Generation of phase-stable infrared transients and electro-optic detection at frequencies up to 140 THz with a compact Er:fiber laser

Ultrabroadband terahertz (THz) optoelectronics has evolved into a powerful tool in femtosecond science and technology [1,2]. Field-sensitive detection of few-cycle THz transients with a constant carrier envelope phase, center frequencies of up to 41 THz, and spectral wings approaching the near infrared has been demonstrated [3]. Nevertheless, the complexity of the required laser systems limits their operation to specialized laboratories. In addition, novel applications in field-sensitive trace gas detection or all-optical phase control of near-infrared pulses call for still higher center frequencies [4]. Here we demonstrate a multi-branch compact EIumleurofiber laser generating intense few-cycle transients with stable carrier-envelope phase and center frequencies tunable up to 107 THz [5]. Electro-optic sampling with 8-fs pulses from the fiber laser map out the oscillating carrier field at frequencies up to 140 THz.