provide an important source of farinfrared radiation which allow exciting experiments that cannot be performed in any other way. Facilities such as FELIX (Nieuwegein, The Netherlands), JFEL (Newport News VA, USA), FELBE (Dresden, Germany), CLIO (Paris, France) and others provide midand far-infrared output in picoseconds pulses wi...

Force detected electron spin resonance at 94 GHz.

Force detected electron spin resonance (FDESR) detects the presence of unpaired electrons in a sample by measuring the change in force on a mechanical resonator as the magnetization of the sample is modulated under magnetic resonance conditions. The magnetization is coupled to the resonator via a magnetic field gradient. It has been used to both detect and image distributions of electron spins,...

Spin Echoes

Intense radiofrequency power in the form of pulses is applied to an ensemble of spins in a liquid placed in a large static magnetic Geld H&. The frequency of the pulsed r-f power satisGes the condition for nuclear magnetic resonance, and the pulses last for times which are short compared with the time in which the nutating macroscopic magnetic moment of the entire spin ensemble can decay. After...