Equivalent classical models for quantum noise in the laser oscillator

Raymond Arrathoon, Anthony E.. Siegman

Peter W. Milonni

It is well known that laser oscillation is initiated by spontaneous radiation ‘‘noise.’’ Evidence for this is often based on the complete theory of laser oscillation, including the quantization of the electromagnetic field. In this article, the buildup of laser oscillation from quantum noise is demonstrated using the most elementary classical equation describing the amplification of laser intensity.

Anthony E.. Siegman, Raymond Arrathoon

Y. Yamamoto, H. A. Haus

Amplitude fluctuations in the light from a laser and the partition noise attributable to a beam splitter are analyzed using an equivalent-circuit model that incorporates amplitude squeezing. When the energy is not carried by photons but by electrons and also when electrons can be treated as classical particles, the circuit model need not be changed. One simply applies the general circuit model to low frequencies h\ensuremath{\nu}\ensuremath{\ll}${\mathit{k}}_{\mathit{B}}$T. Conversion of an electric current to photon flux, and vice versa, converts classical sub-shot-noise spectra of electric currents into quantum squeezing of photon fluxes, and vice versa. The sub-shot-noise character of electric currents, unlike that of quantum squeezing, is not necessarily destroyed by current loss.

Mohammadreza Saemian, Livia Del Balzo, Djamal Gacemi +9 more

We report room temperature heterodyne detection of a quantum cascade laser beaten with a local oscillator on a unipolar quantum photodetector in two different atmospheric windows, at 4.8 µm and 9 µm. A noise equivalent power of few pW is measured by employing an active stabilization technique in which the local oscillator and the signal are locked in phase. The measured heterodyne noise equivalent power is six orders of magnitude lower than that obtained with direct detection.

M. Lax, W. H. Louisell