Spectral properties of edge-emitting semiconductor laser subject to optical feedback from extremely short external cavity

We study theoretically and experimentally spectral and polarization characteristics of hybrid systems of VCSELs integrated within liquid crystal (LC) cells. Three cases are considered: Nematic or cholesteric LC on top of VCSEL, coupled-cavity system with the second cavity next to the VCSEL's one filled in with nematic LC and a system with a nematic LC inside the VCSEL cavity. For the case of nematic liquid crystal - VCSEL coupled cavity system we demonstrate selection between two orthogonal directions of linear polarization of the fundamental mode by changing the LC length or by electro-optical tuning of the LC director. For the case of cholesteric liquid crystal-VCSEL system we demonstrate lasing on circularly polarized (CP) modes due to the LC band gap for CP light. The transition from nematic to isotropic phase of the LC when increasing temperature leads to a drastic change of the polarization of the generated light from left-handed circular to linear polarization. Finally, we investigate the possibility of efficient wavelength tuning by utilizing electrooptical effect in nematic LC layer integrated next to the active region in a VCSEL cavity

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Vertical-cavity surface-emitting laser with liquid crystal overlay

Panajotov

Thienpont

2011

Opt. Express

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We perform a theoretical study of the spectral and polarization threshold characteristics of Vertical-Cavity Surface-Emitting Lasers with Liquid Crystal overlay (LC-VCSEL) in three different configurations of the LC cell. Our model predicts the possibility of selecting between two orthogonal directions of linear polarization (LP) of the fundamental mode (x or y LP) by choosing appropriate LC length. It further predicts very strong polarization discrimination with LP mode threshold gain difference as large as several times the threshold gain of the lasing mode. We also numerically demonstrate an active control of light polarization by electro-optically tuning the LC director and show that either polarization switching between x and y LP modes or continuous change of the LP direction would be possible. Finally, we numerically demonstrate that LC-VCSEL would be capable of efficient wavelength tuning.

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Spectral properties of edge-emitting semiconductor laser subject to optical feedback from extremely short external cavity

Cited by 4 publications

References 24 publications

Vertical-Cavity Surface-Emitting Lasers with coupled cavities and with liquid crystal overlay

Vertical-Cavity Surface-Emitting Lasers with coupled cavities and with liquid crystal overlay

Hybrid VCSEL: liquid crystal systems

Vertical-cavity surface-emitting laser with liquid crystal overlay

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