Linewidth and tuning characteristics of terahertz quantum cascade lasers
Optics letters, 2004•opg.optica.org
We have measured the spectral linewidths of three continuous-wave quantum cascade
lasers operating at terahertz frequencies by heterodyning the free-running quantum cascade
laser with two far-infrared gas lasers. Beat notes are detected with a GaAs diode mixer and a
microwave spectrum analyzer, permitting very precise frequency measurements and giving
instantaneous linewidths of less than∼ 30 kHz. Characteristics are also reported for
frequency tuning as the injection current is varied.
lasers operating at terahertz frequencies by heterodyning the free-running quantum cascade
laser with two far-infrared gas lasers. Beat notes are detected with a GaAs diode mixer and a
microwave spectrum analyzer, permitting very precise frequency measurements and giving
instantaneous linewidths of less than∼ 30 kHz. Characteristics are also reported for
frequency tuning as the injection current is varied.
We have measured the spectral linewidths of three continuous-wave quantum cascade lasers operating at terahertz frequencies by heterodyning the free-running quantum cascade laser with two far-infrared gas lasers. Beat notes are detected with a GaAs diode mixer and a microwave spectrum analyzer, permitting very precise frequency measurements and giving instantaneous linewidths of less than ∼30 kHz. Characteristics are also reported for frequency tuning as the injection current is varied.
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