Phase-locking of the beat signal of two distributed-feedback diode lasers to oscillators working in the MHz to THz range.
We present difference-frequency stabilization of free-running distributed-feedback (DFB) diode lasers, maintaining a stable phase-lock to a local oscillator (LO) signal. The technique has been applied to coherent hybrid THz imaging which employs a high-power electronic radiation source emitting at 0.62 THz and electro-optic detectors. The THz radiation of the narrow-band emitter is mixed with the difference frequency of the DFB diode laser pair. The resulting intermediate frequency is phase-locked to the LO signal from a radio-frequency generator using a fast laser-current control loop. The stabilization scheme can be adapted readily to a wide range of applications which require stabilized laser beat-notes.
Friederich
Fabian
F
Physikalisches Institut, Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main, Germany. friederich@physik.uni-frankfurt.de
Schuricht
Gunter
G
Deninger
Anselm
A
Lison
Frank
F
Spickermann
Gunnar
G
Haring Bolívar
Peter
P
Roskos
Hartmut G
HG